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Synthesis of vinca alkaloids and related compounds, 73. Synthesis and ring transformations of deethylaspidospermane derivatives. Synthesis of (±)‐20‐deethyl‐3‐oxotabersonine
Author(s) -
Kalaus György,
Juhász Imre,
Greiner István,
KajtárPeredy Mária,
Brlik János,
Szabó Lajos,
Szántay Csaba
Publication year - 1995
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.1995199507165
Subject(s) - chemistry , vinca , epimer , ring (chemistry) , stereochemistry , organic chemistry , botany , biology
The reaction of the key compound 14 with methyl 4‐formyl‐butanoate ( 9 ) or with 5‐benzoyloxypentanal ( 13 ) gave the D‐ seco ‐aspidospermane derivatives 17 and 18 , respectively. Compound 17 was indirectly and 18 was directly converted to (±)‐20‐deethylvincadifformine ( 7 ) and (±)‐20‐deethyl‐20‐epivincadifformine ( 8 ). Epimerization occurred in both cases. The thioxo compound 23 was used for the synthesis of (±)‐20‐deethyltabersonine ( 28 ) and (±)‐20‐deethyl‐3‐oxotabersonine ( 27 ). Oxidative ring transformation of the (±)‐20‐deethylvincadifformine ( 7 ) gave (±)‐16‐deethylapovincamine ( 29 ).