- The Synthesis of 1,3-Dithiolan-2-ones on the Reaction of Oxiranes with Carbon Disulfide under High Pressure
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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.
- Taguchi, Yoichi,Yasumoto, Masahiko,Shibuya, Isao,Suhara, Yasuo
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p. 474 - 478
(2007/10/02)
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- The Reaction of Oxiranes with Carbon Disulfide under High Pressure
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The reaction of 2,2-dimethyloxirane with carbon disulfide in the presence of triethylamine was accelerated under high pressure to give 5,5-dimethyl-1,3-oxathiolane-2-thione in a high yield, while 2-hexyl-oxirane under the same reaction condition formed 4-hexyl-1,3-dithiolane-2-thione (2b) as the main product and 5-hexyl-1,3-oxathiolane-2-thione (1b) as a minor product.A feasible mechanism for this formation is that 1b and 2-hexylthiirane (4b) are produced in the first stage of reaction, and that 2b is then formed by the reaction of 1b or 4b with carbon disulfide.In reactions of a variety of oxiranes with carbon disulfide, 1,3-dithiolane- 2-thiones were obtained in high yields under 800 MPa at 100 deg C within 20 h.Concerning the effect of substituents in oxiranes, the selectivity for product 2b is in the decreasing order; 2-phenyl- > 2-methyl- > 2-ethyl- > 2-hexyl- > 2,3-tetramethylene- > 2,2-dimethyl- > 2-(chloromethyl)- .Tertiary amines, such as N,N-dimethyl-ethylamine, pyridine, and N-methylmorpholine, serve as good catalysts for the reaction.
- Taguchi, Yoichi,Yanagiya, Koshin,Shibuya, Isao,Suhara, Yasuo
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p. 921 - 926
(2007/10/02)
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