| 摘要 |
A process for preparing 2-amino-6-alkyl-amino-4,5,6,7-tetrahydrobenzothiazoles of formula (I) wherein the asterisk (*) represents an asymmetric carbon and R1 is C1-C6 alkyl; and enantiomers and mixtures thereof, and their solvates, hydrates and pharmaceutically acceptable salts. The process involves (a) reacting with a secondary amine, optionally in the presence of an acid and a first solvent, to form an enamine; (b) optionally removing the acid and first solvent, and then reacting the enamine with sulfur in the presence of a second solvent; and (c) reacting the previously obtained compound with cyanamide to obtain the formula (I) compound. Pramipexole, a dopamine D-2 agonist, can be made by such process, and is useful for the treatment of Parkinson's disease and schizophrenia.
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