The rates of the thermolysin-catalyzed synthesis of peptides have been determined by means of HPLC. In the condensation of various N-substituted amino acids and peptides with L-leucinanilide, the enzyme exhibits preference for a hydrophobic L-amino acid as the donor of the carbonyl group of the newly formed bond. The presence of another hydrophobic amino acid residue adjacent to the carbonyl-gr...

Four enzyme preparations produced by fungal species belonging to different genera (Aspergillus niger, Corynascus sp., Penicillium verruculosum, Trichoderma reesei) were used for synthesis of disaccharides by D-glucose (60% w/v) condensation catalyzed by -glucosidase. Effects of pH and temperature on the disaccharide synthesis were studied, and glycoside linkage patterns for enzymes from differe...

a rapid and efficient one-pot, four-component protocol towards the synthesis of polyhydroquinoline derivatives has been developed. the condensation of aldehyde, dimedone, ethyl acetoacetate and ammonium acetate in presence of stannous chloride was carried out under solvent free condition to synthesize a variety of polyhydroquinoline derivatives in good to excellent yields. stannous chloride was...

Introduction Chlorodioxins can be formed in a two-step condensation reaction from ortho-substituted chlorophenoxy radicals or anions (1-3). The first route is of significance only where strongly oxidizing conditions exist such as a reaction of chlorine with pentachlorophenol at elevated temperature. For the second route we have investigated the condensation of alkali metal salts of chlorinated ...

(Ss)-3-(p-Tolylsufinyl)-2-furaldimine was synthesized, and condensation of the chiral furaldimine with lithium ester enolates has been examined. The product distribution of the reaction is dependent upon reaction conditions and on the kind of the substituent placed on the esters. Disubstituted ester enolate resulted in the exclusive formation of (4R)-beta-lactam, while unsubstituted, tert-butyl...

The domino Knoevenagel-hetero-Diels-Alder reaction of the aldehyde rac-8, Meldrum’s acid 2 and enol ether 3 leads to the cycloadduct rac-17 as the main product which in a second domino process was transformed into the benzoisoquinolizidine rac-18 by solvolysis, hydrogenolysis, condensation and hydrogenation; rac-18 was used as a substrate for the synthesis of the two diastereomeric epiemetine a...

The three components one pot synthesis of 2-amino-4H-benzo-[b] -pyran derivatives were obtained in good to excellent yields within short reaction time by condensing dimedone, aldehydes and malanonitrile or ethylcyanoacetate using a catalytic amount of (diacetoxyiodo)benzene as hypervalent iodine in aqueous ethanol under reflux conditions have been discussed. This aqua mediated Knoevenagel-cyclo...

Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) as a new nanoporous acid catalyst was used in the one-pot synthesis of polyhydroquinolines derivatives via the Hantzsch four component condensation reaction of aldehydes, b-ketoesters, dimedone and ammonium acetate under solvent free conditions with short reaction time in excellent yields. SBA-P...

The condensation of benzylamine with glyoxal leads to Hexabenzylhexaazaisowurtzitane (HBIW) in acetonitrile solvent with citric acid as a green catalyst under both conventional stirring and ultrasonic irradiation conditions. The influence of four variables, including the amount of catalyst, solvent, reaction time and ultrasonic power, on the reaction yield was investigated. The results showed t...

A convenient, efficient and practical procedure for the synthesis of 1-amidoalkyl 2-naphthols is described by condensation of aromatic aldehydes with amides and 2-naphthol in the presence of P2O5/SiO2 as an efficient catalyst. Moreover, in the present of this catalyst, the synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes is studied by co...