SU1761762A1 - Para-(4-hydroxy-2,3,5,6-tetrafluorobenzyl)-polystyrene as activator for peptides synthesis - Google Patents

Abstract

The invention relates to the preparation of polymeric reagents for peptide synthesis. The aim of the invention is to increase the content of reactive OH groups of the polymer activator. The invention allows to obtain a polymeric activator containing 2.6 mmol of reactive hydroxyl groups per 1 g of polymer and suitable for peptide synthesis, due to a new polymer - para- (4-hydroxy-2,3,5,6-tetrafluorobenzyl) polystyrene.

Description

This invention relates to the field of polymer chemistry, specifically, to polymeric reagents for peptide synthesis.

Known polymeric activated esters (PAEs) of N-protected amino acids used for peptide synthesis were obtained using polymer activators, each of which had certain disadvantages. These may include either a small capacity (for example, the content of reactive OH groups in poly-4-hydroxy-5-nitrostyrene is 0.05-0.5 mmol / g of polymer), or the low reactivity of PAE, obtained on the basis of the data of polymeric activators , which leads to a significant increase in the time of passage of the condensation reaction.

The closest to the technical essence of the present invention is a polymeric activator based on 4-hydroxy-2,3,5,6-tetrafluoroaniline fixed on a polymer matrix, which is a copolymer of styrene with maleic anhydride.

However, a significant drawback of the polymer activator is the very low capacity (the content of reactive OH groups is 0.2-0.3 mmol / g of polymer). The consequence of this is the need to use very large excesses of the reagent in peptide synthesis (10-fold) to achieve an acceptable yield, which is negative from the point of view of the economical process.

The aim of the invention is to increase the capacity (content of reactive OH groups) of the polymer activator.

This goal is achieved by a new structure of a polymeric activator, which is expressed by the formula:

(L

WITH

Vj os

VI

O u

snsn

g

icH-cH2 fcH-cH cH-CH2- / p

CH7

gg

he

where n 458, m 100, p 11.

Example 1. A pair of (4-hydroxy-2,3,5,6-tetrafluorobenzyl) polystyrene.

To a solution of 6.0 g (0.033 mol) of 4-hydroxy-2,3,5,6-tetrafluorotoluene in 30 ml of distilled over P20s CCI was added 8.0 g (0.045 mol) of N-bromosuccinimide and 20 mg of 2.2- azo-bis-isobutyronitrile. The mixture is boiled for 1 hour, and then the initial amount of catalyst is added.

Of the total amount of catalyst, it is necessary by reaction (40 mg) 1/2 hour. 20 mg is added at the beginning of the reaction, and the remaining 20 mg (1/2 hour) is added to the boiling reaction mixture after the expiration of 1 hour.

After passing the reaction (6 h), the precipitated succinimide and unreacted N-bromosuccinimide was filtered, washed with SCC. The filtrate is evaporated in vacuo at T 40 ° C. The oily residue, 4-hydroxy-2,3,5, 6-tetrafluorobenzyl bromide, is dried in vacuo at room temperature to constant weight. Yield 84%. The resulting product was dissolved in 20 ml of nitrobenzene and 3.1 g of anhydrous in 20 ml of nitrobenzene was added to a solution of this solution. Then a weighed portion (4.0 g) of a styrene copolymer with 2% divinylbenzene (grain size 50-100 µm, manufactured by the chemical plant of the city of Olaine, the polymer was preliminarily dried in vacuum at 100 ° C to constant weight) was added. All of these operations are performed at room temperature. The reaction mixture was stirred at 60 ° C for 24 hours. The polymer was then filtered and washed with nitrobenzene (150 ml), chloroform (100 ml), acetone (200 ml), 4 n HCl (300 ml), water (300 ml), ethanol (200 ml). The polymer is dried under vacuum to constant weight. The weight of the modified polymer is 2.52 g, the weight capacity is 3.0 mmol per gram, calculated on the number of 4-hydroxy-2,3,5,6-tetrafluorobenzyl groups. The number of OH groups (capacity by the number of reactive groups) is 2.6 mmol / g of polymer according to the results of titration with perchloric acid.

From the data on titration results, 18% by weight of polystyrene units underwent modifications.

IR Spectrum: 1250.147070500.1610.3050, 3250-3300.

Found,%: C 63.72; H 3.65. Calculated,%: C 63.85; H 3.54. Example 2. Polymeric activated esters of N-protected amino acids

(PAE).

A solution of N-protected amino acid (12 mmol) in 30 ml of dimethylformamide is mixed with 3 g of para- (4-hydroxy-2,3,5,6-tetrafluorobenzyl) polystyrene activator

at 0 ° C for 10 minutes, then a solution of 2.4 g (12 mmol) of M, m-dicyclohexyl-carbodiimide in 15 ml of dimethylformamide is added. Stirring is continued for 30 minutes. at 0 ° C and 10 hours. at room temperature.

The polymer is filtered off, washed with an equivalent volume mixture of isopropyl alcohol-chloroform (5x50 ml), ether (2x50 ml), dried in vacuum at 60 ° C to a constant weight. The capacity of the obtained PAE by weight

amounted to:

for BOC-Leu-P0,56 mmol / g

BOC-Pro-R0,49 mmol / g

BOC-lte-P0.60 mmol / g

Z-Tyr (OBzl) -P0.97 mmol / g

where P is the residue of a pair of 4-hydroxy-2,3,5,6-tetrafluorobenzyl polystyrene, Boc-lte is tert-butyloxycarbonyl isoleucine. Z-Tyr (OBzl) - carbobenzoxy-o-benzyltyrosine, Boc-Leu - tert-butyloxycarbonyl leucine,

Vo-Pro - tertbutyloxycarbonylproline.

Example 3. Synthesis of peptides. 0.14 ml (1 mmol) of triethylamine and then a 2-fold excess of the corresponding polymeric activated ester relative to a molar amount of reactive hydroxyl is added to a solution of 0.5 mmol of the amino components in the form of methyl hydrochloride or benzyl tosylate groups In the case of peptides: Z-Tyr (OBzl) -Gly-OMe, Z-Tyr (OBzl) -Jle-OMe, Boc-Pro-Phe-OMe C-terminal amino acid methyl ester was used as the amino component. For

peptides: Boc-Leu-Leu-OBzl, BOC-Jle-Leu-Leu-oBzl used benzyl ester tosylate. The suspension is stirred at room temperature. The progress of the reaction is monitored by TLC for the disappearance of the amino component (Silufol plates, benzene-acetone system 3: 1). After 30-60 minutes (depending on the nature of the amino acids), the polymer is filtered off, washed with methylene chloride and the filtrate is evaporated. Remainder

dissolved in 50 ml of ethyl acetate and washed with 5% solution of NaHCOs (2x50) with water, 0, E n H204, water, dried over Na2SO4. After distilling off the solvent in vacuum, a crystalline product or oil is obtained, which

Claims (1)

The crystalline solution is crystallized by drying in a vacuum. mind.para- (4-hydroxy-2,3,5,6-tetrafluorben Products chromatographically homogen-yl) polystyrene of the formula, c; n-ch v v (Silufol, acetone-benzene 1: 3), their temperature is 5 / s) I melting patterns correspond to SN-SN SN-AUn-SN literary.L. D 1JL GGR Output,% So pl., ° C RfC9J l ° J 105Ng Z-Tyr / Obzl / -Gly-OMe 99 127-128 0, Z-Tyr / OBzl / -Jle-OMe 86 1120.62Јn where n 458, m 100, p 11, BOC-Leu-Leu-OBzl90 oil 0.52 as a polymeric activator for synBOC-Jle-Leu-Leu-OBzl 84 133-35 0.64 15 peptide synthesis. BOC-Pro-Phe-OMe 98 74-75 0.41