通过微波辅助聚磷酸乙酯(PPE)促进的ω-硫代酰胺醇的闭环反应,开发了一种高效且通用的合成2-取代的噻唑啉和5,6-二氢-4 H -1,3-噻嗪的方法。环化反应涉及S N 2型机理,具有反应时间短,产率高和可预测的立体化学结果的优点。无环前体是通过改进的二酰化-硫磺化-皂化顺序,从市售的ω-氨基醇中以高收率制备的。整个过程无金属且操作简单。
CuCl-catalyzed radical cyclisation of N-α-perchloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides
作者:Andrea Cornia、Fulvia Felluga、Vincenzo Frenna、Franco Ghelfi、Andrew F. Parsons、Mariella Pattarozzi、Fabrizio Roncaglia、Domenico Spinelli
DOI:10.1016/j.tet.2012.04.117
日期:2012.7
The copper-catalyzed radical cyclization (RC) of N-α-perchloroacyl cyclic ketene-N,X(X=O, NR, S)-acetals was studied. While the RC of N-acyl ketene-N,O-acetals was unsuccessful, the 5-endo cyclization of the other ketene acetals provided much better results, with the following order of cyclization efficiency: hexa-atomic cyclic ketene-N,NR-acetals
DDQ-Induced Dehydrogenation of Heterocycles for CC Double Bond Formation: Synthesis of 2-Thiazoles and 2-Oxazoles
作者:Xiangnan Li、Cheng Li、Bing Yin、Cong Li、Ping Liu、Jianli Li、Zhen Shi
DOI:10.1002/asia.201300267
日期:2013.7
Strong as an Ox: 2‐Thiazoles and 2‐oxazoles are formed by oxidation of 2‐thiazolines and 2‐oxazolines without requiring substituents at the C4 and C5 positions. DDQ plays an important role as the oxidant in this transformation and metal is unnecessary. This general procedure shows good functional group tolerance and provides a wide variety of 2‐thiazoles and 2‐oxazoles in moderate to excellent yields
Thionation ofN-(?-Halogenoalkyl)-Substituted Amides withLawesson's Reagent: Facile Synthesis of 4,5-Dihydro-1,3-thiazoles and 5,6-Dihydro-4H-1,3-thiazines
作者:Yasuhiro Kodama、Mayuko Ori、Takehiko Nishio
DOI:10.1002/hlca.200590000
日期:2005.2
The thionation and cyclization of N-(ω-halogenoalkyl)-substitutedamides (and related compounds) with Lawesson's reagent (LR=2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide) has been investigated. Treatment of the amides 1 with LR gave the corresponding thioamides 2 in moderate to good yields (Table). The latter, upon treatment with base, afforded, either in a separate step or in
Condensation of the triisobutylaluminum complex of cysteamine HCl with a variety of carboxylic esters furnishes thiazolines in onestep. This new method has been applied to chiral α-aminoesters to give α-amino thiazolines of high optical purity, yet N-benzyl protection of the amine is required.
Tandem reactions of nitriles with 2-aminoethanethiolhydrochloride or amino alcohols in the presence of a catalytic amount of cupric methacrylate (CuII2L4, L = methacrylate) were employed to prepare 2-thiazolines and 2-oxazolines under mild reaction conditions. The synthetic procedure showed high selectivity for the synthesis of mono- and bis-thiazolines and oxazolines, and a variety of 2-thiazolines