Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles
摘要:
beta-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30 degreesC-rt. In addition, hydrazine 6 condenses with beta-ketonitriles and beta-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOR/DMSO at 45 degreesC. (C) 2003 Elsevier Ltd. All rights reserved.
(E)-2-Iodo-1-tosyl-1-alkenes readily available by iodosulfonization of 1-alkynes were found to be useful synthons for the regio- and/or stereoselective preparation of 1-tosyl-1-alkynes, 1-tosyl-2-alkynes, (Z)-vinyl and (Z)-allyl sulfones, β-tosyl enamines, α-tosyl ketones, α-tosyl aldehyde acetal, and β-disubstituted vinyl sulfones.
A Michael Route to Acetals and Thioacetals: Preparation of Acetals (Thioacetals) of 2-Sulfonylacetaldehyde from Alkynyl and Other Unsaturated Aryl Sulfones
作者:Sergio Cossu、Ottorino De Lucchi、Fabrizio Fabris、Roberto Ballini、Giovanna Bosica
DOI:10.1055/s-1996-4406
日期:1996.12
A simple protocol for the direct transformation of arylsulfonylalkynes 1, (Z)- and (E)-1,2-bis(phenylsulfonyl)ethylene (2), and (E)-1-chloro-2-phenylsulfonylethylene (3) into the acetals or thioacetals of acetyl sulfones is presented. It engages the NaH-catalyzed reaction of an alcohol or a thiol with 1-3 at room temperature for 2-12 hours. Emphasis is given to enantiopure C 2 symmetric diols for the production of chiral building blocks to be used in asymmetric synthesis.
本文介绍了将芳基磺酰基炔 1、(Z)- 和 (E)-1,2- 双(苯磺酰基)乙烯 (2) 以及 (E)-1-chloro-2-phenylsulfonylethylene (3) 直接转化为乙酰砜的乙醛或硫代乙醛的简单方案。它涉及醇或硫醇与 1-3 在室温下 2-12 小时的 NaH 催化反应。重点是对映纯 C 2 对称二元醇,以生产用于不对称合成的手性构件。
Selenosulfonation of acetylenes: preparation of novel .beta.-(phenylseleno)vinyl sulfones and their conversion to acetylenic and .beta.-functionalized sulfones
作者:Thomas G. Back、Scott Collins、Russell G. Kerr
DOI:10.1021/jo00166a030
日期:1983.9
Grignard Reagents of Sulfones. VI. Alkylation and Related Reactions<sup>1</sup>
作者:Lamar Field、John R. Holsten、R. Donald Clark
DOI:10.1021/ja01519a068
日期:1959.5
Maioli; Modena, Gazzetta Chimica Italiana, 1959, vol. 89, p. 854,859