Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles

被引：30

作者：

Dastrup, DM

Yap, AH

Weinreb, SM

Henry, JR

Lechleiter, AJ

机构：

[1] Penn State Univ, Dept Chem, University Pk, PA 16802 USA

[2] Eli Lilly & Co, Lilly Res Labs, Indianapolis, IN 46285 USA

来源：

TETRAHEDRON | 2004年 / 60卷 / 04期

基金：

美国国家科学基金会; 美国国家卫生研究院;

关键词：

protecting groups; nitrogen heterocycles;

D O I：

10.1016/j.tet.2003.11.046

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

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.

引用

页码：901 / 906

页数：6