- A New Synthesis for 1,2,4-Triazolo[1,5-a]-pyridines and 1,2,4-Triazolo[1,5-a]isoquinolines
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Condensation of cyano acid hydrazide 1 with cyclopentanone in refluxing ethanolic piperidine yields hydrazone 2. With mixtures of aliphatic aldehydes and different active methylene reagents, 2 reacts to 1,2,4-triazolo[1,5-a]pyridines (8a-f). Compound 2 also reacts with arylidenes 9a-g to give triazolopyridines 10a-g. Reaction of 2 with aromatic aldehydes affords compounds 13a-c. Diazotation of 2 with aryldiazonium chloride in ethanol at 0°C leads to the azo adducts 15a-d. The thieno-1,2,4-triazolopyridine 16 is obtained by reaction of 8a with elementary sulfur. 16 undergoes cycloaddition with ω-nitrostyrene, maleic anhydride, N-arylmalemide, and acrylonitrile yielding the isoquinolines 21-24. All new compounds have been characterized by their IR, 1H NMR, and mass spectra.
- Hussein,Sherif,Atalla
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- Discovery of 2-(1H-indazol-1-yl)-thiazole derivatives as selective EP 1 receptor antagonists for treatment of overactive bladder by core structure replacement
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We have designed a series of potent EP1 receptor antagonists. These antagonists are a series of 2-(1H-indazol-1-yl)-thiazoles in which the core structure was replaced with pyrazole-phenyl groups. In preliminary conscious rat cystometry experiments, two representative candidates, 2 and 22, increased bladder capacity. In particular, the increase using 22 was approximately 2-fold that of the baseline. More detailed profiling of this compound and further optimization of this series promises to provide a novel class of drug for treating overactive bladder (OAB).
- Atobe, Masakazu,Naganuma, Kenji,Kawanishi, Masashi,Morimoto, Akifumi,Kasahara, Ken-Ichi,Ohashi, Shigeki,Suzuki, Hiroko,Hayashi, Takahiko,Miyoshi, Shiro
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p. 1327 - 1333
(2014/03/21)
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- New synthesis for 1,2,4-triazolo[1,5-a]pyridines and new 1,2,4-triazolo[1,5-a]isoquinolines
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Synthesis of 1,2,4-triazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]isoquinolines is presented.
- Hussein,Sherif,Atalla
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p. 872 - 879
(2007/10/03)
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- Diels-alder cycloadditions of 1,3,4,-oxadiazin-6-ones with electron rich pi systems
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A study of the cycloaddition behavior of several 2,5-disubstituted 1,3,4-oxadiazin-6-ones with electron rich pi bonds has been carried out. trans-1-Propenylpyrrolidine was found to react with the oxadiazinone ring system to give rise to a ring opened diazatrienyl substituted carboxylic acid. Further heating of the acid results in decarboxylation, hydrolysis, cyclization and pyrrolidine elimination to produce a disubstituted pyrazole. Reaction with the trisubstituted enamine 1 - ( 2 - methyl-propenyl) pyrrolidine, was also studied in some detail. The cycloadditions encountered can be rationalized as proceeding by an initial Diels-Alder reaction followed by cheletropic extrusion of nitrogen to produce a ketoketene intermediate. The fate of the ketene is markedly dependent upon the overall pattern of substitution. Some of the products formed can be explained in terms of a competitive migration of the pyrrolidino group to the ketene and benzoyl groups. With one system the major cycloadduct is derived from the Diels-Alder reaction of a transient azaketene tautomer formed by an electrocyclic opening of the oxadiazinone ring.
- Padwa, Albert,Eisenbarth, Philipp
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p. 283 - 296
(2007/10/02)
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