Thiourea to bicyclic scaffolds: highly regio- and stereoselective routes to dithiazolopyrimidines

A catalyst-free method for the synthesis of 1,4,2-dithiazoles from isothiocyanates and hydroxylamine triflic acid salts

A catalyst-free method for the preparation of 1,4,2-dithiazoles is developed by reactions of isothiocyanates with hydroxylamine triflic acid salts. This reaction achieves C-S, C-N, and S-N bond formation, and a range of products are obtained in moderate to good yields. The obvious feature is using shelf-stable hydroxylamine triflic acid salts as a N source to synthesize heterocycles under mild conditions.

Design, synthesis and biological evaluation of 4-aminoquinoline-guanylthiourea derivatives as antimalarial agents

Guanylthiourea (GTU) has been identified as an important antifolate antimalarial pharmacophore unit, whereas, 4-amino quinolones are already known for antimalarial activity. In the present work molecules carrying 4-aminoquinoline and GTU moiety have been designed using molecular docking analysis with PfDHFR enzyme and heme unit. The docking results indicated that the necessary interactions (Asp54 and Ile14) and docking score (-9.63 to -7.36 kcal/mmol) were comparable to WR99210 (-9.89 kcal/mol). From these results nine molecules were selected for synthesis. In vitro analysis of these synthesized compounds reveal that out of the nine molecules, eight show antimalarial activity in the range of 0.61-7.55 μM for PfD6 strain and 0.43-8.04 μM for PfW2 strain. Further, molecular dynamics simulations were performed on the most active molecule to establish comparative binding interactions of these compounds and reference ligand with Plasmodium falciparum dihydrofolate reductase (PfDHFR).

CeCl₃.7H2O/NaI-promoted direct synthesis of 1,3-benzoxazine-2-thione n-nucleosides under microwave irradiation

A microwave-assisted efficient and direct synthetic route to 1,3-benzoxazine-2-thione N-nucleos ides via CeCl₃.7H2O/NaI catalyzed cycloisomerization of salicylaldehyde 4-(β-D-ribofuranosyl) thiosemicarbazones followed by reductive dehydrazination is reported.

An expeditious synthesis of benzoxazine-2-thione c-nucleosides Via Cu(OTf)2-mediated dehydrazinative beta-glycosylation

A novel expeditious synthetic protocol for 1,3-benzoxazine-2-thione C-nucleosides via Cu(OTf)2-mediated dehydrazinative beta-glycosylation of 4-hydrazino-2H-benz[e]-1,3-oxazine-2-thiones with unprotected D-ribose is reported.