The reaction of several α-aminoacids and peptides (containing Gly, L-Ala, L-Leu, L- or DL-Phe, and/or L- or D-Val) with air-diluted nitrogen oxides has been studied to roughly mimic the N-nitrosation of peptide bonds that the contaminated urban air might produce in pulmonary tissues. Most N-protected α-aminoacids give practically quantitative yields of N-nitroso derivatives. N-Protected dipeptides
已经研究了几种α-氨基酸和多肽(包含Gly,L-Ala,L-Leu,L-或DL-Phe和/或L-或D-Val)与空气稀释的氮氧化物的反应模拟被污染的城市空气可能在肺组织中产生的肽键的N-亚硝化。大多数N-保护的α-氨基酸可提供定量的N-亚硝基衍生物。受N保护的二肽提供二亚硝化肽,二亚硝化化合物和单亚硝化化合物的混合物,选择性单亚硝化产物,或根本不发生反应,这主要取决于空间效应。对于一些更高的肽,观察到相同的趋势。保留了原料的手性的(多)亚硝化肽的特征是1 H和13在温和的条件下,经吡咯烷和氨基酯裂解,得到13 C NMR光谱,得到(新的)酰胺或肽以及重氮衍生物。
Efficient three-step sequence for the deamination of α-aminoesters. Application to the synthesis of CysLT1 antagonists
and efficient three-step sequence for the deamination of α-aminoesters is reported. This method is based on the NaBH4-mediated selective reduction of α-diazoesters to α-hydrazonoesters and has been successfully applied to the deamination of several representative α-aminoesters including some l-cysteine ethyl ester derivatives, key intermediates in the synthesis of a series of CysLT1 antagonists.
Exploring the reaction of iodine with<i>α</i>-diazo esters
作者:Giancarlo Verardo、Paola Geatti、Alberto Gambi
DOI:10.1002/poc.1420
日期:2009.1
In this paper we describe the unprecedented reaction between α‐diazoesters 1 and iodine. The reaction, carried out in the presence of aqueous NaHCO3, afforded the Z‐isomer of the corresponding unsaturated‐2‐iodo ester 8. The configuration of compounds 8 was determined using the 3JCH coupling between carbonyl carbon atom and alkene proton. Mechanistic considerations accounting for the observed phenomena
Novel compounds of the formula (I), in which D, W, X, Y, T and R
1
are as defined in Patent Claim
1
, are inhibitors of coagulation factor Xa and can be employed for the prophylaxis and/or therapy of thromboembolic diseases and for the treatment of tumours.
Novel compounds of the formula (I), in which D, W, X, Y, T and R1 are as defined in Patent Claim 1, are inhibitors of coagulation factor Xa and can be employed for the prophylaxis and/or therapy of thromboembolic diseases and for the treatment of tumors.