Synthese von N‐(4‐Aminobutyl)‐16‐aza‐19‐nonadecanlactam und N‐(4‐Aminobutyl)‐17‐aza‐20‐icosanlactam (Desoxoinandenin)

Abstract

Synthesis of N-(CAminobutyl)-16-aza-lPnonadecanelactam and N-(4-Aminobutyl)-17-aza-20-icosanelactam(Desoxoinandenine) SummaryAccording to Scheme I , the two homologous macrocyclic spermidine derivatives 12 and 23 were synthesized. Key steps in both cases were two different types of ring-enlargement reactions. Compound 12 was identical with a degradation product of the naturally occurring spermidine alkaloids of inandenine-type.

Cascade ring expansion reactions for the synthesis of medium-sized rings and macrocycles

“…Ring expansion reactions have enthralled synthetic organic chemists for decades. The eponymous ring expansion methods developed in the groups of Grob 1 and Eschenmoser 2 are arguably the most well-known, and these methods, alongside seminal studies by Hesse, 3 Cookson 4 and many others 5 occupy prominent places in the annals of organic chemistry. One of the major appeals of ring expansion methods is their ability to enable non-obvious retrosynthetic disconnections through controlled rearrangement reactions.…”

A Novel NO2/OH Exchange in α‐Nitro Ketones: A mechanistic investigation

“…In particular, a-nitro cycloalkanones have been thoroughly studied as substrates for the preparation of ring-enlarged carbocycles, lactones, and lactams. They have been used for the synthesis of the ketone fragrances (+)-muscone and E.ualtone~"' [3] [4], the lactones phoracantholide I (racemic [5] and enantiomerically enriched [6]), ( f )-dihydrorecifeiolide and (*)-I 5-hexadecanolide [5], the lactone antibiotic A 26771 B [7], the macrocyclic spermidine alkaloids ( + )-inandenin-10-01, inandenin-10-one, and (f)-oncinotine [S], and analogs thereof [9], and for the preparation of other macrocyclic frameworks such as cyclophanes [lo-121 or benzolactones [13]. Two different ring-enlargement types have been applied in these investigations : the ZIP reaction that incorporates the side chains of a-substituted a-nitro ketones 1 into the ring (7j,pe A , Scheme I ) and the ring-enlargement reaction that cleaves the one-atom bridge of bicyclic a-nitro ketones 4 (Type B, Scheme I).…”