92525-20-7

Upstream product

• 930-36-9 1-methyl-1H-pyrazole 
• 92524-98-6 trimethyl(1-methylpyrazol-3-yl)silane 
• 98-88-4 benzoyl chloride 
• 151049-87-5 3-bromo-1-methyl-1H-pyrazole 
• 186581-53-3 diazomethane 
• 960-41-8 (E)-1-phenyl-3-(phenylsulfonyl)prop-2-en-1-one 
• 21860-48-0 (E)-1-phenyl-3-tosylprop-2-en-1-one 
• 222718-47-0 (E)-3-(4-Chloro-benzenesulfonyl)-1-phenyl-propenone 
• 92525-10-5 3-iodine-1-methyl-1H-pyrazole 
• 65-85-0 benzoic acid 

Relevant academic research and scientific papers

A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides

A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.

Reactivity of Bifunctional Alkenes with Diazomethane

The cycloaddition of diazomethane to 1-aroyl-2-arylsulfonylethenes (1) and 1,2-bis(arylsulfonyl)ethenes (IV) under different conditions led to a variety of pyrazolines and pyrazoles. The reactivity of pyrazolines was also studied by pyrolysis, nitrosation and acylation.

Synthesis of 3-Substituted-1-methylpyrazoles

Reaction of 3-bromo-1-methylpyrazole 1 with t-butyllithium at -100 deg C followed by quenching of the lithiopyrazole intermediate allows regiospecific introduction of substituents into the 3-position of the 1-methylpyrazole ring.

Regioselective Halo- and Carbodesilylation of (Trimethylsilyl)-1-methylpyrazoles

The isomeric 3-, 4-, and 5-(trimethylsilyl)- as well as the 3,4-, 3,5-, and 4,5-bis(trimethylsilyl)-1-methylpyrazoles (2, 7, 3, 5, 9, and 10, respectively) are obtained by methylation of the corresponding (trimethylsilyl)-1H-pyrazoles or by silylation of Grignard or lithio derivatives of appropriate 1-methylpyrazoles with chlorotrimethylsilane. 5 and 10 are halodesilylated regioselectively by Br2 or ICl in the 4-position, yielding 13 and 15.With addditional bromine, these monobromo compounds suffer exclusively bromodesilylation to give 3,4- and 4,5-dibromo-1-methylpyrazole (14 and 16, respectively).These findings are in accord with the electrophilic substitution reactivity indices for 1-methylpyrazole (8) and with ipso-directing influence of the Me3Si group.The reaction of 5 with I2, unexpectedly, attacks preferentially at the 3-position.Regioselective carbodesilylation in the 5-position is observed in the fluoride-catalyzed reactions of 3, 9, and 10 with carbon electrophiles.The high regiospecificity of this reaction is rationalized in terms of carbanion stabilization at the individual pyrazole positions.