Nano-TiO2 as a novel and efficient catalyst for the synthesis of pyridine dicarbonitriles

Pyridine dicarbonitriles have been synthesized in good yields via a one-pot multi–component reaction of aldehyde, malononitrile, and thiol in the presence of nano-TiO2 as a catalyst in ethanol. KEY WORDS: Pyridine dicarbonitriles, Multi–component reaction, One-pot, Nano-TiO2 Bull. Chem. Soc. Ethiop. 2014, 28(1), 149-153.DOI: http://dx.doi.org/10.4314/bcse.v28i1.1

Constructive Quantum Interference in Single-Molecule Benzodichalcogenophene Junctions

Heteroatom substitution into the cores of alternant, aromatic hydrocarbons containing only even-membered rings is attracting increasing interest as a method of tuning their electrical conductance. Here, the effect of heteroatom substitution into molecular cores of non-alternant hydrocarbons, containing odd-membered rings, is examined. Benzodichalcogenophene (BDC) compounds are rigid, planar pi-conjugated structures, with molecular cores containing five-membered rings fused to a six-membered aryl ring. To probe the sensitivity or resilience of constructive quantum interference (CQI) in these non-bipartite molecular cores, two C-2-symmetric molecules (I and II) and one asymmetric molecule (III) were investigated. I (II) contains S (O) heteroatoms in each of the five-membered rings, while III contains an S in one five-membered ring and an O in the other. Differences in their conductances arise primarily from the longer S-C and shorter O-C bond lengths compared with the C-C bond and the associated changes in their resonance integrals. Although the conductance of III is significantly lower than the conductances of the others, CQI was found to be resilient and persist in all molecules

A novel one-pot synthesis of spirooxindole derivatives catalyzed by nano ZnO

Nano zinc oxide was explored as a heterogeneous and reusable catalyst for the one-pot synthesis of spirooxindoles via three-component reaction between urea, isatin, and 1,3-dicarbonyl compounds

KHSO4-catalyzed Three-component Synthesis of α-Aminonitriles

Asimple, convenient and general method has been developed for the synthesis of-aminonitriles by a one-pot three-component condensation of aldehydes, amines and trimethyl silyl cyanide under solvent-free conditions in the presence of a catalytic amount of KHSO4 in good yields. The new method compares well in terms of yields with alternative methods. In general the reaction times are much shorter and the work up much easier.Keywords: One-pot, KHSO4, trimethyl silyl cyanide, α-aminonitrile