| 摘要 |
<p>The invention relates to a mixture comprising a starting carboxylic acid, an esterifying reagent capable of forming an active ester, and a base; and a process for preparing active esters by adding a halogenating agent to a mixture obtained by mixing in an organic solvent a starting carboxylic acid with an esterifying reagent capable of forming an active ester and a base to conduct a reaction. Independent of the structure of the starting carboxylic acid, active esters useful as intermediates of drugs or the like can be each prepared from inexpensive reagents in one pot in a high yield without isomerization.</p> |
