Direct N-heterocyclization of hydrazines to access styrylated pyrazoles: synthesis of 1,3,5-trisubstituted pyrazoles and dihydropyrazoles
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Natural Biopolymers is an Efficient Catalyst for the Synthesis of 1,3,5-Trisubstituted Pyrazoles
Cellulose sulfuric acid is an efficient metal-free catalyst for the synthesis of 1,3,5-trisubstituted pyrazoles via the condensation of 1,3-diketones and hydrazines. The reaction was carried out in Solvent-free condition at room temperature and the products were isolated in good to excellent yields. Mild reaction conditions, as well as ease of operation and workup are some advantages of the pro...
متن کاملSelective synthesis of 4-(sulfonyl)-methyl-1H-pyrazoles and (E)-4,5-dihydro-1H-pyrazoles from N-allenic sulfonylhydrazones.
Selective synthesis of 4-(sulfonyl)-methyl-1H-pyrazoles and (E)-4,5-dihydro-1H-pyrazoles from N-allenic sulfonylhydrazones with sulfonyl group migrations has been developed. A key feature of these reactions is that the migrations of the sulfonyl groups to different positions can be controlled by changing the Lewis acids.
متن کاملMicrowave Synthesis of Arylmethyl Substituted Pyrazoles
The synthesis under MW irradiation without solvent of 19 pyrazoles, of which only 8 were known, is described. They bear C-methyl groups and trityl, diphenylmethyl and benzyl groups at positions 1 and 4 of the pyrazole ring. In the reaction between pyrazole and trityl bromide an unexpected reaction occurred and 4-(9-phenyl-9H-fluoren-9-yl)-1Hpyrazole (7) was isolated.
متن کاملSynthesis of tetrasubstituted pyrazoles containing pyridinyl substituents
A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I2/HIO3 gives the appropriate 4-iodopyrazol...
متن کاملPyrazoles pdf
Zolo1, 2-apyrazole-1-one or its salts are used as a hair dye with red. In addition, pyrazolo3, 4-cpyrazoles are useful for the treatment of.novel glucosyl pyrazole derivatives starting from D-glucose. Pyrazoles are chemical compounds of synthetic origin that.Pyrazoles: Synthetic Strategies and Their Pharmaceutical. Abstract: Pyrazoles are an important class of five membered heterocyclic compoun...
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ژورنال
عنوان ژورنال: RSC Advances
سال: 2018
ISSN: 2046-2069
DOI: 10.1039/c8ra04550j