Design and synthesis of chiral 2H-chromene-N-imidazolo-amino acid conjugates as aldose reductase inhibitors.

Aldose reductase (ALR2) inhibitors provide a viable mode to fight against diabetic complications. ALR2 exhibit plasticity in the active site vicinities and possible shifts in the nearby two supporting alpha helices. Therefore, a novel series of amino acid conjugates of chromene-3-imidazoles (13-15) were designed and synthesized based on natural isoflavonoids.

Design, semisynthesis and cytotoxic activity of novel ester derivatives of betulinic acid-1,2,4 oxadiazoles.

Taking into consideration of the biological activity of betulinic acid derivatives containing a oxadiazole ring, the semisynthetic betulinic acid-1,2,4-oxadiazole esters (14-25) were synthesized starting from betulinic acid (1) and 5-(bromomethyl)-3-aryl-1,2,4-oxadiazoles (2-13) and final compounds were tested for cytotoxic activity on three human cancer cell lines in vitro. All tested compounds showed good cytotoxic activity. The structures of synthesized compounds are established based on infrared (IR), nuclear magnetic resonance (NMR), and mass spectrometry.

5-Hydroxydictamnine, a new alkaloid from Atalantia monophylla.

A new furoquinoline alkaloid, 5-hydroxydictamnine, along with β-sitosterol was isolated from the heartwood of Atalantia monophylla. The structure of this alkaloid was established by chemical and spectral evidences together with a nuclear overhauser effect (NOE) experiment.

An unusual novel anti-oxidant dibenzoyl glycoside from Salvinia natans.

An unusual novel and significant anti-oxidant 1,2-dibenzoyl glycoside, natansnin (1), has been isolated from Salvinia natans. The structure of 1 was established by the study of NMR and CD spectral data.

Evaluation of astemizole purity by HPLC.

A liquid chromatographic method is described for the evaluation of Astemizole purity. The method is also applicable for the analysis of pharmaceutical dosage forms of Astemizole using indole as internal standard. Separation was achieved with a micro bondapak C(18) column and phosphate buffer (pH 6.