SYNTHESIS OF SOME NAPHTHO 2,1-b FURO 3,2-d PYRIMIDINES, NAPHTHO 2,1-b FURO 3 ',2 ':4,5 PYRIMIDO 1,2-b BENZO (d) THIAZOLE AND THEIR ANTIMICROBIAL ACTIVITY
Rajashekhar, H; Ramesh, D; Chandrashekhar, C; Mahadevan, KM; Vaidya, VP
The required starting material 3-aminonaphtho [2,1-b] furan-2-carboxamide 1 was synthesized from 2-hydroxy-1-naphthaldehyde, which on acylation with succinic anhydride, maleic anhydride and phthalic anhydride, gave corresponding acylated compounds 2a-c. The treatment of compounds 2a-c with sodium hydroxide at reflux temp followed by acidification produced 2-substituted-3,4-dihydro-4-oxo-naphtho [2,1-b] furo [3,2-b] pyrimidines 3a-c. The compounds 3a-c on further cyclodehydration furnished new pentacyclic heterocycles 5,6-dihydro-naphtho [2,1-b] furo [3,2-d] pyrrolo [1,2-a] pyrimidine -7,9-diones 4a-c. The synthesis of 7-oxo-naphtho [2,1-b] furo [3',2':4,5] pyrimido [1,2-b] benzo [d] thiazole-5,5-dioxide 8 was accomplished by using another starting material i.e., ethyl 3-aminonaphtho [2,1-b] furan 2-carboxylate 5. It was converted to its potassium salt 6, which on reaction with y-saccharin chloride furnished the desired products 7 and 8.