PROCESS FOR PREPARING KALCIUM SALT OF 6-METHYL-3,4-DIHYPRO-1,2,3-OXATHIADINE-4-ONE-2,2-DIOXIDE

摘要

A process for preparing 6- methyl-3,4-dihydro-1,2,3-oxathiadin-4-on-2,2- dioxide.K of formula (I) comprises reacting methylisocyanate of formula CH3-N=C=O with fluorosulfonic acid of formula HOSO2F in the presence of diketene of formula (II) at 0-60 deg.C, esp. 10-35 deg.C. Pref. the molar ratio of melthylisocyanate to fluorosulfonic acid is 1-1.5. (I) is useful as an artificial sweetener.