Process for the preparation of a bsmoc-lys fatty acid compound

Abstract

The invention relates to a process for the preparation of a Bsmoc Lys fatty acid compound of the formula Ia: Bsmoc-Lys (AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH (Ia), wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid and PROT1 is an ester protecting group, and to the use of the compound of the formula Ia for the preparation of peptides.

Description

[0001] P39838

[0002] Process for the preparation of a Bsmoc-Lys fatty acid compound

[0003] TECHNICAL FIELD

[0004] The invention relates to a process for the preparation of a Bsmoc Lys fatty acid compound of the formula la

[0005] Bsmoc-Lys(AEEAc-AEEAc- y -Glu(O-PROTl)-19-carboxy-nonadecanoyl-O-PROTl)-OH

[0006] (la),

[0007] wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid and PROT1 is an ester protecting group and

[0008] to the use of the Bsmoc Lys fatty acid compound of the formula la, prepared according to the process of the invention, for the preparation of peptides, particularly for the preparation of the peptide of VIIIa (SEQ ID NO: 1), or of a pharmaceutically acceptable salt or ester thereof

[0009] X1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2

[0010] (VIIIa)

[0011] wherein X is

[0012]

[0013] ON andAEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

[0014] Likewise the invention relates to a process for the preparation of peptides as outlined above, which makes use of the fatty acid compound of the formula I as side chain.

[0015] BACKGROUND

[0016] While the Bsmoc Lys fatty acid compounds of the formula la are versatile building blocks with a broad scope of potential applications they can find a particular use as side chains in peptides, such as in peptides which have the potential to act as GLP-1R / GIPR agonists as illustrated in the International Patent Publication WO 2022 / 241287. A particular example is shown with the peptide of formula Villa (SEQ ID NO: 1) outlined above.

[0017] WO 2024 / 079043 Al describes the synthesis of a Bsmoc protected fatty acid with a C16 chain length.

[0018] SUMMARY OF INVENTION

[0019] The object of the present invention was to find an improved and scalable approach, which allows to produce the Bsmoc-Lys fatty acid compounds of the formula la in high purity and yield.

[0020] It was found that the object of the invention could be reached by a process for the preparation of a Bsmoc Lys fatty acid compound of the formula la

[0021] Bsmoc-Lys(AEEAc- AEEAc- y -Glu(O-PROTl)-19-carboxy-nonadecanoyl-O-PROTl)-OH

[0022] (la),

[0023] wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid and PROT1 is an ester protecting group,

[0024] which comprises the introduction of the Bsmoc-Lys functionality in the fatty acid compound of the formula Ila

[0025] PROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc- AEEAc-OH)-O-PROT 1

[0026] (Ila),

[0027] wherein AEEAc and PROT1 are as above,

[0028] either according to process variant A, wherein said process variant A comprisesal) converting the fatty acid compound of the formula Ila with a N-hydroxysuccinimide source compound to form the A-hydroxysuccinimide ester of formula Illa,

[0029] PROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-0 Su)-O-PROT 1 (Illa), wherein AEEAc and PROT1 are as above, and

[0030] a2) coupling the A-hydroxysuccinimide ester of formula Illa with Bsmoc-Lys-OH to form the Bsmoc Lys fatty acid compound of the formula la;

[0031] or according to process variant B, wherein said process variant B comprises

[0032] bl) converting the fatty acid compound of the formula Ila with a N-hydroxysuccinimide source compound to form the A-hydroxysuccinimide ester of formula Illa

[0033] PROTl-O-19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-0 Su)-O-PROT1

[0034] (Illa),

[0035] wherein AEEAc and PROT1 are as above,

[0036] b2) coupling the A-hydroxysuccinimide ester of formula Illa with L-Lys-OH to form the Lys fatty acid compound of the formula IVa

[0037] H-Lys (AEEAc-AEEAc- y -Glu(O-PROTl)-19-carboxy-nonadecanoyl-O-PROTl)-OH

[0038] (IVa),

[0039] wherein AEEAc and PROT1 are as above, and

[0040] b3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia;

[0041] or according to process variant C, wherein said process variant C comprises

[0042] cl) converting the fatty acid compound of the formula Ila

[0043] PROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc- AEEAc-OH)-O-PROT 1

[0044] (Ha),wherein AEEAc and PROT1 are as above,

[0045] with an amino- and carboxy-group protected Lys to form a protected Lys fatty acid compound of the formula Va

[0046] PROT3-Lys (AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-O-PROT2

[0047] (Va),

[0048] wherein AEEAc and PROT1 are as above, PROT2 is an ester protecting group and PROT3 is an amino protecting group;

[0049] c2) removing the protecting groups PROT2 and PROT3 to form the Lys fatty acid compound of the formula IVa

[0050] H-Lys(AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH

[0051] (IVa),

[0052] wherein AEEAc and PROT1 are as above, and

[0053] c3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia.

[0054] 2-(2-{2-[2-(2-amino-ethoxy)-ethoxy]-acetylamino}-ethoxy)-ethoxy]-acetic acid (AEEAc-AEEAc) corresponds to 17-amino-10-oxo-3,6,12,15-tetraoxa-9-azaheptadecan-l-oic acid (CAS Reg. No. 1143516-05-5).

[0055] DETAILED DESCRIPTION

[0056] The following definitions are set forth to illustrate and define the meaning and scope of the various terms used to describe the invention herein.

[0057] The term "pharmaceutically acceptable salt" refers to those salts which retain the biological effectiveness and properties of the free bases or free acids, which are not biologically or otherwise undesirable. The salts are formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, in particular hydrochloric acid, and organic acids such as acetic acid, trifluoroacetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid,methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, N-acetyl cysteine and the like. In addition, these salts may be prepared by addition of an inorganic base or an organic base to the free acid. Salts derived from an inorganic base include but are not limited to, the sodium, potassium, lithium, ammonium, calcium, magnesium salts and the like. Salts derived from organic bases include but are not limited to salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, ethanolamine, lysine, arginine, N-ethylpiperidine, piperidine, polyimine resins and the like.

[0058] The term “ester protecting group” refers to protecting groups of carboxylic acid functionalities.

[0059] Some ester protecting groups, like tert-butyl (tBu) are cleavable under acidic conditions, e.g. with trifluoroacetic acid while other ester protecting groups, like e.g. benzyl can be removed via catalytic hydrogenolysis. These different cleaving properties can be advantageously applied in the process of the present invention.

[0060] The term 19-carboxy-nonadecanoyl refers to the moiety

[0061]

[0062] An alternative term for this moiety is O-20-oxoicosanoyl.

[0063] The preferred protecting groups PROT for the compounds used in process variants A, B and C are as follows:

[0064] For PROT1 the protecting group tert-butyl (tBu) is preferred. PROT2 is preferably an ester protecting group which is removable by catalytic hydrogenation, in particular benzyl (Bzl). PROT3 is preferably benzyloxycarbonyl (Cbz).

[0065] Process variant A

[0066] Process variant A, requires the steps ofal) converting the fatty acid compound of the formula Ila with a N-hydroxysuccinimide source compound to form the A-hydroxysuccinimide ester of formula Illa,

[0067] PROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-0 Su)-O-PROT 1 (Illa), wherein AEEAc and PROT1 are as above, and

[0068] a2) coupling the A-hydroxysuccinimide ester of formula Illa with Bsmoc-Lys-OH to form the Bsmoc Lys fatty acid compound of the formula la.

[0069] In a preferred aspect of the invention, the process variant A comprises the formation of

[0070] Bsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH

[0071] (Ib),

[0072] wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, by

[0073] al) converting the fatty acid compound of the formula lib

[0074] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu

[0075] (lib),

[0076] wherein AEEAc is as above,

[0077] with a N-hydroxysuccinimide source compound to form the N-hydroxysuccinimide ester of formula IIIb,

[0078] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu

[0079] (IIIb),

[0080] wherein AEEAc is as above, and

[0081] a2) coupling the N-hydroxysuccinimide ester of formula IIIb with Bsmoc-Lys-OH to form the Bsmoc Lys fatty acid compound of the formula Ib.

[0082] Step al):Suitable A-hydroxysuccinimide sources can be selected from from A’-disuccinimidyl carbonate (DSC), or from A-hydroxysuccinimide in combination with a coupling reagent selected from AA’-dicyclohexylcarbodiimide (DCC), AA'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) or l,l'-carbonyldiimidazole (CDI). AA’-disuccinimidyl carbonate (DSC) is the preferred A-hydroxysuccinimide source compound.

[0083] The reaction is typically performed in the presence of an organic catalyst and an organic solvent at a temperature of 10°C to 30°C, preferably at ambient temperature.

[0084] Suitable organic catalysts are selected from 4-dimethylaminopyridine (DMAP), N-methylmorpholine, N-methylimidazole, preferably from 4-dimethylaminopyridine.

[0085] Suitable organic solvents can be selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), preferably from acetonitrile.

[0086] Step a2)

[0087] The reaction is typically performed in the presence of a silylating agent, an organic base and an organic solvent at a temperature of 10°C to 30°C, preferably at ambient temperature.

[0088] Suitable silylating agents can be selected from trimethylsilylchloride, N, O-bis(trimethylsilyl)acetamide, hexamethyldisilazane, N, O-bis(trimethylsilyl)trifluoroacetamide or trimethylsilyl trifluoromethanesulfonate. Preferably N, O-bis(trimethylsilyl)acetamide is used.

[0089] The organic base is selected from N,N-diisopropylethylamine, triethylamine or N-methylmorpholine, preferably from N,N-diisopropylethylamine and the organic solvent is selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), preferably from acetonitrile.

[0090] The Bsmoc-Lys-OH is usually applied in the form of its HC1 salt.

[0091] Process Variant B:

[0092] Process variant B requires

[0093] bl) converting the fatty acid compound of the formula IIa with a N-hydroxysuccinimide source compound to form the N-hydroxysuccinimide ester of formula IIIa,PROTl-O-19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-OSu)-O-PROTl

[0094] (Illa),

[0095] wherein AEEAc and PROT1 are as above,

[0096] b2) coupling the A-hydroxysuccinimide ester of formula Illa with Lys-OH to form the Lys fatty acid compound of the formula IVa

[0097] H-Lys(AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH

[0098] (IVa),

[0099] wherein AEEAc and PROT1 are as above, and

[0100] b3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia.

[0101] In one preferred aspect of the invention, the process variant B comprises the formation of

[0102] Bsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH

[0103] (Ib),

[0104] wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, by

[0105] bl) converting the fatty acid compound of the formula lib

[0106] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu

[0107] (lib),

[0108] wherein AEEAc is as above,

[0109] with a Ahydroxysuccinimide source compound to form the N-hydroxysuccinimide ester of formula Illb,

[0110] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu

[0111] (IIIb),

[0112] wherein AEEAc is as above,b2) coupling the 7V-hydroxysuccinimide ester of formula Illb with L-Lys-OH to form the Lys fatty acid compound of the formula IVb

[0113] H-Lys(AEEAc-AEEAc- y -Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH

[0114] (IVb),

[0115] wherein AEEAc is as above, and

[0116] b3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVb with Bsmoc-OSu to form the Bsmoc Lys fatty acid compound of the formula lb.

[0117] Step bl)

[0118] Suitable 7V-hydroxysuccinimide sources can be selected from from 7V,7V’-disuccinimidyl carbonate (DSC), or from V-hydroxysuccinimide in combination with a coupling reagent selected from

[0119]

[0120] ’-di cyclohexyl carbodi imide (DCC), V V'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) or 1,1 '-carbonyldiimidazole (CDI). V, V’-disuccinimidyl carbonate (DSC) is the preferred V-hydroxysuccinimide source compound.

[0121] The reaction is typically performed in the presence of an organic catalyst and an organic solvent at a temperature of 10°C to 30°C, preferably at ambient temperature.

[0122] Suitable organic catalysts are selected from 4-dimethylaminopyridine (DMAP), N-methylmorpholine, N-methylimidazole, preferably from 4-dimethylaminopyridine.

[0123] Suitable organic solvents can be selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidon (NMP), N,N-dimethylacetamide (DMAc), preferably from acetonitrile.

[0124] Step b2)

[0125] In order to enable selective coupling of the ε-amino group of L-Lys with the N-hydroxysuccinimide ester of formula IIIa or IIIb, the α-amino group needs to be protected, typically by forming a complex with a Cu-salt. A suitable Cu-salt is Cu-sulfate and the HC1 salt of L-Lys OH is used. This formation of a Cu-lysinate complex can take place at ambienttemperature, in the presence of an inorganic base selected from an alkali hydrogen carbonate or an alkali carbonate in water. Preferred inorganic base is sodium hydrogen carbonate.

[0126] The coupling itself can take place in an aqueous basis environment at a pH of about 8.0 to 8.5 at a temperature of about 0°C to 20°C.

[0127] Upon completion of the coupling reaction the Cu-lysinate complex can be removed by adding EDTA (ethylenediaminetetraacetic acid disodium salt dehydrate).

[0128] The isolation of the Lys fatty acid compound of the formula IVa / IVb can be performed by extraction with an organic solvent, preferably 2-methyltetrahydrofuran, followed by crystallization from a different organic solvent, preferably acetonitrile, followed by reslurry in a different organic solvent system, preferably a mixture of acetonitrile and tetrahydrofuran.

[0129] Step b3)

[0130] The reaction of the Lys fatty acid compound of the formula IVa / IVb with Bsmoc OSu can be performed in the presence of an inorganic base selected from an alkali hydrogencarbonate or an alkali carbonate in a solvent selected from water or N, N-dimethylformamide or mixtures thereof at a temperature of 10°C to 30°C, preferably at ambient temperatures.

[0131] Preferred inorganic base is sodium carbonate and preferred solvent is a mixture of water and N,N-dimethylformamide.

[0132] The isolation of the Bsmoc Lys fatty acid compound of the formula la / lb can be performed after acidic quench by extraction with an organic solvent, preferably methyl tertbutyl ether, followed by washing with aqueous DMF and removal of organic solvent.

[0133] Process Variant C:

[0134] Process variant C requires

[0135] cl) converting the fatty acid compound of the formula Ila with an amino- and carboxy -group protected Lys to form a protected Lys fatty acid compound of the formula Va

[0136] PROT3-Lys (AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-O-PROT2

[0137] (Va),wherein AEEAc and PROT1 are as above, PROT2 is an ester protecting group and PROT3 is an amino protecting group;

[0138] c2) removing the protecting groups PROT2 and PROT3 to form the Lys fatty acid compound of the formula IVa

[0139] H-Lys(AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH

[0140] (IVa),

[0141] wherein AEEAc and PROT1 are as above, and

[0142] c3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia.

[0143] In a preferred aspect of the invention, the process variant C comprises the formation of

[0144] Bsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH

[0145] (Ib),

[0146] wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, by

[0147] cl) converting the fatty acid compound of the formula lib

[0148] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu

[0149] (lib)

[0150] wherein AEEAc is as above,

[0151] with Cbz-Lys-OBzl to form a protected Lys fatty acid compound of the formula Vb

[0152] Cbz-Lys (AEEAc- AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-O-Bzl

[0153] (Vb)

[0154] wherein AEEAc is as above,

[0155] c2) removing the Bzl and Cbz protecting groups to form the Lys fatty acid compound of the formula IVb

[0156] H-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(IVb),

[0157] wherein AEEAc is as above, and

[0158] c3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVb with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula lb.

[0159] Step cl)

[0160] The formation of the Lys fatty acid compound of the formula Va / Vb can be performed in the presence of a coupling agent, an organic base and an organic solvent.

[0161] Suitable coupling agents can be selected from benzotriazol- 1-yloxytris (dimethylamino) phosphonium hexafluorophosphate (BOP), b enzotri azol -1-yl oxy tripyrrolidino phosphonium hexafluorophosphate (PyBOP), bromotripyrrolidinophosphonium hexafluorophosphate (PyBrOP), (7-azabenzotriazol-l-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyAOP), N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium tetrafluoroborate N-oxide (TBTU), 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium hexafluorophosphate (HBTU), 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate, N-[(dimethylamino)-3H-1,2,3-triazolo-[4,5-b]pyridin-3-yloxy)methylene]-N-methylmethanaminium hexafluorophosphate (HATU), propanephosphonic acid anhydride (T3P) or from a combinations of N,N'-diisopropylcarbodiimide (DIC) with N-hydroxysuccinimide, with 4-(dimethylamino)pyridine (DMAP), with 2-hydroxypyridine-N-oxide (HOPO) or with (ethyl-cyano (hydroximino) acetate) (Oxyma Pure) or from a combination of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) with 2-hydroxypyridine-N-oxide (HOPO).

[0162] Preferred coupling agent is 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium hexafluorophosphate (HBTU).

[0163] The organic base can be selected from N,N-diisopropylethylamine (DIPEA), N-methylmorpholine (NMM), N-methylimidazol (NMI) or triethylamine. Preferably N,N-diisopropylethylamine is used.

[0164] Suitable organic solvents can be selected from N,N-dimethylformamide, methyl tert-butyl ether (MTBE), toluene, acetonitrile or mixtures thereof. Preferred is a solvent mixture of N,N-dimethylformamide and methyl tert-butyl ether (MTBE).The reaction temperature is chosen between 10°C to 30°C, preferably at ambient temperature.

[0165] Upon completion of the reaction the Lys fatty acid compound of the formula IVa / Vb can be taken up in an organic solvent, preferably 2-methlytetrahydrofuran and subjected to the hydrogenation in step c2).

[0166] Step c2)

[0167] The removal of the protecting group PROT2, preferably Bzl and PROT3, preferably Cbz, is typically performed by catalytic hydrogenation with hydrogen and a Pd-catalyst in an organic solvent.

[0168] Suitable Pd catalysts are Pd 0.5 to 20.0 % on carbon and suitable solvents are toluene, tetrahydrofuran, 2-methyltetrahydrofuran or ethyl acetate, preferably 2-methyltetrahydrofuran.

[0169] The hydrogenation can take place at a temperature of 10°C to 30°C, preferably at ambient temperature and hydrogen pressures between 1 bar and 5 bar, preferably 1 to 3 bar, more preferably at ambient hydrogen pressure.

[0170] The isolation of the Lys fatty acid compound of the formula IVa / IVb can be performed by filtering off the catalyst, washing the filtrate and by crystallization with a suitable organic solvent, preferably acetonitrile.

[0171] Step c3)

[0172] The reaction of the Lys fatty acid compound of the formula IVa / IVb with Bsmoc OSu can be performed in the presence of an inorganic base selected from an alkali hydrogencarbonate or an alkali carbonate in a solvent selected from water or N, N-dimethylformamide or mixtures thereof at a temperature of 10°C to 30°C, preferably at ambient temperatures.

[0173] Preferred inorganic base is sodium carbonate and preferred solvent is a mixture of water and N,N-dimethylformamide.

[0174] The isolation of the Bsmoc Lys fatty acid compound of the formula la / lb can be performed after acidic quench by extraction with an organic solvent, preferably methyl tertbutyl ether, followed by washing with aqueous DMF and removal of organic solvent..In another aspect of the invention, the fatty acid compound of formula la or lb, prepared in accordance with the process of the present invention can be used for the preparation of peptides, particularly for the preparation of the peptide of formula Villa (SEQ ID NO: 1), or of a pharmaceutically acceptable salt or ester thereof

[0175] X1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2

[0176]

[0177] wherein X1is

[0178]

[0179] AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

[0180] In another aspect, the invention comprises the use of the fatty acid compound of the formula la or lb, prepared according to the process of the present invention, for the preparation of peptide compounds, particularly for the preparation of peptides of the formula Villa (SEQ ID NO: 1), or of a pharmaceutically acceptable salt or ester thereof

[0181] X1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2

[0182] (VIIIa)

[0183] wherein X1is

[0184]

[0185] CN andAEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

[0186] In another aspect, the invention comprises a process for the preparation of a peptide comprising the addition of the fatty acid compound of the formula la or lb, prepared according to the process of the preset invention, as a side chain.

[0187] In a particular aspect the invention, the peptide has the formula Villa (SEQ ID NO:1), or is a pharmaceutically acceptable salt or ester thereof

[0188] X1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2

[0189] (VIIIa)

[0190] wherein X1is

[0191]

[0192] CN and

[0193] AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.Examples

[0194] Abbreviations:

[0195] Boc tert-butyloxycarbonyl

[0196] BSA N, O-bis(trimethylsilyl)acetamide

[0197] Bsmoc 1,1-dioxobenzo[b]thiophene-2-ylmethyloxycarbonyl

[0198] Bzl benzyl

[0199] Cbz benzyloxycarbonyl

[0200] DIPEA diisopropylethylamine

[0201] DMAc N,N-dimethylacetamide

[0202] DMAP 4-dimethylaminopyridine

[0203] DMF N, N-dimethylformamide

[0204] DMSO dimethylsulfoxide

[0205] DSC N, N’-disuccinimidyl carbonate

[0206] EDTA ethylenediamine tetra-acetic acid

[0207] Eic eicosanedioic acid

[0208] EtOAc ethyl acetate

[0209] HBTU hexaafluorophosphate benzotriazole tetramethyl uronium

[0210] MeCN acetonitrile

[0211] 2-MeTHF 2-methyltetrahydrofuran

[0212] MTBE methyl tert-butyl ether

[0213] NMP N-methylpyrrolidone

[0214] sc side chain (AEEAc-AEEAc- γ –Glu(O-tBu)-19- carboxy-nonadecanoyl-O-tBu)

[0215] tBu tert-butylTMSC1 trimethylsilylchloride

[0216] Synthesis of tBu-O-19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-OH)-O-tBu

[0217] L-Glu(OBzl)-OtBu·HCl, HBTU DIPEA, DMF / toluene (1:3 v / v)

[0218] tBu-O-19-carboxy-nonadecanoic acid tBu-O-19-carboxy-nonadecanoyl-L-Glu(OBzl)-OtBu toluene solution Pd / C, H2(1 atm) toluene

[0219] DSC, DMAP

[0220] tBu-O-19-carboxy-nonadecanoyl)-L-Glu(OSu)-OtBu tBu-O-19-carboxy-nonadecanoyl-L-Glu-OtBu MeCN suspension AEEA-AEEA, TMSCI DIPEA, MeCN

[0221]

[0222] tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu

[0223] tBu-O-19-carboxy-nonadecanoyl acid (100 g, 251mmol, 1.0 equiv.), L-Glu(OBzl)-OtBu·HCl (88.7 g, 263 mmol, 1.05 equiv.) and HBTU (99.9 g, 263mmol, 1.05 equiv.) were taken up in DMF (100 mL, 1 vol.) and toluene (300 mL, 3vol.) at ambient temperature. DIPEA (81.1 g, 627mmol, 2.5equiv) was added over 1 h, and the resulting reaction mixture was stirred at ambient temperature for 4 h. Upon completion of the reaction, toluene (200 mL, 2.0 vol.) and water (300 mL, 3 vol.) were added and the phases were separated. The organic phase was sequentially washed with 8% NaHCO₃ solution (300 mL + 100 mL, 3.0 vol. + 1.0 vol.) and water (100 mL, 1.0 vol.) before it was treated with charcoal (2g, 2 w%) at ambienttemperature for 3 h. The resulting mixture was filtered, and the filter cake was washed with toluene (2x100 mL, 2 xl. O vol.). The resulting filtrate containing tBu-O-19-carboxy-nonadecanoyl-L-Glu(OBzl)-OtBu was directly used in the following transformation (assumed yield 100%).

[0224] 1H NMR (400 MHz, DMSO-d6): δ 8.05 (d, J= 7.6 Hz, 1H), 7.39–7.30 (m, 5H), 5.09 (s, 2H), 4.14 (ddd, J=8.8, 8.0, 1.2 Hz, 1H), 2.46–2.36 (m, 2H), 2.16 (t, J= 7.2 Hz, 2H), 2.08 (t, J= 7.2 Hz, 2H), 2.01–1.92 (m, 1H), 1.84–1.74 (m, 1H), 1.52–1.42 (m, 4H), 1.39 (s, 9H), 1.38 (s, 9H), 1.22 (s, br, 28H).

[0225] 5% wet Pd / C (3.38 g, 2 w% with respect to the amount of tBu-O-19-carboxy-nonadecanoyl-L-Glu(OBzl)-OtBu, water content 50%) was added to the above solution of tBu-O-19-carboxy-nonadecanoyl-L-Glu(OBzl)-OtBu in toluene (251 mmol, 1.0 equiv) and the resulting reaction mixture was stirred under a H2atmosphere at ambient pressure and temperature for 18 h. Upon completion of the reaction, the mixture was filtered, the filter cake was washed with toluene (2x100 mL, 2x 0.6 vol.), and the resulting filtrate was concentrated under reduced pressure. The resulting oil was taken up in MeCN (500 mL, 3.0 vol.) and the mixture was partially concentrated under reduced pressure to afford a suspension. Another portion of MeCN (500 mL, 3.0 vol.) was added and the suspension was again concentrated under reduced pressure to afford a suspension (ca. 700 g) containing tBu-O-19-carboxy-nonadecanoyl-L-Glu-OtBu, which was directly used in the following transformation (assumed yield 100%).

[0226] 1H NMR (400 MHz, DMSO-d6): δ 12.14 (s, 1H), 8.04 (d, J= 8.0 Hz, 1H), 4.11 (ddd, J= 8.8, 8.0, 1.2 Hz, 1H), 2.26 (td, J= 8.0, 3.6 Hz, 2H), 2.16 (t, J= 7.6 Hz, 2H), 2.09 (t, J= 7.6 Hz, 2H), 1.94–1.85 (m, 1H), 1.78–1.68 (m, 1H), 1.52–1.42 (m, 4H), 1.39 (s, br, 18H), 1.23 (s, br, 28H).

[0227] DSC (70.7 g, 276 mmol, 1.1 equiv.) and the above suspension of tBu-O-19-carboxy-nonadecanoyl-L-Glu-OtBu in MeCN (251 mmol, 1.0 equiv) were taken up in MeCN (760 mL, 5.0 vol.), and the resulting suspension was stirred at ambient temperature for 30 min before DMAP (3.1 g, 25 mmol, 0.10 equiv.) was added. The resulting reaction mixture was stirred at 30 °C for 1 h. Upon completion of the reaction, the mixture was cooled to 0 C and was stirred at this temperature for 3 h. The mixture was then warmed to ambient temperature, stirred for 1 h, and cooled again to 0 °C and stirred for 3 h. The resulting suspension was filtered, and the filter cake was washed with pre-cooled (0 °C) MeCN (2x 70 mL, 2x0.5 vol.) and dried under vacuum at 25 °C to afford tBu-O-19-carboxy-nonadecanoyl)-L-Glu(OSu)-OtBu (160 g, 90% yield over 3 steps, 96.7% assay purity) as a white solid.1H NMR (400 MHz, DMSO-d6): δ 8.11 (d, J= 7.6 Hz, 1H), 4.16 (ddd, J= 9.2, 7.6, 1.6 Hz, 1H), 2.81 (s, 4H), 2.79–2.63 (m, 2H), 2.16 (t, J= 6.0 Hz, 2H), 2.11 (t, J= 6.0 Hz, 2H), 2.06–1.99 (m, 1H), 1.93–1.83 (m, 1H), 1.50–1.45 (m, 4H), 1.39 (s, 9H), 1.38 (s, 9H), 1.23 (s, br, 28H).

[0228] TMSC1 (10.4 g, 95.7 mmol, 1.30 equiv.) was taken up in MeCN (258 mL, 5.0 vol.). AEEAc-AEEAc (25.0 g, 81.1 mmol, 1.10 equiv.) was added in one portion at ambient temperature, and the resulting suspension was stirred at this temperature for 1 h to afford a clear solution. A suspension of tBu-O-19-carboxy-nonadecanoyl)-L-Glu(OSu)-OtBu ( (52.0 g, 73.8 mmol, 1.0 equiv.) in MeCN (258 mL, 5 vol.) was added, followed by DIPEA (23.9 g, 185 mmol, 2.5 equiv.). The resulting reaction mixture was stirred at ambient temperature for 2 h. Upon completion of the reaction, water (2 mL) was added, and the mixture was stirred at ambient temperature for 10 min before 10% aq. HC1 (2.7 mL) was added and the mixture was concentrated under reduced pressure. The resulting oil was taken up in 2-MeTHF (260 mL, 5 vol.) and water (156 mL, 3 vol.), and 10% aq. HC1 (43 mL, 0.8 vol.) was added. The phases were separated, and the organic phase was washed with 2% aq. NaCl solution (6x156 mL, 6x3 vol.) and concentrated under reduced pressure. The resulting residue was taken up in MeCN (260 mL, 5.0 vol.), and the resulting mixture was again concentrated under reduced pressure. This step was repeated once again. Then, the residue was taken up in MeCN (520 mL, 10.0 vol.), and the mixture was cooled to -15 °C. The resulting suspension was stirred at this temperature for 3 h before it was filtered and the filter cake was washed with pre-cooled (-10 °C) MeCN (50 mL, 1.0 vol.). The resulting solid was dried under vacuum while gradually increasing the temperature from -10 °C to 20 °C to afford tBu-O-19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-OH)-O-tBu (58 g, 90% yield, purity 99.7 area%) as a white solid.

[0229] 1H NMR (400 MHz, DMSO-d6): δ 8.05 (d, J= 7.5 Hz, 1H), 7.89 (t, J= 5.5 Hz, 1H), 7.65 (t, J = 5.7 Hz, 1H), 4.07–4.02 (m, 1H), 4.00 (s, 2H), 3.87 (s, 2H), 3.59–3.51 (m, 8H), 3.44–3.34 (m, 5H), 3.27 (q, J= 5.8 Hz, 2H), 3.20 (q, J= 5.8 Hz, 2H), 2.17–2.07 (m, 6H), 1.93–1.84 (m, 1H), 1.78–1.68 (m, 1H), 1.47 (s, br, 4H), 1.37 (s, br, 18H), 1.23 (s, br, 28H).Synthesis of Bsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH) (or Bsmoc-Lys(sc)-OH)

[0230] Route A

[0231] NHBoc

[0232] H2N

[0233] aq. HCI, MeCN

[0234]

[0235] Bsmoc-Lys-OH-HCI

[0236] NMP solution

[0237] a) Synthesis of Bsmoc-Lys-OH HC1

[0238] Copper sulfate pentahydrate (7.0 g, 28 mmol, 0.5 equiv.) was added in portions to a solution of L-Lys-OH·HCl (10 g, 54.7 mmol, 1.0 equiv.) and NaHCO₃ (9.2 g, 110 mmol, 2.0equiv.) in water (200 mL, 20.0 vol.) at ambient temperature. The resulting blue solution was warmed to 40° C and di tert-butyl dicarbonate (17.9 g, 82.0 mmol, 1.5 equiv.) was added dropwise while maintaining the pH of the reaction mixture at 9.0-9.5 by addition of aq. NaOH (30 w%, 22 mL). The resulting mixture was allowed to stir at 40° C for 4 h. Upon completion of the reaction, EtOAc (20 mL, 2.0 vol.) was added to the blue suspension and the mixture was stirred at 40° C for 2 h. Then, the suspension was acidified with aq. HC1 (30 w%, 20 mL, 2 vol.) to pH 3.0-3.5. A blue solid was isolated by filtration, which was purified by re-slurry in water (100 mL, 10.0 vol.) and dried to afford L-Lys(Boc) copper complex (10.8 g, 71% yield) as a blue solid.

[0239] Acetone (67 mL, 6 vol.) was added to a mixture of L-Lys(Boc) copper complex (10.8 g, 19.5 mmol, 1.0 equiv), ethylenediaminetetraacetic acid disodium salt dihydrate (8.7 g, 23.4 mmol, 1.2 eq.), and NaHCO₃ (4.9 g, 58 mmol, 3.0 equiv.) in water (48 mL, 4.4 vol.) ambient temperature. The resulting blue mixture was stirred at this temperature for 15 min. Then, BsmocOSu (11.8 g, 35.1mmol, 1.8 eq.) was added in portions over 20 min and the reaction mixture was stirred at ambient temperature for 1 h. Upon completion of reaction, MTBE (120mL, 11.0 vol.) was added and the pH of the mixture was adjusted to 3.0-3.5 by addition of aq. HC1 (30 w %). The phases were separated and the organic phase was washed with water (4 x 35 mL, 4 x 3.0 vol.) and concentrated under reduced pressure to afford Bsmoc-Lys(Boc)-OH (14.1 g, 86% yield, purity 98 area%) as an oil.

[0240] A mixture of Bsmoc-Lys(Boc)-OH (14.1 g, 30.1mmol, 1.00 eq.), MeCN (26 mL, 1.8 vol.), water (52 mL, 3.7 vol.) and aq. HC1 (30 w%, 11.0 g, 90 mmol, 3.0 eq.) was stirred at ambient temperature for 8 h. Upon completion of the reaction, the mixture was concentrated under reduced pressure to remove MeCN. The resulting aqueous solution was washed with CH2Cl2(3 x 30 mL, 3 x 2.0 vol.) and concentrated under reduced pressure to afford a sticky oil. NMP (20 mL, 1.4 vol.) and MeCN (80 mL, 5.7 vol.) were added to the residue and the resulting solution was concentrated under reduced pressure to afford a clear NMP solution of Bsmoc-Lys-OH HCl (35 g, assumed yield 100%, purity 98.5 area%) which was directly used in the following transformation.

[0241] b) Synthesis of Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy-nonadecanoyl-O-ZBu)-OH

[0242] tBu-O-19-carboxy-nonadecanoyl- tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-fBu L-Glu(AEEAc-AEEAc-OH)-O-tBu MeCN solution Bsmoc-Lys-OH. HCI BSA, DIPEA MeCN / NMP

[0243]

[0244] Bsmoc-Lys(AEEAc-AEEAc-Y-Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH

[0245] To a mixture of ZBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu (1.7 g, 1.9 mmol, 1.0 eq.) and DSC (0.61 g, 2.4 mmol, 1.2 equiv.) in MeCN (17 mL, 10.0 vol.) at ambient temperature was added DMAP (24 mg, 0.19 mmol, 0.1 eq.) in one portion. The resulting mixture was stirred at this temperature for 1 h to afford a clear solution of / Bu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu in MeCN. In a separate vessel, the above NMP solution of Bsmoc-Lys-OH HC1 (3.5 g, 3.0 mmol, 1.5 equiv.) was cooled to 0° C. BSA (0.92 g, 4.5 mmol, 2.4 equiv.) was added and the resulting mixture was stirred at 0° C for 15 min. The above ZBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu solution was added at 0° C over 5 min, followed by the dropwise addition of DIPEA (0.58 g, 4.5 mmol, 2.4 equiv.). The resulting reaction mixture was stirred at 0° C for 8 h. Upon completion of reaction, the reaction mixture was quenched with aq. HC1 and the mixture was concentrated under reduced pressure to afford an oily residue, to which EtOAc (25 mL, 15.0 vol.) was added. The phases were separated and the organic phase was washed with water (4 x 8 mL, 4 x 5.0 vol.) and concentrated under reduced pressure to furnish Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy -nonadecan oyl-O-ZBu)-OH (1.5 g, 64% yield, purity 73 area%) as a gummy oil.

[0246] Route B

[0247] Synthesis of Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy-nonadecanoyl-O-ZBu)- OH

[0248] DSC, DMAP MeCN

[0249] fBu-O-19-carboxy-nonadecanoyl- tBu-O-19-carboxy-nonadecanoyl- L-Glu(AEEAc-AEEAc-OH)-O-fBu L-Glu(AEEAc-AEEAc-OSu)-O-tBu MeCN solution 1) L-Lys-OH HCI NaHCO3, water 2) EDTA 2Na 2-MeTHF

[0250] BsmocOSu, Na2CO3 DMF, H2O

[0251] Bsmoc-Lys(AEEAc-AEEAc-Y-Glu(O-tBu)- H-Lys(AEEAc-AEEAc-Y-Glu(O-tBu)-

[0252]

[0253] 19-carboxy-nonadecanoyl-0-tBu)-OH 19-carboxy-nonadecanoyl-0-tBi / )-OH

[0254] DMAP (0.13 g, 1.1 mmol, 0.1 equiv) was added to a mixture of ZBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-ZBu (9.0 g, 10.0 mmol, 1.0 equiv) and DSC (2.9 g, 11.0 mmol, 1.1 equiv.) in MeCN (45 mL, 5 vol.) at ambient temperature. The resultingreaction mixture was stirred at ambient temperature for 1 h to afford a clear solution of / Bu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-ZBu in MeCN.

[0255] L-Lys-OH HC1 (3.76 g, 20.6 mmol, 2.0 equiv), water (45 mL, 5.0 vol.), sodium bicarbonate (3.46 g, 41 mmol, 4.0 equiv.) and copper sulfate pentahydrate (2.70 g, 10.8 mmol, 1.05 eq.) were mixed at ambient temperature. The resulting blue solution was cooled to 0° C and the above solution of ZBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu was slowly added while keeping the pH of the reaction mixture at pH 8.0-8.5 by addition of aq. NaOH (30 w%). The resulting dark blue reaction mixture was stirred at 0° C for 1 h. Upon completion of reaction, ethylenediaminetetraacetic acid disodium salt dihydrate (8.43 g, 22.6 mmol, 2.2 equiv.) and 2-MeTHF (100 mL, 11.0 vol.) were added before aq. HC1 (30 w%, 3 mL) was added to adjust the pH of the mixture to 3.0-3.5. The phases were separated and the organic phase was washed with 2% aq. NaCl solution (3 x 50 mL, 3 x 5.6 vol.), dried over Na2SO4, filtered, and concentrated under reduced pressure. MeCN (150 mL, 16.7 vol.) was added to the residue and the resulting suspension was stirred at ambient temperature for 1 h. The solid was isolated by filtration and the wet cake was re-slurried in MeCN (100 mL, 11.0 vol.) and THF (10 mL / 1.1 vol.) twice, followed by drying of the solid to afford H-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy-nonadecanoyl-O-ZBu)-OH as a white solid (7.0 g, 68% yield, purity 98.2 area%).

[0256] 'H NMR (400 MHz, DMSO-6): d 8.09 (d, J= 7.3 Hz, 1H), 7.97 (t, J= 4.9 Hz, 1H), 7.71 (t, J = 5.9 Hz, 2H), 4.03 (dd, J= 13.6, 8.0 Hz, 1H), 3.88 (s, 2H), 3.86 (s, 2H), 3.56 (s, br, 8H), 3.47-3.39 (m, 5H), 3.28 (dd, J= 11.2, 5.2 Hz, 2H), 3.20 (dd, J= 10.8, 5.2 Hz, 2H), 3.09 (dd, J= 12.0, 6.0 Hz, 2H), 2.18-2.08 (m, 6H), 1.93-1.83 (m, 1H), 1.77-1.61 (m, 3H), 1.54-1.23 (m, 54H).

[0257] A solution of BsmocOSu (0.74 g, 2.2 mmol, 1.1 eq.) in DMF (20 mL, 10.0 vol.) was added to a mixture of H-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)- 19-carboxy -nonadecan oyl-O- / Bu)-OH (2.0 g, 2.0 mmol, 1.0 equiv.) and Na2CO3(0.25 g, 2.4 mmol, 1.2 equiv.) in DMF (20 mL, 10.0 vol.) and water (40 mL, 20.0 vol.) at ambient temperature. The resulting reaction mixture was stirred at this temperature for 1 h. Upon completion of reaction, the mixture was quenched with aq. HC1 (30 w%, 0.2 g) and then extracted with MTBE (40 mL, 20.0 vol.). The phases were separated and the organic phase was washed with a mixture of DMF (20 mL, 10.0 vol.) and water (40 mL, 20.0 vol.) three times, followed by concentration under reduced pressure to afford an oily residue which was diluted with 2-MeTHF (40 mL, 20.0 vol.). The resulting solution was washed with 2% aq. NaCl solution (2 x 20 mL, 2 x 10.0 vol.) and concentrated under reduced pressure to afford Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH (2.4 g, quant, yield, purity 98.9 area%) as an oil.

[0258] 'H NMR (400 MHz, DMSO-6): d 12.59 (s, br, 1H), 8.05 (d, J= 7.5 Hz, 1H), 7.91-7.88 (m, 2H), 7.73-7.60 (m, 6H), 7.53 (s, 1H), 5.01 (dd, J= 20.0, 14.3 Hz, 2H), 4.07-4.00 (m, 1H), 3.93-3.87 (m, 1H), 3.87 (s, 2H), 3.84 (s, 2H), 3.55 (s, br, 8H), 3.46-3.39 (m, 4H), 3.28 (dd, J = 11.6, 6.0 Hz, 2H), 3.20 (dd, J= 11.6, 5.6 Hz, 2H), 3.06 (dd, J= 12.8, 6.4 Hz, 2H), 2.18-2.07 (m, 6H), 1.93-1.84 (m, 1H), 1.72-1.56 (m, 3H), 1.47-1.23 (m, 54H).

[0259] Route C

[0260] a) Synthesis of Cbz-Lys-OBzl p-TsOH

[0261] 1) CUSO4-5H2O, BOC2O

[0262] CO2H CO2H DCHA

[0263] NaHCO3, water

[0264] Cbz.N>^^N, Boc H2N^>^ ‘NH2-HCI

[0265] 2) EDTA 2Na, K2CO3H H

[0266] CbzOSu, water

[0267] L-Lys-OH HCI Cbz-Lys(Boc)-OH ■ DCH A

[0268] BzIBr, K2CO3, DMF

[0269]

[0270] CO2Bzl

[0271] H H

[0272] Cbz-Lys(Boc)-OBzl

[0273] 1) HCI, EtOAc

[0274] 2) p-TsOH, MTBE

[0275] CO2Bzl Cbz^

[0276] N NH2p-TsOH

[0277]

[0278] H

[0279] Cbz-Lys-OBzl p-TsOH

[0280] Copper sulfate pentahydrate (74.8 g, 0.30 mol, 0.5 equiv.) was added in portions to a solution of L-Lys-OH HCI (110 g, 0.60 mol, 1.0 equiv.) and NaHCO3(101 g, 1.20 mol, 2.0 equiv.) in water (2.2 L, 20.0 vol.) at ambient temperature. The resulting blue solution was heated to 40° C and di tert-butyl dicarbonate (196 g, 0.90 mol, 1.5 equiv.) was added dropwise while maintaining the pH of the reaction mixture at 9.0-9.5 by addition of aq. NaOH (30 w%, 440mL). The resulting reaction mixture was stirred at 40° C for 4 h. Upon completion of the reaction, EtOAc (500 mL, 4.5 vol.) was added to the blue suspension and the resulting mixture was stirred at 40° C for 2 h. The suspension was then acidified with aq. HC1 (30 w%, 275 mL, 2.5 vol.) to pH 3.0-3.5. A blue wet solid (347 g) was isolated by filtration, to which was added K2CO3 (157 g, 1.1 mol, 1.0 equiv), ethylenediaminetetraacetic acid disodium salt dihydrate (111 g, 0.30 mol, 1.0 equiv.) and water (2.2 L, 20.0 vol.). The mixture was stirred at ambient temperature to afford a clear blue solution. A solution of CbzOSu (142 g, 0.57 mol, 0.95 equiv.) in acetone (1.2 L, 11.0 vol.) was slowly charged into the blue reaction mixture and the resulting mixture was stirred at ambient temperature for 3 h. Upon completion of the reaction, the reaction mixture was acidified with aq. HC1 (30 w%, 175 mL, 1.6 vol.) to pH 3.0-3.5 and extracted with EtOAc (1 L + 0.5 L, 9.0 vol. + 4.5 vol.). The combined organic phases were washed with water (300 mL, 2.7 vol.) and then heated to 45 °C. Dicyclohexylamine (103 g, 0.57 mol, 0.95 equiv.) was added and the resulting suspension was stirred at 45° C for 1 h and then at ambient temperature for 1 h. The resulting solid was isolated by filtration and dried to afford Cbz-Lys(Boc)-OH DCHA (278 g, 82% yield, purity 99.8 area%) as a white solid.

[0281] A suspension of Cbz-Lys(Boc)-OH DCHA (56.2 g, 0.10 mol, 1.0 equiv) in EtOAc (560 mL, 10 vol.) and water (100 mL, 1.8 vol.) was acidified with aq. H2SO4(20 w%, 50 mL, 0.9 vol.) to pH 2.0-2.5. The phases were separated and the organic phase was washed with water (2 x 200 mL, 2 x 3.6 vol.) and concentrated under reduced pressure to afford an oily residue. The residue was dissolved in DMF (116 mL, 2.0 vol.) and treated with K2CO3 (27.6 g, 0.20 mol, 2.0 equiv.) and benzyl bromide (18.7 g, 0.11 mol, 1.1 equiv.). The resulting suspension was stirred at ambient temperature for 2 h. Upon completion of the reaction, water (500 mL, 9 vol.) and heptane (200 mL, 3.6 vol.) were successively added and the resulting suspension was stirred at ambient temperature for Ih. The resulting solid was isolated by filtration and dried to afford Cbz-Lys(Boc)-OBzl (45 g, 96% yield, purity 99.7 area%) as a white solid.

[0282] HC1 gas (7.0 g, 0.19 mol, 2.5 equiv) was bubbled into a solution of Z-Lys(Boc)-OBzl (36 g, 77 mmol, 1.0 equiv) in EtOAc (216 mL, 6.0 vol.) at 10-25° C and the resulting reaction mixture was stirred at ambient temperature for 1 h. Upon completion of reaction, the reaction mixture was slowly added to a mixture of NaHCOs (19.3 g, 0.23 mol, 3.0 equiv.) in water (180 mL, 5 vol.). The phases were separated and the organic phase was sequentially washed with water (180 mL, 5.0 vol.) and sat. aq. NaCl solution (200 mL, 5.0 vol.) and concentrated under reduced pressure. The resulting residue was taken up in MTBE (300 mL, 8.0 vol.), / ?-TsOH H2O (14.9 g, 78 mmol, 1.0 equiv) was added, and the resulting suspension was stirredat ambient temperature for 1 h. The resulting solid was isolated by filtration and dried to afford Cbz-Lys-OBzl / ?-TsOH (35.2 g, 85% yield, purity 99.8 area %) as a white solid.

[0283] b) Synthesis of Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy-nonadecanoyl-O-ZBu)-OH

[0284] Cbz-Lys-OBzl p-TsOH HBTU, DIPEA DMF / MTBE

[0285] fBu-O-19-carboxy-nonadecanoyl- Cbz-Lys(AEEAc-AEEAc-y— Glu(O-tB u)- L-Glu(AEEAc-AEEAc-OH)-O-fBu 19-carboxy-nonadecanoyl-O-tBu)-O-Bzl H2, Pd / C 2-MeTHF

[0286] Bsmoc-Lys(AEEAc-AEEAc-Y-Glu(O-tBu)- H-Lys(AEEAc-AEEAc-y-Glu(O-tBu)-

[0287]

[0288] 19-carboxy-nonadecanoyl-O-tBu)-OH 19-carboxy-nonadecanoyl-O-tBu)-OH

[0289] DIPEA (1.7 g, 13 mmol, 2.3 equiv.) was slowly added to a mixture of ZBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-ZBu (5 g, 5.7 mmol, 1.0 equiv.), Cbz-Lys-OBzl / ?-TsOH (5 g, 9.2 mmol, 1.6 equiv) and HBTU (2.2 g, 5.8 mmol, 1.02 equiv.) in DMF (15 mL, 3.0 vol.) and MTBE (30 mL, 6.0 vol.) at ambient temperature. The resulting mixture was stirred at ambient temperature for 1 h. Upon completion of the reaction, the mixture was sequentially washed with water (20 mL, 4.0 vol.), 8% aq. NaHCOs solution (2 x 20 mL, 2 x 4.0 vol.) and 5% aq. citric acid solution (2 x 20 mL, 2 x 4.0 vol.) and concentrated under reduced pressure. The resulting crude Cbz-Lys(sc)-OBzl was taken up in 2-MeTHF (60 mL, 12.0 vol.) and 5% wet Pd / C (0.3 g, water content 60%) was added. The resulting suspension was stirred under a H2atmosphere at ambient pressure and ambient temperature for 4 h. Upon completion of the reaction, the mixture was filtered and the filtrate was washed with sat. aq. NaCl solution (2 x 30 mL, 2 x 6.0 vol.), dried over Na2SO4, filtered, and concentrated under reduced pressure. MeCN (100 mL, 20.0 vol.) was added to the residue and the resulting suspension was stirred at ambient temperature for 1 h. The resulting solid was isolated byfiltration and dried to afford H-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-l 9-carboxy-nonadecanoyl-O-ZBu)-OH (4.8 g, 84% yield, purity 99.1 area%) as a white solid.

[0290] The coupling of H-Ly s( AEE Ac- AEE Ac-y-Gl u(O- / Bu)- 19-carboxy-nonadecanoyl-O-ZBu)-OH with BsmocOSu and the formation of Bsmoc-Lys(AEEAc-AEEAc-y-Glu(O-ZBu)-19-carboxy-nonadecanoyl-O-ZBu)-OH was performed in accordance with Route B, as described above.

[0291] ***

Claims

Claims:

1. Process for the preparation of a Bsmoc Lys fatty acid compound of the formula laBsmoc-Lys(AEEAc-AEEAc- y -Glu(O-PROTl)-19-carboxy-nonadecanoyl-O-PROTl)-OH(la),wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid and PROT1 is an ester protecting group,comprising the introduction of the Bsmoc-Lys functionality in the fatty acid compound of the formula IlaPROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc- AEEAc-OH)-O-PROT 1(Ila),wherein AEEAc and PROT1 are as above,either according to process variant A, wherein said process variant A comprisesal) converting the fatty acid compound of the formula Ila with a N-hydroxysuccinimide source compound to form the A-hydroxysuccinimide ester of formula Illa,PROT 1 -O- 19-carboxy-nonadecanoyl-L-Glu (AEEAc- AEEAc-0 Su)-O-PROT 1 (Illa), wherein AEEAc and PROT1 are as above, anda2) coupling the A-hydroxy succinimide ester of formula Illa with Bsmoc-Lys-OH to form the Bsmoc Lys fatty acid compound of the formula la;or according to process variant B, wherein said process variant B comprisesbl) converting the fatty acid compound of the formula Ila with a A-hydroxysuccinimide source compound to form the A-hydroxysuccinimide ester of formula Illa,PROT 1-0-19-carboxy-nonadecanoyl-L-Glu (AEEAc-AEEAc-OSu)-O-PROTl(Illa),wherein AEEAc and PROT1 are as above,b2) coupling the V-hydroxysuccinimide ester of formula Illa with Lys-OH to form the Lys fatty acid compound of the formula IVaH-Lys(AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH(IVa),wherein AEEAc and PROT1 are as above, andb3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia;or according to process variant C, wherein said process variant C comprisescl) converting the fatty acid compound of the formula Ila with an amino- and carboxy -group protected Lys to form a protected Lys fatty acid compound of the formula VaPROT3-Lys (AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-O-PROT2(Va),wherein AEEAc and PROT1 are as above, PROT2 is an ester protecting group and PROT3 is an amino protecting group;c2) removing the protecting groups PROT2 and PROT3 to form the Lys fatty acid compound of the formula IVaH-Lys(AEEAc-AEEAc- γ –Glu(O-PROT1)-19-carboxy-nonadecanoyl-O-PROT1)-OH(IVa),wherein AEEAc and PROT1 are as above, andc3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVa with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula Ia.

2. Process of claim 1, wherein PROT1 is tert-butyl (tBu).

3. Process of claims 1 or 2, wherein PR0T2 is an ester protecting group which is removable by catalytic hydrogenation.

4. Process of claim 3, wherein PR0T2 is benzyl.

5. Process of any one of claims 1 to 4, wherein PR0T3 is benzyloxy carbonyl (Cbz).

6. Process of any one of claims 1 to 5, wherein process variant A comprises the formation ofBsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(Ib),wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, byal) converting the fatty acid compound of the formula libtBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu(lib),wherein AEEAc is as above,with a N-hydroxysuccinimide source compound to form the N-hydroxysuccinimide ester of formula IIIb,tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu(IIIb),wherein AEEAc is as above, anda2) coupling the A-hydroxy succinimide ester of formula Illb with Bsmoc-Lys-OH to form the Bsmoc Lys fatty acid compound of the formula lb.

7. Process of any one of claims 1 to 6, wherein in process variant A, step al) the A-hydroxysuccinimide source is selected from from AA’-disuccinimidyl carbonate (DSC), or from A-hydroxysuccinimide in combination with a coupling reagent selected from A, A’-dicyclohexylcarbodiimide (DCC), N,N′-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) or 1,1′-carbonyldiimidazole (CDI).

8. Process of any one of claims 1 to 7, wherein in process variant A, step al) the conversion is performed in the presence of an organic catalyst selected from 4-dimethylaminopyridine, N-methylmorpholine or from N-methylimidazole.

9. Process of any one of claims 1 to 8, wherein in process variant A, step al) the conversion is performed in the presence of an organic solvent selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidone (NMP) or N,N′-dimethylacetamide (DMAc).

10. Process of any one of claims 1 to 9, wherein in process variant A, step a2) the coupling with Bsmoc-Lys-OH is performed in the presence of a silylating agent selected from trimethylsilylchloride, N,O-bis(trimethylsilyl)acetamide, hexamethyldisilazane, N,O-bis(trimethylsilyl)trifluoroacetamide or trimethyl silyl trifluoromethanesulfonate.

11. Process of any one of claims 1 to 10, wherein in process variant A, step a2) the coupling with Bsmoc-Lys-OH is performed in the presence of an organic base selected from A, A-diisopropylethylamine, triethylamine or / ' / -methylmorpholine.

12. Process of any one of claims 1 to 11, wherein in process variant A, step a2) the coupling with Bsmoc-Lys-OH is performed in the presence of an organic solvent selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidone (NMP) or N,N-dimethylacetamide (DMAc).

13. Process of any one of claims 1 to 12, wherein in process variant A, step a2) Bsmoc-Lys-OH is applied in the form of its HC1 salt.

14. Process of any one of claims 1 to 5, wherein process variant B comprises the formation ofBsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(Ib),wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, bybl) converting the fatty acid compound of the formula libtBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu(lib),wherein AEEAc is as above,with a N-hydroxysuccinimide source compound to form the N-hydroxysuccinimide ester of formula IIIb,tBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OSu)-O-tBu(IIIb),wherein AEEAc is as above,b2) coupling the N-hydroxysuccinimide ester of formula IIIb with Lys-OH to form the Lys fatty acid compound of the formula IVbH-Lys(AEEAc-AEEAc- y -Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(IVb),wherein AEEAc is as above, andb3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVb with Bsmoc-OSu to form the Bsmoc Lys fatty acid compound of the formula lb.

15. Process of any one of claims 1 to 5 or 14, wherein in process variant B, step bl) the A-hydroxysuccinimide source is selected from from AA’-disuccinimidyl carbonate (DSC), or from A-hydroxysuccinimide in combination with a coupling reagent selected from N, N’~ dicyclohexylcarbodiimide (DCC), AA'-diisopropylcarbodiimide (DIC), l-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) or 1,1 '-carbonyldiimidazole (CDI).

16. Process of any one of claims 1 to 5 or 14 or 15, wherein in process variant B, step bl) the conversion is performed in the presence of an organic catalyst selected from 4-dimethylaminopyridine, N-methylmorpholine or from N-methylimidazole.

17. Process of any one of claims 1 to 5 or 14 to 16, wherein in process variant B, step bl) the conversion is performed in the presence of an organic solvent selected from acetonitrile, dichloromethane, N-methyl-2-pyrrolidone (NMP) or from N,N-dimethylacetamide (DMAc).

18. Process of any one of claims 1 to 5 or 14 to 17, wherein in process variant B, step b2) the a-amino group of Lys-OH or the HC1 salt thereof is complexed with a copper salt and the formed Cu-lysinate with free ε-amino group is coupled to the N-hydroxysuccinimide ester of formula IIIb, in the presence of an inorganic base selected from an alkali hydrogencarbonate or an alkali carbonate in water.

19. Process of any one of claims 1 to 5 or 14 to 18, wherein in process variant B, step b3) the introduction of Bsmoc OSu is performed in the presence of an inorganic base selected from an alkali hydrogencarbonate or an alkali carbonate in a solvent selected from water or N, N-dimethylformamide or mixtures thereof.

20. Process of any one of claims 1 to 5, wherein process variant C comprises the formation ofBsmoc-Lys(AEEAc-AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(Ib),wherein AEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid, bycl) converting the fatty acid compound of the formula libtBu-O-19-carboxy-nonadecanoyl-L-Glu(AEEAc-AEEAc-OH)-O-tBu(lib)wherein AEEAc is as above,with Cbz-Lys-OBzl to form a protected Lys fatty acid compound of the formula VbCbz-Lys (AEEAc- AEEAc- γ –Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-O-Bzl(Vb)wherein AEEAc is as above,c2) removing the Bzl and Cbz protecting groups to form the Lys fatty acid compound of the formula IVbH-Lys(AEEAc-AEEAc- y -Glu(O-tBu)-19-carboxy-nonadecanoyl-O-tBu)-OH(IVb),wherein AEEAc is as above, andc3) introducing Bsmoc by converting the Lys fatty acid compound of the formula IVb with Bsmoc OSu to form the Bsmoc Lys fatty acid compound of the formula lb.

21. Process of any one of claims 1 to 5 or 20, wherein in process variant C, step cl) the conversion is performed in the presence of a coupling agent selected from benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP), benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (PyBOP), bromotripyrrolidinophosphonium hexafluorophosphate (PyBrOP), (7-azabenzotriazol-l-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyAOP), N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium tetrafluoroborate N-oxide (TBTU), 2-(lH-benzotriazole-l-yl)-l,l,3,3-tetramethylaminium hexafluorophosphate (HBTU), 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate, N-[(dimethylamino)-3H-1,2,3-triazolo-[4,5-b]pyridin-3-yloxy)methylene]-N-methylmethanaminium hexafluorophosphate (HATU), propanephosphonic acid anhydride (T3P) or from a combinations of N,N′-diisopropylcarbodiimide (DIC) with N-hydroxysuccinimide, with 4-(dimethylamino)pyridine (DMAP), with 2-hydroxypyridine-N-oxide (HOPO) or with (ethylcyano (hydroximino)acetate) (Oxyma Pure) or from a combination of l-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) with 2-hydroxypyridine-N-oxide (HOPO).

22. Process of any one of claims 1 to 5 or 20 or 21, wherein in process variant C, step cl) the conversion is performed in the presence an organic base selected from N, N-diisopropylethylamine (DIPEA, N-methylmorpholine (NMM), N-methylimidazol (NMI) or triethylamine.

23. Process of any one of claims 1 to 5 or 20 to 22, wherein in process variant C, step cl) the conversion is performed in the presence an organic solvent selected from N, N-dimethylformamide, methyl tert-butyl ether (MTBE), toluene, acetonitrile or mixtures thereof.

24. Process any one of claims 1 to 5 or 20 to 23, wherein in process variant C, step c2) the removal of the protecting group PROT2 and PROT3 is performed by catalytic hydrogenation with hydrogen and a Pd-catalyst in an organic solvent.

25. Process of any one of claims 1 to 5 or 20 to 24, wherein in process variant C, step c3) the introduction of Bsmoc OSu is performed in the presence of an inorganic base selected from an alkali hydrogencarbonate or an alkali carbonate in a solvent selected from water or N,N-dimethylformamide or mixtures thereof..

26. Use of the fatty acid compound of the formula la or lb, prepared according to any one of claims 1 to 25, for the preparation of peptides.

27. Use of claim 26 for the preparation of the peptide of formula Villa, or of a pharmaceutically acceptable salt or ester thereofX1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2(VIIIa)wherein X1isAEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

28. Process for the preparation of a peptide comprising the addition of the fatty acid compound of the formula la or lb, prepared according to any one of claims 1 to 25, as side chain.

29. Process of claim 28, wherein the peptide has the formula Villa, or of a pharmaceutically acceptable salt or ester thereofX1-β-Ala2-Glu3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Tyr10-Ser11-Ile12-Aib13-Leu14-Asp15-Lys16-Ile17-Ala18-Gln19-Lys20(AEEAc-AEEAc-y-Glu-19-carboxynonadecanoyl)-Ala21-Phe22-Val23-Gln24-Trp25-Leu26-Ile27-Ala28-Gly29-Gly30-Pro31-Ser32-Ser33-Gly34-Ala35-Pro36-Pro37-Pro38-Ser39-NH2(VIIIa) wherein X1isCN andAEEAc stands for 2-(2-(2-aminoethoxy)ethoxy)acetic acid.***

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