Chlorobenzene → 5-Chloro-3-methyl-2-phenyl-1-benzothiophene

Participants

Reaction Conditions

Reaction Steps

55.7 parts by weight of p-chlorophenylthiophenylmethylmethyl ketone and 500 parts by weight polyphosphoric acid are combined in a stoppered flask and heated with stirring for 3.5 hours at 180° C. 350 Parts by volume of chlorobenzene is added to the reaction mixture and the resulting solution is heated at reflux temperature for an additional hour. After cooling the organic phase of this reaction solution is decanted off; the inorganic phase is dissolved in ice water and extracted once each with benzene and ethyl ether. The combined organic phases are then washed once with a saturated solution of sodium bicarbonate, washed once with brine, and dried over magnesium sulfate. Concentration of this solution in vacuo affords a dark solid. Crystallization of this solid (2xs) from heptane affords a brown solid. Sublimation at 135° C/0.1mm of this brown solid affords 5-chloro-3-methyl-2-phenylbenzo[b]thiophene, melting at 108.5°-110° C. This compound is represented by the following structural formula. ##STR10##

Provenance & Evidence