Pyridine → HCID 131732955, compound

Participants

Reaction Conditions

Reaction Steps

Z-Pro-Gly-OtBu was dissolved in AcOEt at 25° C. and Pd/C (0.02 eq.) was added to the peptide solution. The solution was stirred at 25° C. followed by the introduction of hydrogen under pressure (0.3 bar). After the reaction was considered as complete by HPLC, the solution was filtered to remove the catalyst which was washed with AcOEt. The solution of H-Pro-Gly-OtBu (1.05 eq.) was cooled to −15° C. Z-Val-Gln-OH was dissolved in a mixture of DMA and AcOEt and the resulting solution was cooled to −15° C. Dipea (1.05 eq.) was introduced to neutralize the carboxylic function, and then pyridine (1.05 eq.) and PivCl were introduced to activate the acid function. The H-Pro-Gly-OtBu solution was transferred to the activated dipeptide as quickly as possible and the slurry was stirred for at least 0.5 hours and left to warm to room temperature. The reaction mixture was neutralized by addition of water, diluted with AcOEt and the organic phase was washed with a 5% aqueous solution of KHSO4, with a 5% aqueous solution of NaHCO3, with a 5% aqueous solution of NaCl and finally with water. The organic phase was collected and concentrated under reduced pressure until water content in the evaporates was ≦1% weight. The concentrate was diluted with hot isopropyl ether and left to cool to 25° C. under gentle stirring to crystallize the peptide. The solid was recovered by filtration, once washed with hot IPE and dried under vacuum until IPE content in the peptide was <5% weight. Z-Val-Gln-Pro-Gly-OtBu (SEQ ID NO 22) was dissolved in ethanol at room temperature and Pd/C (0.02 eq.) was added to the peptide solution. The solution was stirred at 25° C. followed by the introduction of hydrogen under pressure (0.3 bar). The solution was stirred for at least 2 hrs and the completion of the reaction was checked by HPLC. The solution was filtered to remove the catalyst and washed with ethanol. After evaporation, the free tetrapeptide was then precipitated by transferring the solution in MTBE at −10° C. The solution was left to mature at −10° C. for at least 30 minutes. The solid was filtered and washed with MTBE. After drying under vacuum not less than 80% of H-Val-Gln-Pro-Gly-OtBu (SEQ ID NO 18) was recovered.

Provenance & Evidence