The title compound {systematic name: spiro-[cyclo-pentane-1,2'(1'H)-quinazolin]-4'(3'H)-one]}, C(12)H(14)N(2)O, has been reported previously [Klemm, Weakley, Gilbertson & Song (1998 ▶). J. Heterocycl Chem. 35, 1269-1273]. Its structure has been redetermined at 113 K with greater precision for all data. The mol-ecule is built up from two fused six-membered rings and one five-membered ring linked...

The title compound, C(28)H(30)N(2), is a symmetrical 2:2 product from the condensation of indole and cyclo-hexa-none. It is the only reported 5,11-dihydro-indolo[3,2-b]carbazole compound in which the spiro atoms are quaternary C atoms. Crystals were grown by vapor diffusion in a three-zone electric furnace. The mol-ecule resides on a crystallographic inversion center. The cyclo-hexyl rings are ...

The title compound, C(35)H(38)N(4)O(3), was prepared as a spiro-lactam ring formation of rhodamine dye for comparison with a ring-opened form. The xanthene ring system is approximately planar. The dihedral angles formed by the spiro-lactam and phenol rings with the xanthene ring system are 85.7 and 109.4°, respectively. Each of the mol-ecules in the crystal structure contains one intra-molecula...

The synthesis and characterization of a fluorene–spirobifluorene alternating copolymer, P(OF-SBF), are described. In the case of the spiro-segment, the two fluorene rings are orthogonally arranged and connected through a tetrahedral bonding carbon atom (the spiro center). As a consequence, the polymer chain periodically zigzags, with an angle of 90u at each spiro center. This structural feature...

In the title compound, C(31)H(28)ClN(3)O(8), the pyrrolidine ring exhibits an envelope conformation, with the spiro C atom located at the flap position. A spiro junction links the oxindole ring system and the pyrrolidine ring. The planar oxindole ring system is twisted with respect to the nitro-benzene and chloro-benzene rings, with dihedral angles of 62.34 (11) and 75.93 (9)°, respectively. In...

In the title compound, C27H27BrFNO4, which is an inhibitor of acetyl-CoA carboxyl-ase, the cyclo-hexane ring displays a chair comformation with the spiro-C and meth-oxy-bearing C atoms deviating by 0.681 (7) and -0.655 (1) Å, resppectively, from the mean plane formed by the other four C atoms of the spiro-C6 ring. The mean planes of the cyclo-hexane and 2-bromo-4-fluoro-phenyl rings are nearly ...

Abstract Bicyclic alkenes, including oxa- and azabicyclic readily undergo activation with facial selectivity in the presence of transition-metal complexes. This is due to intrinsic angle strain on carbon–carbon double bonds such unsymmetrical bicyclic systems. During past decades considerable progress has been made area ring opening strained rings by employing concept C–H activation. short revi...

The asymmetric unit of the title compound, C(5)H(8)O(6)S(2), consists of two spiro-[5.5]undecane mol-ecules. The nonplanar six-membered rings adopt chair conformations. In the crystal structure, weak inter-molecular C-H⋯O inter-actions, together with close O⋯S contacts in the range 3.308 (3)-3.315 (3) Å, stabilize the packing.

In the title compound, C(28)H(20)F(3)NO(3), the pyrrolidine ring adopts a half-chair conformation. The other five-membered rings adopt envelope conformations with the spiro and methylene C atoms as the flap atoms. In the crystal, mol-ecules are connected via weak C-H⋯O hydrogen bonds, forming sheets parallel to the bc plane.

Nine hydrated complexes of Group 2 (alkaline earth) cations with organic ligands which are N-substituted amino acids containing the 6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl group have been structurally characterized. The octahydrated calcium glycinate complex, where the six-coordinate Ca cation lies on an inversion centre in the space group P(-)1, forms a finite (zero-dimensio...