Synthesis of Some 5-Aryl-4,5-dihydropyrazolo[1,5-a]quinolines and 5-Aryl-4,5-dihydro-10H-pyrazolo[1,5-b][2]benzazepines from 1-Phenyl- or 1-Benzyl-5-styrylpyrazoles

Synthesis of Novel Angular Heterocyclic Lignans by an InCl3‐Catalyzed Friedel–Crafts‐Type Cyclization

“…The same reaction at room temperature gave 12a in quantitative yield. Cyclization of 12a into 5a by an intramolecular hydroarylation reaction with polyphosphoric acid [35][36][37] at 100°C or with the mild catalyst [38] RuCl 3 /AgOTf were unsuccessful.…”

Styrylpyrazoles: Properties, Synthesis and Transformations

“…Deshayes et al performed the reaction of enamine 92 with phenyl hydrazine in refluxing ethanol, overnight, to produce 4-ethoxycarbonyl-1-phenyl-5-styrylpyrazole 93 . In the same conditions, the reaction with benzyl hydrazine afforded a 3:1 mixture of two pyrazole isomers, the 1-benzyl-4-ethoxycarbonyl-5-styrylpyrazole 94 as the major product together with 1-benzyl-4-ethoxycarbonyl-3-styrylpyrazole 95 ( Scheme 29 ) [ 85 ].…”

“…Deshayes et al reported the reaction of phosponic esters, prepared from 1-substituted 5-bromomethylpyrazoles 105 and triethyl phosphite, with substituted benzaldehydes and furfural, in dimethoxyethane, as a method to prepare ( E )-4-ethoxycarbonyl-3-methyl-5-styryl-l-substituted pyrazoles 106 ( Scheme 32 ) [ 75 , 85 ].…”

“…C. Deshayes et al reported the electrophilic intramolecular cyclization of 1-benzyl- and 1-phenyl-5-styrylpyrazoles 122 , in the presence of polyphosphoric acid (PPA), which led to the formation of 5-aryl-3-ethoxycarbonyl-4,5-dihydropyrazolo-type compounds 123 and 124 ( Scheme 37 ) [ 85 ]. Both the 5-aryl-3-ethoxycarbonyl-4,5-dihydropyrazolo[1,5- a ]quinolines ( 123 ) and 5-aryl-3-ethoxycarbonyl-4,5-dihydro-10 H -pyrazolo[1,5- b ][2]benzazepines ( 124 ) were obtained with very good yields, save for 124 (R 1 = R 2 = H).…”

“… Transformation of 1-benzyl- and 1-phenyl-5-styrylpyrazoles 122 into 5-aryl-3-ethoxycarbonyl-4,5-dihydropyrazolo-type compounds 123 and 124 [ 85 ]. …”