115483-66-4Relevant articles and documents
Heterocyclic Seven-Membered Ring Compounds, XXXIII. - Synthesis and Properties of 5-Methoxy-1,4-benzothiazepine and of 5-Methoxy-1-methyl-1,4-benzothiazepinium Tetrafluoroborate
Hofmann, Hans,Fischer, Herbert
, p. 2147 - 2150 (2007/10/02)
Acid-catalyzed cyclisation of the amide acetal 2 yields the seven-membered ring lactam 3 which could be N-methylated to give compound 4 by treatment with sodium hydride/methyl iodide.On reaction with trimethyloxonium tetrafluoroborate, 3 was O-alkylated to yield the title thiazepine 5, the thermal stability of which is compared with that of the isomeric 4-methoxy-1,5-benzothiazepine C.Compound 5 could be oxidized to give the sulfone 6; thermolysis of 5 leads to sulfur and 1-methoxyisoquinoline (8).Alkylation of 5 with methyl iodide/silver tetrafluoroborate yields the sulfonium salt 7 which rearranges to 1-methoxy-4-(methylthio)isoquinoline (9) on heating in acetonitrile.