Syntheses of thiopyrone and pyrone derivatives by photocyclization reaction of 3-aryl-2-( Benzothien-3-yl)propenoic acids

✍ Scribed by Kenji Sasaki; Yasuyoshi Satoh; Takashi Hirota; Taiji Nakayama; Yoshinori Tominaga; Raymond N. Castle

• Book ID: 102893999
• Publisher: Journal of Heterocyclic Chemistry
• Year: 2000
• Tongue: English
• Weight: 575 KB
• Volume: 37
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570370446

✦ Synopsis

Abstract

Naphtho[1,2‐b][1]benzothiophene‐6‐carboxylic acids, 6__H__‐benzo[b]naphtho[2,3‐d]thiopyran‐6‐ones and 6__H__‐benzo[b]naphtho[2,3‐d]pyran‐6‐ones were synthesized in one step by the photocyclization reaction of 3‐aryl‐2‐([1]benzothien‐3‐yl)propenoic acids. The photocyclization reaction did not occur when the 3‐aryl group contained the electron‐withdrawing nitro group. The assignment of the ^1^H and ^13^C nmr spectra of 6__H__‐benzo[b]naphtho[2,3‐d]thiopyran‐6‐one and 6__H__‐benzo[b]naphtho[2,3‐d]pyran‐6‐one by two‐dimensional nmr methods is described. The difference between the chemical shift values of H12 for these two compounds is attributed to different molecular geometries.