An efficient synthesis of highly substituted pyrroles from β-oxodithiocarboxylates
摘要:
alpha-Oxoketene-N,S-acetals, prepared by the reaction of alkyl glycinate hydrochlorides with beta-oxodithiocarboxylates followed by alkylation, underwent cyclization in presence of chloromethyleneiminium salt derived from POCl3/DMF to afford alkyl-3-aryl-4-formyl-5-(alkylsulfanyl)-1H-pyrrole-2-carboxylates in excellent yields. Alkyl-3-aryl-5-(alkylsulfanyl)-1H-pyrrole-2-carboxylates were formed in moderate yields when the same N,S-acetals were treated with DBU. (c) 2005 Elsevier Ltd. All rights reserved.
Microwave assisted one-pot synthesis of pyrrolo[2,1-<i>b</i>]thiazol-6-ones from α-aroyl ketene-<i>N</i>,<i>S</i>-acetals
作者:Paulson Mathew、M. Prasidha、C. V. Asokan
DOI:10.1002/jhet.334
日期:——
α‐Aroyl ketene‐N,S‐acetals 3 prepared by the reaction of β‐oxothioamides 1 with phenacyl bromides 2, underwent sequential cyclizations under microwave irradiation to afford pyrrolo[2,1‐b]thiazol‐6‐ones 6 in good yields. A double cyclization takes place regioselectively in onepot and variety of functionalized pyrrolo[2,1‐b]thiazol‐6‐ones were prepared by this protocol. The mode of cyclization under
由β-氧代硫代酰胺1与苯甲酰溴2反应制得的α-芳基酮烯N,S缩醛3在微波辐射下依次环化生成吡咯并[2,1 - b ]噻唑-6-酮6,收率高。在一个锅中区域选择性地进行双环化,并根据该方案制备了多种功能化的吡咯并[2,1-b]噻唑-6-酮。微波条件下的环化方式与常规加热不同。J.杂环化学。(2010)。
Application of Functionalized<i>N</i>,<i>S</i>-Ketene Acetals-Microwave-Assisted Three-Component Domino Reaction for Rapid Direct Access to Imidazo[1,2-<i>a</i>]pyridines
Imidazo[1,2‐a]pyridines have been successfully synthesized in moderate to good yields via a tandem three‐component reaction of ethyl 2‐(3‐oxo‐3‐arylpropanethioamido)acetates with aromatic aldehydes and malononitrile by means of microwave irradiation using DABCO as the catalyst. The advantages of this method including high chemo‐ and regioselectivity make this new strategy highly attractive.
咪唑并[1,2- a ]吡啶已成功合成,其中2-(3-氧代-3-3-芳基丙烷硫代酰胺基)乙酸乙酯与芳族醛和丙二腈通过微波辐射的串联三组分反应以中等至良好的收率合成。 DABCO作为催化剂。这种方法的优势包括高的化学选择性和区域选择性,使这种新策略极具吸引力。