Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...

Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...

The anionic ring-opening polymerizations (AROP) of bio-based N-acetyl homocysteine thiolactone (NHTL) and different epoxides were carried out using benzyl alcohol 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) as initiating system. This polymerization is a rare example AROP in the presence an acidic moiety (acetamido group). Well-defined alternating poly(est...

A pentasaccharide, 4-methoxyphenyl 2-acetamido-2-deoxy-β-d-galactopyranosyl-(1→4)-α-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β-d-galactopyranosyl-(1→6)-[α-l-fucopyranosyl-(1→2)]-β-d-galactopyranoside (1), representing the repeating unit of Escherichia coli O128 antigen, was successfully prepared in 23% overall yield via a convergent '2+3' glycosylation strategy.

fecl3.6h2o was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in etoh at room temperature. the remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. the structures o...

Bioassay-guided fractionation of a CH(2)Cl(2)-MeOH extract of the aerial parts of Albizia inundata resulted in the isolation of two new natural oleanane-type triterpene saponins {3-O-[α-L-arabinopyranosyl(1→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl oleanolic acid (1) and 3-O-[α-L-arabinopyranosyl(1→2)-α-L-arabinopyranosyl(1→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl acacic acid lactone (2)} al...

A study of the comparative specificities of cr-chymotrypsin and subtilisin Carlsberg has been focused mainly on the extent to which a-acetamido groups of some specific and nonspecific activated ester substrates affect the reactivity of each enzyme. Comparisons are based upon k, and k,: K,,, corrected for substrate intrinsic reactivities ((k,), and (k,: K&J. Among p-nitrophenyl P-phenylpropionat...

A study of the comparative specificities of cr-chymotrypsin and subtilisin Carlsberg has been focused mainly on the extent to which a-acetamido groups of some specific and nonspecific activated ester substrates affect the reactivity of each enzyme. Comparisons are based upon k, and k,: K,,, corrected for substrate intrinsic reactivities ((k,), and (k,: K&J. Among p-nitrophenyl P-phenylpropionat...

β-acetamido ketones were synthesized in excellent yields through one-pot condensation reaction of aldehydes, acetophenones, acetyl chloride, and acetonitrile in the presence of boric acid as a solid heterogeneous catalyst at room temperature. It is the first successful report of boric acid that has been used as solid acid catalyst for the preparation of β-acetamido ketones. The remarkable advan...

BACKGROUND Paullinia pinnata L. (Sapindaceae) is an African woody vine, which is widely used in traditional medicine for the treatment of human malaria, erectile dysfunction and bacterial infections. A phytochemical investigation of its methanol leaf and stem extracts led to the isolation of seven compounds which were evaluated for their antimicrobial properties. METHODS The extracts were fra...