hydrazine monohydrochloride readily formed pyrazoline intermediates under mild conditions. Oxidation of pyrazolines, in situ, employing bromine afforded a wide variety of pyrazoles. The methodology offers a fast, and often chromatography-free protocol for the synthesis of 3,4,5-substituted pyrazoles in good to excellent yields. Alternatively, a more benign oxidation protocol affords 3,5-disubstituted or
Utility of Cyano Acid Hydrazide in Heterocyclic Chemistry: A New Route for the Synthesis of New 1,2,4-Triazolo[1,5-a]pyridines and 1,2,4-Triazolo[1,5-a]isoquinolines
作者:Abdel Haleem Mostafa Hussein
DOI:10.1515/znb-1998-0417
日期:1998.4.1
refluxing ethanolic piperidine to yield the hydrazone 4. Compound 4 reacts with arylidines 5a-i to yield the 1,2.4- triazolo[1,5-a]pyridines 7a-i. Compound 4 also reacts with mixtures of aliphatic aldehydes and different active methylene reagents to yield 1,2,4-triazolo[1,5-a]pyridines 8a-d. Similarly reaction of 4 with arylazomalononitrile to yield the triazolopyridines 10a-d Reaction of 4 with aromatic
A simple, highly efficient, and environmentally friendly method for the synthesis of substituted 1H-pyrazoles by one-pot condensation reaction of α,β-unsaturated carbonyl compounds with tosyl hydrazide in water was developed. The reaction system exhibited tolerance with various functional groups, Aromatic moiety with both electron-rich and electron-deficient substituents could give desired products
Regioselective Preparation of Saturated Spirocyclic and Ring-Expanded Fused Pyrazoles
作者:Rohan R. Merchant、Daniel M. Allwood、David C. Blakemore、Steven V. Ley
DOI:10.1021/jo501624t
日期:2014.9.19
tosylhydrazones, which are easily prepared from their parent ketones. Sigmatropic rearrangement of spirocyclic pyrazoles to fused analogues occurs with concomitant one-carbon expansion of the saturated ring, allowing rapidaccess to a range of pharmaceutically and agrochemically relevant polycyclic structures featuring a broad scope of saturated ring sizes.
The present invention discloses amides and thioamides substituted in the .alpha. or .beta. position with substituted pyrazoles which are useful as herbicides.