Synthesis, characterization and biological activity of some new dihydroisoquinolines and dihydrothieno [2,3-c]isoquinolines.

Bakhite, Etify A.; Ibrahim, Omaima F.; Khamies, Esraa; Abdel-Hafez, Shams H.; Qahtan, Maha Q. M.; Marae, Islam S.

In this work, a versatile compound, 4-cyano-1,6-dimethyl-8-phenyl-7,8-dihydroisoquinoline-3(2H)-thione (3) was synthesized and utilized as a starting compound for the preparaton of the title compounds. Thus, reaction of 3 with iodomethane, 2-chloroacetamide, ethyl chloroacetate, chloroacetonitrile or N-(benzthiazol-2-yl)-2-chloroacetamide by heating in ethanol containing sodium acetate, gave 3-unsubstituted or 3-substituted methylsulfanyl-7,8-dihydroisoquinoline-4-carbonitriles 4 or 6, 8, 10 and 16 respectively. The latter compounds (6, 8, 10 and 16) contain an active methylene group that adds easily to the carbonitrile group to build a thiophene ring, fused to an isoquinoline moiety, upon heating with sodium ethoxide in ethanol thus affording the corresponding 6,7-dihydrothieno[2,3-c]isoquinolines 7, 9, 11 and 17, in nearly quantitative yields. Compounds 9, 11 and 17 underwent further reactions with some reagents to give other 6,7-dihydrothieno[2,3-c]isoquinolines 12-15 and 3,4-dihydropyrimidothienoisoquinoline 18. All synthesized compounds were screened for their biological activity as bactericidal and fungicidal agents. Some of them showed promising antifungal activity.

SODIUM acetate; METHYLENE group; CHEMICAL synthesis; METHYL iodide; THIOPHENES; ISOQUINOLINE

ARKIVOC: Online Journal of Organic Chemistry, 2024, Vol 2024, p1

1551-7004

Academic Journal

10.24820/ark.5550190.p012.273