Preparation method of polyamide with controllable main chain function and sequence

Abstract

The cyclic monomer provided by the invention can be used for preparing polyamide with adjustable main chain function and sequence (unit structure) in various solvents with different polarities under various temperatures and different initiators and monomer concentrations in the absence of a catalyst. An ester group, an ether bond or an amino acid unit on a main chain structure of the polyamide can be designed, regulated and controlled according to product requirements, the PDI of the obtained polyamide can be controlled to be 1.1 or below, which is difficult to realize by other polymerization methods, and the polyamide with a designable structure cannot be obtained by an existing method. Finally, a byproduct lactone compound generated by polymerization can be recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of functional polymer compounds, and in particular relates to a method for preparing polyamide with controllable main chain functions and sequences. Background Art

[0002] Polyamide is commonly known as nylon, and is called nylon when it is made into fiber. The main chain contains repeated amide groups. In a broad sense, polyamino acids also belong to polyamide materials. Polyamide has good wear resistance, oil resistance, corrosion resistance, chemical resistance and excellent mechanical properties. It is an excellent engineering plastic and synthetic fiber, and has been widely used in medical equipment, electrical equipment, automotive parts and construction materials.

[0003] The synthesis of polyamide can be summarized as step polymerization and chain polymerization. Step polymerization is generally prepared by polycondensation of diamine and dibasic acid. This method can prepare polyamide with functionalized main chain, but it cannot synthesize polymers with controllable molecular weight and narrow distribution (PDI < 1.1); chain polymerization is generally prepared by ring-opening polymerization of small-ring lactam. This method can prepare polyamide with higher molecular weight, but due to the small number of atoms on the ring, it cannot synthesize polyamide with functionalized main chain and controllable sequence; polyamino acid is generally prepared by ring-opening polymerization of N-carboxylic acid anhydride monomer. This method can synthesize polyamino acid with higher molecular weight and narrow molecular weight distribution, but because its monomer is sensitive to water, polymerization needs to be carried out under harsh conditions such as anhydrous. In addition, this polymerization method cannot control the sequence of main chain amino acid monomers. At present, there is no relevant realization method for synthesizing polyamide with controllable main chain function and sequence, controllable molecular weight and narrow distribution (PDI < 1.1) under mild conditions without catalysis. Summary of the invention

[0004] In order to improve the above technical problems, the present invention first provides a monomer represented by the following formula A or formula B:

[0005]

[0006] In formula A, Ra and Rb are the same or different and are independently selected from H or C 1-6 alkyl;

[0007] Rc is selected from NO2 or C 1-6 Alkyl; q is 1, 2, 3 or 4;

[0008] Rd, Re are the same or different and are independently selected from an ester bond (-COO-), an ether bond (-O-) or an R bond; the R bond is at least one of an ester bond (-COO-) or an ether bond (-O-) and at least one C 1-10 A group composed of alkylene groups;

[0009] m, n and s are the same or different and are independently selected from 1, 2, 3, 4, 5, 6, 7 or 8;

[0010] Provided that the cyclic structure represented by formula A contains 14 or more ring atoms;

[0011]

[0012] In formula B, Rf and Rg are the same or different and are independently selected from H or C 1-6 alkyl;

[0013] Rh is selected from NO2 or C 1-6 Alkyl; p is 1, 2, 3 or 4;

[0014] Ri is selected from -(C 1-6 alkyl) c -(OC 1-6 alkyl) d -(C 1-6 alkyl) e ;

[0015] Rj is a unit formed by removing OH from the carboxyl group and H from the amino group of any one of the inert side groups of natural amino acids, namely, glycine, alanine, valine, leucine, isoleucine, tryptophan, and phenylalanine, or a unit formed by condensation reaction between the amino group and the carboxyl group of any two or more of the above natural amino acids, wherein one end is a carbonyl group and the other end is NH; the NH end of the group represented by Rj is connected to the carbonyl group in ring B, and the carbonyl end is connected to O in ring B;

[0016] a, b, d are the same or different and are independently selected from 1, 2, 3, 4, 5, 6, 7 or 8;

[0017] c and e are the same or different and are independently selected from 0, 1, 2, 3, 4, 5, 6, 7 or 8

[0018] The condition is that the cyclic structure represented by formula B contains 14 or more ring atoms.

[0019] According to an embodiment of the present invention, in formula A, Ra and Rb are the same and are selected from methyl or ethyl;

[0020] The number of Rc is 2, in which case Rc is selected from NO2 and methyl; or the number of Rc is 3, in which case Rc is selected from 1 NO2 and 2 methyl;

[0021] Rd, Re are the same or different and are independently selected from an ester bond (-COO-) or an ether bond (-O-);

[0022] m, n and s are the same or different and are independently selected from 1, 2, 3, 4, 5 or 6.

[0023] According to an embodiment of the present invention, formula A is selected from the structure shown in the following formula A1,

[0024]

[0025] wherein m, n and s are the same or different and are independently selected from 2, 3, 4 or 5;

[0026] Ra, Rb are the same and are selected from methyl or ethyl;

[0027] The number of Rc is 3, and in this case, Rc is selected from 1 NO2 and 2 methyl groups.

[0028] As an example, the formula A is selected from the following monomers M1:

[0029]

[0030] According to an embodiment of the present invention, in formula B, Rf and Rg are the same and are selected from methyl or ethyl;

[0031] The number of Rf is 2, in which case Rh is selected from NO2 and methyl; or the number of Rh is 3, in which case Rh is selected from 1 NO2 and 2 methyl groups.

[0032] Ri is selected from -(C 1-3 alkyl) c -(OC 1-3 alkyl) d -(C 1-3 alkyl) e ;

[0033] Rj is selected from a unit having a carbonyl group at one end and an NH group at the other end formed by removing OH from the carboxyl group and H from the amino group of any one of the natural amino acids valine, glycine, and alanine, or a unit having a carbonyl group at one end and an NH group at the other end formed by a condensation reaction between the amino group and the carboxyl group of any two or more of the above natural amino acids; the NH end of the group represented by Rj is connected to the carbonyl group in ring B, and the carbonyl end is connected to O in ring B;

[0034] a, b, d are the same or different and are independently selected from 1, 2, 3, 4 or 5;

[0035] c and e are the same or different and are independently selected from 0, 1, 2 or 3;

[0036] The condition is that the cyclic structure represented by formula B contains 14 or more ring atoms.

[0037] According to an embodiment of the present invention, in formula B, Rj is selected from a unit having a carbonyl group at one end and an NH group at the other end formed by condensation reaction of valine, alanine and glycine, for example, Rj is selected from

[0038] As an example, formula B is selected from monomers M2 shown below:

[0039]

[0040] The present invention also provides a method for preparing the monomer represented by formula A, comprising the following steps:

[0041]

[0042] Compound 2f' first removes the Boc protecting group in an acidic environment, and then undergoes a ring-closing reaction in the presence of an acid-binding agent to obtain monomer A;

[0043] wherein s, m, n, q, Ra, Rb, Rc, Rd, and Re have the same definitions as described above.

[0044] According to an embodiment of the present invention, the monomer represented by formula A is prepared by the following method: Compound 2f' is reacted with TFA by stirring, and after the reaction is completed, TEA is added to react to obtain the monomer represented by formula A.

[0045] According to an embodiment of the present invention, when the monomer represented by formula A is selected from formula A1, compound 2f' is prepared by the following method:

[0046]

[0047] a1) Compound 1a'-1 reacts with compound 1a'-2 to obtain compound 1a';

[0048] a2) Compound 1a' undergoes reduction reaction in the presence of sodium borohydride to obtain compound 1b';

[0049] a3) Compound 1b' is reacted in the presence of lithium borohydride to obtain compound 1c';

[0050] a4) Compound 1c' reacts with compound TBSCl to obtain compound 1d';

[0051] a5) reacting compound 2a'-1 with boc anhydride to obtain compound 2a';

[0052] a6) Compound 2a′ and compound The reaction yields compound 2b';

[0053] a7) Compound 2b' and compound The reaction gave compound 2c';

[0054] a8) Compound 2c' is subjected to condensation reaction with compound 1d' to obtain compound 2d';

[0055] a9) Compound 2d' is first reacted with Amberlyst 15, and the resulting product is then reacted with PDC to obtain compound 2e';

[0056] a10) Compound 2e' reacts with pentafluorophenol to obtain compound 2f';

[0057] wherein s, m, n, q, Ra, Rb, and Rc have the same definitions as described above.

[0058] The present invention also provides a method for preparing the monomer represented by formula B, comprising the following steps:

[0059]

[0060] Compound 3f' first removes the Boc protecting group in an acidic environment, and then undergoes a ring-closing reaction in the presence of an acid-binding agent to obtain monomer B;

[0061] wherein a, b, p, Rf, Rg, Rh, Ri and Rj have the same meanings as described above.

[0062] According to an embodiment of the present invention, the monomer represented by formula B is prepared by the following method: Compound 3f' is reacted with TFA by stirring, and after the reaction is completed, TEA is added to react to obtain the monomer represented by formula B.

[0063] According to an embodiment of the present invention, compound 3f' is prepared by the following method:

[0064]

[0065] b1) Compound 3c' is subjected to a hydrolysis reaction, and then reacted with compound 2d'-1 to obtain compound 3d';

[0066] b2) Compound 3d' is first reacted with Amberlyst 15, and the resulting product is then reacted with PDC to obtain compound 3e';

[0067] b3) Compound 3e' reacts with pentafluorophenol to obtain compound 3f';

[0068] wherein a, b, p, Rf, Rg, Rh, Ri, and Rj are as defined above; R7 is selected from C 1-6 alkyl;

[0069] The preparation process of 2d'-1 is the same as that of 1d'.

[0070] The present invention also provides the intermediate shown below:

[0071]

[0072]

[0073] wherein s, m, n, a, b, p, q, Ra, Rb, Rc, Re, Rd, Rf, Rg, Rh, Ri, and Rj are as defined above.

[0074] The present invention also provides the use of the monomer compound represented by formula A in preparing the polyamide represented by formula I below:

[0075]

[0076] Wherein, s, m, n, Re, and Rd have the above definitions;

[0077] n1 is an integer from 1 to 100.

[0078] The present invention also provides the use of the monomer compound represented by formula B in preparing the polyamide represented by formula II:

[0079]

[0080] wherein n2 is an integer of 1-100; a, b, Ri and Rj have the same definitions as above.

[0081] As an example, the polymer represented by Formula I or Formula II is selected from the following structures:

[0082]

[0083] Wherein, n1 and n2 are the same or different and are independently selected from integers of 1-90;

[0084] According to an embodiment of the present invention, the relative molecular weight of the polymer main chain represented by Formula I and Formula II is greater than 20,000, such as 22,000.

[0085] According to an embodiment of the present invention, n1 and n2 are the same or different and are independently selected from integers of 2-80, such as integers of 5-50, 10-30.

[0086] According to an embodiment of the present invention, the PDI of the polyamide represented by Formula I or Formula II is 1.1 or less, for example, 1.05.

[0087] The present invention also provides a polyamide represented by Formula I or Formula II:

[0088]

[0089] Wherein, s, m, n, Re, Rd, n1 have the above definitions;

[0090]

[0091] wherein n2, a, b, Ri and Rj have the same definitions as described above.

[0092] The present invention also provides a method for preparing a polyamide represented by formula I or II, comprising the following steps: subjecting the monomer represented by formula A or formula B to a nucleophilic substitution reaction in the presence of an initiator primary amine and / or secondary amine, followed by a ring-opening polymerization reaction to obtain a polyamide represented by formula I or II;

[0093]

[0094] Among them, s, m, n, a, b, p, q, Ra, Rb, Rc, Re, Rd, Rf, Rg, Rh, Ri, Rj, n1, and n2 have the definitions as described above.

[0095] According to an embodiment of the present invention, the molar feed ratio of the monomer compound represented by formula A, B to the initiator is the same or different, and is independently (1-100):1, for example, 25:1 or 50:1 or 100:1.

[0096] According to an embodiment of the present invention, the initiator is selected from n-hexylamine.

[0097] According to an embodiment of the present invention, the reaction can be carried out in various types of solvents, for example, in chlorobenzene, DMSO, DMF, and the like.

[0098] According to an embodiment of the present invention, the reaction does not require a capture agent, a catalyst, etc., and can be carried out only with the presence of an initiator.

[0099] According to an embodiment of the present invention, the concentrations of the polymer monomers represented by formula A and B are the same or different and are independently 0.1-1.5M, for example 1.5M.

[0100] According to an embodiment of the present invention, the reaction may be carried out at 70-110°C, such as 90°C.

[0101] According to an embodiment of the present invention, the reaction time is 1-24h.

[0102] According to an embodiment of the present invention, after the reaction is completed, the end-capping agent is used to cap the end-portion, followed by precipitation with ether.

[0103] The present invention also provides the use of the polyamide represented by the above formula I as a degradable material.

[0104] The present invention also provides the use of the polyamide represented by the above formula II as a polypeptide.

[0105] Beneficial effects of the present invention

[0106] The cyclic monomer provided by the present invention can be used in the absence of a catalyst, in a variety of solvents with different polarities, at a variety of temperatures and different initiators and monomer concentrations to prepare polyamides with adjustable main chain functions and sequences (unit structures). The ester groups, ether bonds or amino acid units on the main chain structure can be designed and regulated according to product needs, and the PDI of the obtained polyamide can be controlled below 1.1, which is difficult to achieve with other polymerization methods, and the existing methods cannot obtain the polyamides with designable structures of the present application. Finally, the byproduct lactone compound generated by the polymerization of the present application can be recycled.

[0107] The numerical ranges involved in this application include the endpoints of the range and all numbers between the endpoints. For example, the number "1-100" refers to the endpoints 1 and 100 and all numbers between the endpoints, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 ... 99. Other numerical ranges have the same definition, such as "C 1-6 Alkyl", "C 1-10 "Alkylene" and "C 1-6 The numerical range in "alkylene" etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0108] Figure 1 is a structural diagram of the monomer M1 prepared in Example 1;

[0109] Figure 2 is a structural diagram of the monomer M2 prepared in Example 1;

[0110] Figure 3 is a structural diagram of the high molecular weight polymer I-1 prepared in Example 2;

[0111] Figure 4 is a structural diagram of the high molecular weight polymer II-1 prepared in Example 2;

[0112] Figure 5 is the NMR spectrum of the monomer M1 prepared in Example 1 (the deuterated reagent used is deuterated dimethyl sulfoxide);

[0113] Figure 6 is the NMR spectrum of the monomer M2 prepared in Example 1 (the deuterated reagent used is deuterated dimethyl sulfoxide);

[0114] Figure 7 This is the NMR spectrum of the high molecular weight polymer I-1 prepared in Example 2 (the deuterated reagent used is deuterated dimethyl sulfoxide, and the conversion rate is calculated);

[0115] Figure 8 This is the in-situ NMR spectrum of the high molecular weight polymer II-1 prepared in Example 2 (the deuterated reagent used is deuterated dimethyl sulfoxide);

[0116] Fig. 9 is the GPC chart of the high molecular weight polymer I-1 prepared in Example 2;

[0117] Fig.10 is the GPC chart of the high molecular weight polymer II-1 prepared in Example 2;

[0118] Fig.11 is the synthesis route of monomer M1 in Example 1;

[0119] Fig.12 is the synthesis route of monomer M2 in Example 1;

[0120] Fig.13 is the GPC diagram of the polymer before and after degradation in Example 3;

[0121] Fig.14 is the GPC chart of the high molecular weight polymer I-2 prepared in Example 4;

[0122] Fig.15 is the GPC chart of the high molecular weight polymer I-3 prepared in Example 4;

[0123] Fig.16 is the GPC chart of the high molecular weight polymer I-4 prepared in Example 4;

[0124] Fig.17 is the GPC chart of the high molecular weight polymer I-5 prepared in Example 4;

[0125] Fig.18 is the GPC chart of the high molecular weight polymer I-6 prepared in Example 4;

[0126] Fig.19 This is the GPC chart of the high molecular weight polymer I-7 prepared in Example 4. DETAILED DESCRIPTION

[0127] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0128] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0129] The test methods in the following examples adopt nuclear magnetic resonance and gel permeation chromatography:

[0130] The liquid NMR spectrometer model was Bruker Avance 400;

[0131] The gel permeation chromatography characterization conditions were: mobile phase DMF, column oven 50°C, flow rate 1 mL / min, and two chromatographic columns AgilentPL Mixed C and Mixed D connected in series.

[0132] Example 1

[0133] 1.1 Preparation route of polymer monomer M1 Fig.11 As shown, the specific steps are:

[0134] 1) 3,5-dimethylphenol (40 g) was dissolved in ether / water (640 mL, v / v=1 / 1), sodium nitrate (27.87 g) and concentrated hydrochloric acid (28 mL) were slowly added to the above solution, and the reaction was completed when the solution turned deep red. Ethyl acetate was then added for extraction, the organic phase was dried, and the solvent was removed by rotary evaporation. Column chromatography (petroleum ether) was used for purification to obtain 3,5-dimethyl-2-nitrophenol (23 g, yield 42%).

[0135] 2) Dissolve 3,5-dimethyl-2-nitrophenol (23 g) and 3,3-dimethyl acrylate (15.7 g) in 100 mL of methanesulfonic acid and stir at 70°C for 6 h. After cooling, dilute with water, extract with ethyl acetate, dry the organic phase, and remove the solvent by rotary evaporation. Recover 3,5-dimethyl-2-nitrophenol by column chromatography with petroleum ether. 石油醚 :V 二氯甲烷 :V 乙酸乙酯 =10:5:1) to give the crude product 1a. Recrystallization from dichloromethane and petroleum ether gave the purified 1a. The reaction was repeated to obtain a sufficient amount of 1a.

[0136] 3) Dissolve 1a (10 g) in 160 mL of tetrahydrofuran, slowly add 4 g of sodium borohydride, and stir at 68°C for 12 h. Slowly add saturated ammonium chloride solution under ice-water bath to quench, add ethyl acetate to extract, dry the organic phase, and remove the solvent by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =5:1) to give compound 1b (9.3 g, yield 93%).

[0137] 4) Dissolve 1b (9.3 g) in 140 mL of tetrahydrofuran, slowly add 2 g of lithium borohydride, and stir at 68°C for 12 h. Slowly add saturated ammonium chloride solution in an ice-water bath to quench, add ethyl acetate to extract, dry the organic phase, and remove the solvent by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =5:1) to afford 1c (7.5 g, yield 80%).

[0138] 5) Dissolve 1c (7.5 g), TBSCl (5 g) and triethylamine (2.5 g) in 60 mL of dichloromethane and react at room temperature for 2 h. Concentrate the solution and perform column chromatography (V石油醚 :V 乙酸乙酯 =5:1) to obtain 1d (10.5 g, yield 97%).

[0139] 6) Mix 6-aminocaproic acid (4.00 g), sodium hydroxide (1.22 g) and Boc anhydride (7.32 g) and dissolve them in 120 mL (V 1，4-二氧六环 :V 水 =2:1), stirred at room temperature for 3h. Ethyl acetate (50ml) was added for separation, the aqueous phase was adjusted to pH 2 with 1M dilute hydrochloric acid, then extracted with ethyl acetate (2×50ml), and the organic phase was washed with saturated sodium chloride, the organic phase was collected and dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain 2a (7.05g, yield 99%).

[0140] 7) 2a (7.00 g) and 1,4-butanediol (13.64 g) were mixed and dissolved in 120 mL of tetrahydrofuran, EDC·HCl (11.64 g) and DMAP (0.74 g) were added, and the mixture was stirred at room temperature overnight, and the solvent was removed by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =1:1) to give 2b (6.95 g, yield 76%).

[0141] 8) 2b (6.85 g), triethylamine (5.71 g) and glutaric anhydride (3.86 g) were mixed and dissolved in 90 mL of dichloromethane, stirred at room temperature overnight, and the solvent was removed by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =1:1) to give 2c (9.25 g, yield 98%).

[0142] 9) 1d (7.34 g), 2c (9.16 g), EDC·HCl (7.68 g) and DMAP (0.49 g) were mixed and dissolved in 85 ml of tetrahydrofuran and stirred at 50°C for 2 h. After drying by spin column chromatography (V 石油醚 :V 乙酸乙酯 =5:1) to give 2d (14.25 g, yield 93%).

[0143] 10) Dissolve 2d (14.00 g) in 90 mL of methanol, add Amberlyst 15 (11.71 g), and stir at room temperature for 1 h. After filtering, remove the solvent by rotary evaporation to obtain the intermediate. Mix the intermediate, PDC (47.85 g) and diatomaceous earth (47.85 g) and dissolve them in 90 mL of DMF, and stir at room temperature overnight. Dilute with ether (90 ml), filter with diatomaceous earth, add water (100 ml) to separate the liquids, adjust the pH to 2 with 1 M dilute hydrochloric acid, wash the organic phase with water (2×100 ml), collect the organic phase, dry, and remove the solvent by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯=1:2) to give 2e (6.66 g, yield 55%).

[0144] 11) 2e (6.50 g) was mixed with pentafluorophenol (2.70 g) and EDC·HCl (3.76 g) and dissolved in 56 mL THF. DMAP (0.24 g) was added and stirred at room temperature overnight. The solvent was removed by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =2:1) ​​to give 2f (5.83 g, yield 72%).

[0145] 12) Dissolve 2f (5.71 g) and TFA (35 mL) in 35 mL DCM, stir for 30 min, remove trifluoroacetic acid and dichloromethane by rotary evaporation, dissolve in 140 mL dichloromethane, add dropwise to a solution of 17.07 g TEA in 900 mL dichloromethane using a syringe pump for 3 h, and remove the solvent by rotary evaporation. Column chromatography (V 石油醚 :V 乙酸乙酯 =1:1) to obtain monomer M1 (3.50 g, yield 94%). Its structure is as follows Figure 1 As shown, the NMR spectrum is shown in Figure 5.

[0146] 1.2 Preparation route of polymer monomer M2 Fig.12 As shown, the specific steps are:

[0147] 1) At 0°C, L-valine methyl ester hydrochloride (5.45 g) and N,N-diisopropylethylamine (6.29 g) were dissolved in 130 mL of dichloromethane, and then 5,8,11-trioxa-2-azatridecanedioic acid 1-tert-butyl ester (10.00 g), EDC·HCl (7.49 g) and HOBt (5.27 g) were added and reacted at room temperature overnight. After being dried by spin drying, column chromatography (V 二氯甲烷 :V 甲醇 =50:1) to afford 3a (12.98 g, yield 95%).

[0148] 2) 3a (12.85 g) was dissolved in 120 mL of a mixed solvent of tetrahydrofuran and water at 0°C. 四氢呋喃 :V 水 =2:1), add lithium hydroxide (1.35g), stir at room temperature for 1h. Adjust the pH to 2 with 1M dilute hydrochloric acid, then add ethyl acetate (80ml), extract with ethyl acetate (3×40ml), collect the organic phase, dry and spin dry to obtain the intermediate. Dissolve the intermediate in 120ml of dichloromethane, add EDC·HCl (7.05g), HOBt (4.96g), L-alanine methyl ester hydrochloride (4.48g) and N,N-diisopropylethylamine (5.92g) at 0℃, react at room temperature overnight, spin dry and column chromatography (V 二氯甲烷 :V甲醇 =40:1) to give 3b (11.27 g, yield 75%).

[0149] 3) 3b (11.10 g) was dissolved in 90 mL of a mixed solvent of tetrahydrofuran and water at 0°C. 四氢呋喃 :V 水 =2:1), add lithium hydroxide (0.99g), stir at room temperature for 1h. Adjust the pH to 2 with 1M dilute hydrochloric acid, then add ethyl acetate (50ml), extract with ethyl acetate (3×30ml), collect the organic phase, dry and spin dry to obtain the intermediate. Dissolve the intermediate in 90ml of dichloromethane, add EDC·HCl (5.21g), HOBt (3.66g), glycine methyl ester hydrochloride (2.91g) and N,N-diisopropylethylamine (4.37g) at 0℃, react at room temperature overnight, column chromatography (V 二氯甲烷 :V 甲醇 =30:1) to afford 3c (11.08 g, yield 90%).

[0150] 4) 3c (10.85 g) was dissolved in 80 mL of a mixed solvent of tetrahydrofuran and water at 0°C. 四氢呋喃 :V 水 =2:1), add lithium hydroxide (0.86g), stir at room temperature for 1h. Adjust the pH to 2 with 1M dilute hydrochloric acid, then add ethyl acetate (40ml), extract with ethyl acetate (3×25ml), collect the organic phase, dry and spin dry to obtain the intermediate. Dissolve the intermediate in 80ml tetrahydrofuran, add 1d (8.07g), EDC·HCl (4.58g) and DMAP (0.61g) at 0℃, stir at 50℃ for 2 hours, spin dry column chromatography (V 二氯甲烷 :V 甲醇 =30:1) to afford 3d (13.00 g, yield 74%).

[0151] 5) 3d (12.50 g) was dissolved in 55 mL of methanol, and Amberlyst 15 (9.14 g) was added. The mixture was stirred at room temperature for 1 h. After filtering, the solvent was removed by rotary evaporation to obtain the intermediate. The intermediate, PDC (37.37 g) and diatomaceous earth (37.37 g) were mixed and dissolved in 55 mL of DMF, stirred overnight at room temperature, diluted with ether (55 ml), then filtered through diatomaceous earth, and separated by adding water (80 ml). The pH was adjusted to 2 with 1 M dilute hydrochloric acid. The organic phase was washed with water (2×80 ml), the organic phase was collected, dried, and the solvent was removed by rotary evaporation. Column chromatography (V 二氯甲烷 :V 甲醇 =30:1) to give 3e (4.65 g, yield 42%).

[0152] 6) 3e (4.00 g), pentafluorophenol (1.42 g), EDC·HCl (1.97 g) and DMAP (0.16 g) were mixed and dissolved in 50 mL THF, stirred at room temperature overnight, and the solvent was removed by rotary evaporation. Column chromatography (V 二氯甲烷 :V 甲醇 =30:1) to afford 3f (2.43 g, yield 50%).

[0153] 7) 3f (2.00 g) and TFA (6 mL) were dissolved in 15 mL DCM, stirred for 15 min, trifluoroacetic acid and dichloromethane were removed by rotary evaporation, dissolved in 42 mL dichloromethane, and added dropwise to a solution of 0.71 g TEA in 280 mL dichloromethane using a syringe pump for 3 h, and the solvent was removed by rotary evaporation. Column chromatography (V 二氯甲烷 :V 甲醇 =20:1) to obtain monomer M2 (0.58 g, yield 42%). Its structure is as follows Figure 2 As shown, the NMR spectrum is shown in Figure 6.

[0154] Example 2

[0155] 2.1 Preparation of polymer I-1, the specific steps are:

[0156] Add monomer M1 (82.2 mg, 0.15 mmol) to 0.1 mL DMF, then add n-hexylamine (0.6 mg, 6 μmol) to initiate polymerization, stir in an oil bath at 90 °C for 10 h, add a capping agent and stir for 6 h. Sediment in ether solvent, remove excess monomers and small molecules, and obtain a high molecular weight linear main chain polymer, the structure of which is as follows Figure 3 As shown, the GPC test results are as follows Fig. 9 As shown. Fig. 9 It can be seen that its relative molecular weight is 25000 and PDI is 1.08. Its NMR test results are as follows Figure 7 As shown by Figure 7 It can be seen that the degree of polymerization is 21.

[0157] 2.2 Preparation of polymer II-1, the specific steps are:

[0158] Monomer M2 (83.2 mg, 0.125 mmol) was added to 0.1 mL DMF, and then n-hexylamine (0.5 mg, 5 μmol) was added to initiate polymerization, and the mixture was heated in an oil bath at 90°C for 1 h. A high molecular weight linear main chain polymer was obtained, and its structure is shown in FIG. Figure 4 The NMR characterization results are shown in Figure 8 As shown, the GPC test results are as follows Fig.10 As shown. Fig.10 It can be seen that its relative molecular weight is 23000 and PDI is 1.05. Figure 8 It can be seen that the degree of polymerization is 24.

[0159] Example 3

[0160] The organic base degradation experiment of polymer I-1 has the following specific steps:

[0161] 20 mg of polymer I-1 was dissolved in a mixed solution of 1.8 mL of dichloromethane and 0.2 mL of methanol, and 5.4 mg of 1,5,7-triazabicyclo[4.4.0]dec-5-ene was added. The reaction was monitored at room temperature for 5 hours, and 4.4 μl of acetic acid was added to quench the reaction. The GPC characterization of the polymer before degradation and after spin drying was as follows: Fig.13 As shown (wherein, polymer represents the test result before degradation, and 5h represents the test result after degradation).

[0162] Example 4

[0163] Referring to the method of Example 2.1, the solvent was replaced with DMSO, the oil bath time was 14 h, the molecular weight of polymer I-2 was 27000, and the PDI was 1.08. The GPC test results are as follows Fig.14 shown.

[0164] Referring to the method of Example 2.1, the solvent was replaced with chlorobenzene, the oil bath time was 24 h, the molecular weight of polymer I-3 was 22800, and the PDI was 1.07. The GPC test results are as follows Fig.15 shown.

[0165] Referring to the method of Example 2.1, the temperature was changed to 80°C and the oil bath time was 24h. The molecular weight of polymer I-4 was 24600 and the PDI was 1.08. The GPC test results are as follows Fig.16 shown.

[0166] Referring to the method of Example 2.1, the solvent was replaced with 110°C and the oil bath time was 4h. The molecular weight of polymer I-5 was 28600 and the PDI was 1.08. The GPC test results are as follows Fig.17 shown.

[0167] Referring to the method of Example 2.1, the monomer concentration was replaced with 0.5M, the oil bath time was 18h, the molecular weight of polymer I-6 was 24900, and the PDI was 1.08. The GPC test results are as follows Fig.18 shown.

[0168] Referring to the method of Example 2.1, the molar ratio of monomer to n-hexylamine was replaced with 100:1, the monomer concentration was 1.5 M, the oil bath time was 24 h, the molecular weight of polymer I-7 was 61000, and the PDI was 1.10. The GPC test results are as follows Fig.19 shown.

[0169] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A compound represented by formula A or formula B: In formula A, Ra and Rb are the same or different and are independently selected from H or C 1-6 alkyl; Rc is selected from NO2 or C 1-6 Alkyl; q is 1, 2, 3 or 4; Rd, Re are the same or different and are independently selected from an ester bond (-COO-), an ether bond (-O-) or an R bond; the R bond is at least one of an ester bond (-COO-) or an ether bond (-O-) and at least one C 1-10 A group composed of alkylene groups; m, n and s are the same or different and are independently selected from 1, 2, 3, 4, 5, 6, 7 or 8; Provided that the cyclic structure represented by formula A contains 14 or more ring atoms; In formula B, Rf and Rg are the same or different and are independently selected from H or C 1-6 alkyl; Rh is selected from NO2 or C 1-6 Alkyl; p is 1, 2, 3 or 4; Ri is selected from -(C 1-6 alkyl) c -(OC 1-6 alkyl) d -(C 1-6 alkyl) e ; Rj is selected from the non-polar amino acids glycine, alanine, valine, leucine, isoleucine, tryptophan, and phenylalanine, which are inert side groups in natural amino acids, wherein the carboxyl group removes OH and the amino group removes H to form a unit with a carbonyl group at one end and an NH at the other end, or a unit with a carbonyl group at one end and an NH at the other end formed by a condensation reaction between the amino group and the carboxyl group of any two or more of the above natural amino acids; the NH end of the group represented by Rj is connected to the carbonyl group in ring B, and the carbonyl end is connected to O in ring B; a, b, d are the same or different and are independently selected from 1, 2, 3, 4, 5, 6, 7 or 8; c and e are the same or different and are independently selected from 0, 1, 2, 3, 4, 5, 6, 7 or 8 The condition is that the cyclic structure represented by formula B contains 14 or more ring atoms.

2. The compound according to claim 1, characterized in that In formula A, Ra and Rb are the same and are selected from methyl or ethyl; The number of Rc is 2, in which case Rc is selected from NO2 and methyl; or the number of Rc is 3, in which case Rc is selected from 1 NO2 and 2 methyl; Rd, Re are the same or different and are independently selected from an ester bond (-COO-) or an ether bond (-O-); m, n and s are the same or different and are independently selected from 1, 2, 3, 4, 5 or 6. Preferably, formula A is selected from the structure shown in the following formula A1, wherein m, n and s are the same or different and are independently selected from 2, 3, 4 or 5; Ra, Rb are the same and are selected from methyl or ethyl; The number of Rc is 3, and in this case, Rc is selected from 1 NO2 and 2 methyl groups. Preferably, formula A is selected from the following monomers M1: Preferably, in formula B, Rf and Rg are the same and are selected from methyl or ethyl; The number of Rf is 2, in which case Rh is selected from NO2 and methyl; or the number of Rh is 3, in which case Rh is selected from 1 NO2 and 2 methyl groups. Ri is selected from -(C 1-3 alkyl) c -(OC 1-3 alkyl) d -(C 1-3 alkyl) e ; Rj is selected from a unit having a carbonyl group at one end and an NH group at the other end formed by removing OH from the carboxyl group and H from the amino group of any one of the natural amino acids valine, glycine, and alanine, or a unit having a carbonyl group at one end and an NH group at the other end formed by a condensation reaction between the amino group and the carboxyl group of any two or more of the above natural amino acids; the NH end of the group represented by Rj is connected to the carbonyl group in ring B, and the carbonyl end is connected to O in ring B; a, b, d are the same or different and are independently selected from 1, 2, 3, 4 or 5; c and e are the same or different and are independently selected from 0, 1, 2 or 3; The condition is that the cyclic structure represented by formula B contains 14 or more ring atoms. Preferably, in formula B, Rj is selected from a unit formed by condensation reaction of valine, alanine and glycine, with a carbonyl group at one end and NH at the other end. Preferably, formula B is selected from monomers M2 shown below:

3. The method for preparing the compound according to claim 1 or 2, characterized in that: The preparation process of the compound of formula A comprises the following steps: Compound 2f' first removes the Boc protecting group in an acidic environment, and then undergoes a ring-closing reaction in the presence of an acid-binding agent to obtain monomer A; Wherein, s, m, n, q, Ra, Rb, Rc, Rd and Re have the definitions as described in claim 1 or 2. Preferably, the method for preparing the monomer represented by formula B comprises the following steps: Compound 3f' first removes the Boc protecting group in an acidic environment, and then undergoes a ring-closing reaction in the presence of an acid-binding agent to obtain monomer B; wherein a, b, p, Rf, Rg, Rh, Ri and Rj have the definitions as defined in claim 1 or 2.

4. Intermediates as shown below: in, s, m, n, a, b, p, q, Ra, Rb, Rc, Re, Rd, Rf, Rg, Rh, Ri, and Rj have the definitions described in claim 1 or 2.

5. Use of the compound according to claim 1 or 2 in the preparation of polyamide, characterized in that: The monomer compound represented by formula A is used to prepare the polyamide represented by the following formula Ⅰ: Wherein, s, m, n, Re, and Rd have the definitions in claim 1 or 2; n1 is an integer from 1 to 100. Preferably, the monomer compound shown in formula B prepares the polyamide shown in formula II: Wherein, n2 is an integer of 1-100; a, b, Ri and Rj have the definitions as described in claim 1 or 2.

6. The use according to claim 5, characterized in that The polymer represented by formula I or formula II is selected from the following structures: Wherein, n1 and n2 are the same or different and are independently selected from integers of 1-90.

7. Polyamide represented by formula I or formula II: in, s, m, n, Re, Rd, n1 have the definitions in claim 5 or 6; wherein n2, a, b, Ri and Rj have the definitions as defined in claim 5 or 6.

8. The method for preparing polyamide according to claim 7, characterized in that: The method comprises the following steps: the compound represented by formula A or formula B according to claim 1 or 2 undergoes a nucleophilic substitution reaction in the presence of a primary amine and / or a secondary amine as an initiator, followed by a ring-opening polymerization reaction to obtain a polyamide represented by formula I or II; Among them, s, m, n, a, b, p, q, Ra, Rb, Rc, Re, Rd, Rf, Rg, Rh, Ri, Rj, n1, and n2 have the definitions described in claim 1 or 2.

9. Use of the polyamide represented by formula I according to claim 7 as a degradable material.

10. Use of the polyamide represented by formula II as claimed in claim 7 as a polypeptide.

Images