Boron tribromide → HCID 18973644, compound

Participants

Reaction Conditions

Reaction Steps

Preparation of the starting compound 4-((3-ethyl-4-methyl-2-oxo-3-pyrroline-1-carboxamido) methyl)-6-sulfamoyl-7-ethoxychroman ##STR54## 9.5 ml (0.1 mol) of boron tribromide are added dropwise to a solution of 10.6 g (0.025 mol of 4-((3-ethyl-4-methyl-2-oxo-3-pyrroline-1-carboxamido) methyl)-6-sulfamoyl-7-methoxychroman in 75 ml of methylene chloride cooled to -10° C. After standing overnight at 20° C., the excess boron tribromide is destroyed after cooling to -10° C. by cautious dropwise addition of methanol. The mixture is then introduced into ice/water and extracted several times with methylene chloride. The combined methylene chloride extracts are dried, evaporated and recrystallized from methanol. 4-((3-Ethyl-4-methyl-2-oxo-3-pyrroline-1-carboxamido) methyl)-6-sulfamoyl-7-hydroxychroman of melting point 175° C. is obtained.

Provenance & Evidence