Dichloromethane → trans-Thiothixene

Participants

Reaction Steps

5N aqueous sodium hydroxide was added to a suspension of thiothixene.2H3PO4 (63.96 g., 100 mmoles, ca. 85% trans/ 15% cis) in water (750 ml.)/methylene chloride (750 ml.) until the aqueous phase was strongly basic. The phases were separated and the aqueous phase extracted with an additional 200 ml. portion of methylene chloride. The combined methylene chloride extract was dried (Na2SO4), filtered and evaporated in vacuo to a light brown oil (ca. 45 g., ca. 100% yield, ca. 85% trans/15% cis). The oil was dissolved in warm acetonitrile (100 ml.) and the solution cooled to room temperature. Some solids, probably trans-thiothixene, formed upon cooling. Potassium t-butoxide (1.1 g., 9.8 mmoles) was added and the mixture stirred overnight at room temperature. Analysis of the reaction mixture, which contained solids, showed a ca. 85% cis/ 15% trans ratio of isomers. Water (10 ml.) was then added and the reaction mixture stirred briefly at room temperature. The tan cis-thiothixene solids were then filtered, washed with acetonitrile, and dried (35.0 g., 78.9% yield, 5% trans, m.p. 143°-145° C.).

Provenance & Evidence