| 摘要 |
<p>5-Alkoxy-1,2,4-triazolo[4,3-c]pyrimidine-3(2H)-thione compounds (I), such as 5-ethoxy-8-fluoro-1,2-,4-triazolo[4,3-c]pyrimidine-3(2H)-thione, were prepared by cyclization of 2-alkoxy-4-hydrazinopyrimidine compounds (II), such as 2-ethoxy-5-fluoro-4-hydrazinopyrimidine, with carbon disulfide and hydrogen peroxide. The reaction can be carried out in the presence of a trialkylamine, such as triethylamine, in which case a trialkylammonium salt is obtained. The products are useful intermediates in the preparation of 5-alkoxy(1,2,4)triazolo(1,5-c)pyrimidine-2-sulfonamide herbicides.</p> |
