2-Pyrazoline, 3-benzoyl-4-phenyl

A.2 Synthesis of Five-Membered Heterocycles A. 2.1 3-Benzoyl-4-phenyl-A 1-pyrazoline... 

To the cold ethereal diazomethane solution prepared from 10 g of nitro-somethylurea (about 2.8 g CH2N2, 0.067 mol volume 100 ml) was added a solution of benzalacetophenone 1 (14.5 g, 0.07 mol) in 150 ml of ether (Scheme A.8). Within 5 min a precipitate formed. After 1 h at — 14°C filtration yielded 13.5 g of the colorless 3-benzoyl-4-phenyl-A1-pyrazoline 2. Partial evaporation of the ether gave an additional 3 g of the material. The total yield, based on 13.5 g of benzalacetophenone (0.065 mol), was 100%. The material may be crystallized from methyl or ethyl alcohol, a mixture of ethyl acetate and petroleum ether, a mixture of chloroform and petroleum ether, or carbon tetrachloride. The best results were obtained using methyl alcohol. Melting point 92-93°C. 

C17H14N202 4-benzoyl-3-methyl-l-phenyl-2-pyrazolin-5-one 4551-69-3 492.65 43.178 2 30136 C17H20N2S promazine 58-40-2 479.65 411 1,2... 

Benzoyl-3-methyl-l-phenyl-2-pyrazolin-5-thione has been prepared by Michaelis and co-workers977,990 by the reaction of sodium and potassium hydrogen sulfide with 4-benzoyl-5-chloro-3-methyl-l-phenyl-pyrazole. The thiono compound forms a methiodide and gives the characteristic reactions of both ketones and 2-pyrazolin-5-thiones. 

Benzoyl-2,3-dimethyl-l-phenyl-5-imino-3-pyrazoline is prepared by treating the methiodide of 4-benzoyl-3-methyl-l-phenyl-5-imino-2-pyrazoline with base.977... 

Bis(3-methyl-2-benzoyl-l-phenyl-3-pyrazolin-5-one) has been reported as the product obtained from treatment of 4,4 -bis(3-methyl-l-phenyl-2-pyrazolin-5-one) with benzoyl chloride.1056... 

In a similar reaction benzylideneacetophenone affords 3-benzoyl-4-phenyl-pyrazoline, also almost quantitatively.17 A large number of pyrazoline derivatives can be obtained in similar reactions of diazomethane or diazoacetic ester. 

Diethylamine added to an ethereal soln. of 3-acetyl-3-benzoyl-4-phenyl-Zl -pyrazo-line, and stored ca. 10 days in a refrigerator l-acetyl-3-benzoyl-4-phenyl-j2 pyrazoline. Y 95%. F. e. s. R. Danion-Bougot and R. Carrie, Bl. 1972, 3511. 

Lam et al. synthesized isoxazolines 469 and pyrazolines 470 via monoalkylation with dimsyl anion and styrene oxide 480 and following an oxidation/ elimination strategy [292]. Oxidation of secondary alcohols 481 is performed via Jones oxidation and cyclization with cleavage from the resin follows in a separate step. Diverse elements can be introduced to the heterocycle using either hydroxylamine 483 or hydrazine derivatives 484 (Scheme 72). Corresponding six-membered heterocycles like pyridazine derivatives 471 can be obtained when the linked molecule 482 bears a benzoyl substituent instead of the phenyl substituent at the a-C-atom [293]. 

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