TITLE:
An Efficient and Convenient Synthesis of Certain 2-Thioxothiazole,2-oxo-1,2-dihydropridine, 2-Oxo-2H-pyran,2,4-diaminothiophene and Pyrazolo[5,1-c][1,2,4]triazine Derivatives Containing Antipyrine Moiety
AUTHORS:
Seif-Eldin Nasr Ayyad, Fathy Muhammad Abdelaziz El-Taweel, Abdel-Ghani Ali Elagamey, Tahani Mahmoud El-Mashad
KEYWORDS:
Thioxothiazoles; Pyridine; Thiophene; Pyrazolotriazines
JOURNAL NAME:
International Journal of Organic Chemistry,
Vol.2 No.2,
June
27,
2012
ABSTRACT: 2-Thioxothiazole derivatives 5a-c were prepared by reacting a mixture of 1a-c, CS2/KOH and 4-(2-chloroacetyl)-1, 5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one(3). Reacting 2-cyano-N-(4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-2H- pyrazol-4-yl)-2-thioxothiazol-3(2H)-yl)acetamide (5c) with mercaptoacetic acid, arylidenemalononitriles 8 and (E)- 3-(dimethylamino)-1-(furan-2-yl)prop-2-en-1-one (12) give 4-oxo-4,5-dihydrothiazole 6, 2-oxo-1,2-dihydropyridine 10 and 2-oxo-2H-pyran 15 respectively. Heating a mixture of 5c, malononitrile and elemental sulfur yield 2,4-diaminothio- phene 19. Coupling of 5c with the diazotized aminopyrazole 20 and aryldiazonium salts 23 give pyrazolo[5,1-c][1,2,4] triazines 22 and arylhydrazones 25 respectively.