Crystal structure of 6-(4-chloro-phen-yl)-6a-nitro-6,6a,6b,7,9,11a-hexa-hydro-spiro[chromeno[3',4':3,4]pyrrolo-[1,2-c]thia-zole-11,11'-indeno-[1,2-b]quinoxaline] chloro-form monosolvate.

In the title compound, C33H23ClN4O3S·CHCl3, the thia-zole ring adopts an envelope conformation with the N atom as the flap, and the pyrrolidine ring adopts a half-chair conformation. The thia-zole ring mean plane makes a dihedral angle of 59.31 (1)° with the pyrrolidine ring mean plane, 71.67 (1)° with the chromene ring and 82.59 (1)° with the chloro-benzene ring. An intra-molecular C-H⋯N hydrogen bond occurs. In the crystal, a second C-H⋯N hydrogen bond links the main and solvent mol-ecules. The solvent chloroform molecule is disordered about two positions with an occupancy ratio of 0.508 (14):0.492 (14).

Allyl 2-(2,2-dimethyl-3a,6a-di-hydro-furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl-ate.

In the title compound, C20H18O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap, and its mean plane makes a dihedral angle of 73.25 (2)° with the pyran ring mean plane. The furan ring makes dihedral angles of 67.43 (12) and 6.20 (11)° with the mean plane of the dioxolane and pyran rings, respectively. The O atom attached to the pyran ring deviates by 0.0219 (2) Šfrom its mean plane. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming chains along [010] and enclosing R 2 (2)(9) loops. They stack along the a axis with π-π inter-actions involving the 4H-chromene units [centroid-centroid distances of 3.6389 (13) and 3.6555 (13) Å]. The terminal CH2=CH- atoms of the allyl acetate group are disordered over two sets of sites with a refined occupancy ratio of 0.717 (6):0.283 (6).

Methyl 2-(2,2-dimethyl-3a,6a-di-hydro-furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl-ate.

In the title mol-ecule, C18H16O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap. The furan ring is almost coplanar with the pyran ring, with a dihedral angle of 1.04 (10)° between the planes, and it makes a dihedral angle of 67.97 (11)° with the mean plane of the dioxolane ring. The latter makes a dihedral angle of 67.15 (10)° with the pyran ring. The O atom attached to the pyran ring deviates by -0.009 (1) Å. The crystal packing features C-H⋯O hydrogen bonds, forming a three-dimensional structure. The meth-oxy-carbonyl atoms are disordered over two positions, with a refined occupancy ratio of 0.508 (18):0.492 (18).

2-Methyl-4-(naphthalen-2-yl)-3a-nitro-3,3a,4,9b-tetra-hydro-2H-spiro-[chromeno[3,4-c]pyrrole-1,3'-indolin]-2'-one.

In the title compound, C29H23N3O4, the 2-methylpyrrolidine ring adopts a twist conformation on the N-C bond involving the spiro C atom, while the hydropyran ring adopts an envelope conformation with the methine C atom bonded to the O atom as the flap. The mean plane of the indoline-2-one ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 89.73 (8)°. The latter ring makes dihedral angles of 47.80 (8) with the naphthalene ring system and 32.38 (8)° with the hydropyran ring mean plane. There is an intra-molecular C-H⋯O hydrogen bond involving the indoline-2-one O atom. In the crystal, adjacent mol-ecules are linked via N-H⋯O hydrogen bonds, forming chains propagating along [100]. The chains are linked via weak C-H⋯O hydrogen bonds, forming two-dimensional networks, lying parallel to (101), and consolidated by C-H⋯π inter-actions.

6-(4-Meth-oxy-phen-yl)-6a-nitro-6,6a,6b,7,8,9,10,12a-octa-hydro-spiro-[chromeno[3,4-a]indolizine-12,3'-indolin]-2'-one.

In the title compound, C29H27N3O5, the hydropyran ring adopts an envelope conformation with the methine C atom bearing the para-meth-oxy-benzene ring as the flap. The central pyrrolidine ring has a twist conformation on the N-C bond involving the spiro C atom. The piperidine ring adopts a chair conformation. An intra-molecular C-H⋯O contact closes an S(7) ring. In the crystal, inversion dimers linked by C-H⋯O inter-actions generate R 2 (2)(18) loops and N-H⋯O hydrogen bonds connect the dimers into [100] chains.

6a-Nitro-6-phenyl-6,6a,6b,7,8,9,10,12a-octa-hydro-spiro-[chromeno[3,4-a]indol-izine-12,3'-indolin]-2'-one.

In the title compound, C28H25N3O4, the central pyrrolidine ring adopts adopts an envelope conformation with the N atom as the flap and the piperidine ring adopts a chair conformation. The pendant pyrrolidine ring is almost planar (r.m.s. deviation = 0.008 Å). An intra-molecular C-H⋯O inter-action closes an S(6) ring. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R 2 (2)(8) loops.