Collect. Czech. Chem. Commun. 1987, 52, 2758-2774

Potential antihistamine agents: 4-(6,11-Dihydrodibenzo[b,e]thiepin-11-ylidene)-1-methyltetrahydrothiopyranium iodide and similar sulfonium salts derived from related tricyclic systems

Zdeněk Polívkaa, Jiří Holubeka, Miloš Buděšínskýb, Oluše Matoušováa, Emil Sváteka, Jan Metyša and Miroslav Protivaa

a Research Institute for Pharmacy and Biochemistry, 130 60 Prague 3
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


Thioxanthone, 10,11-dihydrodibenzo[a,d]cyclohepten-5-one, dibenzo[b,e]thiepin-11(6H)-one, its 2-methyl derivative, and thieno[2,3-c]-2-benzothiepin-4(9H)-one were reacted with 4-tetrahydrothiopyranylmagnesium bromide and the obtained tertiary alcohols IVabc, VIc, and XIX were dehydrated to the olefinic sulfides IXabc, Xc, and XXI. Addition of methyl iodide afforded the title compounds XIabc, XIIc, and XXII. The Grignard reactions were accompanied by the 1,6-addition giving the ketones XVI-XVIII as by-products. The reductive properties of tetrahydrothiopyranylmagnesium bromide were most striking in the case of reaction with 2-chlorothioxanthone; the isolation of thioxanthene and thioxanthone showed that nuclear dehalogenation took also place. Reactions of 11-chloro-6,11-dihydrodibenzo[b,e]thiepin and benzhydryl chloride with tetrahydrothiopyran-4-ol gave the sulfides XXV and XXVIII; whereas the latter reacted with methyl iodide under the formation of sulfonium salt XXIX, the former was cleaved and gave 4-hydroxyl-1-methyltetrahydrothiopyranium iodide (XXVI). The sulfonium salts are free of the central effects but their antihistamine activity is rather low.