New sugar alcohol derivs. - such as 1,4 cyclic sulphate(s) of sugar alcohol(s) having protected hydroxy gps., for use as intermediates

摘要

The following are claimed (A) a 1,4 cyclic sulphate of a sugar alcohol having protected hydroxy gps. (B) a process for prepg. a 1,4 cyclic sulphate of a sugar alcohol having protected OH gps., in which a sugar alcohol having free 1- and 4-OH gps., its remaining OH gps. being protected, is reacted with thionyl chloride in the presence of an acid binding agent and the resulting 1,4 cyclic sulphite is oxidised to the corresp. 1,4 cyclic sulphate. (C) A process for prepg. a 3-deoxy-2-octulosonic acid cpd. or a 3-deoxy-2-heptulosonic acid cpd. having protected or unprotected OH gps., or their salts or esters, which comprises reacting either a 1,4-cyclic sulphate of a hexitol having protected 2-, 3-, 5- and 6-OH gps. or a 1,4 cyclic sulphate of a pentitol having protected 2-, 3- and 5-OH gps., with an anion of a dithioacetal cpd. of a glyoxylic acid ester, hydrolysing the sulphate gp., removing the dithioacetal gp., opt. removing the OH protecting gps. and opt. converting the resulting ester into the free acid, a salt or another ester.