METHOD FOR PREPARING 2,6-DIAMINO-4,5,6,7-TETRAHYDROBENZOTHIAZOLE Russian patent published in 2007 - IPC C07D277/82 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to an improved method for synthesis of 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole. Method involves the following successive steps: (i) interaction of bromine with 4-acetamidocyclohexanone an aqueous solution to yield 2-bromo-4-acetamidocyclohexanone; (ii) addition of thiourea to yield 6-acetylamino-2-amino-4,5,6,7-tetrahydrobenzothiazole; (iii) addition of hydrobromic acid an aqueous solution to yield 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole without isolation of 6-acetylamino-2-amino-4,5,6,7-tetrahydrobenzothiazole synthesized at stage (ii); (iv) isolation of 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole and if necessary separation of 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole isolated at stage (iv) for R-(+)- and S-(-)-enantiomers, and isolation of R-(+)- and/or S-(-)-enantiomer. 2,6-Diamino-4,5,6,7-tetrahydrobenzothiazole is used for synthesis of pramipexole. Also, invention relates to a method for synthesis of pramipexole by synthesis of 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole by using the method said and its conversion to pramipexole and if necessary by separation of pramipexole for its R-(+)- and S-(-)-enantiomers and isolation of R-(+)- and/or S-(-)-enantiomer.

EFFECT: improved method of synthesis.

15 cl, 1 sch, 3 ex