Process for producing fused imidazole compound, reformatsky reagent in stable form, and process for producing the same

摘要

The present invention provides an industrially advantageous process for producing a steroid C17,20 lyase inhibitor represented by the general formula (I): and a Reformatsky reagent in a stable form suitable for the process. In the present invention, a compound represented by the general formula (I) is produced by reducing a specific beta-hydroxy ester compound derivative or a salt thereof obtained from a specific carbonyl compound in a Reformatsky reaction in the presence of a metal hydride complex and a metal halide, and then subjecting it to a ring-closing reaction. In the above Reformatsky reaction, it is useful to use a stable solution of a compound represented by the general formula BrZnCH2COOC2H5 or a crystal of the compound which is represented by the formula (BrZnCH2COOC2H5.THF)2.