3-Methoxypyrazoles from 1,1-dimethoxyethene,few original results |
| |
Authors: | Elise Salanouve Sandrine Guillou Marine Bizouarne Frédéric J Bonhomme Yves L Janin |
| |
Institution: | 1. Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris cedex 15, France;2. CNRS, UMR 3523, 28 rue du Dr. Roux, 75724 Paris cedex 15, France |
| |
Abstract: | From the condensation between 1,1-dimethoxyethene and anhydrides, synthetically useful β,β–dimethoxy–α,β-unsaturated ketones were prepared. Upon addition of hydrazine, followed by iodination, 4-iodinated 3-methoxypyrazoles were obtained. The occurrence of a side compound also provided insights in the scope of this synthesis. In a second part, 1-(4-chlorophenyl)-3,3-dimethoxyprop-2-en-1-one was obtained from 1,1-dimethoxyethene and 4-chlorobenzoylchloride. The subsequent addition of hydrazine or phenylhydrazine led to 5-(4-chlorophenyl)-3-methoxy-1H-pyrazole or 1-phenyl-5-(4-chlorophenyl)-3-methoxypyrazole in unprecedented 64 or 54% overall yield. Unexpectedly, addition of 2-pyridylhydrazine led to the 2-(1,2,4]triazolo4,3-a]pyridin-3-yl)-1-(4-chlorophenyl) ethanone. This led us to design original conditions, which led to the target 1-(2-pyridyl)-5-(4-chlorophenyl)-3-methoxypyrazole in a 39% overall yield. Additional examples are provided, starting from various carboxychlorides. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|