In the title compound, C(24)H(24)O(4), a derivative of the potent insecticide and miticide spiro-mesifen, one cyclo-pentane C atom is disordered over two positions with occupancies of 0.574 (12) and 0.426 (12), resulting in respective envelope and twisted conformations for the cyclo-pentane ring. The atom at the flap position is 0.620 (5) Å out of the mean plane formed by the other four atoms o...

The title tetronic acid derivative, C(20)H(23)ClO(4), which is a spiro-diclofen analogue, has two crystallographically independent mol-ecules in the asymmetric unit (Z' = 2). The cyclo-hexane rings in the respective mol-ecules A and B adopt chair conformations [four C atoms are planar with mean deviations of 0.013 (2) and 0.001 (2) Å, and the flap positions deviate by 0.653 (4) and -0.663 (3) Å...

The title compound, C(28)H(30)N(2)OS(2), was obtained by thio-nation of 3',6'-bis-(diethyl-amino)-3H-spiro-[isobenzofuran-1,9'-xan-thene]-3-one with 2,4-bis-(p-methoxy-phen-yl)-1,3-dithia-diphos-phetane disulfide (Lawesson's reagent). The planes of the two benzene rings of the xanthene system are inclined at a dihedral angle of 17.4 (1)°, and the plane of the dithio-phthalide group and the plan...

In the title compound, C24H23N5O3, the oxindole ring system is nearly planar, with a dihedral angle between the two fused rings of 3.3 (1)°. In the fused pyrrolo-oxazole ring system, the oxazole and pyrrolidine rings adopt envelope conformations with the spiro C atom and one of the methyl-ene C atoms, respectively, as the flap atoms. In the crystal, mol-ecules are linked into a helical chain al...

In the title spiro compound, C(29)H(24)N(4)S, the quinoxaline and thia-diazole ring systems share a common C atom; their mean planes are aligned at 87.0 (1)° in one mol-ecule and at 84.1 (1)° in the other independent mol-ecule. The thia-zole ring possesses two aromatic ring substituents and is roughly coplanar with these rings [the dihedral angles between the thia-diazole and phenyl rings are 1...

In the title compound, C(26)H(22)N(2)O(4), the pyrrolidine ring adopts a twisted conformation and the other five-membered rings adopt envelope conformations with the spiro C atoms as the flap atoms. The naphthalene ring system of the dihydro-acenaphthyl-ene group forms dihedral angles of 89.2 (9) and 75.5 (6)° with the pyrrolidine and indole rings, respectively. The pyrrolidine ring makes a dih...

In the title spiro compound, C(25)H(22)N(4)S, the planar quinoxaline (r.m.s. deviation = 0.070 Å) and planar thia-diazole (r.m.s. deviation = 0.060 Å) ring systems share a common C atom; their mean planes are aligned at 89.7 (1)°. The thia-zole ring possesses two aromatic ring substituents and is nearly coplanar with these rings [the dihedral angles between the thia-diazole and phenyl rings are...

In the title compound, C30H23NO2, the five-membered rings are both in envelope conformations with the same spiro C atom as the flap. The benzene ring and the two phenyl rings are inclined to the mean plane of the indene ring system by 83.98 (8), 81.46 (8) and 72.31 (7)°. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds into inversion dimers. The dimers are further connecte...

Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the Biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. Spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient ...

In the title compound, C(21)H(23)NOS, the thia-zolidine ring adopts a twist conformation about one of its C-S bonds, while the cyclo-hexane ring has a chair conformation. The S and N atoms attached to the spiro C atom are in axial and equatorial orientations, respectively. The thia-zolidine ring forms dihedral angles of 86.24 (14) and 31.82 (15)° with the directly attached and remote terminal b...