Synthesis of 3-(alpha- and beta-D-arabinofuranosyl)-6-chloro-1,2,4-triazolo[4,3-b]pyridazine.

Di-O-isopropylidene- and O-methanesulfonyl-protected 1-C-(6-chloro-1,2,4-triazolo[4,3-b]pyridazin-3-yl)pentitols were prepared in three to four steps from D-galactose, D-glucose, D-mannose, and 2,3:5,6-di-O-isopropylidene-alpha-D-mannofuranose. Acid-catalysed treatment of (1S)- and (1R)-1-C-(6-chloro-1,2,4-triazolo[4,3-b]-pyridazin-3-yl)-2,3:4,5-di-O-isopropylidene-1-O-methanesulfonyl-D-arabinitols in refluxing 1,2-dimethoxyethane furnished 3-(alpha- and beta-D-arabinofuranosyl)-6-chloro-1,2,4-triazolo[4,3-b]pyridazine, respectively. Several structures, including the structure of the 3-(beta-D-arabinofuranosyl)-6-chloro-1,2,4-triazolo[4,3-b]pyridazine, were also determined by single-crystal X-ray diffraction analysis.

Unusual reactions of 5,5-dimethyl-2-(indenyl-2)-3-pyrazolidinone with acetylenedicarboxylates.

[reaction: see text] Reaction of 5,5-dimethyl-3-pyrazolidinone (1) with 2-indanone (2) gave 5,5-dimethyl-2-(1H-indenyl-2)-3-pyrazolidinone (3) instead of the expected azomethine imine 4. Although reaction of 2-substituted 3-pyrazolidinones with acetylenedicarboxylates usually gives ring expansion products, such as 1,2-diazepines, treatment of 3 with dialkyl acetylenedicarboxylates (5, R = Me; 6 R = Et) resulted in the formation of rel-(7aR,12aS)-6,7-bis(alkoxycarbonyl)-3,4-dihydro-4,4-dimethyl-7aH-indano[1,2-b]pyrrolo[1,2-a]pyrimidin-2-ones (7, R = Me; 9, R = Et) as major products and 3,4-bis(alkoxycarbonyl)-7,7-dimethyl-2-(indenyl-2)-6,7-dihydro-2H,6H-1,2-diazepin-5-ones (8, R = Me: 10, R = Et) as minor products.

Antibacterial tests of bismuth(III)-quinolone (ciprofloxacin, cf) compounds against Helicobacter pylori and some other bacteria. Crystal structure of (cfH2)2[Bi2Cl10].4H2O.

The antibacterial tests of two bismuth(III)-ciprofloxacin (cf) compounds against Helicobacter pylori (H. pylori) and some other bacteria were performed. The results have shown that the activity of both compounds is comparable to that of ciprofloxacin hydrochloride.