- CONVERSION OF DIHYDRO-1,4-OXATHIIN-3-CARBOXAMIDE TO THE ISOMERIC DIHYDRO-1,4-OXATHIIN-2-CARBOXAMIDE
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The preparation of isomeric dihydro-1,4-oxathiin (3) from the dihydro-1,4-oxathin (1) via dichloro-1,4-oxathiane (4) is described.Chlorination of 1 followed by treatment of the resulting dichloride (4) with aqueous acetone gave dihydroxy-1,4-oxathiin (5).The solvolysis to produce intermediate chlorohydrin (11) was favored relative to elimination reaction to give exomethylene compound (8).Dehydration of 5 followed by reduction afforded α-hydroxy-1,3-oxathiolane (2) which is a key compound to prepare the isomeric dihydro-1,4-oxathiin (3).The reason for more facile displacement of chlorine at C-2 in comparison with that at C-4 in 4 was also discussed.
- Hahn, Hoh-Gyu,Chang, Kee-Hyuk,Lee, Wha Suk
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p. 921 - 931
(2007/10/02)
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