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Synthese der Spermidin‐Alkaloide (±)‐Inandenin‐10‐ol, Inandenin‐10‐on und (±)‐Oncinotin
Author(s) -
Bienz Stefan,
Guggisberg Armin,
Wälchli Rudolf,
Hesse Manfred
Publication year - 1988
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19880710718
Subject(s) - chemistry , yield (engineering) , ring (chemistry) , amination , reductive amination , derivative (finance) , reagent , hydrazine (antidepressant) , spermidine , stereochemistry , aldehyde , medicinal chemistry , organic chemistry , catalysis , materials science , chromatography , economics , financial economics , metallurgy , enzyme
Syntheses of the Spermidine Alkaloids (±)‐Inandenin‐10‐ol, Inandenin‐10‐one, and (±)‐Oncinotine New syntheses of the title compounds using two‐ring‐enlargement reactions are described. Starting from the aldehyde 1 , the corresponding 4′‐aza derivative 15 could be obtained by reductive amination with the appropriate and protected spermidine derivative 14 ( Scheme 4 ). Enlargement of the carbocyclic ring in 15 by five members gave, after further transformations, the hydroxylactam 18 . Transamidation of 18 , the second ring‐enlargement step, led to (±)‐inandenin‐10‐ol (7;22.9% overall yield) and, after oxidation, to inandenin‐10‐one ( 8 ; 22.5%, overall yield). (±)‐Oncinotine 6 was synthesized by two pathways ( Scheme 6 ): protection of the terminal NH 2 group by treatment with the Nefkens reagent and replacement of the OH group by Cl gave 24 , which by thermal transamidation followed by direct ring closure led to the oncinotine derivative 26 . The same intermediate could be obtained in higher yield via 28 by oxidation and protection of 18 followed by transamidation and reductive ring closure. Treatment of 26 with hydrazine finally gave (±)‐oncinotine 6 in 15.9% overall yield.