(1′S)-4-(3,4-Dichlorophenyl)-1′-(3,5-dimethoxyphenyl)-1,2,3,4-tetrahydronaphthalene-2-spiro-2′-pyrrolizidine-3′-spiro-3′′-indoline-1,2′′-dione

In the title compound C37H32Cl2N2O4, the unsubstituted pyrrolidine ring shows a twist conformation whereas the substituted pyrrolidine ring shows an envelope conformation. The dimethoxy benzene ring is perpendicular to the tetralone ring, making a dihedral angle of 89.94 (5)°. Molecules are linked into centrosymmetric dimers by N—H⋯O hydrogen bonds and the crystal structure is stabilized by C—H⋯π interactions and C—H⋯O hydrogen bonds. One methoxy group is disordered over two positions with the site occupancy factors of 0.84 (2) and 0.16 (2).

In the title compound C 37 H 32 Cl 2 N 2 O 4 , the unsubstituted pyrrolidine ring shows a twist conformation whereas the substituted pyrrolidine ring shows an envelope conformation. The dimethoxy benzene ring is perpendicular to the tetralone ring, making a dihedral angle of 89.94 (5) . Molecules are linked into centrosymmetric dimers by N-HÁ Á ÁO hydrogen bonds and the crystal structure is stabilized by C-HÁ Á Á interactions and C-HÁ Á ÁO hydrogen bonds. One methoxy group is disordered over two positions with the site occupancy factors of 0.84 (2) and 0.16 (2).

Comment
Spiro compounds represent an important class of naturally occurring substances exhibiting significant biological properties.
The spirooxindole system is the core structure of many pharmacological agents and natural alkaloids (Ma & Hecht, 2004).
Spirotryprostatin A, a natural alkaloid isolated from the fermentation broth of Aspergillus fumigatus, has been identified as a novel inhibitor of microtubule assembly (Usui et al., 1998). Because of their synthetic and biological potential, considerable interest has been focused on the synthesis of spirooxindole derivatives via 1,3-dipolar cycloaddition reactions (Raghunathan & Suresh Babu, 2006). Chiral polyhydroxy alkaloids show remarkable biological properties. Among these, pyrrolidine alkaloids carrying an aromatic substituent on the ring are of a rare class found in nature (Reddy & Rao, 2006).They are useful in preventing and treating rheumatoid arthritis, asthma, allergies, rhinitis and related diseases (Mitsuaki et al., 1997). The dimethoxy benzene ring C30-C35 is perpendicular to the tetralone ring C6/C15/C16/C21/C22/C23 and the phenyl ring C16-C21 making a dihedral angle of 89.94 (5)° and 89.98 (6)° respectively. The phenyl and the tetralone rings are almost coplanar with each other making a dihedral angle of 6.53 (5)°.
In the crystal packing, atoms O1 and N2 are involved in intermolecular N-H···O interactions and atoms O1 and O2 are involved in intramolecular C-H···O interactions. The molecules pack into distinct layers facilitated by C-H···π interactions.
Figures Fig. 1. The molecular structure of the title compound with 30% probability displacement ellipsoids. (1'S)-4-(3,4-Dichlorophenyl)-1'-(3,5-dimethoxyphenyl)-1,2,3,4-tetrahydronaphthalene-2-spiro-2'-pyrrolizidine-3'-spiro-3''-indoline-1,2''-dione  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.