Urolithin derivatives and therapeutic uses

Abstract

Disclosed are compounds, compositions, and methods useful for inhibiting ferroptosis in a subject in need thereof.

Description

[0001] Related Applications

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 392,611, filed on July 27, 2022. Background Art

[0003] Urolithins have potent effects on improving many health conditions, and they have been shown to be highly biologically active in vitro and in vivo. Urolithins have been proposed as treatments for a variety of conditions, including those associated with insufficient mitochondrial activity, including obesity, memory loss, reduced metabolic rate, metabolic syndrome, diabetes, cardiovascular disease, hyperlipidemia, neurodegenerative diseases, cognitive disorders, mood disorders, stress, anxiety disorders, fatty liver disease, for improving liver function and weight management. In particular, urolithins have been shown to have beneficial effects in enhancing muscle function. Summary of the invention

[0004] One aspect of the present invention provides compounds, compositions and methods useful for inhibiting ferroptosis.

[0005] Therefore, provided herein is a compound having the structure of formula (I):

[0006]

[0007] in

[0008] Y1 and Y2 are each alkyl; or, together with the carbon to which they are bound, form an unsubstituted or substituted spirocycloalkyl;

[0009] R1, R4, R5 and R8 are independently selected from -H and halogen;

[0010] R2 and R7 are independently selected from -H, -OH, -OAc, -NH2, halogen, -CN, -CF3, -CO2H, -NO2, -NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino, alkyl-R9, alkenyl-R9, alkynyl-R9, -OR 10 、-NHR 10 、-NR 11 C(O)R 12 、-C(O)NR 11 R 12 and-NR 11 S02R 12 ;

[0011] R3 and R6 are independently selected from alkyl and cycloalkyl;

[0012] Each occurrence of R9 is independently selected from OH, NH2, O-alkyl, O-alkyl-O-alkyl, alkylamino, NHC(O)-alkyl, N(CH3)C(O)-alkyl, NHSO2-alkyl, N(CH3)SO2-alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl;

[0013] R 10 is selected from the group consisting of alkyl, hydroxyalkyl, aminoalkyl, alkyl-O-alkyl, alkyl-O-alkyl-OH, alkyl-O-alkyl-O-alkyl, alkenyl, alkynyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl, alkyl-heterocycloalkyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl, SO3H, SO2-alkyl and SO2-haloalkyl;

[0014] Each occurrence of R 11 is selected from H and alkyl; and

[0015] Each occurrence of R 12 is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, O-alkyl, aminoalkyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl and alkyl-heterocycloalkyl;

[0016] Provided that when R1, R4, R5 and R8 are each -H, R2 and R7 are each -OH, and R3 and R6 are each CH3, then Y1 and Y2 are not each -Me or do not form, together with the carbon to which they are bonded, an unsubstituted spirobutyl group;

[0017] or a pharmaceutically acceptable salt thereof.

[0018] Also provided herein is a compound having a structure of formula (II):

[0019]

[0020] in

[0021] X1 and X2 are each alkyl; or, together with the carbon to which they are bonded, form an unsubstituted or substituted spirocycloalkyl;

[0022] R1′, R4′, R5′ and R8′ are independently selected from —H, —OH, —NH2, alkyl and halogen;

[0023] R2′, R3′, R6′ and R7′ are independently selected from —H, —OH, —OAc, —NH2, halogen, —CN, —CF3, —CO2H, —NO2, —NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino and —OR8′; and

[0024] R8′ is selected from alkyl, hydroxyalkyl, aminoalkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl;

[0025] or a pharmaceutically acceptable salt thereof.

[0026] Unless otherwise limited, all technical and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. The full texts of all publications, patent applications, patents and other references mentioned herein are incorporated by reference. In the event of a conflict, this specification (including definitions) shall prevail. In addition, materials, methods and examples are illustrative only and are not intended to be limiting.

[0027] Other features, objects, and advantages of the invention will be apparent from the detailed description, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a table summarizing the anti-ferroptosis activity of selected compounds. 50 : Half-maximal effective concentration (nM) of exemplary compounds of the present invention. Ferroptosis pEC 50 : EC of exemplary compounds of the invention 50 Negative logarithm of . Maximum efficacy percentage (%): Concentration (μM) of the exemplary compound of the present invention at the maximum efficacy percentage. DETAILED DESCRIPTION

[0029] definition

[0030] For convenience, certain terms used in this specification, examples and appended claims are collected here before further description of the present invention. These definitions should be read in light of the remainder of this disclosure and should be as understood by those skilled in the art. Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art.

[0031] To facilitate understanding of the present invention, certain terms and phrases are defined below and throughout the specification.

[0032] As used herein, the articles "a" and "an" refer to one or more than one (ie, at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.

[0033] The phrase "and / or" as used herein in the specification and claims should be understood to mean "either or both" of the elements so united (i.e., elements that exist together in some cases and separately in other cases). Multiple elements listed with "and / or" should be understood in the same way, i.e., "one or more" of the elements so united. In addition to the elements explicitly identified by the "and / or" clause, other elements may optionally be present, whether related or unrelated to those elements explicitly identified. Thus, as a non-limiting example, when used in conjunction with open language (such as "comprising"), reference to "A and / or B" may refer to only A (optionally including elements other than B) in one embodiment; to only B (optionally including elements other than A) in another embodiment; to both A and B (optionally including other elements) in yet another embodiment; and so on.

[0034] As used herein in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" should be interpreted as inclusive, that is, including at least one element in a number of elements or a list of elements, but also including more than one element, and other items that are not listed optionally. Only terms that clearly indicate the opposite meaning, such as "only one" or "exactly one", or when used in the claims, "consisting of..." will refer to the inclusion of exactly one element in a number of elements or a list of elements. In general, the term "or" as used herein should only be interpreted as indicating exclusive alternatives (i.e., "one or the other but not both") when followed by an exclusive term (such as "either", "one of them", "only one of them" or "exactly one of them"). "Substantially consisting of...", when used in the claims, should have the usual meaning as used in the field of patent law.

[0035] As used herein in the specification and claims, the phrase "at least one" when referring to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list of elements, but does not necessarily include at least one of each element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than the elements explicitly identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to the explicitly identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") may refer to at least one (optionally including more than one) A without B (and optionally including elements other than B); in another embodiment, to at least one (optionally including more than one) B without A (and optionally including elements other than A); in yet another embodiment, to at least one (optionally including more than one) A, and at least one (optionally including more than one) B (and optionally including other elements); and so on.

[0036] It should also be understood that in any method claimed herein that includes more than one step or action, the order of the steps or actions of the method is not necessarily limited to the order in which the steps or actions of the method are listed unless the context dictates otherwise.

[0037] In the claims and the foregoing specification, all transitional phrases such as "comprises," "comprising," "carrying," "having," "containing," "involving," "holding," "consisting of," etc. shall be understood as open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in Section 2111.03 of the United States Patent Office Manual of Patent Examining Procedures.

[0038] Certain compounds contained in the compositions of the present invention may exist in specific geometric or stereoisomeric forms. In addition, the polymers of the present invention may also be optically active. The present invention contemplates all such compounds as falling within the scope of the present invention, including cis and trans isomers, R- and S-enantiomers, diastereomers, (D)-isomers, (L)-isomers, their racemic mixtures and other mixtures thereof. Additional asymmetric carbon atoms may be present in substituents (such as alkyl). All such isomers and mixtures thereof are intended to be included in the present invention.

[0039] "Geometric isomers" means isomers that differ in the orientation of the substituted atoms relative to the carbon-carbon double bond, relative to the cycloalkyl ring, or relative to a bridged bicyclic system. The atoms on each side of the carbon-carbon double bond (except H) can be in the E (substituents are on opposite sides of the carbon-carbon double bond) or Z (substituents are on the same side) configuration. "R", "S", "S*", "R*", "E", "Z", "cis" and "trans" represent the configuration relative to the core molecule. Some of the disclosed compounds may exist in the form of "atropisomers" or as "atropisomers". Atropisomers are stereoisomers that arise due to hindered rotation around a single bond, where the steric strain barrier to rotation is high enough to allow separation of conformational isomers. The compounds of the present invention can be prepared as individual isomers by isomer-specific synthesis, or can be prepared as individual isomers by separation from a mixture of isomers. Conventional resolution techniques include forming salts of the free bases of each isomer of an isomeric pair using an optically active acid (followed by fractional crystallization and regeneration of the free base); forming salts of the acid forms of each isomer of an isomeric pair using an optically active amine (followed by fractional crystallization and regeneration of the free acid); forming esters or amides of each isomer of an isomeric pair using an optically pure acid, amine or alcohol (followed by chromatographic separation and removal of the chiral auxiliary); or resolving isomeric mixtures of starting materials or final products using various well-known chromatographic methods.

[0040] For example, if a specific enantiomer of a compound of the invention is desired, it can be prepared by asymmetric synthesis or by derivatization with a chiral auxiliary, wherein the resulting diastereomeric mixture is separated and the auxiliary group is cleaved to provide the pure desired enantiomer. Alternatively, in the case where the molecule contains a basic functional group (such as an amino group) or an acidic functional group (such as a carboxyl group), diastereomeric salts can be formed with appropriate optically active acids or bases, followed by separation of the diastereomers so formed by fractional crystallization or chromatographic means well known in the art, and the pure enantiomers are then recovered.

[0041] The percent purity by mole fraction is the ratio of the number of moles of an enantiomer (or diastereomer) to the number of moles of an enantiomer (or diastereomer) plus the number of moles of its optical isomers. When the stereochemistry of a disclosed compound is named or depicted by structure, the purity of the named or depicted stereoisomer relative to the other stereoisomers is at least about 60%, about 70%, about 80%, about 90%, about 99%, or about 99.9% by mole fraction. When a single enantiomer is named or depicted by structure, the purity of the depicted or named enantiomer is at least about 60%, about 70%, about 80%, about 90%, about 99%, or about 99.9% by mole fraction. When a single diastereomer is named or depicted by structure, the purity of the depicted or named diastereomer is at least about 60%, about 70%, about 80%, about 90%, about 99%, or about 99.9% by mole fraction.

[0042] When a disclosed compound is named or depicted by a structure without indicating stereochemistry and the compound has at least one chiral center, it is understood that the name or structure encompasses the enantiomers of the compound without the corresponding optical isomers, the racemic mixture of the compound, or a mixture enriched in one enantiomer relative to its corresponding optical isomer. When a disclosed compound is named or depicted by a structure without indicating stereochemistry and has two or more chiral centers, it is understood that the name or structure encompasses the diastereomers without other diastereomers, a plurality of diastereomers without other diastereoisomer pairs, a mixture of diastereomers, a mixture of diastereoisomer pairs, a mixture of diastereomers in which one diastereomer is enriched relative to one or more other diastereomers, or a mixture of diastereomers in which one or more diastereomers are enriched relative to other diastereomers. The present invention encompasses all of these forms.

[0043] The structures depicted herein are also meant to include compounds which differ only in the presence of one or more isotopically enriched atoms. For example, by replacing hydrogen with deuterium or tritium, or replacing carbon with 13 C- or 14 Compounds produced by C-enriched carbon substitution are within the scope of the present invention.

[0044] The term "prodrug" as used herein encompasses compounds that are converted to therapeutically active agents under physiological conditions. Common methods for preparing prodrugs include hydrolysis under physiological conditions to reveal selected portions of the desired molecule. In other embodiments, the prodrug is converted by an enzymatic activity of the host animal.

[0045] As used herein, the phrase "pharmaceutically acceptable excipient" or "pharmaceutically acceptable carrier" means a pharmaceutically acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, which participates in the delivery or transport of the subject chemical from one organ or part of the body to another organ or part of the body. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation, not injurious to the patient, and substantially non-pyrogenic. Some examples of materials that can be used as pharmaceutically acceptable carriers include: (1) sugars such as lactose, glucose and sucrose; (2) starches such as corn starch and potato starch; (3) cellulose and its derivatives such as sodium carboxymethylcellulose, ethyl cellulose and cellulose acetate; (4) tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients such as cocoa butter and suppository waxes; (9) oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and and soybean oil; (10) glycols, such as propylene glycol; (11) polyols, such as glycerol, sorbitol, mannitol, and polyethylene glycol; (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffers, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethanol; (20) phosphate buffer solution; and (21) other non-toxic compatible substances used in pharmaceutical preparations. In certain embodiments, the pharmaceutical composition of the present invention is non-pyrogenic, that is, it does not cause a significant increase in body temperature when administered to a patient.

[0046] The term "pharmaceutically acceptable salt" refers to relatively nontoxic inorganic and organic acid addition salts of one or more of the compounds. These salts can be prepared in situ during the final isolation and purification of one or more of the compounds, or by reacting one or more purified compounds in their free base form with a suitable organic or inorganic acid alone and isolating the salt so formed. Representative salts include hydrobromide, hydrochloride, sulfate, bisulfate, phosphate, nitrate, acetate, valerate, oleate, palmitate, stearate, laurate, benzoate, lactate, phosphate, toluenesulfonate, citrate, maleate, fumarate, succinate, tartrate, naphthoate, mesylate, glucoheptonate, lactobionate, and laurylsulfonate, among others. (See, e.g., Berge et al. (1977) "Pharmaceutical Salts," J. Pharm. Sci. 66: 1-19.)

[0047] In other cases, the compounds useful in the methods of the invention may contain one or more acidic functional groups and thus be able to form pharmaceutically acceptable salts with pharmaceutically acceptable bases. In these cases, the term "pharmaceutically acceptable salt" refers to relatively nontoxic inorganic and organic base addition salts of one or more compounds. These salts can also be prepared in situ during the final separation and purification of one or more of the compounds, or can be prepared by reacting one or more purified compounds with a suitable base (such as a pharmaceutically acceptable hydroxide, carbonate or bicarbonate of a metal cation) in its free acid form, with ammonia or with a pharmaceutically acceptable organic primary amine, secondary amine or tertiary amine. Representative alkali metal salts or alkaline earth metal salts include lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts and aluminum salts, etc. Representative organic amines that can be used to form base addition salts include ethylamine, diethylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, etc. (see, for example, Berge et al., supra).

[0048] The term "pharmaceutically acceptable co-crystal" refers to a solid coformer that does not form formal ionic interactions with a small molecule.

[0049] A "therapeutically effective amount" (or "effective amount") of a compound for use in therapy means an amount of the compound in a formulation that, when administered as part of a desired dosing regimen (to a mammal, preferably a human), will relieve symptoms, ameliorate symptoms, or slow the onset of a disease condition, at a reasonable benefit / risk ratio applicable to any drug treatment, according to clinically acceptable criteria for the condition or disorder being treated or for cosmetic purposes.

[0050] The terms "preventive or therapeutic" treatment are art-recognized and include administering one or more of the subject compositions to a host. If the treatment is administered prior to clinical manifestation of an unwanted condition (e.g., a disease or other unwanted condition of the host animal), the treatment is preventive (i.e., it protects the host from developing the unwanted condition), while if the treatment is administered after manifestation of the unwanted condition, the treatment is therapeutic (i.e., intended to alleviate, ameliorate, or stabilize an existing unwanted condition or its side effects).

[0051] The term "patient" or "subject" refers to a mammal in need of a particular treatment. In certain embodiments, the patient is a primate, canine, feline, or equine. In certain embodiments, the patient is a human.

[0052] Aliphatic chains include alkyl, alkenyl and alkynyl categories defined below. Straight chain aliphatic chains are limited to the unbranched carbon chain portion. As used herein, the term "aliphatic group" refers to a straight, branched or cyclic aliphatic hydrocarbon group, and includes saturated and unsaturated aliphatic groups, such as alkyl, alkenyl or alkynyl.

[0053] "Alkyl" refers to a fully saturated cyclic or acyclic, branched or unbranched carbon chain moiety having a specified number of carbon atoms or up to 30 carbon atoms (if not specified). For example, an alkyl group of 1 to 8 carbon atoms refers to moieties such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl, and those moieties that are positional isomers of these moieties. Alkyl groups of 10 to 30 carbon atoms include decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, and tetracosyl. In certain embodiments, a straight or branched alkyl group has 30 or fewer carbon atoms in its backbone (e.g., C1-C2 for a straight chain). 30 , for the branched chain C3-C 30 ), and more preferably 20 or less carbon atoms. The alkyl group may be substituted or unsubstituted.

[0054] As used herein, the term "heteroalkyl" refers to an alkyl moiety as defined above containing one or more oxygen, sulfur, nitrogen, phosphorus or silicon atoms in the place of a carbon atom.

[0055] As used herein, the term "haloalkyl" refers to an alkyl group as defined above substituted with at least one halogen.

[0056] As used herein, the term "hydroxyalkyl" refers to an alkyl group, as defined herein, substituted with at least one hydroxy group.

[0057] As used herein, the term "alkylene" refers to an alkyl group having a specified number of carbons, such as 2 to 12 carbon atoms, which contains two points of attachment to the rest of the compound on its longest carbon chain. Non-limiting examples of alkylene groups include methylene-(CH2)-, ethylene-(CH2CH2)-, n-propylene-(CH2CH2CH2)-, isopropylene-(CH2CH(CH3))-, etc. Alkylene groups can be cyclic or acyclic, branched or unbranched carbon chain moieties, and can be optionally substituted with one or more substituents.

[0058] "Cycloalkyl" means a monocyclic or bicyclic or bridged or spirocyclic or polycyclic saturated carbocyclic ring each having 3 to 12 carbon atoms. Preferred cycloalkyls have 3 to 10 carbon atoms in their ring structure, and more preferably have 3 to 6 carbon atoms in the ring structure. Cycloalkyls may be substituted or unsubstituted.

[0059] As used herein, the term "halocycloalkyl" refers to a cycloalkyl group as defined above substituted with at least one halogen.

[0060] "Cycloheteroalkyl" or "heterocycloalkyl" refers to a cycloalkyl moiety as defined above containing one or more oxygen, sulfur, nitrogen, phosphorus or silicon atoms in place of a carbon atom. Preferred cycloheteroalkyls have 4-8 carbon atoms and heteroatoms in their ring structure, and more preferably have 4-6 carbon atoms and heteroatoms in the ring structure. Cycloheteroalkyl or heterocycloalkyl may be substituted or unsubstituted.

[0061] Unless otherwise specified the number of carbons, "lower alkyl" as used herein refers to an alkyl as defined above, but having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl in its backbone structure. Likewise, "lower alkenyl" and "lower alkynyl" have similar chain lengths. Throughout the application, preferred alkyl is a lower alkyl. In certain embodiments, the substituents designated as alkyl herein are lower alkyl.

[0062] "Alkenyl" refers to any cyclic or acyclic, branched or unbranched, unsaturated carbon chain moiety having the number of carbon atoms specified, or, if no limit to the number of carbon atoms is specified, up to 26 carbon atoms; and having one or more double bonds located in the moiety. Examples of alkenyl groups of 6 to 26 carbon atoms are hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricosenyl, and tetracosenyl in various isomeric forms, wherein the one or more unsaturated bonds may be located in any position in the moiety and may have a (Z) or (E) configuration around the one or more double bonds.

[0063] "Alkynyl" refers to an alkenyl-scoped hydrocarbyl moiety, but having one or more triple bonds located within the moiety.

[0064] As used herein, the term "aryl" includes 3 to 12 substituted or unsubstituted monocyclic aromatic groups, wherein each atom of the ring is carbon (i.e., carbocyclic aromatic group) or wherein one or more atoms are heteroatoms (i.e., heteroaryl). Preferably, aryl includes 5 to 12 rings, more preferably 6 to 10 rings. The term "aryl" also includes a polycyclic system with two or more rings, wherein two or more carbons are shared by two adjacent rings, wherein at least one ring in the ring is aromatic, for example, other rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl and / or heterocyclic radical. Carbocyclic aromatic groups include benzene, naphthalene, phenanthrene, phenol, aniline, etc. Heteroaryl includes substituted or unsubstituted aromatic 3 to 12 ring structures, more preferably 5 to 12 rings, more preferably 5 to 10 rings, and its ring structure includes one to four heteroatoms. Heteroaryl groups include, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine and pyrimidine, etc. Aryl and heteroaryl groups may be monocyclic, bicyclic or polycyclic.

[0065] The term "halo", "halo" or "halogen" as used herein means halogen, and includes, for example and without limitation, fluorine, chlorine, bromine, iodine, etc. in both radioactive and non-radioactive forms. In a preferred embodiment, halo is selected from the group consisting of fluorine, chlorine and bromine.

[0066] The term "heterocyclyl" or "heterocyclic group" refers to a 3- to 12-membered ring structure, more preferably a 5- to 12-membered ring, more preferably a 5- to 10-membered ring, the ring structure of which contains 1 to 4 heteroatoms. The heterocycle may be monocyclic, bicyclic, spirocyclic or polycyclic. Heterocyclic groups include, for example, thiophene, thianthrene, furan, pyran, isobenzofuran, chromene, xanthene, xanthene, pyrrole, imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, pyrimidine, phenanthroline, phenazine, phenpyrazine, phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane, thiolane, oxazole, piperidine, piperazine, morpholine, lactones, lactams such as azetidinone and pyrrolidone, sultams, sultones, and the like. The heterocycle may be substituted at one or more positions with substituents as described above, for example, halogen, alkyl, arylalkyl, alkenyl, alkynyl, cycloalkyl, hydroxy, amino, nitro, sulfhydryl, imino, amido, phosphate, phosphonate, phosphite, carbonyl, carboxyl, silyl, sulfamoyl, sulfinyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moiety, -CF3, -CN, and the like.

[0067] The term "substituted" refers to a portion of a substituent having a replacement hydrogen on one or more carbons of the main chain. It should be understood that "substituted" or "substituted by..." includes implicit conditions, i.e., such substitution is based on the allowed valence of the substituted atom and the substituent, and the substitution produces a stable compound, for example, it does not spontaneously undergo transformations such as by rearrangement, cyclization, elimination, etc. As used herein, the term "substituted" is considered to include all allowed substituents of organic compounds. In a broad sense, allowable substituents include non-cyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and non-aromatic substituents of organic compounds. Allowable substituents can be one or more substituents and are the same or different for appropriate organic compounds. For the purposes of the present invention, heteroatoms such as nitrogen can have hydrogen substituents and / or any allowable substituents of organic compounds that satisfy the valence of heteroatoms as described herein. Substituents may include any of the substituents described herein, for example, halogen, hydroxy, carbonyl (e.g., carboxyl, alkoxycarbonyl, formyl or acyl), thiocarbonyl (e.g., thioester, thioacetate or thioformate), alkoxy, phosphoryl, phosphate, phosphonate, phosphite, amino, amido, amidine, imine, cyano, nitro, azido, sulfhydryl, alkylthio, sulfate, sulfonate, sulfamoyl, sulfonamido, sulfonyl, heterocyclyl, arylalkyl or aromatic or heteroaromatic moieties. In preferred embodiments, the substituents on the substituted alkyl are selected from C 1-6 Alkyl, C 3-6 In some embodiments, the substituted alkyl radicals are substituted alkyl radicals, such as cycloalkyl, halogen, carbonyl, cyano or hydroxyl radicals. In a more preferred embodiment, the substituents on the substituted alkyl radicals are selected from fluorine, carbonyl, cyano or hydroxyl radicals. It will be appreciated by those skilled in the art that the substituents themselves may be substituted where appropriate. Unless specifically stated as "unsubstituted", references to chemical moieties herein are to be understood to include substituted variants. For example, references to "aryl" or moieties implicitly include substituted and unsubstituted variants.

[0068] As used herein, the definition of each expression (eg, alkyl, m, n, etc.), when it occurs more than one time in any structure, is intended to be independent of its definition elsewhere in the same structure.

[0069] As used herein, "small molecule" refers to a small organic molecule or inorganic molecule having a molecular weight lower than about 3,000 Daltons. In general, the molecular weight of the small molecule that can be used for the present invention is less than 3,000 Daltons (Da). The small molecule can be, for example, at least about 100Da to about 3,000Da (e.g., about 100Da to about 3,000Da, about 100Da to about 2500Da, about 100Da to about 2,000Da, about 100Da to about 1,750Da, about 100Da to about 1,500Da, about 100Da to about 1,250Da, about 100Da to about 1,000Da, about 100Da to about 750Da, about 100Da to about 500Da, about 200Da to about 1500Da, about 500Da to about 1000Da, about 300Da to about 1000Da, or about 100Da to about 250Da).

[0070] In some embodiments, "small molecule" refers to an organic, inorganic or organometallic compound that generally has a molecular weight of less than about 1000. In some embodiments, a small molecule is an organic compound that is about 1 nm in size. In some embodiments, small molecule drugs of the present invention encompass oligopeptides and other biomolecules that have a molecular weight of less than about 1000.

[0071] An "effective amount" is an amount sufficient to produce a beneficial or desired result. For example, a therapeutic amount is an amount that achieves a desired therapeutic effect. This amount may be the same or different from a preventive effective amount, which is the amount necessary to prevent the onset of a disease or disease symptom. An effective amount may be administered in one or more administrations, applications, or doses. The therapeutically effective amount of a composition depends on the composition selected. The composition may be administered once or more per day to once or more per week; including once every other day. Those skilled in the art will appreciate that certain factors may affect the dosage and schedule required to effectively treat a subject, including but not limited to the severity of the disease or condition, previous treatment, the general health and / or age of the subject, and other diseases present. In addition, treatment of a subject with a therapeutically effective amount of a composition described herein may include a single treatment or a series of treatments.

[0072] The terms "decrease," "reduce," "reduced," "reduction," "decrease," and "inhibit" are generally used herein to refer to a statistically significant amount of decrease relative to a reference. However, for the avoidance of doubt, "reduce", "reduction" or "decrease" or "inhibit" generally means a decrease of at least 10% compared to a reference level, and can include, for example, a decrease of at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 98%, at least about 99% compared to a reference level, up to and including, for example, the complete absence of a given entity or parameter, or a decrease of between 10-99% compared to the absence of a given treatment.

[0073] The terms "increased", "increase" or "enhance" or "activate" are generally used herein to mean an increase by a statistically significant amount; for the avoidance of any doubt, the terms "increased", "increase" or "enhance" or "activate" mean an increase of at least 10% compared to a reference level, such as an increase of at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90% or up to and including a 100% increase, or any increase between 10%-100%, or at least about 2-fold, or at least about 3-fold, or at least about 4-fold, or at least about 5-fold or at least about 10-fold compared to a reference level, or any increase between 2-fold and 10-fold or more.

[0074] As used herein, the term "modulate" includes up-regulation and down-regulation, eg, enhancing or inhibiting a response.

[0075] "Radiopharmaceutical" as defined herein refers to an agent containing at least one radioactive isotope that emits radiation. Radioactive agents are routinely used in nuclear medicine for the diagnosis and / or therapy of various diseases. Radiolabeled agents, such as radiolabeled antibodies, contain a radioisotope (RI) that acts as a radiation source. As contemplated herein, the term "radioisotope" includes metal and non-metallic radioisotopes. Radioisotopes are selected based on the medical application of radiolabeled agents. When the radioisotope is a metal radioisotope, a chelating agent is generally used to bind the metal radioisotope to the rest of the molecule. When the radioisotope is a non-metallic radioisotope, the non-metallic radioisotope is generally directly or via a joint to the rest of the molecule.

[0076] For purposes of this invention, the chemical elements are identified according to the CAS version of the Periodic Table of the Elements, Handbook of Chemistry and Physics, 67th Edition, 1986-87, inside cover.

[0077] Compounds of the present invention

[0078] One aspect of the present invention provides a compound of formula (I):

[0079]

[0080] in

[0081] Y1 and Y2 are each alkyl; or, together with the carbon to which they are bound, form an unsubstituted or substituted spirocycloalkyl;

[0082] R1, R4, R5 and R8 are independently selected from -H and halogen;

[0083] R2 and R7 are independently selected from -H, -OH, -OAc, -NH2, halogen, -CN, -CF3, -CO2H, -NO2, -NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino, alkyl-R9, alkenyl-R9, alkynyl-R9, -OR 10 、-NHR 10 、-NR 11 C(O)R 12 、-C(O)NR 11 R 12 and-NR 11 S02R 12 ;

[0084] R3 and R6 are independently selected from alkyl and cycloalkyl;

[0085] Each occurrence of R9 is independently selected from OH, NH2, O-alkyl, O-alkyl-O-alkyl, alkylamino, NHC(O)-alkyl, N(CH3)C(O)-alkyl, NHSO2-alkyl, N(CH3)SO2-alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl;

[0086] R 10 is selected from the group consisting of alkyl, hydroxyalkyl, aminoalkyl, alkyl-O-alkyl, alkyl-O-alkyl-OH, alkyl-O-alkyl-O-alkyl, alkenyl, alkynyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl, alkyl-heterocycloalkyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl, SO3H, SO2-alkyl and SO2-haloalkyl;

[0087] Each occurrence of R 11 is selected from H and alkyl; and

[0088] Each occurrence of R 12 is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, O-alkyl, aminoalkyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl and alkyl-heterocycloalkyl;

[0089] Provided that when R1, R4, R5 and R8 are each -H, R2 and R7 are each -OH, and R3 and R6 are each CH3, then Y1 and Y2 are not each -Me or do not form, together with the carbon to which they are bonded, an unsubstituted spirobutyl group;

[0090] or a pharmaceutically acceptable salt thereof.

[0091] In certain embodiments, R3 and R6 are alkyl.

[0092] In certain embodiments, Y1 and Y2 are each independently C1-C4 alkyl.

[0093] In certain embodiments, Y1 and Y2 are each -CH3.

[0094] In certain embodiments, Y1 and Y2, together with the carbon to which they are bound, combine to form an unsubstituted spirocycloalkyl.

[0095] In certain embodiments, Y1 and Y2, together with the carbons to which they are bound, combine to form an unsubstituted spirocyclopropyl, cyclobutyl, or cyclopentyl.

[0096] In certain embodiments, R3 and R6 are each independently C1-C4 alkyl.

[0097] In certain embodiments, R3 and R6 are each independently selected from -CH3 and -CH2CH3.

[0098] In certain embodiments, R3 and R6 are each -CH3.

[0099] In certain embodiments, R3 and R6 are each -CH2CH3.

[0100] In certain embodiments, one of R3 and R6 is -CH3 and the other of R3 and R6 is -CH2CH3.

[0101] In certain embodiments, R3 and R6 are cycloalkyl.

[0102] In certain embodiments, R3 and R6 are each independently C3-C5 cycloalkyl.

[0103] In certain embodiments, R3 and R6 are each cyclopropyl.

[0104] In certain embodiments, one of R3 and R6 is C1-C4 alkyl and the other of R3 and R6 is C3-C5 cycloalkyl.

[0105] In certain embodiments, one of R3 and R6 is -CH3, and the other of R3 and R6 is cyclopropyl.

[0106] In certain embodiments, the compound has a structure selected from:

[0107]

[0108]

[0109] In certain embodiments, the compound has a structure selected from:

[0110]

[0111] In certain embodiments, R2 and R7 are independently selected from -OH, -NH2, alkylamino and -OR 10 .

[0112] In certain embodiments, R2 and R7 are each OH.

[0113] In certain embodiments, R2 is -OH; and R7 is -OCH3.

[0114] In certain embodiments, R7 is -OH; and R2 is -OCH3.

[0115] In certain embodiments, R2 is selected from -NH2, -NHCH3, and -NH(CH3)2; and R7 is OH.

[0116] In certain embodiments, R7 is selected from -NH2, -NHCH3, and -NH(CH3)2; and R2 is OH.

[0117] In certain embodiments, R1, R4, R5 and R8 are each -H.

[0118] Another aspect of the present invention provides a compound of formula (II):

[0119]

[0120] in

[0121] X1 and X2 are each alkyl; or, together with the carbon to which they are bonded, form an unsubstituted or substituted spirocycloalkyl;

[0122] R1′, R4′, R5′ and R8′ are independently selected from —H, —OH, —NH2, alkyl and halogen;

[0123] R2′, R3′, R6′ and R7′ are independently selected from —H, —OH, —OAc, —NH2, halogen, —CN, —CF3, —CO2H, —NO2, —NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino and —OR8′; and

[0124] R8′ is selected from alkyl, hydroxyalkyl, aminoalkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl;

[0125] or a pharmaceutically acceptable salt thereof.

[0126] In certain embodiments, X1 and X2 are each independently C1-C4 alkyl.

[0127] In certain embodiments, X1 and X2 are each -CH3.

[0128] In certain embodiments, X1 and X2, together with the carbon to which they are bound, combine to form an unsubstituted spirocycloalkyl.

[0129] In certain embodiments, X1 and X2, together with the carbons to which they are bound, combine to form an unsubstituted spirocyclopropyl, cyclobutyl, or cyclopentyl.

[0130] In certain embodiments, the compound has a structure selected from:

[0131]

[0132] In certain embodiments, R2' and R7' are independently selected from -OH, -NH2, alkylamino and -OR 10 .

[0133] In certain embodiments, R2' and R7' are each OH.

[0134] In certain embodiments, R2' is -OH; and R7' is -OCH3.

[0135] In certain embodiments, R7' is -OH; and R2' is -OCH3.

[0136] In certain embodiments, R2′ is selected from —NH2, —NHCH3, and —NH(CH3)2; and R7′ is OH.

[0137] In certain embodiments, R7′ is selected from —NH2, —NHCH3, and —NH(CH3)2; and R2′ is OH.

[0138] In certain embodiments, R3' and R6' are each independently -H or C1-C4 alkyl.

[0139] In certain embodiments, R3' and R6' are each independently -H or -CH3.

[0140] In certain embodiments, R1' and R8' are each independently -H or C1-C4 alkyl.

[0141] In certain embodiments, R1' and R8' are each independently -H or -CH3.

[0142] In certain embodiments, R4' and R5' are each independently -H or -OH.

[0143] In certain embodiments, the compound is selected from Table 1.

[0144] Table 1.

[0145]

[0146]

[0147] In certain embodiments, the compound is selected from Table 2.

[0148] Table 2.

[0149]

[0150] In some embodiments, the compounds are atropisomers. Additionally, unless otherwise indicated, structures depicted herein are also intended to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, by replacing hydrogen with deuterium or tritium, or replacing carbon with 13 C- or 14Compounds produced by substitution of C-enriched carbon are within the scope of the present invention. Such compounds can be used, for example, as analytical tools, as probes in biological assays, or as therapeutic agents according to the present invention. For example, with respect to the variable R 1 For example, the (C1-C4)alkyl or -O-(C1-C4)alkyl group may be suitably deuterated (eg, -CD3, -OCD3).

[0151] Any of the compounds of the invention may also be radiolabeled for use in the preparation of radiopharmaceuticals.

[0152] Treatment

[0153] One aspect of the present invention relates to a method of inhibiting ferroptosis, comprising administering an effective amount of a compound of formula (I) or (II) to a subject in need thereof.

[0154] Another aspect of the present invention relates to a method of treating an inflammatory disease, a neuronal disease or a neurodegenerative disease mediated at least in part by ferroptosis, comprising administering to a subject in need thereof an effective amount of a compound of formula (I) or (II).

[0155] Another aspect of the present invention relates to a method of treating an inflammatory disease mediated at least in part by ferroptosis, comprising administering to a subject in need thereof an effective amount of a compound of formula (I) or (II).

[0156] Another aspect of the present invention relates to a method of treating a neuronal disease mediated at least in part by ferroptosis, comprising administering to a subject in need thereof an effective amount of a compound of formula (I) or (II).

[0157] Another aspect of the present invention relates to a method of treating a neurodegenerative disease mediated at least in part by ferroptosis, comprising administering to a subject in need thereof an effective amount of a compound of formula (I) or (II).

[0158] Another aspect of the present invention relates to a method of treating a mitochondrial disease in a subject in need thereof, comprising administering to the subject an effective amount of a compound of formula (I) or (II).

[0159] In one embodiment, the mitochondrial disease affects the muscles of the subject, such as mitochondrial myopathy. In another embodiment, the mitochondrial disease affects the eyes of the subject, such as progressive external ophthalmoplegia. In other embodiments, the mitochondrial disease is Alpers disease, Barth syndrome, beta-oxidation deficiency, carnitine deficiency, carnitine-acyl-carnitine deficiency, chronic progressive external ophthalmoplegia syndrome, or coenzyme Q10 deficiency.

[0160] In one aspect, the present invention relates to a method for treating a muscle or neuromuscular disease in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound of any one of formula (I) or (II). In one embodiment, the muscle or neuromuscular disease is sarcopenia. In another embodiment, the muscle or neuromuscular disease is muscular dystrophy. In another embodiment, the muscle or neuromuscular disease is myopathy. In another embodiment, the muscle or neuromuscular disease is Duchenne muscular dystrophy. In another embodiment, the muscle or neuromuscular disease is inclusion body myositis (IBM) or sporadic inclusion body myositis (sIBM). In another embodiment, the muscle or neuromuscular disease is selected from mitochondrial myopathy. In other embodiments, the muscle or neuromuscular disease is muscle aging and weakness, frailty, sarcopenia, mitochondrial myopathy or muscle rhabdomyolysis.

[0161] In one aspect, the present invention relates to a method for treating a neuron or neurodegenerative disease in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound of any one of formula (I) or (II). In some embodiments, the neuron or neurodegenerative disease is Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis (also known as ALS and Lou Gehrig's disease) and AIDS dementia complex, adrenoleukodystrophy, Alexander disease, Alpers disease, ataxia telangiectasia, Batten disease, bovine spongiform encephalopathy (BSE), Canavan disease, corticobasal degeneration, Creutzfeldt-Jakob disease, Lewy body dementia, fatal family history of leukodystrophy, ... Familial insomnia, frontotemporal lobar degeneration, Kennedy's disease, Krabbe disease, Lyme disease, Machado-Joseph disease, multiple sclerosis, multiple system atrophy, neuroacanthocytosis, Niemann-Pick disease, Pick's disease, primary lateral sclerosis, progressive supranuclear palsy, Refsum's disease, Sandhoff's disease, diffuse myelinating sclerosis, spinocerebellar ataxia, subacute mixed degeneration of the spinal cord, tabes dorsalis, Tay-Sachs disease, toxic encephalopathy, transmissible spongiform encephalopathy, and wiggly hedgehog syndrome.

[0162] In one aspect, the invention relates to a method of treating ischemia-reperfusion injury in a subject in need thereof, comprising administering to the subject an effective amount of a compound of any one of formula (I) or (II).

[0163] Pharmaceutical compositions, routes of administration and dosing

[0164] In certain embodiments, the present invention relates to a pharmaceutical composition comprising a compound of the present invention and a pharmaceutically acceptable carrier. In certain embodiments, the present invention relates to a pharmaceutical composition comprising a compound of any one of formula (I) or (II) and a pharmaceutically acceptable carrier. In certain embodiments, the pharmaceutical composition comprises a plurality of compounds of the present invention and a pharmaceutically acceptable carrier.

[0165] In certain embodiments, the pharmaceutical compositions of the present invention further comprise at least one additional pharmaceutically active agent other than the compounds of the present invention. The at least one additional pharmaceutically active agent may be an agent useful for treating ischemia-reperfusion injury.

[0166] Pharmaceutical compositions of the present invention can be prepared by combining one or more compounds of the present invention with a pharmaceutically acceptable carrier and, optionally, one or more additional pharmaceutically active agents.

[0167] As stated above, "effective amount" refers to any amount sufficient to achieve the desired biological effect. In conjunction with the teachings provided herein, by selecting between various active compounds and trade-offs (such as efficacy, relative bioavailability, patient weight, severity of adverse side effects and mode of administration), a preventive or therapeutic treatment regimen that does not cause substantial unwanted toxicity but is effective for treating a particular subject can be planned. The effective amount for any particular application may vary depending on factors such as the disease or illness being treated, the specific compound of the present invention being administered, the size of the subject, or the severity of the disease or illness. Those of ordinary skill in the art can empirically determine the effective amount of the specific compound of the present invention and / or other therapeutic agents without excessive experimentation. A maximum dose can be used, i.e., the highest safe dose according to some medical diagnosis. Multiple doses per day can be considered to achieve appropriate systemic levels of the compound. Appropriate systemic levels can be determined, for example, by measuring the peak or sustained plasma levels of the patient's drug. "Dosage" and "dosage" are used interchangeably herein.

[0168] The formulations of the present invention may be administered in a pharmaceutically acceptable solution which may routinely contain pharmaceutically acceptable concentrations of salt, buffering agents, preservatives, compatible carriers, adjuvants and optionally other therapeutic ingredients.

[0169] The pharmaceutical composition of the present invention contains an effective amount of a compound as described herein and a therapeutic agent optionally contained in a pharmaceutically acceptable carrier. The term "pharmaceutically acceptable carrier" means one or more compatible solid or liquid fillers, diluents or encapsulating materials that are suitable for administration to humans or other vertebrates. The term "carrier" refers to a natural or synthetic organic or inorganic ingredient that is combined with an active ingredient to facilitate application. The components of the pharmaceutical composition can also be blended with the compounds of the present invention and with each other in such a manner that there is no interaction that substantially impairs the desired drug efficiency.

[0170] Those skilled in the relevant art will appreciate that, based on the description of the invention contained herein, other suitable modifications and adaptations of the compositions and methods described herein are apparent and may be made without departing from the scope of the invention or any embodiment thereof, given the information known to those skilled in the art, based on the description of the invention contained herein. Now that the invention has been described in detail, the invention will be more clearly understood by reference to the following examples, which are included herein only for illustrative purposes and are not intended to limit the invention.

[0171] Example

[0172] The present invention is further described in the following examples, which do not limit the scope of the invention described in the claims.

[0173] Example 1: Synthesis of Representative Compounds of the Invention

[0174] Unless otherwise stated, all reactions were performed using oven-dried glassware and under an inert atmosphere (nitrogen). Unless otherwise stated, all solvents were used as purchased. Commercial reagents were used as purchased without further purification. Organic solutions were concentrated on a Büchi rotary evaporator under reduced pressure.

[0175] Use Merck Kieselgel 60 F254 (230-400 mesh) fluorescently treated silica to carry out thin layer chromatography, and visualize under UV light (254 and 366nm) and / or by dyeing with potassium permanganate aqueous solution. Record the H NMR spectrum at 400MHz on a Bruker spectrometer in deuterated solvents or at 60MHz on a Nanalysis NMReady-60PRO spectrometer, wherein the residual proton solvent is as an internal standard. Record the C NMR spectrum at 100MHz on a Bruker spectrometer in deuterated solvents, wherein the central peak of the deuterated solvent is as an internal standard. Chemical shift (δ) is given in parts per million (ppm), and coupling constant (J) is given in Hertz (Hz) rounded to the nearest 0.1Hz. The H NMR spectrum is reported as δ / ppm (multiplicity, proton number, coupling constant J / Hz) relative to tetramethylsilane low field. 13 C NMR spectra are reported as δ / ppm. TLC-MS data were obtained on an Advion Expression CMS coupled to a PlateExpress TLC-plate reader. Medium pressure liquid chromatography (MPLC) was performed on a Biotage Isolera Four with built-in UV detector and fraction collector with Interchim silica gel columns.

[0176] 1. ((8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethyl Synthesis of silane

[0177]

[0178] ((8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane was prepared from 3-hydroxy-4-methylbenzoic acid in 7 steps

[0179] Solution 1.

[0180]

[0181] Step 1: Synthesis of methyl 3-hydroxy-4-methylbenzoate

[0182]

[0183] Sulfuric acid (1.3 g, 0.70 mL, 0.2 eq., 13 mmol) was added to a suspension of 3-hydroxy-4-methylbenzoic acid (10 g, 1 eq., 66 mmol) in methanol (2.1 g, 0.16 L, 0.4 mole, 1 eq., 66 mmol) and the mixture was refluxed overnight. The methanol was evaporated under vacuum and the crude material was extracted with EtOAc and a saturated solution of Na2CO3. The organic phase was washed with water, dried over sodium sulfate and concentrated under vacuum to give methyl 3-hydroxy-4-methylbenzoate (8.7 g, 52 mmol, 80%) as a white solid. 1 H NMR (400MHz, DMSO) δ9.73 (d, J=0.5Hz, 1H), 7.39 (d, J=1.7Hz, 1H), 7.31 (dd, J=7.7, 1.7Hz, 1H), 7.19 (d, J=7.7Hz, 1H), 3.80 (s, 3H), 2.17 (d, J=0.6Hz, 3H).

[0184] Step 2: Synthesis of methyl 3-(benzyloxy)-4-methylbenzoate

[0185]

[0186] Methyl 3-hydroxy-4-methylbenzoate (8.7 g, 1 eq., 52 mmol) was dissolved in acetonitrile (2.1 g, 0.13 L, 0.4 mole, 1 eq., 52 mmol). Potassium carbonate (7.2 g, 1 eq., 52 mmol) was added followed by benzyl bromide (9.0 g, 6.2 mL, 1 eq., 52 mmol) and the mixture was heated at 50 °C overnight. Water was added and the aqueous phase was extracted with EtOAc. The organic phase was washed with water and brine, dried over sodium sulfate, and evaporated under vacuum to give methyl 3-(benzyloxy)-4-methylbenzoate (10.9 g, 42.5 mmol, 81%) as a pale yellow solid. 1 H NMR (400MHz, CDCl3) δ7.61-7.57 (m, 2H), 7.51-7.30 (m, 6H), 7.23-7.19 (m, 1H), 5.14 (s, 2H), 3.91 (s, 3H), 2.33 (d, J = 0.7Hz, 3H).

[0187] Step 3: Synthesis of methyl 5-(benzyloxy)-2-bromo-4-methylbenzoate

[0188]

[0189] Bromine (8.16g, 2.63mL, 1.2 equivalents, 51.0mmol) is added to a room temperature suspension of methyl 3-(benzyloxy)-4-methylbenzoate (10.9g, 1 equivalent, 42.5mmol) in acetic acid (51.1g, 48.7mL, 20 equivalents, 851mmol) and water (38.3g, 38.3mL, 50 equivalents, 2.13mol), and the resulting mixture is heated to 60°C overnight. After cooling to room temperature, ice is added and the reaction mixture is stirred at room temperature for 2 hours. The precipitate is filtered off and rinsed with cold water, dried under vacuum to give methyl 5-(benzyloxy)-2-bromo-4-methylbenzoate (13g, 39mmol, 91%) as a white solid. 1 H NMR (400MHz, CDCl3) δ7.46-7.32 (m, 7H), 5.09 (s, 2H), 3.92 (s, 3H), 2.27 (d, J = 0.8Hz, 3H).

[0190] Step 4: Synthesis of 5-(benzyloxy)-2-bromo-4-methylbenzoic acid

[0191]

[0192] Methyl 5-(benzyloxy)-2-bromo-4-methylbenzoate (3000.00 mg, 1 eq., 8.950 mmol) was dissolved in methanol (286.8 mg, 17.90 mL, 0.5 mole, 1 eq., 8.950 mmol) and THF (645.4 mg, 44.75 mL, 0.2 mole, 1 eq., 8.950 mmol) at room temperature. Then cooled to 0 ° C. A solution of LiOH (643.0 mg, 3 eq., 26.85 mmol) in water (161.3 mg, 17.90 mL, 0.5 mole, 1 eq., 8.950 mmol) was added dropwise and stirring was continued overnight. Methanol and THF were evaporated under vacuum. The obtained crude material was extracted twice with ethyl acetate and HCl 1M. The combined organic phases were washed once with brine, dried over sodium sulfate and concentrated under vacuum to give 5-(benzyloxy)-2-bromo-4-methylbenzoic acid (2.7 g, 8.4 mmol, 94%) as a white solid. 1 H NMR (400MHz, DMSO) δ13.26 (s, 1H), 7.52 (d, J = 0.9Hz, 1H), 7.48-7.44 (m, 2H), 7.43-7.38 (m, 3H), 7.36-7.31 (m, 1H), 5.17 (s, 2H), 2.26-2.19 (m, 3H).

[0193] Step 5: Synthesis of 8-(benzyloxy)-3-hydroxy-2,9-dimethyl-6H-benzo[c]chromen-6-one

[0194]

[0195] Sodium carbonate (2.970 g, 3.0 Eq, 28.02 mmol) was dissolved in water (168.3 mg, 46.70 mL, 0.2 mole, 1 equivalent, 9.341 mmol) at room temperature. 4-methylbenzene-1,3-diol (2.319 g, 2.0 equivalents, 18.68 mmol) was added in batches and heated at 60 ° C for 30 minutes. 5-(Benzyloxy)-2-bromo-4-methylbenzoic acid (3000 mg, 1 equivalent, 9.341 mmol) was added in batches and continued to stir at 60 ° C for 1 hour. CuI (1.245 g, 0.7 equivalents, 6.539 mmol) was added and the reaction mixture was heated at the same temperature overnight. A precipitate was formed after the addition of CuI. The precipitate was filtered out and washed with water and HCl 1M in sequence. The solid was dried under high vacuum to afford 8-(benzyloxy)-3-hydroxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (1.8 g, 5.2 mmol, 56%) as a beige solid. 1 H NMR (400MHz, DMSO) δ10.16 (s, 1H), 8.12 (s, 1H), 7.97 (s, 1H), 7.63 (s, 1H), 7.51 (d, J=7.0Hz, 2H) , 7.42 (t, J=7.4Hz, 2H), 7.36-7.32 (m, 1H), 6.74 (s, 1H), 5.26 (s, 2H), 2.39 (s, 3H), 2.21 (s, 3H).

[0196] Step 6: Synthesis of 8-(benzyloxy)-3-((tert-butyldimethylsilyl)oxy)-2,9-dimethyl-6H-benzo[c]chromen-6-one

[0197]

[0198] 8-(Benzyloxy)-3-hydroxy-2,9-dimethyl-6H-benzo[c]chromene-6-one (1.7 g, 1 equivalent, 4.9 mmol) was dissolved in DMF (0.36 g, 49 mL, 0.1 mole, 1 equivalent, 4.9 mmol) at room temperature. Triethylamine (1.2 g, 1.7 mL, 2.5 equivalents, 12 mmol) was added and the mixture was cooled to 0 ° C. TBDMS-Cl (0.89 g, 1.2 equivalents, 5.9 mmol) was added and the mixture was continued to stir overnight at room temperature. The reaction mixture was extracted with HCl 1M and EtOAc. The combined organic phase was washed with water and brine in sequence, dried over sodium sulfate and concentrated under vacuum. The crude material was purified by flash column chromatography on silica (0%-50% EtOAc in Hex) to afford 8-(benzyloxy)-3-((tert-butyldimethylsilyl)oxy)-2,9-dimethyl-6H-benzo[c]chromen-6-one (1.18 g, 2.56 mmol, 52%). f = 0.7 (EtOAc / cyclohexane 20%). 1 H NMR (400MHz, CDCl3) δ7.80 (d, J=1.0Hz, 1H), 7.78 (s, 1H), 7.73 (s, 1H), 7.51-7.47 (m, 2H), 7.45-7.39 (m, 2H), 7.3 8-7.33 (m, 1H), 6.79 (s, 1H), 5.20 (s, 2H), 2.46 (d, J=0.8Hz, 3H), 2.30 (d, J=0.7Hz, 3H), 1.04 (s, 9H), 0.28 (s, 6H).

[0199] Step 7: Synthesis of ((8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane

[0200]

[0201] 8-(Benzyloxy)-3-((tert-butyldimethylsilyl)oxy)-2,9-dimethyl-6H-benzo[c]chromen-6-one (1170 mg, 1 eq, 2.540 mmol) was dissolved in THF (183.2 mg, 25.40 mL, 0.1 mol, 1 eq, 2.540 mmol) and the reaction was cooled to 0°C in an ice bath. Methylmagnesium bromide (1.333 g, 3.725 mL, 3 mol, 4.4 eq, 11.18 mmol) was then added all at once. The reaction was stirred at 0°C for 10 minutes and then warmed to room temperature. Stirring was continued at room temperature for 1 hour after which the reaction was quenched with water and extracted with EtOAc (3x). The combined organic layers were dried over anhydrous Na2SO4, filtered and concentrated under vacuum. The crude material was dissolved in EtOAc 20 mL, PTSOH (48.31 mg, 0.1 eq., 254.0 μmol) was added in one portion, and the mixture was heated at 60° C. for 1 hour. The reaction mixture was extracted once with EtOAc and saturated sodium bicarbonate solution, dried over sodium sulfate and concentrated under vacuum to give ((8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane (1100 mg, 2.317 mmol, 91.23%) as a light brown solid. f = 0.6 (EtOAc / cyclohexane 20%). 1 H NMR (400MHz, CDCl3) δ7.57-7.46 (m, 2H), 7.45-7.38 (m, 2H), 7.37-7.30 (m, 1H), 7.21 (s, 1H), 6.85 (d, J=0.9Hz, 1H), 6.44 ( s, 1H), 5.14 (s, 2H), 2.24 (d, J=0.8Hz, 3H), 2.14 (s, 3H), 1.51 (s, 3H), 1.40 (s, 3H), 1.03 (s, 9H), 0.26 (s, 3H), 0.25 (s, 3H).

[0202] 2. Synthesis of 2,6,6,9-tetramethyl-8-(methylamino)-6H-benzo[c]chromen-3-ol (2a)

[0203]

[0204] 2a was synthesized in 4 steps starting from ((8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane.

[0205] Solution 2.

[0206]

[0207] Step 1: Synthesis of 3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol

[0208]

[0209] ((8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane (400 mg, 1 eq., 843 μmol) was dissolved in methanol (27.0 mg, 8.43 mL, 0.1 mole, 1 eq., 843 μmol) and dichloromethane (71.6 mg, 4.21 mL, 0.2 mole, 1 eq., 843 μmol). Palladium hydroxide on carbon (118 mg, 20% Wt, 0.2 eq., 169 μmol) was added in one portion and the suspension was hydrogenated at atmospheric pressure overnight. Upon completion, the reaction mixture was filtered through a pad of celite. p-Toluenesulfonic acid monohydrate (16.0 mg, 12.9 μL, 0.1 equiv, 84.3 μmol) was added, and the mixture was concentrated and loaded onto silica for purification by flash column chromatography (SiO2, 12 g, 0%-5% MeOH in DCM) to give 3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (150 mg, 390 μmol, 46.3%) as a white solid. 1 H NMR (400MHz, DMSO) δ9.35 (s, 1H), 7.49 (s, 1H), 7.44 (s, 1H), 6.67 (s, 1H), 6. 26 (s, 1H), 2.15 (s, 3H), 2.13 (s, 3H), 1.47 (s, 6H), 0.98 (s, 9H), 0.20 (s, 6H).

[0210] Step 2: Synthesis of 33-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate

[0211]

[0212] At 0 ℃, trifluoromethanesulfonic anhydride (165mg, 98.8 μ L, 1.5 equivalents, 585 μ mol) is added dropwise to 3-((tert-butyldimethylsilyl) oxygen base)-2,6,6,9-tetramethyl-6H-benzo [c] chromene-8-ol (150mg, 1 equivalent, 390 μ mol) and pyridine (309mg, 315 μ L, 10 equivalents, 3.90mmol) in a solution in DCM 10mL, and the mixture is stirred at room temperature for 3 hours. The reaction is monitored by TLC eluent EtOAc / cyclohexane 10%. Dichloromethane is evaporated under vacuum, and the crude material is extracted with HCl 1M and EtOAc. The organic phase was washed once with water, dried over sodium sulfate and concentrated under vacuum to give 3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate (140 mg, 271 μmol, 69.5%) which was used in the next step without further purification. f 0.6 (EtOAc / cyclohexane 40%).

[0213] Step 3: Synthesis of 3-((tert-butyldimethylsilyl)oxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-8-amine

[0214]

[0215] t-Bu XPhos (23 mg, 0.4 equivalents, 54 μmol) was added to a suspension of tris(dibenzylideneacetone)dipalladium (25 mg, 0.2 equivalents, 27 μmol) in dioxane 8 mL, and the mixture was stirred at room temperature for 5 minutes. Trifluoromethanesulfonic acid 3-((, tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromene-8-yl ester (70 mg, 1 equivalent, 0.14 mmol), methylamine (63 mg, 1.0 mL, 2 moles, 15 equivalents, 2.0 mmol) and cesium carbonate (427 mg, 1.31 mmol) were added in sequence, and the reaction mixture was refluxed for 3 hours. Water was added and the mixture was extracted 3 times with EA. The combined organic phase was dried over sodium sulfate, filtered and concentrated under vacuum. The crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 5% to 10% 20% to give 3-((tert-butyldimethylsilyl)oxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-8-amine (40 mg, 0.10 mmol, 74%) as a pale yellow oil. The product was contaminated with ligand. f 0.5 (EtOAc / cyclohexane 20%). MS (ESI+): m / z = 397.24, found 398.3.

[0216] Step 4: Synthesis of 2,6,6,9-tetramethyl-8-(methylamino)-6H-benzo[c]chromen-3-ol (2a)

[0217]

[0218] 3-((tert-Butyldimethylsilyl)oxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-8-amine (40 mg, 1 eq, 0.10 mmol) was dissolved in anhydrous methanol (3.2 mg, 2.0 mL, 0.05 mole, 1 eq, 0.10 mmol), methanolic hydrogen chloride solution (34 mg, 0.40 mL, 1.25 mole, 5 eq, 0.50 mmol) was added at room temperature and the mixture was stirred overnight. The solvent was evaporated and the crude material was loaded onto silica and purified by FC: eluent MeOH / DCM 0% to 20% to give 2,6,6,9-tetramethyl-8-(methylamino)-6H-benzo[c]chromen-3-ol (10 mg, 35 μmol, 35%). f 0.5(MeOH / DCM 10%)

[0219] 1 H NMR (400MHz, DMSO) δ9.17 (s, 1H), 7.32 (s, 1H), 7.29 (s, 1H), 6.32 (s, 1H), 6.28 (s, 1H), 2.75 (s, 3H), 2.10 (s, 3H), 2.08 (s, 3H), 1.48 (s, 6H).

[0220] 3. Synthesis of 8-amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (2)

[0221]

[0222] 2 Prepared from 33-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate in 2 steps

[0223] Solution 3.

[0224]

[0225] Step 1: Synthesis of tert-butyl (3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate

[0226]

[0227] t-BuXPhos (29.6 mg, 0.2 equivalents, 69.7 μmol) was added to a suspension of tris(dibenzylideneacetone)dipalladium (31.9 mg, 0.1 equivalents, 34.8 μmol) in dioxane 8 ml, and the mixture was stirred at room temperature for 5 minutes. 3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate (180 mg, 1 equivalent, 348 μmol), tert-butyl carbamate (163 mg, 4 equivalents, 1.39 mmol) and cesium carbonate (427 mg, 1.31 mmol) were added, and the reaction mixture was refluxed for 1 hour. Water was added and the mixture was extracted 3 times with EA. The combined organic phases were dried over sodium sulfate, filtered and concentrated under vacuum, and the crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 20% to give tert-butyl (3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate (70 mg, 0.14 mmol, 42%) as a pale yellow solid. f 0.5 (EtOAc / cyclohexane 20%) 1 H NMR (400MHz, CDCl3) δ7.72 (s, 1H), 7.39 (d, J = 1.1Hz, 2H), 6.39 (s, 1H), 6.27 (s, 1H ), 2.28(s, 3H), 2.20(s, 3H), 1.61(s, 6H), 1.55(s, 9H), 1.01(s, 9H), 0.24(s, 6H).

[0228] Step 2: 8-Amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (2) Synthesis

[0229]

[0230] By (3-((tert-butyldimethylsilyl)oxy)-2,6,6,9-tetramethyl-6H-benzo [c] chromene-8-yl) tert-butyl carbamate (20mg, 1 equivalent, 41μmol) is dissolved in DCM (2mL) and is cooled to 0 ℃.TFA (0.28g, 0.19mL, 60 equivalents, 2.5mmol) is added dropwise and stirring is continued overnight.Reaction mixture is extracted twice with EtOAc and NaHCO saturated solution.The organic phase merged is dried over sodium sulfate, filtered and concentrated under vacuum, and the crude material is loaded on silica and purified by FC eluent MeOH / DCM 0% to 5% to 10% 20%, 8-amino-2,6,6,9-tetramethyl-6H-benzo [c] chromene-3-ol (10mg, 37μmol, 90%) is obtained as a white solid.

[0231] 1 H NMR (400MHz, DMSO) δ 9.18 (s, 1H), 7.31 (s, 1H), 7.25 (s, 1H), 6.52 (s, 1H), 6.27 (s, 1H), 2.08 (s, 6H), 1.44 (s, 6H).

[0232] 4. Synthesis of 3-amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (1)

[0233]

[0234] 1 was prepared from ((8-benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane in 5 steps

[0235] Solution 4.

[0236]

[0237] Step 1: Synthesis of 8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol

[0238]

[0239] ((8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)oxy)(tert-butyl)dimethylsilane (470 mg, 1 eq., 990 μmol) was dissolved in anhydrous methanol (31.7 mg, 9.90 mL, 0.1 mole, 1 eq., 990 μmol) and DCM (84.1 mg, 4.95 mL, 0.2 mole, 1 eq., 990 μmol) (SM is insoluble in MeOH), acetyl chloride (155 mg, 141 μL, 2 eq., 1.98 mmol) was added dropwise and stirring was continued overnight. Tlc showed no more SM. The solvent was evaporated under vacuum and the crude material was extracted with EA and a saturated solution of sodium bicarbonate. The organic phase was dried over sodium sulfate and concentrated under vacuum to give 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (317 mg, 879 μmol, 88.8%) as a light brown solid which was used in the next step without further purification.

[0240] 1 H NMR (400MHz, DMSO) δ9.36 (d, J=1.5Hz, 1H), 7.49 (d, J=7.7Hz, 3H), 7.44-7.38 (m, 3H), 7.32 (td, J=6.9 , 1.5Hz, 1H), 6.91 (s, 1H), 6.30 (d, J=1.7Hz, 1H), 5.15 (s, 2H), 2.21 (s, 3H), 2.10 (s, 3H), 1.49 (s, 6H).

[0241] Step 2: Synthesis of 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl trifluoromethanesulfonate

[0242]

[0243] Trifluoromethanesulfonic anhydride (352 mg, 211 μL, 1.5 eq., 1.25 mmol) was added dropwise to a solution of 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (300 mg, 1 eq., 832 μmol) and pyridine (658 mg, 673 μL, 10 eq., 8.32 mmol) in DCM 10 mL at 0°C, and the mixture was stirred at room temperature for 3 hours. DCM was evaporated under vacuum, and the crude material was extracted with NH4Cl saturated solution and EA. The organic phase was washed once with water, dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EA / cyclohexane 0% to 15% to give trifluoromethanesulfonic acid 8-methoxy-6-oxo-6H-benzo[c]chromen-3-yl ester (550 mg, 1.47 mmol, 42%). 1H NMR (400MHz, CDCl3) δ7.53 (s, 1H), 7.49-7.31 (m, 6H), 6.83 (s, 1H), 6.71 (s, 1H), 5.12 (s, 2H), 2.36 (d, J=0.6Hz, 3H), 2.33 (d, J=0.8Hz, 3H), 1.58 (s, 6H).

[0244] Step 3: Synthesis of tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate

[0245]

[0246] t-Bu XPhos (36.2 mg, 0.14 eq., 85.3 μmol) was added to a suspension of tris(dibenzylideneacetone)dipalladium (39.0 mg, 0.07 eq., 42.6 μmol) in toluene 6.5 mL, and the mixture was stirred at room temperature for 5 minutes. 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl trifluoromethanesulfonate (300 mg, 1 eq., 609 μmol), tert-butyl carbamate (428 mg, 6 eq., 3.65 mmol) and cesium carbonate (427 mg, 1.31 mmol) were added, and the reaction mixture was refluxed for 1 hour. Water was added and the mixture was extracted 3 times with EA. The combined organic phases were dried over sodium sulfate, filtered and concentrated under vacuum.

[0247] The crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 5% to 10% 20% to give tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (60 mg, 0.13 mmol, 21%). f 0.5 (EtOAc / cyclohexane 20%). MS (APCI+): m / z=460.

[0248] Step 4: Synthesis of 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine

[0249]

[0250] TFA (0.74 g, 0.50 mL, 50 eq., 6.5 mmol) was added to a solution of tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (60 mg, 1 eq., 0.13 mmol) in DCM (11 mg, 1.3 mL, 0.1 mole, 1 eq., 0.13 mmol) at 0 °C and stirred at room temperature for 1 hour. The solvent was evaporated under vacuum and the crude material was partitioned between EtOAc and a saturated solution of sodium bicarbonate. The aqueous phase was extracted 3 times with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum to give 8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine (50 mg, 0.14 mmol, 110%) as a light brown oil, which was used as the crude material for the next step. MS (APCI+): m / z=360.

[0251] Step 5: Synthesis of 3-amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (1)

[0252]

[0253] 8-(Benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine (50 mg, 1 eq., 0.14 mmol) was dissolved in methanol (4.5 mg, 4.6 mL, 0.03 mole, 1 eq., 0.14 mmol) and DCM (12 mg, 1.4 mL, 0.1 mole, 1 eq., 0.14 mmol). Palladium hydroxide on carbon (9.8 mg, 20% Wt, 0.1 eq., 14 μmol) was added and the mixture was hydrogenated at atmospheric pressure for 2 hours. The crude material was filtered through a pad of celite and purified by FC eluent EtOAc / cyH 0% to 80% to give 3-amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (20 mg, 74 μmol, 53%).

[0254] Rf 0.4 (EtOAc / cyclohexane 20%).

[0255] 1 H NMR (400MHz, DMSO) δ9.14 (s, 1H), 7.30 (s, 1H), 7.24 (s, 1H), 6.62 (s, 1H), 6.1 2 (s, 1H), 4.85 (s, 2H), 2.13 (d, J=0.7Hz, 3H), 2.04-1.87 (m, 3H), 1.44 (s, 6H). MS: m / z: 270[M+H] + .

[0256] 5. Synthesis of 2,6,6,9-tetramethyl-3-(methylamino)-6H-benzo[c]chromen-8-ol (8)

[0257]

[0258] 8 was prepared from tert-butyl (8-benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate in 4 steps

[0259] Solution 5.

[0260]

[0261] Step 1: Synthesis of tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)(methyl)carbamate

[0262]

[0263] Sodium hydride (17 mg, 60% Wt, 2 eq., 435 μmol) was added to a solution of tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (100 mg, 1 eq., 218 μmol) in DMF (4 mL) at 0°C. Iodomethane (92.7 mg, 40.8 μL, 3 eq., 653 μmol) was then added and stirring continued for 1 hour. The NH4Cl solution was saturated and the aqueous phase was extracted with EtOAc. The organic phase was washed with water and dried over sodium sulfate. The solvent was concentrated under vacuum to give m (crude material) = 100 mg, which was used in the next step without further purification.

[0264] 1 H NMR (400MHz, CDCl3) δ7.74-7.43 (m, 3H), 7.44-7.35 (m, 2H), 7.33 (d, J=7.3Hz, 1H), 6.77-6.68 (m, 1H ), 6.21 (s, 1H), 5.09 (s, 1H), 2.96 (d, J=0.5Hz, 3H), 2.89 (d, J=0.7Hz, 3H), 2.31 (s, 3H), 1.59 (s, 9H).

[0265] Step 2: Synthesis of 8-(benzyloxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-3-amine

[0266]

[0267] Tert-butyl (8-(benzyloxy)-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)(methyl)carbamate 100 mg (crude) was dissolved in DCM (3 mL) and treated with TFA (496 mg, 335 μL, 20 equiv., 4.35 mmol) at 0°C for 1 hour and then warmed to room temperature overnight. A saturated solution of NaHCO3 was added and the aqueous phase was extracted twice with EtOAC. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by flash column chromatography on silica (0%-50% EtOAc in Hex) to give 8-(benzyloxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-3-amine (70 mg, 0.19 mmol, 86%). f = 0.5 (EtOAc / cyclohexane 20%). m / z = 373.20, found 374.2.

[0268] Step 3: Synthesis of 2,6,6,9-tetramethyl-3-(methylamino)-6H-benzo[c]chromen-8-ol (8)

[0269]

[0270] 8-(Benzyloxy)-N,2,6,6,9-pentamethyl-6H-benzo[c]chromen-3-amine (70 mg, 1 eq, 0.19 mmol) was hydrogenated in the presence of palladium hydroxide on carbon (13 mg, 20% Wt, 0.1 eq, 19 μmol) in MeOH (6.0 mg, 3.7 mL, 0.05 mole, 1 eq, 0.19 mmol) at atmospheric pressure overnight. The crude material was purified by flash column chromatography on silica (0%-50% EtOAc in Hex) to give 2,6,6,9-tetramethyl-3-(methylamino)-6H-benzo[c]chromen-8-ol (21 mg, 74 μmol, 40%) as a white solid. f = 0.5 (EtOAc / cyclohexane 50%).

[0271] 1 H NMR (400MHz, DMSO) δ9.14 (s, 1H), 7.31 (s, 1H), 7.28 (s, 1H), 6.63 (s, 1H), 5.96 (s, 1H), 5.08 (q, J=4.8Hz, 1H), 2.69 (d, J=4.9Hz, 3H), 2.13 (d, J=0.7Hz, 3H), 2.05 (d, J=0.7Hz, 3H), 1.46 (s, 6H). MS: m / z: 284[M+H] + .

[0272] 6. Synthesis of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (6)

[0273]

[0274] 6 was prepared from 8-(benzyloxy)-3-hydroxy-2,9-dimethyl-6H-benzo[c]chromen-6-one in 4 steps

[0275] Solution 6.

[0276]

[0277] Step 1: Synthesis of 8-(benzyloxy)-3-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one

[0278]

[0279] 8-(Benzyloxy)-3-hydroxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (700 mg, 1 eq., 2.02 mmol) was dissolved in acetone (117 mg, 40.4 mL, 0.05 mole, 1 eq., 2.02 mmol) at room temperature. Potassium carbonate (1.12 g, 4 eq., 8.08 mmol) was added, followed by iodomethane (1.43 g, 632 μL, 5 eq., 10.1 mmol), and the mixture was refluxed overnight. Water was added and the aqueous phase was extracted 3 times with EOAc, dried over sodium sulfate and concentrated under vacuum to give a pale yellow solid, which was triturated in EtOAc to give 8-(benzyloxy)-3-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (680 mg, 1.89 mmol, 93.4%) as a beige solid. 1 H NMR (400MHz, CDCl3) δ7.82-7.79 (m, 1H), 7.78 (s, 1H), 7.71 (d, J = 1.0Hz, 1H), 7.55-7.46 (m, 2H), 7.45-7.38 (m , 2H), 7.37-7.31 (m, 1H), 6.80 (s, 1H), 5.20 (s, 2H), 3.88 (s, 3H), 2.47 (d, J=0.8Hz, 3H), 2.30 (d, J=0.8Hz, 3H).

[0280] Step 2: Synthesis of 8-(benzyloxy)-3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene

[0281]

[0282] 8-(Benzyloxy)-3-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (350 mg, 1 eq, 971 μmol) was dissolved in THF (70.0 mg, 13.9 mL, 0.07 mole, 1 eq, 971 μmol) and methylmagnesium bromide (579 mg, 1.62 mL, 3 moles, 5 eq, 4.86 mmol) was added dropwise at room temperature and stirring was continued overnight. The reaction mixture was poured into HCl 1M and extracted twice with EtOAc, dried over sodium sulfate and concentrated under vacuum to give 170 mg of the open chain intermediate. The open chain intermediate was heated in toluene in the presence of PTSOH (18.5 mg, 0.1 eq, 97.1 μmol) for 1 hour. The reaction mixture was extracted with EtOAc and a saturated solution of sodium bicarbonate. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was loaded onto silica and purified by FC eluent MeOH / DCM 0% to 5% to 10% 20% to give 8-amino-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (10 mg, 37 μmol, 90%) as a white solid. 1 H NMR (400MHz, CDCl3) δ7.47-7.43(m, 3H), 7.43-7.37(m, 3H), 7.35-7.32(m, 1H), 6.71(s, 1H), 6. 45 (s, 1H), 5.10 (s, 2H), 3.82 (s, 3H), 2.32 (d, J = 0.7Hz, 3H), 2.21 (d, J = 1.0Hz, 3H), 1.59 (s, 6H).

[0283] Step 3: Synthesis of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (6)

[0284]

[0285] A suspension of 8-(benzyloxy)-3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene (240 mg, 1 eq., 641 μmol) and palladium hydroxide on carbon (18.0 mg, 0.2 eq., 128 μmol) in methanol (20.5 mg, 6.41 mL, 0.1 mole, 1 eq., 641 μmol) was hydrogenated at atmospheric pressure for 2 hours. The reaction mixture was filtered through a pad of celite. The open-chain intermediate was heated in toluene in the presence of p-toluenesulfonic acid monohydrate (18.3 mg, 14.7 μL, 0.15 eq., 96.1 μmol) for 30 minutes. The aqueous phase of the saturated sodium bicarbonate solution was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was loaded onto silica and purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (170 mg, 598 μmol, 93.3%). f 0.7 (EtOAc / cyclohexane 20%). 1 H NMR (400MHz, DMSO) δ9.32 (s, 1H), 7.73-7.45 (m, 1H), 7.43 (s, 1H), 6.67 (s, 1H), 6.46 (s, 1H), 3.75 (s, 3H), 2.15 (s, 3H), 2.12 (s, 3H), 1.48 (s, 6H).

[0286] 7. Synthesis of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-amine (4)

[0287]

[0288] 4 was prepared from 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-ol (6) in 3 steps

[0289] Solution 7.

[0290]

[0291] Step 1: Synthesis of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate

[0292]

[0293] Trifluoromethanesulfonic anhydride (360 mg, 215 μL, 2.5 eq., 1.27 mmol) was added dropwise to a solution of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene-8-ol (145 mg, 1 eq., 510 μmol) and pyridine (403 mg, 412 μL, 10 eq., 5.10 mmol) in DCM (10 mL) at 0°C, and the mixture was stirred at room temperature for 3 hours. Dichloromethane was evaporated under vacuum, and the crude material was extracted with NH4Cl saturated solution and EA. The organic phase was washed once with water, dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EA / cyclohexane 0% to 15% to give trifluoromethanesulfonic acid 8-methoxy-6-oxo-6H-benzo[c]chromene-3-yl ester (550 mg, 1.47 mmol, 42%) as a pale yellow foam. f 0.6 (EtOAc / cyclohexane 40%) was used as crude material in the next step without further purification.

[0294] Step 2: Synthesis of tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate

[0295]

[0296] t-Bu XPhos (22.8 mg, 0.16 eq., 53.8 μmol) was added to a suspension of tris(dibenzylideneacetone)dipalladium (24.6 mg, 0.08 eq., 26.9 μmol) in toluene (6.5 mL), and the mixture was stirred at room temperature for 5 minutes. 3-Methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl trifluoromethanesulfonate (140 mg, 1 eq., 336 μmol), tert-butyl carbamate (197 mg, 5 eq., 1.68 mmol) and cesium carbonate (427 mg, 1.31 mmol) were added, and the reaction mixture was refluxed for 1 hour. Water was added and the mixture was extracted 3 times with EA. The combined organic phases were dried over sodium sulfate, filtered and concentrated under vacuum, and the crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 5% to 10% 20% to give tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate contaminated with tBuXPhos (70 mg, 0.18 mmol, 54%). MS (APCI+): m / z=384. R f = 0.5 (EtOAc / cyclohexane 20%) as a light brown solid.

[0297] Step 3: Synthesis of 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-amine (4)

[0298]

[0299] TFA (0.31 g, 0.21 mL, 20 eq., 2.7 mmol) was added to a mixture of tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate (70 mg, 75% Wt, 1 eq., 0.14 mmol) in DCM (12 mg, 2.7 mL, 0.05 mole, 1 eq., 0.14 mmol) at 0°C and stirring was continued for 3 hours at room temperature. DCM was evaporated under reduced pressure and the crude material was extracted with EtOAc / NaHCO3. The organic phase was dried over sodium sulfate. The crude material was purified by biotage eluent EtOAc / cyclohexane 0% to 30% to give 3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-amine (28 mg, 99 μmol, 72%) as a white solid. f = 0.2 (EtOAc / cyclohexane 20%). 1 H NMR (400MHz, DMSO) δ7.41 (s, 1H), 7.31 (s, 1H), 6.56 (s, 1H), 6.43 (s, 1H), 5.30 (s, 2H), 3.73 (s, 3H), 2.10 (s, 3H), 2.09 (s, 3H), 1.46 (s, 6H). MS: m / z: 270[M+H] + .

[0300] 8. Synthesis of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (5)

[0301]

[0302] 5 was prepared from methylresorcinol in 4 steps.

[0303] Solution 8.

[0304]

[0305] Step 1: Synthesis of 3-hydroxy-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one

[0306]

[0307] 4-Methylbenzene-1,3-diol (2.026 g, 2.0 eq, 16.32 mmol) was dissolved in water (147.1 mg, 40.80 mL, 0.2 mole, 1 eq, 8.161 mmol) and sodium carbonate (2.595 g, 3.0 eq, 24.48 mmol) was added and the mixture was heated to 60°C until all dissolved. 2-Bromo-5-methoxy-4-methylbenzoic acid (2000 mg, 1 eq, 8.161 mmol) was then added and stirring was continued at 75°C for 4 hours. Copper (I) iodide (777.1 mg, 0.5 eq, 4.080 mmol) was added in one portion and the reaction was stirred at 75°C for 12 hours. The precipitate was filtered off and the filter cake was washed successively with water and HCl 1M and then dried under vacuum overnight to give 3-hydroxy-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (1.6 g, 5.9 mmol, 73%) as a beige solid. 1 H NMR (400MHz, DMSO) δ 10.12 (s, 1H), 8.07 (s, 1H), 7.94 (s, 1H), 7.51 (s, 1H), 6.73 (s, 1H), 3.90 (s, 3H), 2.33 (s, 3H), 2.21 (s, 3H).

[0308] Step 2: Synthesis of 3-(benzyloxy)-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one

[0309]

[0310] 3-Hydroxy-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (1500 mg, 1 eq., 5.550 mmol) was dissolved in acetone (322.3 mg, 55.50 mL, 0.1 mole, 1 eq., 5.550 mmol). Benzyl bromide (854.3 mg, 594.1 μL, 0.9 eq., 4.995 mmol) was added and the mixture was heated at 70° C. overnight. The suspension was filtered off and the filtrate was evaporated under vacuum, and the precipitate was triturated in Et2O and filtered to give 3-(benzyloxy)-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (1.72 g, 4.77 mmol, 86.0%) as a light brown solid. 1H NMR (400MHz, DMSO) δ8.17 (s, 1H), 8.08 (s, 1H), 7.56 (s, 1H), 7.52-7.47 (m, 2H), 7.42 (t, J=7.4 Hz, 2H), 7.40-7.31 (m, 1H), 7.08 (s, 1H), 5.23 (s, 2H), 3.92 (s, 3H), 2.36 (s, 3H), 2.30 (s, 3H).

[0311] Step 3: Synthesis of 3-(benzyloxy)-8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene

[0312]

[0313] 3-(Benzyloxy)-8-methoxy-2,9-dimethyl-6H-benzo[c]chromen-6-one (200 mg, 1 eq., 555 μmol) was dissolved in THF (40.0 mg, 7.93 mL, 0.07 mole, 1 eq., 555 μmol) and methylmagnesium bromide (304 mg, 851 μL, 3 moles, 4.6 eq., 2.55 mmol) was added dropwise at room temperature and stirring was continued overnight. The reaction mixture was poured into HCl 1M and extracted twice with EtOAc, dried over sodium sulfate and concentrated under vacuum to give the open chain intermediate 170 mg. The open chain intermediate was heated in toluene at 70°C for 1 hour in the presence of PTSOH (10.6 mg, 0.1 eq., 55.5 μmol). Toluene was evaporated and the crude material was extracted with a saturated solution of NaHCO3 and dried over sodium sulfate to give 3-(benzyloxy)-8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene (160 mg, 427 μmol, 77.0%) as a light brown oil. MS (APCI+): m / z=375. 1 HNMR (400MHz, CDCl3) δ7.55-7.29 (m, 7H), 6.65 (s, 1H), 6.53 (s, 1H), 5.06 (s, 2H), 3.86 (s, 3H), 2.28 (d, J=0.7Hz, 3H), 2.26 (d, J=0.7Hz, 3H), 1.62 (s, 6H).

[0314] Step 4: Synthesis of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-ol (5)

[0315]

[0316] A suspension of 3-(benzyloxy)-8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene (800 mg, 1 eq., 2.14 mmol) and palladium hydroxide on carbon (300 mg, 20% Wt, 0.2 eq., 427 μmol) in MeOH (5 mL) was hydrogenated at atmospheric pressure for 2 h. The suspension was filtered through a pad of celite and the solvent evaporated under vacuum to give 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene-3-ol (600 mg, 2.11 mmol, 98.8%) as a white foam. f 0.5EA / Hexane 10 / 90. 1 H NMR (400MHz, CDCl3) δ14.11 (s, 1H), 12.22 (d, J=0.9Hz, 1H), 12.18 (s, 1H), 11.55 (s, 1H), 11.0 7 (s, 1H), 8.57 (s, 3H), 8.08 (s, 2H), 6.92 (d, J=0.7Hz, 3H), 6.86 (d, J=0.7Hz, 3H), 6.28 (s, 6H).

[0317] 9. Synthesis of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine (3)

[0318]

[0319] 3 from 6 in 3 steps.

[0320] Step 1: Synthesis of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl trifluoromethanesulfonate

[0321]

[0322] Trifluoromethanesulfonic anhydride (570 mg, 342 μL, 2.5 eq., 2.02 mmol) was added dropwise to a solution of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromene-3-ol (230 mg, 1 eq., 809 μmol) and pyridine (640 mg, 654 μL, 10 eq., 8.09 mmol) in DCM (10 mL) at 0°C, and the mixture was stirred at room temperature for 3 hours. DCM was evaporated under vacuum, and the crude material was extracted with NH4Cl saturated solution and EA. The organic phase was washed once with water, dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EA / cyclohexane 0% to 15% to give trifluoromethanesulfonic acid 8-methoxy-6-oxo-6H-benzo[c]chromene-3-yl ester (550 mg, 1.47 mmol, 42%) as a white solid. f0.6 (EA / cyclohexane 40%) was used as crude material.

[0323] Step 2: Synthesis of tert-butyl (8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate

[0324]

[0325] t-BuXPhos (42.8 mg, 0.14 eq., 101 μmol) was added to a suspension of tris(dibenzylideneacetone)dipalladium (46.2 mg, 0.07 eq., 50.4 μmol) in toluene (6.5 mL), and the mixture was stirred at room temperature for 5 minutes. 8-Methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl trifluoromethanesulfonate (300 mg, 1 eq., 720 μmol), tert-butyl carbamate (338 mg, 4 eq., 2.88 mmol) and cesium carbonate (427 mg, 1.31 mmol) were added, and the reaction mixture was refluxed overnight. A saturated solution of N4Cl was added, and the mixture was extracted 3 times with EA. The combined organic phases were dried over sodium sulfate, filtered and concentrated under vacuum, and the crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 5% to 10% 20% to give tert-butyl (8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (145 mg, 378 μmol, 52.5%) contaminated with tBuXPhos. The product was used in the next step without further purification. f 0.5 (EA / cyclohexane 20%).

[0326] Step 3: Synthesis of 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine 3

[0327]

[0328] Tert-butyl (8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (70 mg, 1 eq., 0.18 mmol) was dissolved in anhydrous DCM (16 mg, 12 μL, 1 eq., 0.18 mmol) and cooled to 0°C, then TFA (0.21 g, 0.14 mL, 10 eq., 1.8 mmol) was added dropwise and stirring was continued for 2 hours at room temperature. A saturated solution of Na2CO3 was added and the mixture was extracted twice with EA. The combined organic phases were dried over sodium sulfate, filtered and concentrated under vacuum. The crude material was loaded onto silica and purified by FC eluent EA / cyclohexane 0% to 5% to 10% 20% to give 8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-amine (20 mg, 71 μmol, 39%). f 0.2 (EA / cyclohexane 20%). 1 H NMR (400MHz, DMSO) δ7.38 (s, 1H), 7.28 (s, 1H), 6.76 (s, 1H), 6.13 (s, 1H), 4.90 (s, 2H), 3.79 (s, 3H), 2.32-2.09 (s, 3H), 2.04 (s, 3H), 1.50 (s, 6H).

[0329] 10. Synthesis of 7-amino-1,6,9,9-tetramethyl-9H-fluorene-2,4-diol (14a)

[0330]

[0331] 14a was prepared in one step from tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate by treatment with BBr3 via a rearrangement involving formation of a carbocation.

[0332] Solution 9.

[0333]

[0334] BBr (235.2 mg, 938.7 μL, 1 mole, 4 equivalents, 938.7 μmol) was added to a suspension of tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)carbamate (90.00 mg, 1 equivalent, 234.7 μmol) in DCM (19.93 mg, 4.694 mL, 0.05 mole, 1 equivalent, 234.7 μmol) at -78 ° C. over 5 minutes, and the mixture was warmed to room temperature overnight. The reaction mixture was quenched with a saturated solution of NaHCO and the aqueous phase was extracted with EtOAc. The combined organic phases were dried over sodium sulfate and the organic residue was subjected to column chromatography biotage FC EtOAc / cyclohexane 0% to 20% to give 7-amino-1,6,9,9-tetramethyl-9H-fluorene-2,4-diol (20 mg, 74 μmol, 32%) as a white solid. Rf 0.5 (MeOH / DCM 10%). 1 H NMR (400MHz, DMSO) δ9.13 (s, 1H), 8.89 (s, 1H), 7.40 (s, 1H), 6.62 (s, 1H), 6.32 (s, 1H), 4.78 (s, 2H), 2.16 (s, 3H), 2.06 (s, 3H), 1.39 (d, J=2.1Hz, 6H).

[0335] 11. Synthesis of 2,6,6,9-Tetramethyl-8-(methylamino)-6H-benzo[c]chromen-3-ol (14)

[0336] Solution 10.

[0337]

[0338] BBr (100.8 mg, 402.5 μL, 1 mole, 4 equivalents, 402.5 μmol) was added to a suspension of tert-butyl (3-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-8-yl)(methyl)carbamate (40.00 mg, 1 equivalent, 100.6 μmol) in DCM (8.546 mg, 1.006 mL, 0.1 mole, 1 equivalent, 100.6 μmol) at -78 ° C. over 5 minutes, and the mixture was warmed to room temperature overnight. The reaction mixture was quenched with a saturated solution of NaHCO and the aqueous phase was extracted with EtOAc. The combined organic phases were dried over sodium sulfate and the organic residue was subjected to column chromatography biotage FC EtOAc / cyclohexane 0% to 20% to give 2,6,6,9-tetramethyl-8-(methylamino)-6H-benzo[c]chromen-3-ol (19 mg, 67 μmol, 67%) as a light brown solid. f 0.5 (MeOH / DCM 10%). 1H NMR (400MHz, DMSO) δ9.15 (s, 1H), 8.91 (s, 1H), 7.45 (s, 1H), 6.50 (s, 1H), 6.33 (s, 1 H), 4.86 (s, 1H), 2.78 (s, 3H), 2.17 (s, 3H), 2.09 (s, 3H), 1.44 (s, 3H), 1.43 (s, 3H). MS(APCI+): m / z=284.

[0339] 12. Synthesis of 3,8,9,9-tetramethyl-7-(methylamino)-9H-fluorene-2,5-diol (15)

[0340] Solution 11.

[0341]

[0342] BBr3 (0.11 g, 0.45 mL, 1 mole, 3 eq., 0.45 mmol) was added to a suspension of tert-butyl (8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)(methyl)carbamate (60 mg, 1 eq., 0.15 mmol) in DCM (13 mg, 3.0 mL, 0.05 mole, 1 eq., 0.15 mmol) at -78°C over 2 minutes, and the mixture was warmed to room temperature overnight. The reaction mixture was quenched with a saturated solution of NaHCO3 and the aqueous phase was extracted with EtOAc. The combined organic phases were dried over sodium sulfate and the organic residue was subjected to column chromatography biotage FC MeOH / DCM 0% to 20% to give 3,8,9,9-tetramethyl-7-(methylamino)-9H-fluorene-2,5-diol (20 mg, 71 μmol, 47%) as a white solid. f 0.5 (MeOH / DCM 10%). 1 H NMR (400MHz, DMSO) δ9.14 (s, 1H), 8.88 (s, 1H), 7.49 (s, 1H), 6.75 (s, 1H), 6.03 (s, 1H) , 4.88(s, 1H), 2.77-2.70(m, 3H), 2.16(s, 3H), 2.14(s, 3H), 1.44(s, 3H), 1.44(s, 3H). MS(APCI+): m / z=284.

[0343] 13. Synthesis of 7-amino-3,8,9,9-tetramethyl-9H-fluorene-2,5-diol (13)

[0344] Solution 12.

[0345]

[0346] BBr3 (0.18 g, 0.73 mL, 1 mole, 4 eq., 0.73 mmol) was added to a suspension of tert-butyl (8-methoxy-2,6,6,9-tetramethyl-6H-benzo[c]chromen-3-yl)carbamate (70 mg, 1 eq., 0.18 mmol) in DCM (13 mg, 3.0 mL, 0.05 mole, 1 eq., 0.15 mmol) at -78°C over 2 minutes, and the mixture was warmed to room temperature overnight. The reaction mixture was quenched with a saturated solution of NaHCO3 and the aqueous phase was extracted with EtOAc. The combined organic phases were dried over sodium sulfate and the organic residue was subjected to column chromatography biotage FC MeOH / DCM 0% to 20% to give 7-amino-3,8,9,9-tetramethyl-9H-fluorene-2,5-diol (20 mg, 74 μmol, 41%) as a white solid. f 0.5 (MeOH / DCM 10%). 1 H NMR (400MHz, DMSO) δ9.00 (s, 1H), 8.82 (s, 1H), 7.44 (s, 1H), 6.70 (s, 1H), 6.13 (s, 1H), 4.66 (s, 2H), 2.11 (d, J = 0.7Hz, 3H), 2.09 (s, 3H), 1.39 (s, 6H). MS(APCI+): m / z=270.

[0347] 14. Synthesis of 2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane]-3,8-diol (7)

[0348]

[0349] 7 was prepared in 4 steps from methyl 5-(benzyloxy)-2-bromo-4-methylbenzoate and 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane according to the synthetic intermediates.

[0350] Solution 13.

[0351]

[0352] Step 1: Synthesis of methyl 4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylate

[0353]

[0354] Methyl 5-(benzyloxy)-2-bromo-4-methylbenzoate (1000 mg, 1 eq., 2.983 mmol), 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.225 g, 1.2 eq., 3.580 mmol) and 1,2-bis(diphenylphosphino)ethanepalladium(II) dichloride (171.8 mg, 0.1 eq., 298.3 μmol) were suspended in THF (215.1 mg, 29.83 mL, 0.1 mole, 1 eq., 2.983 mmol) and degassed with nitrogen for 5 minutes. A solution of sodium bicarbonate (551.4 mg, 2.2 eq., 6.563 mmol) in water (10 g, 10 mL, 0.3 mole, 1.0 eq., 3.0 mmol) was added at room temperature, and the mixture was refluxed overnight. After cooling to room temperature, a saturated solution of NH4Cl was added and the aqueous phase was extracted twice with EA. The combined organic phases were dried over sodium sulfate, concentrated under vacuum, and the organic residue was subjected to column chromatography biotage FCEA / cyclohexane 0% to 10% to give 4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylic acid methyl ester (870 mg, 1.85 mmol, 62.0%) as a white solid. f 0.3 (EA / cyclohexane 5%). 1 H NMR (400MHz, CDCl3) δ7.60-7.32 (m, 11H), 7.15 (t, J=0.9Hz, 1H), 7.08 (dq, J=8.6, 0.9Hz, 1H), 6.68 (dd, J=11. 7, 1.2Hz, 1H), 5.18 (s, 2H), 5.11 (s, 2H), 3.73 (d, J=1.1Hz, 3H), 2.36 (d, J=0.8Hz, 3H), 2.30 (d, J=1.2Hz, 3H).

[0355] Step 2: Synthesis of 1-(4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-yl)cyclopropan-1-ol

[0356]

[0357] Under nitrogen protection, ethylmagnesium bromide solution / 1M THF (1.70 g, 12.8 mL, 1 mole, 15 equivalents, 12.8 mmol) was added dropwise to 4,4'-bis(benzyloxy)-2'-fluoro-5,5'-dimethyl-[1,1'-biphenyl]-2-carboxylic acid methyl ester (400 mg, 1 equivalent, 850 μmol) and titanium tetraisopropoxide (747 mg, 0.78 mL, 97% Wt, 3 equivalents, 2.55 mmol) in THF (61.3 mg, 10.6 mL, 0.08 mole, 1 equivalent, 850 μmol) at 0°C for 5 minutes. The reactant was then stirred at 0°C for 30 minutes: TLC showed no more SM. The mixture was quenched with HCl 1M. After filtration, the solution was extracted with 3×30 mL of EtOAc, washed with distilled water, and dried over MgSO4, then filtered and concentrated. The organic residue was subjected to column chromatography biotage FC EtOAc / cyclohexane 0% to 20% to give 1-(4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-yl)cyclopropan-1-ol (170 mg, 363 μmol, 42.7%)

[0358] R f 0.2 (EA / cyclohexane 10%) as a colorless oil. 1 H NMR (400MHz, CDCl3) δ7.52-7.33 (m, 10H), 7.16 (s, 1H), 7.06 (dd, J=8.9, 0.9Hz, 1H), 7.02 (d, J=0.9Hz, 1H), 6.72 (d, J=12 .0Hz, 1H), 5.15 (s, 2H), 5.11 (s, 2H), 2.29 (d, J=0.7Hz, 3H), 2.26 (d, J=0.9Hz, 3H), 0.99-0.79 (m, 2H), 0.65-0.55 (m, 2H).

[0359] Step 3: Synthesis of 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane]

[0360]

[0361] A solution of 1-(4,4'-bis(benzyloxy)-2'-fluoro-5,5'-dimethyl-[1,1'-biphenyl]-2-yl)cyclopropan-1-ol (170.00 mg, 1 eq., 362.81 μmol) in DMF (4 mL) was heated at 110°C. Sodium hydride (61 mg, 1.53 mmol, 5 eq., 60% in oil) was added in one portion and heating was continued for 5 minutes. TLC showed no more SM. The reaction mixture was diluted with EtOAc and poured into a solution of ice and a saturated solution of NaHCO3. The aqueous phase was extracted twice with EtOAc and the combined organic phases were dried over sodium sulfate and evaporated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane] (50 mg, 0.11 mmol, 31%) as a colorless oil. f 0.4 (EA / cyclohexane 5%). 1 H NMR (400MHz, DMSO) δ7.64-7.57 (m, 1H), 7.57-7.53 (m, 1H), 7.51-7.43 (m, 4H), 7.40 (td, J=7.1, 1.0Hz, 4H), 7.35-7.30 (m, 2H), 6.64 (s , 1H), 6.54 (s, 1H), 5.13 (s, 2H), 5.09 (s, 2H), 2.23 (d, J=0.7Hz, 3H), 2.19 (d, J=0.7Hz, 3H), 1.24-1.16 (m, 2H), 1.11 (t, J=3.4Hz, 2H).

[0362] Step 4: Synthesis of 2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane]-3,8-diol (7)

[0363]

[0364] 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane](50.00mg, 1.00 equivalent, 111.5μmol) is dissolved in MeOH(4mL).Add nickel chloride hexahydrate (264.9mg, 10 equivalents, 1.115mmol).Sodium tetrahydroborate (84.34mg, 78.89μL, 20 equivalents, 2.229mmol) (gas evolution) is added carefully in batches.TLC shows that there is no more starting material.The mixture is filtered out and the crude material is loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 4%, to obtain 2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopropane]-3,8-diol (20mg, 75μmol 67%) as a white solid.Rf 0.4(MeOH / DCM 4%). 1 H NMR (400MHz, DMSO) δ9.36 (s, 1H), 9.25 (s, 1H), 7.41 (s, 1H), 7.41 (s, 1H), 6.32 (s, 1H), 6.25(s, 1H), 2.14(s, 3H), 2.10(s, 3H), 1.22-1.10(m, 2H), 0.98-0.87(m, 2H). MS: m / z: 269[M+H] + .

[0365] 15. Synthesis of 2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane](9)

[0366]

[0367] 9 was prepared in three steps from the intermediate methyl 4,4'-bis(benzyloxy)-2'-fluoro-5,5'-dimethyl-[1,1'-biphenyl]-2-carboxylate.

[0368] Solution 14.

[0369]

[0370] Step 1: Synthesis of 1-(4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-yl)cyclopentan-1-ol

[0371]

[0372] To anhydrous magnesium (39.7 mg, 4.8 eq., 1.6322 mmol) in anhydrous ether (25.20 mg, 6.8007 mL, 0.05 mole, 1 eq., 340.03 μmol) was added 1,4-dibromobutane (440.52 mg, 242.0 μL, 6 eq., 2.0402 mmol) at room temperature and the reaction mixture was stirred for 2 hours. To this cloudy solution was added a solution of methyl 4,4′-bis(benzyloxy)-2′-fluoro-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylate (160.00 mg, 1 eq., 340.03 μmol) in anhydrous THF (1 mL) and the reaction was stirred for 5 hours. TLC showed some sm still (polar product formed, TLC MS showed M-18). The reaction was quenched with NH4Cl saturated solution and extracted with EtOAc, dried over sodium sulfate and evaporated under vacuum to give methyl 4,4'-bis(benzyloxy)-2'-fluoro-5,5'-dimethyl-[1,1'-biphenyl]-2-carboxylate (160.00 mg, 1 eq., 340.03 μmol) crude material which was used in the next step without further purification. f =0.2 (EA / cyclohexane 10%).

[0373] Step 2: Synthesis of 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane]

[0374]

[0375] In a round-bottom flask, 1-(4,4'-bis(benzyloxy)-2'-fluoro-5,5'-dimethyl-[1,1'-biphenyl]-2-yl)cyclopentan-1-ol (100 mg, 1 eq., 201 μmol) was dissolved in anhydrous DMF (3 mL) and heated at 120°C, then NaH (40 mg, 60% Wt, 5 eq., 1.01 mmol) was added portionwise and stirring was continued at 120°C for 10 minutes. The mixture was cooled to room temperature, a saturated solution of NaHCO3 was added and the aqueous phase was extracted twice with EA. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was loaded onto silica gel and purified by FC eluent EtOAc / Cyh 0% to 10% to afford 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane] (60 mg, 0.13 mmol, 63%) as a white solid. f 0.6 (EA / cyclohexane 10%). MS (APCI+): m / z=476. 1H NMR (400MHz, CDCl3) δ7.51-7.42 (m, 6H), 7.39 (td, J=7.4, 1.7Hz, 4H), 7.33 (td, J=7.0, 1.8Hz, 2H), 6.72 (s, 1H), 6.52 (s, 1H), 5. 10 (s, 2H), 5.05 (s, 2H), 2.32 (d, J=0.7Hz, 3H), 2.27 (d, J=0.9Hz, 3H), 2.25-2.15 (m, 2H), 2.03-1.82 (m, 4H), 1.81-1.70 (m, 2H).

[0376] Step 3: Synthesis of 2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane]-3,8-diol (9)

[0377]

[0378] 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane](60mg, 1 eq., 0.13mmol) was dissolved in methanol (4.0mg, 2.5mL, 0.05 mole, 1 eq., 0.13mmol) at room temperature. Carbon-supported palladium hydroxide (18mg, 20% Wt, 0.2 eq., 25μmol) was added and the suspension was hydrogenated at atmospheric pressure for 4 hours. The suspension was filtered through a celite pad and the solvent was concentrated under vacuum. The crude material was loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 10% to give 3,8-bis(benzyloxy)-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane](60mg, 0.13mmol, 63%) as a white solid. f 0.4 (MeOH / DCM 10%). MS: m / z: 297[M+H] + . 1 H NMR (400MHz, DMSO) δ9.27 (s, 1H), 9.25 (s, 1H), 7.37 (d, J = 2.0Hz, 2H), 6.66 (s, 1H), 6. 28 (s, 1H), 2.14 (d, J=0.7Hz, 3H), 2.09 (s, 3H), 2.05-2.00 (m, 2H), 1.91-1.67 (m, 6H).

[0379] 16. Synthesis of 9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (10)

[0380] 11 was prepared from 1-(benzyloxy)-5-bromo-2-ethyl-4-iodobenzene and (4-(benzyloxy)-2-fluoro-5-methylphenyl)boronic acid (see patent lamazentis) in 4 steps.

[0381] Solution 15.

[0382]

[0383] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5-ethyl-2′-fluoro-5′-methyl-1,1′-biphenyl

[0384]

[0385] 1-(Benzyloxy)-5-bromo-4-iodo-2-methylbenzene (370 mg, 0.918 mmol) and (4-(benzyloxy)-2-fluoro-5-methylphenyl)boronic acid (334 mg, 1.29 mmol, 1.4 eq) were dissolved in dioxane (10 mL). Tetrakis(triphenylphosphine)palladium(o) (85 mg, 0.073 mmol, 0.08 eq) was added and the solution was degassed for 5 minutes. Saturated sodium bicarbonate solution (1.8 mL, 1.84 mmol, 2 eq) was then added dropwise and the mixture was heated at 90 °C overnight. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC biotage EA / CyH 0% to 5% to give 4,4′-bis(benzyloxy)-2-bromo-2′-fluoro-5,5′-dimethyl-1,1′-biphenyl (340 mg, 0.692 mmol, 75%) as a colorless oil. f 0.3 (EA / cyclohexane 10%). 1 H NMR (400MHz, CDCl3) δ7.50-7.31 (m, 10H), 7.19 (s, 1H), 7.12-7.06 (m, 1H), 7.06-7.02 ( m, 1H), 6.70 (d, J=11.4Hz, 1H), 5.09 (s, 4H), 2.95-2.54 (m, 2H), 1.21 (t, J=7.5Hz, 3H).

[0386] Step 2: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5,5′-diethyl-2′-fluoro-1,1′-biphenyl

[0387]

[0388] nBuLi (53.28 mg, 519.78 μL, 1.6 moles, 1.8 equiv., 831.65 μmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5,5′-diethyl-2′-fluoro-1,1′-biphenyl (240.00 mg, 1 equiv., 462.03 μmol) in THF (7 mL) at −78° C. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (161.9 mg, 173 μL, 5 equiv., 2.3101 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4'-bis(benzyloxy)-5,5'-diethyl-2'-fluoro-[1,1'-biphenyl]-2-yl)cyclobutan-1-ol (80 mg, 0.16 mmol, 34%). The next step, where the desired product could finally be isolated. f 0.3 (EA / cyclohexane 20%)

[0389] 1 H NMR (400MHz, CDCl3) δ7.58-7.28 (m, 10H), 7.08 (d, J=8.9Hz, 1H), 6.97 (s, 1H), 6.89 (s, 1H), 6.68 (d, J=11.7Hz, 1H), 5.13 (s, 2H) , 5.08 (d, J=2.1Hz, 2H), 2.70 (dq, J=9.9, 7.5Hz, 4H), 2.26 (m, 2H), 2.06 (m, 3H), 1.85-1.71 (m, 1H), 1.22 (td, J=7.5, 5.6Hz, 5H).

[0390] Step 3: Synthesis of 3,8-bis(benzyloxy)-9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]

[0391]

[0392] Sodium hydride (46 mg, 60% Wt, 5 eq., 1.16 mmol) was added to a solution of 1-(4,4′-bis(benzyloxy)-5-ethyl-2′-fluoro-5′-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (115 mg, 1 eq., 232 μmol) in DMF (3 mL) at 120°C and stirring was continued at 120°C for 15 min. The mixture was cooled to room temperature, saturated NH4Cl solution was added and the aqueous phase was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and evaporated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 10% to give 3,8-bis(benzyloxy)-9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane] (90 mg, 0.19 mmol, 82%) as a colorless oil. f 0.5 (EA / cyclohexane 10%). 1 HNMR (400MHz, CDCl3) δ7.53-7.27 (m, 12H), 6.94 (s, 1H), 6.60 (s, 1H), 5.17 (s, 2H), 5.08 (s, 2H), 2.76 (q, J=7.5Hz, 2H), 2.53 (ddd, J=13.0, 10.0, 8.5Hz, 2H), 2.36 (ddd, J=13.1, 8.8, 4.2Hz, 1H), 2.28 (s, 3H), 2.01 (dt, J=15.6, 5.2Hz, 1H), 1.74 (dt, J=11.3, 8.7Hz, 1H), 1.28 (t, J=7.5Hz, 3H).

[0393] Step 4: Synthesis of 9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (10)

[0394]

[0395] 3,8-bis(benzyloxy)-9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane](80.00mg, 1.00 equiv., 167.8 μmol) was dissolved in MeOH (4mL). Nickel chloride hexahydrate (199.5mg, 5 equiv., 839.2 μmol) was added. Sodium tetrahydroborate (63.50mg, 59.40 μL, 10 equiv., 1.678mmol) was added in batches (gas evolution) until all the starting material was consumed. TLC showed no more starting material. The mixture was filtered out and the crude material was loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 4% to give 9-ethyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (40mg, 0.13mmol, 80%) as a white solid. f 0.4 (MeOH / DCM 4%). 1 H NMR (400MHz, DMSO) δ9.35 (s, 1H), 9.32 (s, 1H), 7.40 (s, 1H), 7.37 (s, 1H), 6 .87 (s, 1H), 6.38 (s, 1H), 2.58 (t, J=7.5Hz, 2H), 2.39 (ddd, J=12.7, 10.0, 8 .6Hz, 2H), 2.23 (ddd, J=12.7, 8.7, 4.0Hz, 2H), 2.09 (s, 3H), 1.95 (ddd, J=2 0.6, 9.7, 4.4Hz, 1H), 1.74 (dt, J=11.0, 8.6Hz, 1H), 1.16 (t, J=7.5Hz, 3H). MS: m / z: 297 [M+H] + .

[0396] 17. Synthesis of 2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (11)

[0397]

[0398] 11 was prepared from 1-(benzyloxy)-5-bromo-4-iodo-2-methylbenzene) and 2-(4-(benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 4 steps.

[0399] Synthesis of 2-(4-Benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

[0400]

[0401] Solution 16.

[0402]

[0403] Step 1: Synthesis of 2-ethyl-5-fluorophenol

[0404]

[0405] Step a - NaBH4 (245 mg, 1 eq., 6.49 mmol) was added in batches to a stirred solution of 1-(4-fluoro-2-hydroxyphenyl)ethan-1-one (1.00 g, 1 eq., 6.49 mmol) in methanol (24 g, 30 mL, 1.1 e+2 eq., 0.74 mol) at 0 ° C. over 30 minutes. The reaction mixture was stirred at room temperature for 15 hours. The reaction mixture was then quenched with NH4Cl. The residue was diluted with ethyl acetate. The organic extract was washed with water, brine, dried over anhydrous sodium sulfate and evaporated to give crude 5-fluoro-2-(1-hydroxyethyl)phenol, which was used in the next step without any purification.

[0406] Step b-TFA (7.40g, 5.00mL, 10 equivalents, 64.9mmol) is added dropwise to a solution of 5-fluoro-2-(1-hydroxyethyl)phenol (intermediate) (4g), triethylsilane (1.51g, 2.07mL, 2 equivalents, 13.0mmol) in 15mL dichloromethane at 0°C. The reaction mixture is stirred at room temperature for 15 hours. The reaction mixture is then evaporated under vacuum, and the crude material is extracted twice with Na2CO3 saturated solution and EtOAc. The organic solvent is dried over sodium sulfate and evaporated under vacuum. The crude material is purified by FC eluent EtOAc / cyclohexane 0% to 7%, to obtain 5-bromo-2-ethylphenol (2.2g, 11mmol, 55%) as a light yellow oil, which crystallizes at room temperature. 1 H NMR (400MHz, CDCl3) δ7.11-6.99 (m, 1H), 6.59 (td, J=8.4, 2.5Hz, 1H), 6.52 (dd , J=9.9, 2.5Hz, 1H), 4.09 (s, 1H), 2.59 (q, J=7.5Hz, 2H), 1.22 (t, J=7.5Hz, 3H).

[0407] Step 2: Synthesis of 2-(Benzyloxy)-1-ethyl-4-fluorobenzene

[0408]

[0409] In a 50mL round-bottom flask, 2-ethyl-5-fluorophenol (2000mg, 1.00 equivalent, 14.27mmol) was dissolved in anhydrous acetonitrile (585.8mg, 71.35mL, 0.200 mole, 1 equivalent, 14.27mmol) at room temperature. Potassium carbonate (3.944g, 2.00 equivalent, 28.54mmol) was added, and then benzyl bromide (2.197g, 1.528mL, 0.9 equivalent, 12.84mmol) was added dropwise at room temperature. The suspension was stirred at room temperature overnight. Water was added and the aqueous phase was extracted twice with EA, washed with water and dried over sodium sulfate. The solvent was concentrated under vacuum to give 2-(benzyloxy)-1-ethyl-4-fluorobenzene (3.5g, 15mmol, 110%) as a light yellow oil. 1 H NMR (400MHz, CDCl3) δ7.47-7.30 (m, 7H), 7.10 (dd, J=8.2, 6.9Hz, 1H), 6.71-6.56 (m, 2H), 5.06 (s, 2H), 2.71-2.60 (m, 2H), 1.20 (t, J=7.5Hz, 3H).

[0410] Step 3: Synthesis of 1-(benzyloxy)-4-bromo-2-ethyl-5-fluorobenzene

[0411]

[0412] NBS (1.333 g, 1.15 eq., 7.491 mmol) was added to a solution of 2-(benzyloxy)-1-ethyl-4-fluorobenzene (1.500 g, 1.00 eq., 6.514 mmol) in MeCN (267.4 mg, 21.71 mL, 0.300 mole, 1 eq., 6.514 mmol) at room temperature, and the reaction mixture was stirred overnight. NaOH 1 M (30 mL) was added at room temperature and the aqueous phase was extracted twice with EA. The combined organic phases were washed with water and brine in sequence and dried over sodium sulfate, then concentrated under vacuum to give 1-(benzyloxy)-4-bromo-2-ethyl-5-fluorobenzene (1.70 g, 5.50 mmol, 84.4%) as a pale yellow oil. 1 HNMR (400MHz, CDCl3) δ7.45-7.39 (m, 5H), 7.32-7.27 (m, 1H), 6.70 (d, J=10.4Hz, 1H), 5.04 (s, 2H), 2.75-2.59 (m, 2H), 1.20 (t, J=7.5Hz, 3H).

[0413] Step 4: Synthesis of 2-(4-benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

[0414]

[0415] 1-(Benzyloxy)-4-bromo-2-ethyl-5-fluorobenzene (1.70 g, 1 eq., 5.50 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bis(1,3,2-dioxaborolane) (2.51 g, 1.8 eq., 9.90 mmol), potassium acetate (2.16 g, 4 eq., 22.0 mmol) were added, followed by dioxane (60 mL). The mixture was stirred at 100° C. under N2 for 12 hours. After cooling to 30° C., the reaction mixture was filtered through Celite. The filtrate was concentrated under reduced pressure. Water (300 mL) was added and the aqueous layer was extracted with EtOAc (300 mL×3). The combined organic layers were washed with brine (300 mL), dried over anhydrous Na2SO4, filtered and concentrated to give a crude product. The crude product was purified by flash chromatography on silica gel (EtOAc in petroleum ether = 0% - 10%) to give 2-(4-(benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.1 g, 3.1 mmol, 56%) as a light yellow oil. 1 H NMR (400MHz, CDCl3) δ7.49 (d, J=7.1Hz, 1H), 7.43-7.32 (m, 5H), 6.59 (d, J=11.2H z, 1H), 5.08 (s, 2H), 2.65 (q, J=7.5Hz, 2H), 1.35 (s, 12H), 1.20 (t, J=7.5Hz, 3H).

[0416] 18. Synthesis of 2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (11)

[0417] Solution 17.

[0418]

[0419] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5′-ethyl-2′-fluoro-5-methyl-1,1′-biphenyl

[0420]

[0421] 1-(Benzyloxy)-5-bromo-4-iodo-2-methylbenzene (340 mg, 1 eq., 844 μmol) and 2-(4-(benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (421 mg, 1.4 eq., 1.18 mmol) were dissolved in dioxane (10 mL). Bis-(triphenylphosphino)-palladium chloride (59.2 mg, 0.1 eq., 84.4 μmol) was added and the solution was degassed for 5 minutes. Sodium bicarbonate (213 mg, 2.53 mL, 1 mole, 3 eq., 2.53 mmol) was then added dropwise and the mixture was heated at 90 °C overnight. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC biotage EtOAc / cyclohexane 0% to 1% to 2% to 3% to 4% 5% to give 4,4′-bis(benzyloxy)-2-bromo-5′-ethyl-2′-fluoro-5-methyl-1,1′-biphenyl (276 mg, 546 μmol, 64.7%) as a colorless oil. f 0.3 (EA / cyclohexane 2%). 1 H NMR (400MHz, CDCl3) δ7.54-7.39 (m, 10H), 7.18 (s, 1H), 7.11 (t, J=0.8Hz, 1H), 7.05 (d, J=8.6Hz, 1H), 6.7 1 (d, J=11.5Hz, 1H), 5.09 (s, 4H), 2.70 (qd, J=7.5, 2.1Hz, 2H), 2.25 (d, J=0.8Hz, 3H), 1.27-1.18 (m, 3H).

[0422] Step 2: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5′-ethyl-2′-fluoro-5-methyl-1,1′-biphenyl

[0423]

[0424] nBuLi (94.3 mg, 920 μL, 1.6 moles, 3 eq., 1.47 mmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5′-ethyl-2′-fluoro-5-methyl-1,1′-biphenyl (248 mg, 1 eq., 491 μmol) in THF (7 mL) at −78° C. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (344 mg, 367 μL, 10 eq., 4.91 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4′-bis(benzyloxy)-5′-ethyl-2′-fluoro-5-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (175 mg, 352 μmol, 71.8%).

[0425] R f 0.3 EtOAc / cyclohexane 20%. 1 H NMR (400MHz, CDCl3) δ7.58-7.31 (m, 10H), 7.06 (d, J=8.9Hz, 1H), 6.96 (d, J=0.9Hz, 1H), 6.88 (s, 1H), 6.67 (d, J=11.7Hz, 1H), 5.13 (s, 2H), 5.10 -4.97 (m, 2H), 2.68 (q, J=7.5Hz, 2H), 2.28 (d, J=0.7Hz, 3H), 2.04-1.92 (m, 2H), 1.60 (d, J=3.6Hz, 1H), 1.39-1.32 (m, 1H), 1.21 (t, J=7.5Hz, 3H). 19 FNMR (400MHz, CDCl3) δ-115.97.

[0426] Step 3: Synthesis of 3,8-bis(benzyloxy)-2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]

[0427]

[0428] Sodium hydride (0.18 g, 60% Wt, 20 eq., 4.43 mmol) was added to a solution of 1-(4,4′-bis(benzyloxy)-5′-ethyl-2′-fluoro-5-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (110 mg, 1 eq., 221 μmol) in DMF (3 mL) at 120°C and stirring was continued for 15 min at 120°C. The mixture was cooled to room temperature, saturated NH4Cl solution was added and the aqueous phase was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and evaporated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 10% to give 3,8-bis(benzyloxy)-2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane] (70 mg, 0.15 mmol, 66%) as a white solid. f 0.5.(EA / cyclohexane 10%). 1 HNMR (400MHz, CDCl3) δ7.56-7.27 (m, 12H), 6.93 (s, 1H), 6.60 (s, 1H), 5.17 (s, 2H), 5.07 (s, 2H), 2.70 (q, J=7.5Hz, 2H), 2.60-2 .45 (m, 2H), 2.39-2.35 (m, 2H), 2.35 (d, J=0.7Hz, 3H), 2.09-1.90 (m, 1H), 1.74 (dp, J=11.4, 8.7Hz, 1H), 1.26 (t, J=7.5Hz, 3H).

[0429] Step 4: Synthesis of 2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (11)

[0430]

[0431] 3,8-bis(benzyloxy)-2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane](70.00mg, 1.00 equiv., 146.9 μmol) was dissolved in MeOH (4mL). Nickel chloride hexahydrate (174.5mg, 5 equiv., 734.3 μmol) was added. Sodium tetrahydroborate (55.56mg, 51.97 μL, 10 equiv., 1.469mmol) was added in batches (gas evolution). TLC showed no more starting material. The mixture was filtered out and the crude material was loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 4% to give 2-ethyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (20mg, 67 μmol, 46%) as a white solid. f 0.4 MeOH / DCM 4%. 1H NMR (400MHz, DMSO) δ9.33 (s, 2H), 7.41 (s, 1H), 7.37 (s, 1H), 6.87 (s, 1H), 6.38 (s, 1H), 2.39 (q, J=10.0Hz , 2H), 2.27-2.19(m, 2H), 2.19-2.12(m, 3H), 2.02-1.90(m, 1H), 1.83-1.67(m, 1H), 1.14(t, J=7.5Hz, 3H). MS: m / z: 297[M+H].

[0432] 19. Synthesis of 2,9-triethylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-triol (12)

[0433] 13 was prepared from 1-(benzyloxy)-5-bromo-2-ethyl-4-iodobenzene and 2-(4-(benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 4 steps.

[0434] Solution 18.

[0435]

[0436] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5,5′-diethyl-2′-fluoro-1,1′-biphenyl

[0437]

[0438] 1-(Benzyloxy)-5-bromo-2-ethyl-4-iodobenzene (380 mg, 1 eq., 911 μmol) and 2-(4-(benzyloxy)-5-ethyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (454 mg, 1.4 eq., 1.28 mmol) were dissolved in dioxane (10 mL). Bis-(triphenylphosphino)-palladium chloride (63.9 mg, 0.1 eq., 91.1 μmol) was added and the solution was degassed for 5 minutes. Sodium bicarbonate (230 mg, 2.73 mL, 1 mole, 3 eq., 2.73 mmol) was then added dropwise and the mixture was heated at 90 °C overnight. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC biotage EtOAc / cyclohexane 0% to 1% to 2% to 5% to afford 4,4'-bis(benzyloxy)-2-bromo-5,5'-diethyl-2'-fluoro-1,1'-biphenyl (375 mg, 722 μmol, 79.2%) as a colorless oil. f 0.3 (EA / cyclohexane 2%). 1H NMR (400MHz, CDCl3) δ7.57-7.31 (m, 10H), 7.19 (s, 1H), 7.11 (d, J=0.7Hz, 1H), 7.06 (d, J =8.7Hz, 1H), 6.71 (d, J = 11.5Hz, 1H), 5.09 (s, 4H), 2.74-2.63 (m, 4H), 1.31-1.18 (m, 6H).

[0439] Step 2: Synthesis of 1-(4,4′-bis(benzyloxy)-5,5-diethyl-2′-fluoro-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol

[0440]

[0441] nBuLi (53.28 mg, 519.78 μL, 1.6 moles, 1.8 equiv., 831.65 μmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5,5′-diethyl-2′-fluoro-1,1′-biphenyl (240.00 mg, 1 equiv., 462.03 μmol) in THF (7 mL) at −78° C. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (161.9 mg, 173 μL, 5 equiv., 2.3101 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4′-bis(benzyloxy)-5,5′-diethyl-2′-fluoro-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (80 mg, 0.16 mmol, 34%) as a pale yellow oil. f 0.3 (EA / cyclohexane 20%). 1 H NMR (400MHz, CDCl3) δ7.58-7.28 (m, 10H), 7.08 (d, J=8.9Hz, 1H), 6.97 (s, 1H), 6.89 (s, 1H), 6.68 (d, J=11.7Hz, 1H), 5.13 (s, 2H) , 5.08 (d, J=2.1Hz, 2H), 2.70 (dq, J=9.9, 7.5Hz, 4H), 2.26 (m, 2H), 2.06 (m, 3H), 1.85-1.71 (m, 1H), 1.22 (td, J=7.5, 5.6Hz, 5H).

[0442] Step 3: Synthesis of 3,8-bis(benzyloxy)-2,9-diethylspiro[benzo[c]chromene-6,1′-cyclobutane]

[0443]

[0444] Sodium hydride (0.13 g, 60% Wt, 20 eq., 3.1 mmol) was added to a solution of 1-(4,4′-bis(benzyloxy)-5,5′-diethyl-2′-fluoro-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (80 mg, 1 eq., 0.16 mmol) in DMF (3 mL) at 120°C and stirring was continued for 15 min at 120°C. The mixture was cooled to room temperature, saturated NH4Cl solution was added and the aqueous phase was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and evaporated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 10% to give 3,8-bis(benzyloxy)-2,9-diethylspiro[benzo[c]chromene-6,1′-cyclobutane] (70 mg, 0.14 mmol, 91%) as a white solid. f 0.5 (EA / cyclohexane 10%). 1 H NMR (400MHz, CDCl3) δ7.53-7-30 (m, 12H), 6.94 (s, 1H), 6.60 (s, 1H), 5.18 (s, 2H), 5.08 (s, 2H), 2.76 (q, J=7.6Hz, 2H), 2.70 (q, J=7.6Hz , 2H), 2.60-2.48 (m, 2H), 2.37 (dddd, J=13.1, 8.8, 4.2, 2.4Hz, 2H), 2.05-1.94 (m, 1H), 1.75 (dt, J=11.4, 8.7Hz, 1H), 1.36-1.16 (m, 6H).

[0445] Step 4: Synthesis of 2,9-diethylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (12)

[0446]

[0447] 3,8-bis(benzyloxy)-2,9-diethylspiro[benzo[c]chromene-6,1′-cyclobutane](70.00mg, 1.00 equiv., 142.7 μmol) was dissolved in MeOH (4mL). Nickel chloride hexahydrate (169.5mg, 5 equiv., 713.4 μmol) was added. Sodium tetrahydroborate (53.97mg, 50.49 μL, 10 equiv., 1.427mmol) was added in batches (gas evolution). TLC showed no more starting material. The mixture was filtered out and the crude material was loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 4% to give 2,9-diethylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (29mg, 93 μmol, 65%) as a white solid. f 0.4 (MeOH / DCM 4%). 1 H NMR (400MHz, DMSO) δ9.33 (s, 2H), 7.39 (d, J=1.7Hz, 2H), 6.87 (s, 1H), 6.38 (s, 1H), 2.62-2.51 (m, 4H), 2.45-2.35 ( m, 2H), 2.28-2.18 (m, 2H), 1.95 (ddt, J=15.3, 9.9, 4.7Hz, 1H), 1.74 (dt, J=11.0, 8.6Hz, 1H), 1.15 (q, J=7.4Hz, 6H). MS: m / z: 311[M+H] + .

[0448] 20. Synthesis of 1′,6′-dimethylspiro[cyclopentane-1,9′-fluorene]-2′,4′,7′-triol (16)

[0449] 16 was prepared from methyl 2-bromo-5-methoxy-4-methylbenzoate and 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 4 steps.

[0450] Solution 19.

[0451]

[0452] Step 1: Synthesis of methyl 4′-(benzyloxy)-2′-fluoro-4-methoxy-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylate

[0453]

[0454] Methyl 2-bromo-5-methoxy-4-methylbenzoate (370 mg, 1 eq., 1.43 mmol), 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (635 mg, 1.3 eq., 1.86 mmol) and bis-(triphenylphosphino)-palladium chloride (100 mg, 0.1 eq., 143 μmol) were suspended in THF (103 mg, 14.3 mL, 0.1 mole, 1 eq., 1.43 mmol) and degassed with nitrogen for 5 minutes. A solution of sodium bicarbonate (264 mg, 2.2 eq., 3.14 mmol) in water (25.7 mg, 4.76 mL, 0.3 mole, 1 eq., 1.43 mmol) was added at room temperature and the mixture was refluxed overnight. After cooling to room temperature, a saturated solution of NH4Cl was added and the aqueous phase was extracted twice with EA. The combined organic phases were dried over sodium sulfate, concentrated under vacuum, and the organic residue was subjected to column chromatography biotage FC EA / cyclohexane 0% to 10% to give 4′-(benzyloxy)-2′-fluoro-4-methoxy-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylic acid methyl ester (480 mg, 1.22 mmol, 85.2%) as a colorless oil. f 0.3 (EA / cyclohexane 10%). MS (APCI+): m / z=395.

[0455] Step 2: Synthesis of 1-(4′-(benzyloxy)-4-methoxy-3′,5-dimethyl-[1,1′-biphenyl]-2-yl)cyclopentan-1-ol

[0456]

[0457] 1,4-dibromobutane (394.13 mg, 216.6 μL, 6 equivalents, 1.8254 mmol) was added to anhydrous magnesium (22.18 mg, 3 equivalents, 912.69 μmol) in anhydrous ether (1.127 g, 1.58 mL, 50 equivalents, 15.211 mmol) at room temperature, and the reaction mixture was stirred for 2 hours. A solution of 4′-(benzyloxy)-2′-fluoro-4-methoxy-5,5′-dimethyl-[1,1′-biphenyl]-2-carboxylic acid methyl ester (120.00 mg, 1 equivalent, 304.23 μmol) in anhydrous THF (1 mL) was added to the turbid solution, and the reactant was stirred for 5 hours. TLC showed that there were still some sm (polar product formation, TLC MS showed M-18). The reactant was quenched with NH4Cl and extracted with EtOAc. The combined organic phases were dried over sodium sulfate and evaporated under vacuum to give crude 1-(4′-(benzyloxy)-4-methoxy-3′,5-dimethyl-[1,1′-biphenyl]-2-yl)cyclopentan-1-ol (120 mg, 298 μmol, 98.0%) which was used in the next step without further purification.

[0458] Step 3: Synthesis of 3-(benzyloxy)-8-methoxy-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane]

[0459]

[0460] 1-(4′-(Benzyloxy)-2′-fluoro-4-methoxy-5,5′-dimethyl-[1,1′-biphenyl]-2-yl)cyclopentan-1-ol (120 mg, 1 eq., 285 μmol) was dissolved in DMF (3 mL) and heated at 120° C. NaH (57 mg, 60% Wt, 5 eq., 1.43 mmol) was added portionwise at 120° C. and stirring was continued at 120° C. for 15 minutes. The mixture was cooled to room temperature, NH4Cl saturated solution was added and the aqueous phase was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and evaporated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 10% to give 3-(benzyloxy)-8-methoxy-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane] (40 mg, 0.10 mmol, 35%) as a white solid. R f 0.5.(EA / cyclohexane 10%). MS (APCI+): m / z=401. 1H NMR (400MHz, CDCl3) δ7.48-7.28 (m, 7H), 6.67 (s, 1H), 6.52 (s, 1H), 5.06 (s, 2H), 3.86 (d, J=1.4Hz, 3H), 2.26 (s, 6H), 2.22 (m, 2H), 2.03-1.88 (m, 4H), 1.82 (d, J=7.6Hz, 2H).

[0461] Step 4: Synthesis of 1′,6′-dimethylspiro[cyclopentane-1,9′-fluorene]-2′,4′,7′-triol (16)

[0462]

[0463] BBr (65.68 mg, 262.2 μL, 1 mole, 3 eq., 262.2 μmol) was added to a suspension of 3-(benzyloxy)-8-methoxy-2,9-dimethylspiro[benzo[c]chromene-6,1′-cyclopentane] (35.00 mg, 1 eq., 87.39 μmol) in DCM (4.305 g, 3.261 mL, 580 eq., 50.68 mmol) at −78° C. over 2 minutes and the mixture was warmed to room temperature overnight. The reaction mixture was quenched with a saturated solution of NaHCO and the aqueous phase was extracted with EtOAc. The combined organic phases were dried over sodium sulfate and the organic residue was subjected to column chromatography biotage FC MeOH / DCM 0% to 20% to give 1',6'-dimethylspiro[cyclopentane-1,9'-fluorene]-2',4',7'-triol (15 mg, 51 μmol, 58%) as a white solid. Rf 0.5 MeOH / DCM 10%. 1 H NMR (400MHz, DMSO) δ9.22 (s, 1H), 8.98 (s, 1H), 8.88 (s, 1H), 7.47 (s, 1H), 6.80 (s, 1H), 6.33 (d , J=1.8Hz, 1H), 2.34-2.23(m, 2H), 2.11(s, 3H), 2.10(s, 3H), 2.07(m, 4H), 1.75-1.56(m, 2H). MS: m / z: 297[M+H] + .

[0464] 21. Synthesis of 2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (17)

[0465] 17 was prepared from 1-(benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene and 2-(4-(benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 4 steps:

[0466]

[0467] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5,5′-dicyclopropyl-2′-fluoro-1,1′-biphenyl

[0468]

[0469] 1-(Benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene (340 mg, 1 eq., 792 μmol) and 2-(4-(benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (379 mg, 1.3 eq., 1.03 mmol) were dissolved in dioxane (10 mL). Bis-(triphenylphosphino)-palladium chloride (55.6 mg, 0.1 eq., 79.2 μmol) was added and the solution was degassed for 5 minutes, then sodium bicarbonate (200 mg, 2.38 mL, 1 mole, 3 eq., 2.38 mmol) was dissolved in water (4 mL) and added dropwise, and the mixture was heated at 90 °C for 2 hours. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC biotage EtOAc / cyclohexane 0% to 5% to give 4,4'-bis(benzyloxy)-2-bromo-5,5'-dicyclopropyl-2'-fluoro-1,1'-biphenyl (330 mg, 607 μmol, 76.6%) as a colorless oil. Rf 0.3 EtOAc / cyclohexane 2%. 1 H NMR (400MHz, CDCl3) δ7.67-7.28 (m, 11H), 7.18 (s, 1H), 6.82 (dd, J=5.7, 3.8Hz, 1H), 6.75 (d, J=3.9Hz, 1H ), 6.72 (d, J=6.0Hz, 4H), 2.28-2.09 (m, 2H), 0.92 (dddd, J=7.4, 5.5, 4.4, 1.8Hz, 4H), 0.69-0.60 (m, 4H).

[0470] 19 F NMR (376MHz, CDCl3) δ-116.77.

[0471] Step 2: Synthesis of 1-(4,4′-bis(benzyloxy)-5,5′-dicyclopropyl-2′-fluoro-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol

[0472]

[0473] nBuLi (99.01 mg, 966.00 μL, 1.6 moles, 3 eq., 1.5456 mmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5,5′-dicyclopropyl-2′-fluoro-1,1′-biphenyl (280.00 mg, 1.00 eq., 515.20 μmol) in THF (7 mL) at −78° C. under nitrogen atmosphere. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (361.1 mg, 386 μL, 10 eq., 5.1520 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4'-bis(benzyloxy)-5,5'-dicyclopropyl-2'-fluoro-[1,1'-biphenyl]-2-yl)cyclobutan-1-ol (85 mg, 0.16 mmol, 31%). Rf 0.3 EtOAc / cyclohexane 20%. 1 H NMR (400MHz, CDCl3) δ7.76-7.30 (m, 10H), 6.88 (s, 1H), 6.75 (d, J=8.7Hz, 1H), 6.67 (d, J=11.6Hz, 1H), 6.61 (s, 1H), 5.15 (s, 2H), 5.11(s, 2H), 2.34-2.13(m, 2H), 2.11-1.91(m, 2H), 1.84-1.68(m, 2H), 1.68-1.30(m, 2H), 1.03-0.80(m, 4H), 0.75-0.56(m, 4H). 19 F NMR (376MHz, CDCl3) δ-117.

[0474] Step 3: Synthesis of 3,8-bis(benzyloxy)-2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane]

[0475]

[0476] NaH (18 mg, 60% Wt, 3 eq., 0.45 mmol) was added to a solution of 1-(4,4′-bis(benzyloxy)-5,5′-dicyclopropyl-2′-fluoro-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (80 mg, 1 eq., 0.15 mmol) in DMF (7 mL) at 110° C. Stirring was continued at 110° C. for 15 min. TLC showed no more starting material.

[0477] The reaction mixture was cooled to room temperature. Slowly add NaHCO 1 / 2 saturated solution and extract the aqueous phase twice with EtOAc. The combined organic phase was washed with water and brine in turn and dried over sodium sulfate. The solvent was evaporated and the crude material was purified by FC eluent EtOAc / cyclohexane 0% to 5% to obtain 3,8-bis(benzyloxy)-2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane](65mg, 0.13mmol, 84%). Rf 0.7 EtOAc / cyclohexane 5%. 1 H NMR (400MHz, CDCl3) δ7.53-7.31 (m, 10H), 7.13 (s, 1H), 7.09 (s, 1H), 6.93 (s, 1H) ), 6.60(s, 1H), 5.20(s, 2H), 5.11(s, 2H), 2.57-2.44(m, 2H), 2.42-2.31(m, 2H) , 2.26 (ddd, J=8.5, 5.3, 3.1Hz, 1H), 2.15 (ddd, J=8.5, 5.4, 3.1Hz, 1H), 2.05-1. 92 (m, 1H), 1.73 (dt, J=11.4, 8.7Hz, 1H), 1.05-0.82 (m, 4H), 0.80-0.61 (m, 4H).

[0478] Step 4: Synthesis of 2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol

[0479]

[0480] 3,8-bis(benzyloxy)-2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane](60.00mg, 1.00 equivalent, 116.6μmol) is dissolved in MeOH(4mL). Nickel chloride hexahydrate (138.5mg, 5 equivalents, 582.9μmol) is added. Sodium tetrahydroborate (88.20mg, 82.51μL, 20 equivalents, 2.332mmol) (gas evolution) is added in batches. TLC shows that there is no more starting material. The mixture is filtered out and the crude material is loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 10%, to obtain 2,9-dicyclopropylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (34mg, 0.10mmol, 87%) as pale yellow foam. Rf 0.4 MeOH / DCM 4%. MS: m / z: [M+H] + 335. 1H NMR (400MHz, DMSO) δ9.37 (s, 1H), 9.36 (s, 1H), 7.04 (s, 1H), 7.00 (s, 1H), 6.86 (s, 1H), 6.37 (s, 1H), 2.43-2.31 (m, 2H), 2.27-2.14 (m, 2H), 2.1 3-2.03 (m, 1H), 2.01-1.89 (m, 2H), 1.73 (dt, J=11.0, 8.5Hz, 1H), 0.91- 0.83 (m, 2H), 0.83-0.78 (m, 2H), 0.77-0.73 (m, 2H), 0.73-0.64 (m, 2H).

[0481] 22. Synthesis of 2-cyclopropyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (18)

[0482] 18 was prepared from 1-(benzyloxy)-5-bromo-4-iodo-2-methylbenzene and 2-(4-(benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 4 steps.

[0483]

[0484] Synthesis of 1-(Benzyloxy)-5-bromo-4-iodo-2-methylbenzene

[0485]

[0486] Step 1: Synthesis of 5-bromo-4-iodo-2-methylphenol

[0487]

[0488] 5-Bromo-4-iodo-2-methylphenol was prepared from 5-bromo-2-ethylphenol following the procedure described in Beatrice Felber, Francois Dietrich, Helvetica, 2005, Vol. 88, 120-153.

[0489] Step 2: Synthesis of 1-(benzyloxy)-5-bromo-4-iodo-2-methylbenzene

[0490]

[0491] Benzyl bromide (11.19 mL, 10.07 mmol, 1 eq) was added to a mixture of 5-bromo-4-iodo-2-methylphenol (3.5 g, 11.18 mmol) and potassium carbonate (3.09 g, 22.37 mmol, 2 eq) in ACN (60 mL), and the mixture was heated at 50° C. for 3 h. The reaction mixture was filtered off and concentrated under vacuum to give 1-(benzyloxy)-5-bromo-4-iodo-2-methylbenzene (4 g, 9.9 mmol, 89%), which was used in the next step without further purification. 1 H NMR (400MHz, CDCl3) δ7.59 (d, J=0.9Hz, 1H), 7.44-7.31 (m, 5H), 7.14 (s, 1H), 5.02 (s, 2H), 2.17 (s, 3H).

[0492] 2-(4-Benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Synthesis

[0493] (4-(Benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was prepared from commercially available 2-bromo-5-fluorophenol in 4 steps:

[0494]

[0495] Step 1: Synthesis of 2-cyclopropyl-5-fluorophenol

[0496]

[0497] Tricyclohexyl-phosphine (147mg, 164μL, 0.2 equivalent, 524μmol) and palladium diacetate (58.8mg, 0.1 equivalent, 262μmol) are suspended in degassed toluene (241mg, 26.2mL, 0.1 mole, 1 equivalent, 2.62mmol) and stirred therein for 5 minutes. 2-bromo-5-fluorophenol (500mg, 292μL, 1 equivalent, 2.62mmol) and cyclopropylboronic acid (899mg, 4 equivalents, 10.5mmol) are added successively, and then potassium phosphate (3.33g, 1.30mL, 6 equivalents, 15.7mmol) dissolved in water (47.2mg, 13.1mL, 0.2 mole, 1 equivalent, 2.62mmol) is added. The reaction mixture is heated at 110°C overnight. The reaction mixture is extracted with EA and NH4Cl saturated solution. The combined organic phases were dried over sodium sulfate and then concentrated under vacuum. The crude material was purified by FCbiotage EA / cyclohexane 0% to 35% to give 2-cyclopropyl-5-fluorophenol (340 mg, 2.23 mmol, 85.4%) as a light brown oil. Rf 0.3 eluent EA / cyclohexane 10%.1 H NMR (400MHz, DMSO) δ9.77 (s, 1H), 6.75 (dd, J=8.5, 6.8Hz, 1H), 6.55 (dd, J=10.8, 2.7Hz, 1H), 6.48 (td, J=8.6, 2.7Hz, 1H), 1.98 (ddd, J=8.5, 4.9, 3.1Hz, 1H), 0.86-0.77 (m, 2H), 0.62-0.42 (m, 2H).

[0498] Step 2: Synthesis of 4-bromo-2-cyclopropyl-5-fluorophenol

[0499]

[0500] To a solution of 2-cyclopropyl-5-fluorophenol (2000 mg, 1 eq., 13.14 mmol) in DCM (1.116 g, 65.72 mL, 0.2 mole, 1 eq., 13.14 mmol) and methanol (421.1 mg, 43.81 mL, 0.3 mole, 1 eq., 13.14 mmol) was added tetra-n-butylammonium tribromide (6.337 g, 1 eq., 13.14 mmol) in portions while stirring. The mixture was stirred at 250 ° C for 3 hours. Water (250 mL) was added and the mixture was concentrated under reduced pressure. The aqueous layer was extracted with DCM (300 mL×3). The combined organic layers were washed with brine (600 mL), dried over anhydrous Na2SO4, filtered and concentrated to give the crude product which was purified by flash chromatography on silica gel eluent EtOAc / hexane 30% to give 4-bromo-2-cyclopropyl-5-fluorophenol (1.5 g, 6.5 mmol, 49%). 1 H NMR (400MHz, DMSO) δ 10.11 (s, 1H), 6.97 (d, J=8.1Hz, 1H), 6.71 (d, J=10.4Hz, 1H), 1.98 (tt, J=8.4, 5.3Hz, 1H), 0.94-0.71 (m, 2H), 0.71-0.48 (m, 2H).

[0501] Step 3: Synthesis of 1-(benzyloxy)-4-bromo-2-cyclopropyl-5-fluorobenzene

[0502]

[0503] Benzyl bromide (1.110 g, 772.2 μL, 1 eq., 6.492 mmol) was added to a suspension of 4-bromo-2-cyclopropyl-5-fluorophenol (1500 mg, 1 eq., 6.492 mmol) and potassium carbonate (1.794 g, 2 eq., 12.98 mmol) in acetonitrile (266.5 mg, 64.92 mL, 0.1 mole, 1 eq., 6.492 mmol) at room temperature, and the mixture was heated at 50° C. for 4 hours. The suspension was filtered off and the solvent was evaporated under vacuum to give 1-(benzyloxy)-4-bromo-2-cyclopropyl-5-fluorobenzene (1.98 g, 6.16 mmol, 95.0%) as a colorless product. The compound was used without further purification. 1 H NMR (400MHz, CDCl3) δ7.66-7.28 (m, 5H), 6.99 (dd, J=7.8, 0.6Hz, 1H), 6.69 (d, J=1 0.4Hz, 1H), 5.08 (s, 1H), 2.28-1.96 (m, 1H), 1.10-0.80 (m, 2H), 0.74-0.43 (m, 2H). 19 F NMR (376MHz, CDCl3) δ-109.59.

[0504] Step 4: Synthesis of 2-(4-benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

[0505]

[0506] 1-(Benzyloxy)-4-bromo-2-cyclopropyl-5-fluorobenzene (500 mg, 1 eq., 1.56 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bis(1,3,2-dioxaborolane) (712 mg, 1.8 eq., 2.80 mmol), potassium acetate (611 mg, 4 eq., 6.23 mmol) were added, followed by dioxane (60 mL). The mixture was stirred at 100 °C under N2 for 12 hours. After cooling to 30 °C, the reaction mixture was filtered through Celite. The filtrate was concentrated under reduced pressure. Water (300 mL) was added and the aqueous layer was extracted with EtOAc (300 mL×3). The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated to give a crude product. The crude product was purified by flash chromatography on silica gel (EtOAc in petroleum ether = 0% - 30%) to give 2-(4-(benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (350 mg, 950 μmol, 61.1%) as a colorless oil. 1H NMR (400MHz, CDCl3) δ7.50-7.31 (m, 5H), 7.24 (dd, J=7.1, 0.7Hz, 1H), 6.59 (d, J=1 1.2Hz, 1H), 5.11(s, 2H), 2.15-2.01(m, 1H), 0.98-0.80(m, 2H), 0.76-0.56(m, 2H). 19 F NMR (376MHz, CDCl3) δ-103.82 (d, J=2.5Hz).

[0507] Synthesis of 18

[0508] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5′-cyclopropyl-2′-fluoro-5-methyl-1,1′-biphenyl

[0509]

[0510] 1-(Benzyloxy)-5-bromo-4-iodo-2-methylbenzene (300 mg, 1 eq., 744 μmol) and 2-(4-(benzyloxy)-5-cyclopropyl-2-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (356 mg, 1.3 eq., 968 μmol) were dissolved in dioxane (10 mL). Bis-(triphenylphosphino)-palladium chloride (52.2 mg, 0.1 eq., 74.4 μmol) was added and the solution was degassed for 5 minutes. Sodium bicarbonate (188 mg, 2.23 mL, 1 mole, 3 eq., 2.23 mmol) was then dissolved in water (4 mL) and added dropwise, and the mixture was heated at 90 °C for 2 hours. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 5% to give 4,4'-bis(benzyloxy)-2-bromo-5'-cyclopropyl-2'-fluoro-5-methyl-1,1'-biphenyl (350 mg, 676 μmol, 90.9%) as a colorless oil. Rf 0.3 EtOAc / cyclohexane 2%. 1 H NMR (400MHz, CDCl3) δ7.58-7.38 (m, 10H), 7.17 (s, 1H), 7.07 (t, J=0.8Hz, 1H), 6.75 (d, J=8.4Hz, 0H), 5. 12 (s, 1H), 5.09 (s, 1H), 2.24 (d, J=0.8Hz, 3H), 2.20-2.11 (m, 1H), 0.95-0.84 (m, 2H), 0.68-0.55 (m, 2H).

[0511] Step 2: Synthesis of 1-(4,4′-bis(benzyloxy)-5′-cyclopropyl-2′-fluoro-5-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol

[0512]

[0513] nBuLi (111 mg, 1.09 mL, 1.6 moles in THF, 3 eq., 1.74 mmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5′-cyclopropyl-2′-fluoro-5-methyl-1,1′-biphenyl (300 mg, 1 eq., 580 μmol) in THF (7 mL) at −78° C. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (406 mg, 434 μL, 10 eq., 5.80 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with . The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4'-bis(benzyloxy)-5'-cyclopropyl-2'-fluoro-5-methyl-[1,1'-biphenyl]-2-yl)cyclobutan-1-ol (140 mg, 275 μmol, 47.5%). Rf 0.3 EtOAc / cyclohexane 20%. 1 HNMR (400 MHz, CDCl3) δ 7.56, 7.28 (m, 10H), 6.93 (d, J = 0.9 Hz, 1H), 6.87 (s, 1H), 6.77 (d, J = 8.7 Hz, 1H), 6.67 (d, J = 11.6 Hz, 1H), 5.12 (d, J = 3.2 Hz, 4H), 2.22-2.12 (m, 2H), 2.10-1.92 (m, 5H), 1.79-1.71 (m, 1H), 1.38-1.31 (m, 2H), 0.98-0.87 (m, 2H). MS (APCI+): m / z = 508.2, found 491 (M-17).

[0514] Step 3: Synthesis of 1-(4,4′-bis(benzyloxy)-5′-cyclopropyl-2′-fluoro-5-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol

[0515]

[0516] 1-(4,4′-bis(benzyloxy)-5′-cyclopropyl-2′-fluoro-5-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (125 mg, 1 eq., 246 μmol) was dissolved in DMF (1.5 mL) and heated to 110° C. NaH (29.5 mg, 5 eq., 1.23 mmol) was added in portions and stirring was continued for 15 minutes. The reaction mixture was cooled to room temperature and extracted with EtOAc and NaHCO 3 saturated solution. The organic phase was dried over sodium sulfate and concentrated under vacuum, and the crude material was purified by FC eluent EtOAc / cyclohexane 0% to 30% to give 3,8-bis(benzyloxy)-2-cyclopropyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane] (78 mg, 0.16 mmol, 65%) as a colorless oil. Rf 0.6 EtOAc / cyclohexane 10%. 1 H NMR (400MHz, CDCl3) δ7.57-7.27 (m, 13H), 7.16 (s, 1H), 6.92 (s, 1H), 6.60 (s, 1H), 5.17 (s, 2H), 5.11 (s, 20H), 2.66-2.47 (m, 2H), 2.4 6-2.21 (m, 5H), 2.17 (tt, J=8.5, 5.3Hz, 1H), 2.07-1.92 (m, 1H), 1.73 (dt, J=11.4, 8.7Hz, 1H), 1.01-0.86 (m, 2H), 0.80-0.68 (m, 2H).

[0517] Step 4: Synthesis of 2-cyclopropyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol

[0518]

[0519] 3,8-bis(benzyloxy)-2-cyclopropyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane](70.00mg, 1.00 equivalent, 143.3μmol) was dissolved in MeOH(4mL). Nickel chloride hexahydrate (170.2mg, 5 equivalents, 716.3μmol) was added. Sodium tetrahydroborate (108.4mg, 101.4μL, 20 equivalents, 2.865mmol) was added in batches (gas evolution). TLC showed that there was no more starting material. The mixture was filtered out and the crude material was loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 4%, to give 2-cyclopropyl-9-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (20mg, 65μmol, 45%) as a white solid. Rf 0.4 MeOH / DCM 4%. MS: m / z: [M+H] + 309.1 H NMR (400MHz, DMSO) δ9.38 (s, 1H), 9.32 (s, 1H), 7.42 (s, 1H), 7.04 (s, 1H), 6.85 (s, 1H), 6.38 (s, 1H), 2.38 (q, J=9.9Hz, 2H), 2. 28-2.16 (m, 2H), 2.16 (d, J=0.7Hz, 3H), 2.07-1.90 (m, 2H), 1.82-1.65 (m, 1H), 0.92-0.75 (m, 2H), 0.67 (dt, J=5.5, 2.9Hz, 2H).

[0520] 23. Synthesis of 9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (19)

[0521]

[0522] 19 was prepared from 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (see synthesis of 7) and 1-(benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene.

[0523]

[0524] Synthesis of 1-(Benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene

[0525]

[0526] 1-(Benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene was prepared from commercially available 5-bromo-2-iodophenol in 3 steps.

[0527]

[0528] Step 1: Synthesis of 5-bromo-2-cyclopropylphenol

[0529]

[0530] Tricyclohexyl-phosphine (150.1 mg, 167 μL, 0.16 eq., 535.3 μmol) and palladium diacetate (60.09 mg, 0.08 eq., 267.6 μmol) were suspended in degassed toluene (308.3 mg, 33.45 mL, 0.1 mole, 1 eq., 3.345 mmol) and stirred therein for 2 minutes. 5-Bromo-2-iodophenol (1000 mg, 1 eq., 3.345 mmol) and cyclopropylboronic acid (1.150 g, 4 eq., 13.38 mmol) were added in sequence, followed by potassium phosphate (2.130 g, 830.9 μL, 3 eq., 10.04 mmol) dissolved in water (60.29 mg, 16.73 mL, 0.2 mole, 1 eq., 3.345 mmol). The mixture was heated at 110° C. overnight. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The organic phase was dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 35% to give 5-bromo-2-cyclopropylphenol (350 mg, 1.64 mmol, 49.1%) as a light brown oil. Rf 0.3 eluent EA / cyclohexane 10%. 1 H NMR (400MHz, DMSO) δ9.80 (s, 1H), 6.92 (d, J=2.1Hz, 1H), 6.84 (dd, J=8.2, 2.0Hz, 1H ), 6.69 (d, J=8.2Hz, 1H), 2.07-1.89 (m, 1H), 0.95-0.79 (m, 2H), 0.68-0.52 (m, 2H).

[0531] Step 2: Synthesis of 5-bromo-2-cyclopropyl-4-iodophenol

[0532]

[0533] 5-Bromo-4-iodo-2-methylphenol was prepared from 5-bromo-2-ethylphenol following the procedure described in Beatrice Felber, Francois Dietrich, Helvetica, 2005, Vol. 88, 120-153. 1 H NMR (400MHz, CDCl3) δ7.49 (d, J=0.9Hz, 1H), 7.16 (s, 1H), 1.83-1.62 (m, 1H), 1.10-0.86 (m, 2H), 0.62 (ddd, J=5.8, 3.9, 1.9Hz, 2H).

[0534] Step 3: Synthesis of 1-(benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene

[0535]

[0536] Benzyl bromide (481.64 mg, 334.9 μL, 1 eq, 2.8160 mmol) was added to a mixture of 5-bromo-2-cyclopropylphenol (600.00 mg, 1.00 eq, 2.8160 mmol) and potassium carbonate (778.34 mg, 2 eq, 5.6320 mmol) benzyl bromide (481.64 mg, 334.9 μL, 1 eq, 2.8160 mmol) in ACN (14 mL), and the mixture was heated at 50° C. for 3 hours. The reaction mixture was filtered off and concentrated under vacuum to give 1-(benzyloxy)-5-bromo-4-iodo-2-methylbenzene (4 g, 9.9 mmol, 89%), which was used in the next step without further purification. 1 H NMR (400MHz, CDCl3) δ7.47-7.31 (m, 5H), 7.25 (d, J=0.6Hz, 1H), 7.14 (s, 1H), 5.06 (s, 2H), 2.16-2.04 (m, 1H), 0.98-0.83 (m, 2H), 0.68-0.56 (m, 2H).

[0537] Synthesis of 19

[0538] Step 1: Synthesis of 4,4′-bis(benzyloxy)-2-bromo-5-cyclopropyl-2′-fluoro-5′-methyl-1,1′-biphenyl

[0539]

[0540] 1-(Benzyloxy)-5-bromo-2-cyclopropyl-4-iodobenzene (150 mg, 1 eq., 350 μmol) and 2-(4-(benzyloxy)-2-fluoro-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (156 mg, 1.3 eq., 454 μmol) were dissolved in dioxane (10 mL). Bis-(triphenylphosphino)-palladium chloride (24.5 mg, 0.1 eq., 35.0 μmol) was added and the solution was degassed for 5 minutes. Sodium bicarbonate (88.1 mg, 1.05 mL, 1 mole, 3 eq., 1.05 mmol) was then dissolved in water (4 mL) and added dropwise, and the mixture was heated at 90 °C for 2 hours. Water was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC biotage EtOAc / cyclohexane 0% to 5% to give 4,4'-bis(benzyloxy)-2-bromo-5-cyclopropyl-2'-fluoro-5'-methyl-1,1'-biphenyl (130 mg, 251 μmol, 71.9%) as a colorless oil. Rf 0.3 EtOAc / cyclohexane 2%.1 H NMR (400MHz, CDCl3) δ7.55-7.32 (10m, H), 7.18 (s, 1H), 7.01 (dd, J=8.6, 0.9Hz, 1H), 6.77 (s, 1H), 6. 69 (d, J=11.4Hz, 1H), 5.12 (s, 2H), 5.09 (s, 2H), 2.31 (s, 3H), 1.10-0.88 (m, 2H), 0.74-0.57 (m, 2H).

[0541] Step 2: Synthesis of 1-(4,4′-bis(benzyloxy)-5-cyclopropyl-2′-fluoro-5′-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol

[0542]

[0543] nBuLi (74.28 mg, 724.72 μL, 1.6 moles in THF, 3 eq., 1.1596 mmol) was added to a solution of 4,4′-bis(benzyloxy)-2-bromo-5-cyclopropyl-2′-fluoro-5′-methyl-1,1′-biphenyl (200.00 mg, 1.00 eq., 386.52 μmol) in THF (7 mL) at −78° C. The mixture was stirred at −78° C. for 30 minutes, then 1-oxocyclobutane (270.9 mg, 289 μL, 10 eq., 3.8652 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 6 hours. A saturated solution of NH4Cl was added and the mixture was extracted twice with EtOAc. The combined organic phases were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FC eluent EtOAc / cyclohexane 0% to 20% to give 1-(4,4'-bis(benzyloxy)-5-cyclopropyl-2'-fluoro-5'-methyl-[1,1'-biphenyl]-2-yl)cyclobutan-1-ol (60 mg, 0.12 mmol, 31%). Rf 0.3 EtOAc / cyclohexane 20%. 1 H NMR (400MHz, CDCl3) δ7.54-7.31 (m, 10H), 7.02 (dd, J=8.9, 0.9Hz, 1H), 6.88 (s, 1H), 6.67 (s, 1H), 6.61 (s, 1H), 5.15 (s, 2H), 5.08 (s, 2 H), 2.34-2.11 (m, 5H), 2.10-1.95 (m, 2H), 1.76-1.68 (m, 1H), 1.63-1.41 (m, 1H), 1.04-0.83 (m, 2H), 0.67 (ddd, J=5.3, 3.0, 2.0Hz, 2H).

[0544] Step 3: Synthesis of 3,8-bis(benzyloxy)-9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]

[0545]

[0546] NaH (14 mg, 60% Wt, 3 eq., 0.35 mmol) was added to a solution of 1-(4,4′-bis(benzyloxy)-5-cyclopropyl-2′-fluoro-5′-methyl-[1,1′-biphenyl]-2-yl)cyclobutan-1-ol (60 mg, 1 eq., 0.12 mmol) in DMF (7 mL) at 110° C. Stirring was continued at 110° C. for 15 minutes. The reaction mixture was cooled to room temperature. A saturated solution of NaHCO 1 / 2 was added and the mixture was extracted once with EtOAc. The organic phase was dried over sodium sulfate. The solvent was evaporated under vacuum and the crude material was purified by FC eluent EtOAc / cyclohexane 0% to 10% to give 3,8-bis(benzyloxy)-9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane] (40 mg, 82 μmol, 69%) as a white solid. Rf 0.7 EtOAc / cyclohexane 5 / 95. 1 H NMR (400MHz, CDCl3) δ7.61-7.31 (m, 11H), 7.12 (s, 1H), 6.94 (s, 1H), 6.59 (s, 1H), 5.20 (s, 2H), 5.07 (s, 2H), 2.52 (q, J=1 0.5Hz, 2H), 2.40-2.29(m, 3H), 2.28(s, 3H), 2.05-1.94(m, 1H), 1.80-1.69(m, 1H), 1.09-0.94(m, 2H), 0.79-0.71(m, 2H).

[0547] Step 4: Synthesis of 9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol

[0548]

[0549] 3,8-bis(benzyloxy)-9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane](40.00mg, 1.00 equivalent, 81.86μmol) is dissolved in MeOH(4mL).Add nickel chloride hexahydrate (97.28mg, 5 equivalents, 409.3μmol).Add sodium tetrahydroborate (61.94mg, 57.94μL, 20 equivalents, 1.637mmol) (gas evolution) in batches.TLC shows that there is no more starting material.The mixture is filtered out and the crude material is loaded onto silica gel and purified by FC eluent MeOH / DCM 0% to 20%, to obtain 9-cyclopropyl-2-methylspiro[benzo[c]chromene-6,1′-cyclobutane]-3,8-diol (10mg, 32μmol, 40%) as a yellow solid.Rf 0.4 MeOH / DCM 4%. MS: m / z: [M+H] + 309. 1 H NMR (400MHz, DMSO) δ9.38 (s, 1H), 9.32 (s, 1H), 7.42 (s, 1H), 7.04 (s, 1H), 6.85 (s, 1H), 6.38 (s, 1H), 2.44-2.35 (m, 2H), 2.26 -2.17 (m, 2H), 2.16 (d, J=0.7Hz, 3H), 2.05-1.86 (m, 2H), 1.79-1.66 (m, 1H), 0.91-0.75 (m, 2H), 0.67 (dt, J=5.5, 2.9Hz, 2H).

[0550] Example 2: Anti-ferroptosis assay

[0551] The anti-ferroptosis activity of the compounds was determined by measuring cell viability after co-treatment with the ferroptosis inducer 1S,3R-RSL 3 (CAS No.: 1219810-16-8; hereinafter RSL3). 2.0 Assay to measure cell viability. The assay provides a homogeneous method to determine the number of viable cells in culture by quantifying the amount of ATP present, which indicates the presence of metabolically active cells.

[0552] On day 1, C2C12 myoblasts (ATCC #CRL-1772) were seeded at 1,500 cells / well in conventional DMEM medium in white-walled transparent bottom 96-well plates, supplemented with 10% heat-inactivated fetal bovine serum (FBS) and penicillin-streptomycin (100 U / mL). On day 2, cells were treated with 0.1% DMSO (vehicle, n=8 / plate), 1.25 μM RSL3 (n=8 / plate) as a positive control, and test compounds with a 5-point concentration-response curve (starting from 50 μM, using 2-fold dilution) (n=4 / plate and each concentration) in the presence or absence of RSL3 1.25 μM. On day 3, CellTiter-Glo reagent (2x stock solution) (Promega) was added, mixed on an orbital shaker for two minutes, and incubated in the dark at room temperature for 10 minutes, and then luminescence was measured using a FLUOstar OPTIMA reader (0.25 s). The percent efficacy (PE) for each test compound concentration corresponds to the rescue of cell viability compared to RSL3 1.25 μM alone and each test compound concentration alone:

[0553]

[0554] A score of 0% means that the compound does not have any anti-ferroptotic activity. A score of 100% means that the compound completely rescues cell viability and has the maximum possible anti-ferroptotic activity.

[0555] The concentration at which the compound showed 50% efficacy against ferroptosis-induced cell death (EC50) was calculated using GraphPad Prism v9.4.0. Nonlinear regression of log10 transformed concentrations (log(agonist) vs. response - variable slope (four parameters)) was used with constraints of lower limit = 0 and upper limit = 100. pEC 50 The value corresponds to EC 50 -log10 of the value.

[0556] Incorporated by Reference

[0557] All US patents and US and PCT patent application publications cited herein are hereby incorporated by reference.

[0558] Equivalent solutions

[0559] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the appended claims.

Claims

1. A compound of formula (I): in Y1 and Y2 are each alkyl; or, together with the carbon to which they are bonded, form an unsubstituted or substituted spirocycloalkyl; R1, R4, R5 and R8 are independently selected from -H and halogen; R2 and R7 are independently selected from -H, -OH, -OAc, -NH2, halogen, -CN, -CF3, -CO2H, -NO2, -NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino, alkyl-R9, alkenyl-R9, alkynyl-R9, -OR 10 、-NHR 10 、-NR 11 C(O)R 12 、-C(O)NR 11 R 12 and-NR 11 S02R 12 ; R3 and R6 are independently selected from alkyl and cycloalkyl; Each occurrence of R9 is independently selected from OH, NH2, O-alkyl, O-alkyl-O-alkyl, alkylamino, NHC(O)-alkyl, N(CH3)C(O)-alkyl, NHSO2-alkyl, N(CH3)SO2-alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl; R 10 is selected from the group consisting of alkyl, hydroxyalkyl, aminoalkyl, alkyl-O-alkyl, alkyl-O-alkyl-OH, alkyl-O-alkyl-O-alkyl, alkenyl, alkynyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl, alkyl-heterocycloalkyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl, SO3H, SO2-alkyl and SO2-haloalkyl; Each occurrence of R 11 is selected from H and alkyl; and Each occurrence of R 12 is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, O-alkyl, aminoalkyl, arylalkyl, heteroarylalkyl, alkyl-cycloalkyl and alkyl-heterocycloalkyl; Provided that when R1, R4, R5 and R8 are each -H, R2 and R7 are each -OH, and R3 and R6 are each CH3, then Y1 and Y2 are not each -Me or do not form, together with the carbon to which they are bonded, an unsubstituted spirobutyl group; or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1, wherein R3 and R6 are alkyl.

3. The compound according to claim 2 or 3, wherein Y1 and Y2 are each independently C1-C4 alkyl.

4. The compound of claim 2 or 3, wherein Y1 and Y2 are each -CH3.

5. The compound of claim 2 or 3, wherein Y1 and Y2 together with the carbon to which they are bound combine to form an unsubstituted spirocycloalkyl.

6. The compound of claim 5, wherein Y1 and Y2 together with the carbon to which they are bound combine to form an unsubstituted spirocyclopropyl, cyclobutyl or cyclopentyl.

7. A compound as described in any one of claims 1-6, wherein R3 and R6 are each independently C1-C4 alkyl.

8. The compound of any one of claims 1-7, wherein R3 and R6 are each independently selected from -CH3 and -CH2CH3.

9. The compound of any one of claims 1-7, wherein R3 and R6 are each -CH3.

10. The compound of any one of claims 1-7, wherein R3 and R6 are each -CH2CH3.

11. The compound of any one of claims 1-7, wherein one of R3 and R6 is -CH3, and the other of R3 and R6 is -CH2CH3.

12. The compound of any one of claims 1 and 3-6, wherein R3 and R6 are each independently C3-C5 cycloalkyl.

13. The compound of claim 12, wherein R3 and R6 are each cyclopropyl.

14. The compound of any one of claims 1 and 3-6, wherein one of R3 and R6 is a C1-C4 alkyl group, and the other of R3 and R6 is a C3-C5 cycloalkyl group.

15. The compound of claim 14, wherein one of R3 and R6 is -CH3, and the other of R3 and R6 is cyclopropyl.

16. A compound as described in any one of claims 7-11, wherein the compound has a structure selected from the following:

17. A compound as described in any one of claims 12-15, wherein the compound has a structure selected from the following:

18. A compound as described in any one of claims 1-17, wherein R2 and R7 are independently selected from -OH, -NH2, alkylamino and -OR 10 .

19. The compound of any one of claims 1-17, wherein R2 and R7 are each OH.

20. The compound of any one of claims 1-17, wherein R2 is -OH; and R7 is -OCH3.

21. The compound of any one of claims 1-17, wherein R7 is -OH; and R2 is -OCH3.

22. The compound of any one of claims 1-17, wherein R2 is selected from -NH2, -NHCH3, and -NH(CH3)2; and R7 is OH.

23. The compound of any one of claims 1-17, wherein R7 is selected from -NH2, -NHCH3, and -NH(CH3)2; and R2 is OH.

24. The compound of any one of claims 18-23, wherein R1, R4, R5 and R8 are each -H.

25. The compound of claim 1 having a structure selected from the compounds of Table 1.

26. A compound of formula (II): in X1 and X2 are each alkyl; or, together with the carbon to which they are bonded, form an unsubstituted or substituted spirocycloalkyl; R1′, R4′, R5′ and R8′ are independently selected from —H, —OH, —NH2, alkyl and halogen; R2′, R3′, R6′ and R7′ are independently selected from —H, —OH, —OAc, —NH2, halogen, —CN, —CF3, —CO2H, —NO2, —NHAc, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkylamino and —OR8′; and R8′ is selected from alkyl, hydroxyalkyl, aminoalkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl; or a pharmaceutically acceptable salt thereof.

27. The compound of claim 26, wherein X1 and X2 are each independently C1-C4 alkyl.

28. The compound of claim 26, wherein X1 and X2 are each -CH3.

29. The compound of claim 26, wherein X1 and X2, together with the carbon to which they are bound, combine to form an unsubstituted spirocycloalkyl.

30. The compound of claim 29, wherein X1 and X2, together with the carbon to which they are bound, combine to form an unsubstituted spirocyclopropyl, cyclobutyl or cyclopentyl.

31. A compound as described in any one of claims 26-30, wherein the compound has a structure selected from the following:

32. A compound as described in any one of claims 26-31, wherein R2' and R7' are independently selected from -OH, -NH2, alkylamino and -OR 10 .

33. The compound of any one of claims 26-31, wherein R2' and R7' are each OH.

34. The compound of any one of claims 26-31, wherein R2' is -OH; and R7' is -OCH3.

35. The compound of any one of claims 26-31, wherein R7' is -OH; and R2' is -OCH3.

36. The compound of any one of claims 26-31, wherein R2' is selected from -NH2, -NHCH3 and -NH(CH3)2; and R7' is OH.

37. The compound of any one of claims 26-31, wherein R7' is selected from -NH2, -NHCH3 and -NH(CH3)2; and R2' is OH.

38. The compound of any one of claims 26-32, wherein R3' and R6' are each independently -H or C1-C4 alkyl.

39. The compound of claim 38, wherein R3' and R6' are each independently -H or -CH3.

40. The compound of any one of claims 26-37, wherein R1' and R8' are each independently -H or C1-C4 alkyl.

41. The compound of claim 40, wherein R1' and R8' are each independently -H or -CH3.

42. The compound of any one of claims 26-37, wherein R4' and R5' are each independently -H and -OH.

43. The compound of claim 26, having a structure selected from the compounds of Table 2.

44. A pharmaceutical composition comprising a compound according to any one of claims 1-43; and a pharmaceutically acceptable carrier.

45. A method of inhibiting ferroptosis, comprising administering to a subject in need thereof an effective amount of a compound of any one of claims 1-43.

46. ​​A method of treating an inflammatory disease, a neuronal disease, or a neurodegenerative disease mediated at least in part by ferroptosis, the method comprising administering to a subject in need thereof an effective amount of a compound of any one of claims 1-43.

Images