The pictet-spengler reaction of Nb-hydroxytryptamines and cysteinals. I. Isolation of tetracyclic intermediates and formation of optically active Nb-hydroxy-tetrahydro-β-carbolines.
✍ Scribed by Jinjun Liu; Masako Nakagawa; Tohru Hino
- Book ID
- 104203502
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 935 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
The Pictet-Spengler(P-S) reaction of Nb-hydroxytryptamines 5 and cysteinals 6 in the presence of trifluoroacetic acid(TFA) at room temperature gave the tetracyclic compounds 7a as well as the corresponding Nb-hydroxy-S-carbolines 8. The optically active nitrones 9, isolated from the similar reaction of 5 and optically active 6, gave optically active 7a and 8.
In the continuation of our work directed toward the total synthesis of the potent antiviral marine alkaloid, eudistomins 1, 1 the need arose for the synthesis of Nb-hydroxy-tetrahydro-Pcarboline 2 which may be prepared by use of the Pictet-Spengler reaction (P-S reaction) of Nbhydroxytryptamine 3 with cysteinal 4 (Scheme I). Recently, Ottenheijm and coworkers2 Scheme I X y*lj dy*r _ yyw Eudistomins la(C) X=H,Y=OH,Z=Br 2 s b(E) X=Br.Y=OH,Z=H c(Kj X=Y=H.Z=Br 4 d(L) X=Z=H,Y=Br