the effects of trichloroacetic acid/methylene chloride (tcac/mc) on the mechanical properties and solvent texturing of polyester yarns are studied. the treatments are carried out in unstrained and strained states at different concentrations of tcac for various treatment times. breaking load and elongation-at-break of treated yarns have been recorded. treatments of polyester yarns with tcac/mc i...

A simple, efficient, and high yielding one-pot protocol has been developed for the synthesis of 4H-benzo[b]pyrans scaffolds installing a three-component tandem Knoevenagel-cyclocondensation reaction of an aldehyde, malononitrile and dimedone using guanidinium chloride as polyfunctional organocatalyst under solvent-free conditions in high to excellent yields. Various aromatic aldehydes were util...

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of 1,3-dicarbonyl compounds, Aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amount of Brønsted acidic ionic liquid 3-methyl-1-sulfonic acid imidazolium chloride {[Msim]Cl} under thermal solvent-free conditions reacted easily to afford the co...

Nano-silica-bonded 3-n-propyl-1-sulfonic acid imidazolium chloride (nano-SB-[PSIM]Cl) was applied as a highly efficient, general and heterogeneous catalyst for one pot multi-component reaction of 2-naphthol, arylaldehydes, and thioacetamide leading to 1-thioamidolakyl-2-naphthols. All reactions proceeded with excellent yields in short times under solvent-free conditions. Our protocol was superi...

Organocatalyst trityl chloride (Ph3CCl), by in situ formation of trityl carbocation with inherent instability, efficiently catalyzes the condensation of dimedone (5,5-dimethyl-1,3-cyclohexanedione) (2 equiv.) with arylaldehydes (1 equiv.) under solvent-free conditions to afford 9-aryl-1,8-dioxo-octahydroxanthenes in high to excellent yields and in relatively short reaction times. Formation of t...

The demonstration that certain thiamine analogues specifically and competitively inhibit the thiamine-destroying enzyme of fish tissues afforded an additional method for characterizing the action of the enzyme and analyzing the structural features of the inhibitor molecules in relation to their effectiveness. o-Aminobenzyl-(3)-bmethylthiazolium chloride at 5 X 10m4 M concentration was found to ...

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of 1,3-dicarbonyl compounds, Aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amount of Brønsted acidic ionic liquid 3-methyl-1-sulfonic acid imidazolium chloride {[Msim]Cl} under thermal solvent-free conditions reacted easily to afford the co...

A single clean, good-yielding, environment-friendly microwave-assisted procedure for O-silylation of uridine with tert-butyldimethylsilyl chloride (TBDMSCl), 1,8-Diazabicyclo(5.4.0)undec-7-ene (DBU) and potassium nitrate as catalyst under solvent-free conditions is reported. Subsequent silyl ether deprotection accomplished a reusable acidic resin via microwave irradiation. Both the silylation d...

A simple deep eutectic solvent based on tin (II) chloride was used as a dual catalyst and environmentally benign reaction medium for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives, from aromatic and aliphatic aldehydes, 1,3-dicarbonyl compounds, and urea in good-to-excellent yields and short reaction time. This simple ammonium deep eutectic solvent, easily synthesized from...