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Synthesis of Clausenal, 1,5‐Dimethoxycarbazole‐3‐carbaldehyde and 2,5‐Dimethoxycarbazole‐3‐carbaldehyde
Author(s) -
Kishonti Adrian,
Jäger Anne,
Knölker HansJoachim
Publication year - 2020
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202000917
Subject(s) - chemistry , natural product , carbazole , product (mathematics) , stereochemistry , total synthesis , organic chemistry , mathematics , geometry
Clausenal (1,8‐dimethoxycarbazole‐3‐carbaldehyde) represents the only known naturally occurring 1,8‐dioxygenated carbazole alkaloid. However, the structural assignment for clausenal has recently been questioned because of some discrepancies between a synthetic sample and the natural product with respect to NMR data and melting points. Therefore, we have synthesized clausenal as well as two potential structural alternatives (1,5‐dimethoxycarbazole‐3‐carbaldehyde and 2,5‐dimethoxycarbazole‐3‐carbaldehyde) and compared their spectroscopic data with those reported for the isolated natural product. In conclusion from our investigation, we assume that the original structural assignment reported for clausenal most likely is correct.