Synthesis of Indeno[1,2-b]pyrazineN-Oxides by Reaction of Ninhydrin with 1,2-Bishydroxylamines

✍ Scribed by Mazhukin, Dmitrii G. ;Tikhonov, Aleksei Ya. ;Volodarsky, Leonid B. ;Evlampieva, Natal'ya P. ;Vetchinov, Valerii P. ;Mamatyuk, Victor I.

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 506 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419941005

✦ Synopsis

Abstract

The reaction of the ninhydrin (1) with 1,2‐bishydroxylamines 2a–c affords dihydroindeno[1,2‐b]pyrazine N,N′‐dioxides 5a–c. The intermediates hexahydro‐ and tetrahydroindeno[1,2‐b]pyrazines 3a and 4c, which have been isolated, are easily transformed into 5a, c. Heating of 5b, c or keeping of 5b on alumina gives indeno[1,2‐b]pyrazine N‐oxides 6b, c, N,N′‐dioxide 7c and indeno[1,2‐b]pyrazine 8. Treatment of 5b with a solution of hydrochloric acid in H~2~O/MeOH leads to 6b, whereas treatment of 5b with KOH furnishes mono‐N‐oxides 6b, 9 and dioxide 7b. Compound 8 is prepared by deoxygenation of 6b with TiCl~3~. The reduction of 6b with NaBH~4~ yields alcohol 10 and the reaction of 6b with NH~2~OH/AcOH gives a mixture of isomeric oximes (E)‐11 and (Z)‐11.