Novel (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles from (E)- and (Z)-3-styrylchromones: the unexpected case of (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles

An efficient synthesis of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles from (E)- and (Z)-3-styrylchromones, which does not have a 4′-nitro substituent, have been developed. In this case, both (E)- and (Z)-4′-nitro-3-styrylchromones afforded only (E)-3-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles.