SYNTHESIS AND STRUCTURES OF SOME DIGLYCOLALDEHYDE THIOACETALS

Article abstract of DOI:10.1016/S0008-6215(00)88051-9

Diglycolaldehyde (2,2'-oxybisacetaldehyde, 1a) reacts with thiols under conditions similar to those for monosaccharides.The nature of the reaction products depends on the degree of α-substitution of the thiol.The acyclic dithioacetal 2a was the only product isolated when methanethiol was used, but mixtures of acyclic dithioacetals, cis-2,6-bis(alkylthio)-1,4-dioxanes, and trans-2,6-bis(alkylthio)-1,4-dioxanes were obtained when ethanethiol, 1-propanethiol, and 2-propanethiol were used.From 1a and 2-methylpropane-2-thiol the acyclic dithioacetal 2e and the cis (7) and trans (8) stereoisomers of 3,5-bis(tert-butylthio)-1,4-oxathiane were isolated.On the other hand, when diglycolaldehyde bis(dialkyl acetals) (9a-d) or 2,6-di-isopropoxy-1,4-dioxane (10) were treated with primary or secondary thiols in acid media, the acyclic dithioacetals were isolated as the only products.The acyclic dithioacetal 2e and the oxathiane derivatives 7 and 8 were obtained when 9a-d or 10 were treated with 2-methylpropane-2-thiol under the above conditions.