In the title compound, C(14)H(13)NO(2), the azomethine double bond adopts an E conformation and the benzene rings form a dihedral angle of 77.70 (7)°. In the crystal, mol-ecules are linked by O-H⋯N and C-H⋯O hydrogen bonds and arranged in a zigzag fashion, forming infinite chains parallel to the c axis, resulting in a graph-set R(2) (2)(9) motif.

The azomethine double bond in the title Schiff base, C(20)H(19)N(3)O, has an E configuration. The 13-membered carbazolyl fused ring system [r.m.s. deviation = 0.023 (9) Å] is nearly coplanar with the five-membered pyrazole ring [r.m.s. deviation = 0.003 (4) Å]; the dihedral angle between the two systems is 10.8 (2)°. The crystal studied was a non-merohedral twin having a 35% minor component.

An N-heterocyclic carbene-catalyzed enantioselective [2+3] cyclocondensation of α-chloroaldehydes with azomethine imines was developed. The corresponding pyrazolidinones were obtained in good yields with moderate to good diastereoselectivities and excellent enantioselectivities.

The title compound, C(16)H(17)N(3)O(3)·H(2)O, exists in the E conformation with respect to the azomethine C=N double bond. While the phenyl ring is almost coplanar with the central hydrazinecarboxamide group [dihedral angle = 14.18 (11)°], it is twisted slightly with respect to the other aromatic ring in the mol-ecule, with a dihedral angle of 22.88 (13)°. The packing is dominated by O-H⋯O, N-H...

The effect of substituents on the rate of conrotatory thermal cleavage of aziridine has been studied at the MP2(Full)/6-311++G(d,p)//MP2(Full)/6-31+G(d) level and also using SCS-MP2 methodology. While the parent compound has a high free energy of activation (194.6 kJ mol(-1)), this value could be drastically lowered by substituent effects. Anionic species were found to be particularly effective...

Effects of chemical structure changes on the thermal, mechanical, and crystalline properties of rigid rod epoxy resins have been studied for azomethine epoxy, biphenol epoxy, and tetramethyl biphenol epoxy. Rigid rod epoxies have exhibited better properties than those of the flexible bisphenol A epoxy. The chemical structures of both rigid rod epoxy and curing agent control the properties of cu...

A series of novel dispirooxindoles have been synthesized through three-component 1,3-dipolar cycloaddition of azomethine ylides generated in situ by the decarboxylative condensation of isatin and an α-amino acid with the dipolarophile 5-benzylidene-1,3-dimethylpyrimidine-2,4,6-trione. This method has the advantages of mild reaction conditions, high atom economy, excellent yields, and high reg...

1,3-Dipolar cycloadditions of isatins, benzylamine and benzylideneacetones were studied to prepare a series of novel spiropyrrolidine-oxindoles - 4'-acetyl-3',5'-diarylspiro[indoline-3,2'-pyrrolidin]-2-ones and 3'-acetyl-4',5'-diarylspiro[indoline-3,2'-pyrrolidine]-2-ones in good yields of up to 94% and with good regioselectivities. Regioselectivities are reversible by the addition of water or ...

Acid treatment of densely substituted 2-silyl-1,2-dihydropyridines provides a new and convenient entry to reactive azomethine ylides that can (1) be protonated and reduced with high stereoselectivity to give piperidines, (2) participate in [3 + 2] dipolar cycloaddition to give tropanes, and (3) undergo a Nazarov-like 6-π electrocyclization that upon reduction give 2-azabicyclo[3.1.0] systems.

The 1,3-dipolar cycloaddition of azomethine ylides bearing the biologically active 1,4-dihydropiridine ring to C(60) was investigated by means of quantum mechanical calculations at the semiempirical AM1 and DFT (B3LYP/6-31G) methods. The presence of two chiral centers and one chiral axis in the resulting fulleropyrrolidines leads to four possible [6,6] cycloaddition products. Formation of atrop...