Interactions between the nitrogen lone pair and the biradical centers are weak in 3,4and 3,5-pyridyne, but can be large Ž . enough in the remaining pyridynes where at least one radical site is adjacent to nitrogen to change singlet–triplet splittings by up to 19.6 kcalrmol compared to the corresponding benzynes. Singlet pyridynes having one dehydro site at the 2-position are stabilized relative...

Zeolite catalysts can play an important role in the development of greener organic syntheses through their abilities to act as heterogeneous catalysts, support reagents, entrain by-products, avoid aqueous work-ups and enhance product selectivities via shape-selectivity. We have shown that zeolites under modest conditions can have advantages in para-regioselective nitration, alkylation, acylatio...

Aromatic molecules are key constituents of many pharmaceuticals, electronic materials, and commodity plastics. The utility of these molecules directly reflects the identity and pattern of substituents on the aromatic ring. Here, we report a palladium(II) catalyst system, incorporating an unconventional ortho-dimethylaminopyridine ligand, for the conversion of substituted cyclohexanones to the c...

in this research work, we report the synthesis of macrocyclic diamides from the reaction of diesters and aliphatic diamines in the presence of caesium carbonate. it has been demonstrated that among the carbonate of alkali metals (li2co3, na2co3, k2co3 and cs2co3), cs2co3 appear to be the best catalyst for macrocyclization. diesters with different substitution patterns on the aromatic ring react...

The effect of aromatic ring substitution in the polyester polyol molecule on its physicochemicalproperties and conditions synthesis, fire resistance thermal stability polyurethanefoams was investigated. greater number terephthalic units results viscosityand reactivity during foam formation. obtained foams were characterized by higher thermalstability (TGA) (oxygen index, single flame test).