Electrophilic fluorination of an exocyclic methoxymethylene enol ether derived from N-tert-butyloxycarbonyl-1,5-dideoxy-1,5-imino-3,4-O-isopropylidene-d-erythro-pent-2-ulose (11) provided the 5-fluoro derivative of the powerful β-galactosidase inhibitor 4-epi-isofagomine (8). This structural al...

Pentacarbonyl[(cyclopropyl)methoxymethylene]molybdenum complex reacts with ferrocenyl alkynes to afford ferrocenyl-substituted 2,4-cycloheptadienones as major products, accompanied by varying amounts of 2-cycloheptene-1,4-diones and/or 2-cyclobutenones. 2-Cycloheptene-1,4-diones are secondary re...

A cheap, versatile and convenient method for synthesis of β-lactams using methoxymethylene-N,N-dimethyliminium salt as an acid activator in Staudinger reaction is reported. This method is used for the preparation of monocyclic, spirocyclic, N-alkyl and three-electron-withdrawing group β-lactam...

Ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) catalyzes the key reaction of the Calvin reductive pentose phosphate cycle and as such is responsible for life as we know it. This enzyme has been intensively studied for decades. Evidence that RubisCO phylogenies are incongruent with tho...

Xylulose-1,5-bisphosphate in preparations of ribulose-1,5-bisphosphate (ribulose-P2) arises from non-enzymic epimerization and inhibits the enzyme. Another inhibitor, a diketo degradation product from ribulose-P2, is also present. Both compounds simulate the substrate inhibition of ribulose-P2 c...

This study aims at clarifying the cause of the time-dependent, partial loss of the activity during reaction, fallover, of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) of plant sources. This was done by comparing the reaction courses calculated using the reaction models constructed h...

6-Phosphofructo-1-kinase and fructose-1,6-bisphosphatase are rate-limiting enzymes for glycolysis and gluconeogenesis respectively, in the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in the liver. The effect of ribose 1,5-bisphosphate on the enzymes was investigated. Ribose 1,5-bisphosp...

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the enzyme assimilating CO2 in biology. Despite serious efforts, using many different methods, a detailed understanding of activity and regulation in Rubisco still eludes us. New results in X-ray crystallography may provide a structura...

Background Ribulose 1,5-bisphosphate carboxylase/ oxygenase (rubisco) catalyzes the addition of CO2 to ribulose 1,5-bisphosphate in all photosynthetic organisms. During catalysis, the bisphosphate is depleted by reactions other than carboxylation and some of the products are potent inhibitors of...

Cyclic voltammograms in dimethylsulphoxide (DMSO) are presented and discussed for para- and meta-nitro-substituted N(thiobenzoyl)piperidines (1a, 2a) and morpholines (lb,2b) as well as for the corresponding N(thiocinnamoyl) derivatives (3b, 4a, b). In the first cycle, two main reduction waves (A...

Condensation of 4-hydroxy-6-methyl pyran-2-one 2 with 3-amino-1,2,4-triazole 1 in refluxing alcohol afforded 5-alkoxycarbonylmethyl-7-methyl-1,2,4-triazolo〚1,5-a〛pyrimidines and their isomers 5-alkoxycarbonylmethyl-7-methyl-1,2,4-triazolo〚4,3,-a〛pyrimidines 4. Reaction of hydrazine hydrate with ...

Tetrahydro- and dihydrotriazolo[1,5-a]quinazolines were prepared by reaction of 7-methyl-5-phenyl-4,7-dihydro[1,2,4]triazolo-[1,5-a]pyrimidine with chalcone.

A rapid and efficient method is reported for the synthesis of the [1,2,4]triazolo[1,5-a]pyrimidine motif. Palladium catalyzed Suzuki and Sonogashira cross coupling reactions on 7-chloro-5-methyl-[1,2,4]triazolo[1,5-a]pyrimidine were performed. The direct sp3 arylation of compounds resulting from...

Comparison of NMR data with structures from molecular modelling of 1-(3,5-dimethylphenyl)methyl-3(S)-(1H-indol-3-yl)methyl-6-(S)-phenylmethyl-2,5-piperazinedione (1) showed it to have a specific solution conformation with the phenyl ring over the diketopiperazine ring and the tryptophan sidechai...

Diaryl quinone methides, 4-[(4′-hydroxy-3′,5′-dimethylphenyl)(aryl)-methylene]-2,6-dimethylcyclohexa-2,5-dienone (where aryl = 4-hydroxyphenyl, 1a; 4-methoxyphenyl, 1b; 3,4,5-trimethoxyphenyl, 1c) are synthesised by oxidation of the corresponding bis-phenols. These molecules are solvatochromi...

A new [2.2]paracyclophane compound consisting of two 1,3,5-tris[(2,5-dimethylphenyl)ethynyl]benzenes stacked in proximity to each other. The compound exhibited a unique absorption band (cyclophane band) and an emission from the phane state, both of which were derived from the π–π stacking of ...

The oxidation of aromatic sulfides with achiral oxidizing agents, e.g., sodium metaperiodate (NaIO4) and hydrogen peroxide (H2O2) in the binding domain of bovine serum albumin (BSA), furnished a strong asymmetric bias (max 81%) of the product sulfoxides in fairly high chemical yields. The kineti...

The enantioselective oxidation of allyl sulfides with a vanadyl complex of 3,5-diiodosalicylidene tert-leucinol as a catalyst and aqueous hydrogen peroxide as an oxidant afforded chiral allyl sulfoxides with high enantioselectivities of up to 97.3% ee and moderate yields.

Addition of a wide range of Grignard reagents to acetone protected (2-methyl-5-tert-butyl)phenyl 1-thio-β-D-ribopentodialdo-1,4-furanoside 3b produced useful 5(R)C-substituted products with moderate to good yields, and moderate to perfect stereoselectivities, with no need of additives. n.O.e. A...

A new strategy for the C(sp2)–H imidation and 1,2-imidofluorination of vinylsulfides has been established through simple treatment with N-fluorobis(benzenesulfonyl)imide, which acts as both oxidant and nitrogen source. For alkyl and electron-rich aryl vinylsulfides, alkyl/arylthioenamines are p...