Synthesis of New Derivatives of Heterocyclic Compounds Containing Pyridine, Pyrimidine and Triazole Ortho-Fused to Isoquinoline Moiety

Abstract

Abstract4-Amino-9,10-dimethoxy-2-phenyl-6,7-dihydro-2(H)-pyrido[2,1-a]isoquinoline-1,3-dicarbonitrile derivatives 4a-c were obtained from the reaction of 6,7-dimethoxy-3,4-dihydroisoqinoline-1-acetonitrile 1 with arylidenemalononitrile 2a-c in boiling acetonitile in the presence of piperidine. The reaction of 4a-c with triethyl orthoformate in acetic anhydride at reflux give the ethoxymethyleneamino derivatives 5a-c. Compounds 5a-c were reacted with hydrazine hydrate and give the corresponding 4-amino-3-imino-2-aryl-3,4,8,9-tetrahydro-2(H)-pyrimido[5′,4′:5,6] pyrido [2,1-a]isoquinoline-1-carbonitrile derivatives 6a-c. Refluxing compound 6a in an excess of triethyl orthoformate give 7a. When compounds 6a-c were refluxed with acetic anhydride or benzoyl chloride in pyridine, they afford the corresponding 4-methyl and 4-phenyl derivatives 8a-c and 9a-c, respectively. Compound 6a was refluxed in diethyloxalate and give product 10. Also, the reaction of 6a with C-acylhydrazonoyl halides 13a,b in refluxing chloroform in the presence of triethylamine afford 14a,b. Correct elemental analyses and spectral data (IR, 1 H NMR, 13 C NMR and MS) confirm the structure of the synthesized compounds.

Synthesis, reactions, and antimicrobial activity of some novel pyrazolo[3,4‐d]pyrimidine, pyrazolo[4,3‐e][1,2,4]triazolo[1,5‐c]pyrimidine, and pyrazolo[4,3‐e][1,2,4]triazolo[3,4‐c]pyrimidine derivatives

“…Furthermore, attempts to prepare the isomeric pyrazol [4,3-e] [1,2,4]triazolo [4,3-c] pyrimidines via dehydrative cyclization of the 4-acylhydrazinopyrazolo [3,4-d]pyrimidines were reported to give the corresponding pyrazolo [4,3-e] [1,2,4]triazolo [1,5-c]pyrimidines. [7] In the light of these findings and in continuation of our ongoing research work on the chemistry of hydrazonoyl halides, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] it was thought interesting to synthesize new series of pyrazolo [3,4-d]pyrimidine and pyrazolo [4,3-e] [1,2,4]triazolo [3,4-c]pyrimidine derivatives. Evaluation of antimicrobial activity against some microorganisms was investigated.…”