Reaction of vitamin A with 1,2,4-triazoline-3,5-diones

✍ Scribed by Sachiko Yamada; Kazuhiko Hamano; Masato Shimizu; Hiroshi Ichikawa

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 313 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)79928-x

✦ Synopsis

Vitamin A and its me&x&es reacted with 1,2,4-ttiazoline-3,Mione.s to give 11,14-(retinal) or 7, IO-adduct (retinal and retinoic acid) with high regioselectkity depending on the nature of the terminal functional group. The regiosekctivity of the reaction was discussed in compared with that with singlet o.qvgen. 1,2,4-Triazoline-3,5-diones (TAD) and singlet oxygen undergo similar reactions, [4 + 21, [2 + 21, and ene reactions. Extensive studies have been conducted recently to compare the reactivity of the two reagentsl-5

In ene reactions, TAD112 and singlet oxygen 1~3 showed remarkably similar reactivity though some differences were found in regio-and stereoselectivities. lb& However in the reaction with dienes they showed major differences; TAD undergoes 1,4-addition in a concerted manner when the s-cis conformation of the diene is not sterically congested,4 while singlet oxygen adds to dienes in a stepwise manner via a zwitter ionic intermediate regardless of the structure of the diene. 5 As a part of our studies on the chemical detection of dienes in