Crystal structures of 1-(4-chloro-phen-yl)-4-(4-methyl-phen-yl)-2,5-dioxo-1,2,5,6,7,8-hexa-hydro-quinoline-3-carb-oxy-lic acid and 4-(4-meth-oxy-phen-yl)-1-(4-methyl-phen-yl)-2,5-dioxo-1,2,5,6,7,8-hexa-hydro-quinoline-3-carbo-nitrile.

In the title compounds CHClNO [, namely 1-(4-chloro-phen-yl)-4-(4-methyl-phen-yl)-3,8-dioxo-1,2,5,6,7,8-hexa-hydro-quine-3-carb-oxy-lic acid] and CHNO [, namely 4-(4-meth-oxy-phen-yl)-1-(4-methyl-phen-yl)-2,5-dioxo-1,2,5,6,7,8-hexa-hydro-quinoline-3-carbo-nitrile], each of the cyclo-hexene and di-hydro-pyridine rings of the 1,2,5,6,7,8-hexa-hydro-quinoline moieties adopts a twisted-boat conformation. The asymmetric units of both compounds and consist of two independent mol-ecules ( and ). In , three carbon atoms of the cyclo-hexene ring are disordered over two sets of sites in a 0.

Crystal structure of 2-[9-(2-hy-droxy-phen-yl)-1,8-dioxo-1,2,3,4,5,6,7,8,9,10-deca-hydro-acridin-10-yl]acetic acid.

The title compound, C21H21NO5, crystallizes with two mol-ecules in the asymmetric unit. In each mol-ecule, the central 1,4-di-hydro-pyridine ring adopts a shallow sofa conformations (with the C atom bearing the phenol ring as the flap), whereas the pendant cyclo-hexene rings both have twisted-boat conformations. Each mol-ecule features an intra-molecular O-H⋯O hydrogen bond, which closes an S(8) ring.