3′-Benzoyl-1′-methyl-4′-phenylspiro[acenaphthylene-1(2H),2′-pyrrolidin]-2-one

In the title compound, C29H23NO2, the pyrrolidine ring adopts a twisted conformation about one of the C—N bonds. The acenaphthone ring (r.m.s. deviation = 0.025 Å) lies almost perpendicular to the pyrrolidine ring [dihedral angle = 88.08 (8)°]. The dihedral angle between the phenyl rings is 88.12 (11)°. In the crystal structure, weak C—H⋯π interactions connect the molecules.

In the title compound, C 29 H 23 NO 2 , the pyrrolidine ring adopts a twisted conformation about one of the C-N bonds. The acenaphthone ring (r.m.s. deviation = 0.025 Å ) lies almost perpendicular to the pyrrolidine ring [dihedral angle = 88.08 (8) ]. The dihedral angle between the phenyl rings is 88.12 (11) . In the crystal structure, weak C-HÁ Á Á interactions connect the molecules.

Experimental
Cg5 is the centroid of the C17-C22 ring.
In the title compound C 29 H 23 NO 2 , the C-O bond distance (1.21 Å) of the carbonyl group in the benzoyl moiety indicates n-p overlap. The bond angles and dihedral angle of C9-C12-C1 (101.69 Å) of the acenapthone ring indicate it to be in a plane nearly perpendicular to the pyrrolidine ring. The sum of the angles around N-atom of the pyrrolidine ring accounts for 338.78°. This indicates that the structure approaches pyramidal shape. The study of torsion angle, asymmetry parameters and least-square plane calculation shows that the pyrrolidine ring adopts a envelope conformation and puckered, Q 2 = 0.4030 (18) , 1975). The Pseudorotation parameter P and τ are 136.4 (1)° and 43.71 (1)°r espectively (Rao et al., 1981) showing that C15 and N1 are twisted and puckered.
The crystal structure is stabilized by weak C-H···π interactions.

Experimental
A mixture of chalcone [1,3-diphenyl-2-propen-1-one] (0.40 g, 2 mmol), acenaphthenequinone (0.36 g, 2 mmol), sarcosine (0.17 g, 2 mmol) and methanol (25 ml) was heated for four hours using oil bath using a dimmerstat at a temperature of 40° C. The reaction mixture was cooled to room temperature and poured into ice-cold water. The solid mass obtained was filtered, washed with water, dried and colourless blocks of (I) were obtained by recrystallization using acetone as solvent by slow evaporation method.