A new and expeditious strategy for the synthesis of β-amino acids from Δ2-oxazolines
摘要:
A new, mild two-step synthesis of racemic p-amino acids starting from 2-allkyl-Delta (2)-oxazolines is described. The process implies the initial formation of masked N-substituted or N-unsubstituted beta -enamino acid derivatives followed by chemoselective reduction of the enamino moiety. The process takes place with high yields, total chemoselectivity and moderate diastereoselectivity. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis and C-alkylation of C-protected β-enamino acid derivatives from oxa- thia- and imidazolines
摘要:
Various heterocycles 3a-h can be readily metallated and condensed with a variety of organic nitriles to afford C-protected beta-enamino acid derivatives 1 (or 2). Procedures for alkylation of compounds 1 to obtain 2 as well as a "one-pot" preparation of 2 from 3 are also described. (C) 1999 Elsevier Science Ltd. All rights reserved.
A new method of synthesis of racemic β-amino acids 6 by reduction of masked N-substituted and N-unsubstituted β-enamino acid derivatives 4via C-protected β-amino acids5 is described. The process occurs with high yields, total chemoselectivity and moderate diastereoselectivity. Readily available starting materials, inexpensive reagents and mild conditions are used to furnish derivatives 5 and 6.
An efficient synthesis of uracil derivatives from 2-alkyl-Δ2-oxazolines and nitriles
作者:Santos Fustero、Juan F. Sanz-Cervera、Salvador Mérida、Raquel Román、Salvador Villanova、Carmen Ramírez de Arellano
DOI:10.1016/j.jfluchem.2008.04.004
日期:2008.9
An efficient a rid convenient synthesis of new fluorinated a rid non-fluorinated uracils is described herein. The condensation of nitriles with enolates generated from 2-alkyl-Delta(2)-oxazolines affords fluorinated beta-enamino acid derivatives, which react with triphosgene to give an isomeric mixture of oxazolopyrimidinones. These can then be easily transformed into a single C-6 pyrimidindione derivative through reaction with a suitable nucleophile. (c) 2008 Elsevier B.V. All rights reserved.