The Synthesis of 1,3-Dithiolan-2-ones on the Reaction of Oxiranes with Carbon Disulfide under High Pressure

Article abstract of DOI:10.1246/bcsj.62.474

An equimolar reaction of 2-hexyloxirane with carbon disulfide in hexane was run in the presence of triethylamine under 800 MPa at 100 degC for 20 h, and gave 63percent of 4-hexy-1,3-dithiolan-2-one (3a), 21percent of 4-hexyl-1,3-dithiolane-2-thione (1a) and 5percent of 5-hexyl-1,3-oxathiolan-2-one (4a).Hexane, benzene, and diisopropyl ether were good solvents for the reaction.The reaction of a variety of oxiranes with carbon disulfide produced 1,3-dithiolan-2-one as the main products under 500 MPa at 100 degC for 20 h.Upon a reaction of 2-hexyloxirane with carbon disulfide, 5-hexyl-1,3-oxathiolane-2-thione (2a), and 2-hexylthiirane (5a) were produced during the first stage of reaction.The formation of 1a and 4a began immediately, whereas, the formation of 3a required a long induced period.A feasible mechanism for the formation of 3a is proposed to be a rearrangement of 2a in the presence of the triethylamine, free from carbon disulfide.