76877-97-9

Upstream product

• 76877-98-0 4'-hydroxy-2,3'-dimethyl-1'-phenylspiropyrazolin>-3-one 
• 69730-13-8 2-amino-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)benzamide 

Relevant academic research and scientific papers

Consecutive Pschorr-Sandmeyer reactions in a pyrazole series. Part 2. Access to the [2]benzopyrano[4,3-c]pyrazole system of pharmaceutical interest

The diazonium salts obtained from 2-amino-N-methyl-N-(1-phenyl-3-methylpyrazol-5-yl)benzamide were reacted with cuprous oxide or copper at 5 or 25°C under different pH conditions. Cuprous oxide at 25°C and pH 6.25 yielded the racemic epimers (3′SR,4′RS)- and (3′SR,4′SR)-4′-hydroxy-2 ,4′-dihydro-2,5′-dimethyl-2′-phenlIspiro[isoindoline-1, 3′-3′H-pyrazol]-3-ones 2 and 10 respectively, (RS)-2′,4′-dihydro-2,5′-dimethyl-2′- phenylspiro[isoindoline-1,3′-3′H-pyrazole]-3,4′-dione 9 and N-methylphthalimide 8. The thermal transformation of 2 and 10 into the potentially pharmacologically active 3-methyl-1-phenyl[2]benzopyrano[4,3-c]pyrazol-5(1H)-one 4 was strongly dependent on the structure of the two epimers. When 1 was reacted with cuprous oxide or copper sulfate and sodium halide (chloride or bromide), in the presence of ascorbic acid as initiator, a mixture of epimers (3′SR,4′RS)- and (3′SR,4′SR)-4′-chloro(or bromo)-2′,4′-dihydro-2,5′-dimethyl-2′- phenylspiro[isoindoline-1,3′-3′H-pyrazol]-3-ones 6b and 7b (or 6c and 7c) was obtained. The same epimers were obtained when the diazonium halides (chloride and bromide) 1b,c obtained from 2-amino-N-methyl-N-(1-phenyl-3-methyl-1H-pyrazol-5-yl)benzamide were treated with the appropriate classical Sandmeyer catalysts. The formation of the spiro compounds is based on consecutive Pschorr and Sandmeyer reactions. The X-ray crystal structures of the epimers 2 and 10 have been determined, confirming the given formulations.

Modifications and Extensions of the Pschorr Reaction in Pyrazole Series. Access to the Benzopyranopyrazole System of Pharmaceutical Interest

The Pschorr reaction performed under non-classical reaction conditions on the diazonium chloride derived from 2-amino-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)benzamide 1 afforded the epimers (3'R,4'S)- and (3'R,4'R)-4'-chloro-2',4'-dihydro-2,5'-dime

Studies on the Synthesis of Heterocyclic Compounds. Part IV. Further Investigation of the Pschorr Reaction with Some Pyrazole Derivatives

Thermal decomposition of the diazonium sulfate derived from N-methyl-(1-phenyl-3-methylpyrazol-5-yl)-2-aminobenzamide afforded products formulated as 1-phenyl-3-methylbenzopyranopyrazol-5-one (yield 10percent), 1,4-dimethyl-3-phenylpyrazoloisoquinolin-5-one (yield 10percent), N-methyl-(1-phenyl-3-methyl-pyrazol-5-yl)-2-hydroxybenzamide (yield 8percent) and 4'-hydroxy-2,3'-dimethyl-1'-phenylspiro-pyrazolin>-3-one (yield 20percent).Decomposition of the diazonium sulfate derived from N-methyl-(1,3-diphenyl-pyrazol-5-yl)-2-aminobenzamide gave products formulated as 7,9-dimethyldibenzopyrazolo-diazocin-10-(9H)one (yield 8percent), 4-methyl-1,3-diphenylpyrazoloisoquinoline-5-one (yield 7percent) and 4'-hydroxy-2-methyl-1',3'-diphenylspiropyrazolin>-3-one (yield 10percent).The spiro compounds 6a,b underwent thermal and acid-catalysed conversion into the hitherto unknown 2-benzopyranopyrazole ring system 7a,b in good yield.Analytical and spectral data are presented which supported the structures proposed.