PROCESSES FOR THE PREPARATION OF SUMATRIPTAN AND RELATED COMPOUNDS

摘要

The present invention relates to a process for preparing phenylhydrazines of formula (I) in which R represents CH2SO2NHCH3, CH2CH2SO2Ph, CH2CH2SO2NHMe or a group of structure (A), (B), (C), in which a diazonium salt of formula (II) in which X represents an anion derived from hydrochloric acid, sulphuric acid, acetic acid, phosphoric acid, tetrafluoroboric acid or hydrobromic acid is reduced by a dithionite salt. The resulting phenylhydrazines can be converted to the corresponding indole derivatives by the Fischer indole synthesis.