Abstract
Methyl α-D-mannopyranoside, D-mannose, D-gulose and D-galactose have been converted into their 4,6-O-isopropylidene derivatives by use of isopropenyl methyl ether. The same reagent converts D-gulono- and D- galactono-1,4-lactones into their 5,6-O-isopropylidene derivatives.