Some cyclic trans-vicinal di-secondary thiols have been synthesised in high yields by reduction of the corresponding trithiocarbonates with lithium aluminium hydride. Various approaches to the synthesis of tetrahydrofuran-trans-31 4-dithiol, sulpholane-trans- 3,4-dithiol and indane-trans-1,2-dithiol were investigated, but without success. Further evidence on the course of acetyl migration during the alkaline hydrolysis of trans-2-acetylthiocyclopentanol has been obtained. Quantitative alkaline deacetylation of this compound in the presence of a competitive acceptor confirms the original proposal by Harding and Owen that acetyl migration is intramolecular. A crucial test was performed in which cyclopentene sulphide was prepared in 75% yield from trans-2-mercaptocyclopentyl acetate, which, according to the present theory, is the direct precursor of the episuiphide. Some cyclic trans-vicinal hydroxy-thiols have been synthesised via the corresponding epoxides. A number of isopropylidene derivatives and cyclic carbonates were prepared under mild conditions from the ABSTRACT (cont.) various dithiols and hydroxy-thiols. Some of,these derivatives provide further examples of compounds containing the highly strained system in which two five-membered rings are transfused. Kinetic investigations were made to study the formation of the isopropylidene derivatives by the acid catalysed condensation of acetone with the appropriate dithiols and hydroxy-thiols. A method has been developed in which the progress of the reaction is followed by the disappearance of the thiol value of the mercapto compound. It has been shown that in a large excess of acetone the rate is first-order with respect to thiol, and that it varies approximately with the square of the catalyst concentration. The mechanism proposed by Ross for this type of reaction is discussed and critisized, and a modified mechanism is proposed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602237 |
| Date | January 1963 |
| Creators | Kyaw, Maung |
| Contributors | Owen, L.N |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/13364 |
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