THE SYNTHESIS OF 1,2:5,6-DI-O-ISOPROPYLIDENE-D-MANNITOL: A COMPARATIVE STUDY

Article abstract of DOI:10.1016/0008-6215(84)85087-9

Three different methods of acetonation of D-mannitol using (a) acetone and zinc chloride, (b) 2,2-dimethoxypropane, 1,2-dimethoxyethane, and tin(II)chloride, and (c) 2-methoxypropane, N,N-dimethylformamide, and p-toluenesulfonic acid were studied in detail and compared, using gas-liquid chromatographic techniques.In each reaction, isomeric diacetals are formed, but method a gives the 1,2:5,6-diacetal in the highest yield (63percent).Methods b and c give a more complex mixture of acetals than proposed in the literature, and both methods are less economical than a.A new 1,2:3,6:4,5-tri-O-isopropylidene-D-mannitol could be separated, and its graded hydrolysis was compared to that of the 1,2:3,4:5,6-triacetal.