Bromination and diazo-coupling of pyridinethiones; microwave assisted synthesis of isothiazolopyridine, pyridothiazine and pyridothiazepines.
Isothiazolopyridines, pyridothiazines and pyridothiazepines are important compounds that possess valuable biological activities. This paper reports on the synthesis of these compounds using both conventional chemical methods and modern microwave techniques. 3-Bromo-6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide, 5-arylazo-6-hydroxy-4-methyl-2-thioxo-1,2-dihydropyridine-3-carboxamides, 3,5-bis-arylazo-6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-caboxamide, 4-methyl-2,3,6,7-tetra-hydroisothiazolo[5,4-b]-pyridine-3,6-dione, 2,2'-(methylene-bis-(sulfanediyl))bis(4-methyl-6-oxo-1,6-dihydropyridine-3-carboxamide), 2-hydroxy-5-methyl-4H-pyrido[3,2-e][1,3]-thiazine-4,7(8H)-dione and 2-arylmethylene-8-hydroxy-6-methyl-2,3,4,5-tetrahydropyrido-[3,2-f][1,4]thiazepine-3,5-diones have been prepared from 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide. Some of these compounds were prepared using microwave-assisted reaction conditions, that provided higher yields in shorter times than the conventional methods.
Department of Chemistry, Faculty of Science, Fayoum University, Fayoum 63514, Egypt.
Ayman M S
AM
Youssef
Mohamed E
ME
Azab
Mohamed M
MM
Youssef
D054879:Halogenation; D008872:Microwaves; D058451:Oxidative Coupling; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D013841:Thiazepines / Q000138:chemical synthesis* / Q000737:chemistry; D013843:Thiazines / Q000138:chemical synthesis* / Q000737:chemistry
D011725:Pyridines; D013841:Thiazepines; D013843:Thiazines