Acylation process

A process for the preparation of a compound of formula (I)

• wherein R=C1-C6 alkyl, C1-C6 alkoxy, C3-C7 cycloalkyl, aryl optionally substituted by one or more of hydroxy, C1-C4 alkyl, C1-C4 alkoxy, fluoro, fluoro(C1-C4)alkyl and fluoro(C1-C4)alkoxy, or N-carboxybenzyl-2-pyrrolidinyl and X is hydrogen or one or more substituents independently selected from cyano, halogen, nitro, C1-C6 alkyl, C1-C6 alkoxy, C3-C7 cycloalkyl and aryl optionally substituted by one or more of cyano, halogen, nitro, C1-C4 alkyl, C1-C4 alkoxy, fluoro(C1-C4)alkyl and fluoro(C1-C4)alkoxy;
• which comprises separately and simultaneously adding to a stirred solution of an indole of formula (II)
• wherein X is as hereinbefore defined;
• (i) a solution containing an acid chloride of formula RCOCl wherein R is as hereinbefore defined;
• and
• (ii) a solution containing an alkyl or aryl magnesium halide in such a way that
• (a) the solutions (i) and (ii) are added with sufficient separation to prevent their reacting with one another;
• and
• (b) the solutions (i) and (ii) are added at equivalent rates of molar addition.