Synthesis of 1H‐thieno[3,4‐c]pyrazoles, thieno[3,4‐b]furans, selenolo[3,4‐b]furans and pyrrolo[3,4‐d]thiazoles

Abstract

Starting from the readily available aryl 2‐methyl‐5‐phenyl‐3‐furyl ketones, 5‐methyl‐1H‐1‐phenylpyrazole‐4‐yl ketones and 4‐methyl‐2‐phenyl‐5‐thiazolylcarboxaldehyde, a series of 2‐phenyl‐4‐arylthieno[3,4‐b]‐furan, 2‐phenyl‐4‐(p‐methoxyphenyl)selenolo[3,4‐b]furan, 4‐aryl‐1H‐1‐phenylthieno[3,4‐c]pyrazole and 5‐benzyl‐2‐phenylpyrrolo[3,4‐d]thiazole were prepared in high yield.

A concise review on synthesis, reactions and biological importance of thienopyrazoles

“…Scheme 29The reaction of aryl 5-bromomethyl-1H-1-phenylpyrazole-4-yl ketone 98a-d with thioacetamide in ethanol gave 4-aryl-1-phenyl-1H-thieno[3,4-c]pyrazoles 99a-d in high yields67 (Scheme 30).…”

Photochemistry of 3H-furo[3,4-c]pyrazoles and 3H-thieno[3,4-c]pyrazoles

“…Elution with 5% ethyl acetate/light petroleum gave 12 as a moderately stable reddish oil (252 mg, 42%). MS m/z 153 (12%), 152 (M þ ÀN 2 , 100), 151 (40), 137 (89), 111 (28), 103 (10), 97 (12), 91 (19), 77 (16). 1 The ethereal extracts were washed with brine, dried and concentrated under reduced pressure.…”

“…Synthesis of 3H-furo [3,4-c]pyrazoles and 3H-thieno [3,4-c] pyrazoles 3H-Thieno [3,4-c]pyrazoles and 3H-furo [3,4-c]pyrazoles have not been synthesized to date and few tautomeric thieno [3,4-c] pyrazoles are known. 15,16 3H-Thieno [3,4-c]pyrazoles with methyl and tert-butyl substituents were made for this study. The methyl derivative was made from 3-hexyne-2,5-diol, 6.…”