Stereoselective conversion of 2 H -1,4-oxazin-2-ones into 2,5,5-substituted piperidine-2-carboxamides and 2-methanamines and related octahydro-2 H -pyrido[1,2- a ]pyrazines, potential substance P antagonists
摘要:
4-(Hetero)aryl-2-oxa-5-azabicyclo[2.2.2] octan-3-ones and 3,6-diones, formed via cycloaddition of 2H-1,4-oxazin-2-ones and ethene followed by functional group transformation, undergo lactone cleavage by reaction with amines to yield substituted 2-(hetero)aryl-5-hydroxy-2-piperidinecarboxamides. Subsequent reduction affords the corresponding 2-piperidinemethanamines. Both amide and amine compounds are of interest as potential Substance P antagonists. A detailed NMR study, supported by conformational calculations, of an octahydro-2H-pyrido[1,2-a]pyrazine analogue revealed the existence of a temperature and solvent dependent equilibrium mixture of transoid and cisoid invertomers. (C) 2001 Elsevier Science Ltd. All rights reserved.
通过与取代的炔属化合物的环加成消除反应,合成3-官能化的5-氯-6-甲基-2 H -1,4-恶嗪-2-酮和吡啶。
摘要:
通常在适当的条件下,通过亲电催化避免内酯功能的反应,在3,5-二氯-6-甲基-2 H -1,4-恶嗪-2-酮中实现氯亚胺基的选择性官能化。已表明3-取代的5-氯-6-甲基-2 H -1,4-恶嗪-2-酮中的氮杂二烯体系易于与单取代的炔属化合物反应,并通过环加成消除法以优异的收率得到多官能化吡啶。讨论了通常较高的区域选择性及其对3-取代基性质的依赖性。
Functionalisation in position 3 of 3,5-dichloro-2H-1,4-oxazin-2-ones
作者:Koen J. Van Aken、Lieven Meerpoel、Georges J. Hoornaert
DOI:10.1016/s0040-4039(00)79064-2
日期:1992.5
Electrophilic catalysis is shown to give selective substitution of the imidoyl chloride group in 3,5-dichloro-2H-1,4-oxazin-2-ones, avoiding competitive reactions of the nucleophile with the lactone function. With other nucleophiles (SCN-, CH2N2) cyclisations involving the azadiene- or the imine function take place. Cycloaddition of the obtained oxazinones to acetylenic compounds provides polyfunctionalized pyridines.