SU491617A1 - Method for preparing protected hexapeptide sequence 15-20 of human insulin b-chain as symmetric disulfide - Google Patents

Description

dried, evaporated to a volume of 15 ml. 2 ml of dicyclohexylamine is added to the residue, the precipitated crystals are filtered, washed with ether, and dried. After crystallization from ethyl acetate, 6.1 g (78%) of the product are obtained. Naidio,%: C 67, 17; H 8.24.

C48H67N409-H20.

Calculated,%: C, 66.94; H 7.96.

The thus obtained dicyclohexyl ammonium salt is suspended in ethyl acetate and shaken with 0.5N. sulfuric acid until completely dissolved. The ethyl acetate layer is separated, washed with water, and dried. After evaporation, 4.8 g (100%) of product are obtained with a mp. 157-158 ° C.

o-Nitrophenylsulfenyl leucyl tyrosyl leucyl valine (P1).

Product III is obtained from the product And and pnitrofeyl ether o-ititrophenylsulfonylutinium by the method similar to the previous one, and it is isolated and identified as its dicyclohexylammonium salt. Yield 98%; m.p. 152-154 ° C;

 -11 ° C (with 1, DMF).

Found,%: C 61.6; H 8.13.

C44Nb8Nb08-2N20.

Calculated,%: C 61.31; H 8.42.

Bis- (o-nitrophenylsulfenylleucyltyrosylleucylvalyl) -cystine and lbs-glycine (IV) dimethyl ester.

1.0 g of dimethyl ester of dicarbobenzoxycystinyl-by-glycine is treated with 5 ml of a 25% aqueous solution of hydrogen bromide in acetic acid, after 40 minutes the reaction mixture is diluted with ether, the precipitated crystals are filtered, washed with ether and dissolved in B 5 ml of dimethylformamide. Anhydrous sodium bicarbonate is added to the solution obtained by stirring, filtered off after 5 minutes, 3.4 g of dicyclohexylammonium salt of dictate III and 1.0 g of oxnsuccinimide are added to the filtrate, the mixture is cooled to -15 ° C, and 0.7 g of dicyclohexylcarbodia is added to the mixture. The mixture was kept for 2 days at 0 ° C, the precipitated dicyclohexyl urea was filtered off, the filtrate was diluted with 0.5 and. with sulfuric acid, the precipitated crystals are filtered off, washed with water, 5% sodium bicarbonate, and water.

dried After crystallization from dimethylformamide-water mixture, 2.26 g (88%) of the product with m.p. 237-239 ° C; -50 ° C (with 1, DMF). Found,%: C 54.60; H 6.62.

C76Hio8Ni4O2oS4.

Calculated,%: C 54, 78; H 6.53.

Bis- (o-nitrophenylsulfenylleucyl-tyrosylleucylvalyl) -cystinyl-by-glycium (V).

1.4 g of product IV was dissolved in 10 ml of methanol, and 4.6 ml of 1.0 N was added to the resulting solution. sodium hydroxide solution and stirred at room temperature for 2 hours. The reaction mixture is filtered with activated carbon, the filtrate is diluted with 0.5N. sulfuric acid, the precipitated crystals are filtered off, washed with water, dried. Obtain 1.0 g (75%) of product with so pl. 213 - 215 ° С and ° -2ГС (с 1, DMF).

Found,%: C 54.67; H 6.40.

C74Hio4Nl4O4S4.

Calculated,%: C 54.19; H 6.40.

Amino acid composition, g (theoretical values are given in parentheses): cysteine 0.8 (1); tyrosine 0.7 (1); Barn 1.2 (1); Leucine 2.2 (2).

Claims (1)

Invention Formula Snosob preparation of a protected hexapeptide sequence 15-20 of the B chain of human insulin in the form of a symmetrical disulphide, characterized in that, in order to improve the process, are condensed sequentially with karbobenzoksileytsinom valine, and o-dikarbobenzoksitirozinom nitrofenilsulfenilleytsinom removing protecting groups action of hydrogen bromide in acetic acid or by catalytic hydrogenolysis, the obtained tetrapeptide-o-nitrofeiylsulfenylleucyltyrosylleucylvaline is condensed by the carbodiimide method with dipeptndo 1tsistinil-bys-glitsildimetilovym ether and the resulting methyl ester geksapeptnda subjected to alkaline hydrolysis followed by isolation of the desired product in a known way.