Studies on Quinolin-2(1H)-One Derivatives: Synthetic Access to Pyrano[3,2-c] Quinoline and 3-Substituted Quinoline Derivatives

Abstract

4H-pyrano[3,2-c]quinoline derivatives 6a-f were prepared via reacting arylmethylenemalononitriles 2-c,g with 4-hydroxyquinolines 1a-c or 1e,f. Refluxing  6d  with formic acid or acetic anhydride gave 7-(2-chlorophenyl)-5-methyl-5H-pyrimido [5'4':5,6]pyrano[3,2-c]quinoloine-6,8-(7H,11H)-dione 7 and 7-(2-chlorophenyl)-5,10-dimethyl-5H-pyrimido [5'4':5,6] pyrano[3,2-c] quinoloine-6,8-(7H,9H)-dione 9 respectively.Reacting 1d with 2a,d  gave pyrano[2,3-b] pyridine12a,b.Compounds 1c or 1g reacted with 2e,f to give  11-amino-8-oxo-9-substituted -5,6,8,9-tetrahydro-4H-pyrano[3,2-c]pyrido[3,2,1-ij]quinoline-10-carbonitriles 15a,b. Reacting 1c or 1g with ethoxymethylenemalononitrile 16 afforded 11-imino-4H,5H,6H,9H-benzo[ij][2,3-b]quinolizin-8-one 18. Also, reacting 1c or 1g with methyl 2-benzolyamino-3-dimethylaminopropionate 19 yield N-(6-(1-hydroxy-3-oxo-3,5,6,7-tetrahydropyrido[3,2,1-ij]quinolin-2-yl)-2-oxo-2H-pyran-3-yl)benzamide 21 and N-(8,11-dioxo-5,6,8,11-tetrahydro-4H-pyrano[3,2-c]pyrido[3,2,1-ij]quinolin-10-yl)benzamide 22 respectively. Condensation of 1c with aromatic aldehydes afford 2,2'-(arylmethylene)bis(1-hydroxy-6,7-dihydropyrido[3,2,1-ij]quinolin-3(5H)-ones) 28a-d.