Treatment of 4-heptafluoroisopropyl-2-methoxy-3,5,6-trifluropyridine (4 ) with aqueous ammonia in THF gave 2-amino-3,5-difluoro-4-heptafluoroisopropyl- 6-methoxy pyridine (5) in 7 1% yield. Chlorination of this amine with 'ButOCl at -16°C gave an unstable product, namely 2-dichloroarnino-3,5- difluoro-4-heptafluoroisopropyl-6-methoxy pyridine (6). Iodine-catalysed rearrangement of this dic...

diazotization of 3-amino-2-cmoro pyridine (3) in the presence of dithizone (5) gave dphenyl-2-phenylazo-4h-pyrid[o3 ,2-e] [1,3,4] thiadiazine (6). reaction of 2- chloro-3-nitropyridine (2, g=h) with (5) dfordd 4-phenyl -2-phenylazo -4hpyrido [2,3-el [1,3,4] thiadiazine (7). reduction of the latter with h gas in the presence of raney nickel gave the corresponding amino derivative (12). one pot c...

Diazotization of 3-amino-2-cMoro pyridine (3) in the presence of dithizone (5) gave dphenyl-2-phenylazo-4H-pyrid[o3 ,2-e] [1,3,4] thiadiazine (6). Reaction of 2- chloro-3-nitropyridine (2, G=H) with (5) dfordd 4-phenyl -2-phenylazo -4Hpyrido [2,3-el [1,3,4] thiadiazine (7). Reduction of the latter with H gas in the presence of Raney nickel gave the corresponding amino derivative (12). One ...

Chemical modification of chitosan is increasingly studied for its potential of providing new applications of chitosan. Here, a group of novel chitosan quaternary ammonium derivatives containing pyridine or amino-pyridine were designed and successfully synthesized through chemical modification of chitosan. Pyridine and amino-pyridine were used as functional groups to improve the antifungal activ...

The reactions of isatins, 3-amino-1-pheyl-1H-pyrazol-5(4H)-one, and monocyclic ketones, have been developed for preparation spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]-2,3'(6'H)-dione, spiro[cyclohepta[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3-dione, spiro[cycloocta[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3(6H)-dione, spiro[cyclo dodeca[b]pyrazolo[4,3-e]pyridine-4,3'-indoline]-2′,3(6H...