A simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano SiO2-supported ferric hydrogen sulfate (FHS/SiO2), as a catalyst, under solvent-free conditions. The nano SiO2 support and catalyst were characterized by X-ray diffraction (XRD), transmissio...

The title Schiff base compound, C(15)H(14)BrNO(2), was prepared by the condensation of 2,3-dimeth-oxy-benzaldehyde with 4-bromo-aniline. It adopts an E configuration with respect to the C=N bond. The dihedral angle between the two aromatic rings is 56.79 (8)°. Weak C-H⋯O and C--H⋯π bonds can be found in the crystal structure.

The title compound, C(13)H(15)NO(2), was synthesized from 3,5-dimeth-oxy-benzaldehyde. The dihedral angle between the pyrrole and benzene rings is 89.91 (5)°. In the crystal, weak C-H⋯O and C-H⋯π interactions link the mol-ecules into a three-dimensional network.

Ligand Hsal-his (I) derived from salicylaldehyde and histamine has been covalently bound to chloromethylated polystyrene cross-linked with 5% divinylbenzene. Upon treatment with [VO(acac)(2)] in DMF, the polystyrene-bound ligand (abbreviated as PS-Hsal-his, II) gave the stable polystyrene-bound oxidovanadium(iv) complex PS-[V(IV)O(sal-his)(acac)] , which upon oxidation yielded the dioxidovanadi...

A one-pot, asymmetric multicatalytic formal [3+2] reaction between 1,3-dicarbonyls and alpha,beta-unsaturated aldehydes is described. The multicatalytic process involves a secondary amine catalyzed Michael addition followed by a N-heterocyclic carbene catalyzed intramolecular crossed benzoin reaction to afford densely functionalized cyclopentanones with high enantioselectivities. The reaction p...

The dynamic kinetic resolution of β-halo α-keto esters via an asymmetric cross-benzoin reaction is described. A chiral N-heterocyclic carbene catalyzes the umpolung addition of aldehydes to racemic α-keto esters. The resulting fully substituted β-halo glycolic ester products are obtained with high levels of enantio- and diastereocontrol. The high chemoselectivity observed is a result of greater...

Theoretically, induced defenses should be prevalent within low resource environments like the forest understory where constitutive defenses would be costly. Also, the induced response should be stronger when the herbivore is a generalist rather than a specialist, which often have mechanisms to avoid or overcome plant defenses. These ideas have been previously tested for herbaceous species, and ...