Carbon Disulfide → (10aS)-1,5,10,10a-Tetrahydro-3H-[1,3]thiazolo[3,4-b]isoquinoline-3-thione
Reaction equation
[C:1](=[S:3])=[S:2].OS(O[CH2:9][C@@H:10]1[CH2:19][C:18]2[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=2)[CH2:12][NH:11]1)(=O)=O>[OH-].[Na+]>[CH2:9]1[C@H:10]2[N:11]([CH2:12][C:13]3[CH:14]=[CH:15][CH:16]=[CH:17][C:18]=3[CH2:19]2)[C:1](=[S:3])[S:2]1Participants
4
Procedure
Carbon disulphide (40 g.) is added dropwise at 20° C., with vigorous stirring, to a solution of (S)-3-hydroxysulphonyloxymethyl-1,2,3,4-tetrahydroisoquinoline (100 g) in 0.25N sodium hydroxide solution (4,000 cc.). The reaction is exothermic. A solid precipitates and the reaction mixture then sets solid. Stirring is continued for 3 hours. The reaction mixture is neutralised by adding 4N hydrochloride acid. The crystals formed are filtered off, washed copiously with water and then recrystallised from ethanol (3,000 cc.) to give (S)-1,5,10,10a-tetrahydrothiazolo[3,4-b]-isoquinoline-3-thione (77 g. ) in the form of fine white needles melting at 150° C.