1,2-Ethanediamine, 4-methylbenzenesulfonate (1:?) → 2-(2-imidazolin-2-yl)-1-phenyl-1H-indole

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of 1-phenyl-1H-indole-2-carbonitrile (15 g) and ethylenediamine monotosylate (17.6 g) was heated at 200° C. for 2 hours. After cooling, the reaction mixture was partitioned between toluene (100 ml) and dilute hydrochloric acid (400 ml). The aqueous layer was extracted with diethyl ether, cooled in an ice bath then basified with concentrated ammonia and reextracted with dichloromethane. The combined dichloromethane extracts were washed with water, dried and the solvent removed in vacuo. The residue was purified by chromatography on neutral alumina (grade III) eluting with 1% methanol in dichloromethane, followed by trituration with toluene to give 2-(2-imidazolin-2-yl)-1-phenyl-1H-indole as a white solid: yield 16.6 g (90%); mp 180.5°-182° C. The hydrochloride salt was prepared as described above: yield 16.3 g (95%); mp 263.5°-265.5° C.

Provenance & Evidence