反应详情

The aminations of Equations 43a and 43e are most conveniently effected by adding the requisite sulfonyl chlorides to a solution of the aminopyrazoles LIIa and LIIa' in a suitable solvent such as diethyl ether, tetrahydrofuran, or methylene chloride containing at least two equivalents of an acid scavenger such as triethylamine or dimethylaniline at temperatures between 0° C. and 65° C. The desired sulfonamides of Formulas LIIb and LIIb' are isolated either by filtration, in which case the by-product triethylamine hydrochloride or dimethylaniline hydrochloride is removed by washing with water, or extraction into a suitable organic solvent such as methylene chloride or ethyl acetate. Drying and evaporation of the solvent then affords the products LIIb and LIIb', which are usually sufficiently pure to be carried directly onto the next step.