Synthesis of some new azole, pyrimidine, pyran, and benzoaphtho[b]furan derivatives incorporating thiazolo[3,2-a]benzimidazole moiety

摘要

Reaction of E-3-(N,N-dimethylamino)-1-(3-methylthiazolo[3,2-a]benzimidazol- 2-yl)prop-2-en-1-one (1) with some N-nucleophiles, such as anilines 2a-c, 4-amino-N-pyridin-2-yl-benzenesulfonamide (4a), 4-amino-N-pyrimidin-2-yl- benzenesulfonamide (4b), hydrazine, hydroxylamine, thiourea, and guanidine afforded the corresponding arylaminoprop-2-en-1-one derivatives 3a-c, 5a,b, the pyrazole, isoxazole, pyrimidinethione and aminopyrimidine derivatives 7a, 7b, 9a, and 9b, respectively. The utility of compound 1, as a versatile building block, for the synthesis of the pyranone 13, benzo[b]furan 17a, and naphtho[1,2-b]furan 17b was also explored via its reaction with 2-benzamidoacetic acid (10), 1,4-benzoquinone (14a), and 1,4-naphthoquinone (14b), respectively.