Oxaheterocycles: Di- and Trioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-6,7-diones and Dibenzo[a,c]cycloheptene-3-carbonitriles

Paper

Heterocycles Volume 84, Issue 1    DOI: 10.3987/COM-11-S(P)22

Hardesh K. Maurya, Ramendra Pratap, Vishnu K. Tandon, Pushyamitra Mishra, Brijesh Kumar, Vishnu Ji Ram

An efficient and convenient synthesis of 9-aryl-11,12-dihydro-13H-5,8-dioxabenzo[3,4]cyclohepta[1,2-a] naphthalene-6,7-diones and 9-aryl-11,12-dihydro-5,8,13-trioxabenzo[3,4]cyclohepta[1,2-a]naphthalene-6,7-diones has been delineated through base catalyzed condensation-cyclization of 4-methylsulfanyl-2-oxo-2,5,6,7-tetrahydro-1-oxadibenzo[a,c]cycloheptene-3-carbonitriles and 4-methylsulfanyl-2-oxo-5,6-dihydro-2H-1,7-dioxadibenzo[a,c]cycloheptene-3-carbonitriles with aryl methyl ketone separately. We have also reported the synthesis of 2-aryl-4-sec-amino-6,7-dihydro-5H-dibenzo[a,c]cycloheptene-3-carbonitriles through ring transformationof 4-sec-amino-2-oxo-2,5,6,7-tetrahydro-1-oxadibenzo[a,c]cycloheptene-3-carbonitriles with aryl methyl ketones in the presence of powdered KOH/NaOH in DMF. We have successfully synthesized 4-aryl-2-(piperidin-1-yl)-5,6-dihydro-7-oxadibenzo[a,c]cycloheptene-1-carbonitriles as isomeric products through ring transformation of 6-aryl-4-sec-amino-2H-pyran-2-one-3-carbonitriles by 3,4-dihydro-2H-benzo[b]oxepin-5(2H)-ones.