METHOD FOR PREPARING 4,1',6'-TRICHLORO-4,1',6'-TRIDEOXYGALACTOSUCROSE Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: 4,1',6'-Trichloro-4,1', 6'-trideoxygalactosucrose is prepared by selective acetylation of sucrose in pyridine, chlorination of prepared 6-monoacetylated product at positions 4,1',6', peracetylation of prepared chloro-derivative in pyridine with the following deacetylation and isolation of the end product. Pyridine excess is removed from reaction zone of selective acetylation by distillation off with freezing out. Complete acetate of 4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose is isolated by precipitation with water. Deacetylation is carried out with sodium methoxide in alcohol at room temperature for 4 h, not less, at pH = 9, prepared solution is neutralized, decolorized and evaporated under vacuum up to dry residue. Chlorination is carried out with suspension obtained by addition of phosphorus pentachloride to dimethylformamide (DMFA). Processes for preparing suspension and chlorination are carried out in a single reaction volume. EFFECT: enhanced yield of end product, improved preparing method. 3 cl, 5 ex