High shear stresses are known to trigger destructive bond-scission reactions in polymers. Recent work has shown that the same shear forces can be used to accelerate non-destructive reactions in mechanophores along polymer backbones, and it is demonstrated here that such mechanochemical reactions can be used to strengthen a polymer subjected to otherwise destructive shear forces. Polybutadiene w...

Base-catalyzed urea–formaldehyde condensation reactions were investigated by using a quantum chemistry method. It was found that monomethylolurea or N,N’-dimethylolurea can produce the methyleneurea intermediate (–HN–CO–N=CH2) with the catalysis of base. The E1cb (unimolecular elimination of conjugate base) mechanism was identified for the formation of such an intermediate. The potential energy...

A synthetic strategy based on reactions of cyclic imine oxides, namely 2H-imidazole 1-oxides, with thiophenols mediated by acetyl chloride was successfully applied as a convenient tool to obtain series novel azaheterocyclic molecules, including water-soluble hydrochloride forms. Optimized reaction conditions found herein for the nucleophilic substitution hydrogen (SNH) in non-aromatic substrate...

Following the recent discovery that heme proteins can catalyze the cyclopropanation of styrenyl olefins with high efficiency and selectivity, interest in developing new enzymes for a variety of non-natural carbene transfer reactions has burgeoned. The fact that diazo compounds and other carbene precursors are known mechanism-based inhibitors of P450s, however, led us to investigate if they also...

A straightforward synthetic route to arylazoindazoles via nucleophilic aromatic substitution is presented. Upon deprotonation of the NH group, a C6F5-substituted formazan undergoes facile cyclization as a result of intermolecular nucleophilic substitution (SNAr). This new class of azo photoswitches containing an indazole five-membered heterocycle shows photochemical isomerization with high fati...

Abstract The kinetics of nucleophilic substitution reactions involving 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate were studied kinetically with 4‐Z‐C 6 H 4 O − /4‐Z‐C OH, which facilitated the reactions, in 20 mol% DMSO(aq). followed second‐order and exhibited β acyl = −2.34 to −2.92, ρ (Y) 2.71–3.39, nuc 0.74–0.83, | lg 0.40–0.57. Based on interpretation results, we have concluded ...

A simple method for the synthesis of new bio-based silane coupling agents (SCAs) with a terpene aromatic core by functionalization cheap, natural eugenol and its sulfur derivatives using hydrosilylation C=C bonds HSi(OEt)3, followed nucleophilic substitution reactions OH/SH groups is presented. The obtained alkoxysilanes possess different polymer-reactive functionalities (alkenyl, epoxide, thii...

Perfluorinated aromatics and heteroaromatics are versatile reagents for the modification of amino acids, peptides proteins. This is principally because they undergo rapid selective nucleophilic substitution reactions with biological nucleophiles. They are, therefore, exciting tools which to modulate activities drug-like properties natural synthetic biomolecules in drug discovery append, example...

The palladium-catalysed allylic substitution reaction is one of the most important reactions in transition-metal catalysis and has been well-studied in the past decades. Most of the reactions proceed through an outer-sphere mechanism, affording linear products when monosubstituted allyl reagents are used. Here, we report an efficient Palladium-catalysed protocol for reactions of β-substituted k...