Premium
Umamidierungsreaktionen an cyclischen Amino‐amid‐Systemen . 3. Mitteilung über Umamidierungsreaktionen
Author(s) -
Guggisberg Armin,
Kramer Urs,
Heidelberger Christian,
Charubala Ramamurty,
Stephanou Euripides,
Hesse Manfred,
Schmid Hans
Publication year - 1978
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.19780610315
Subject(s) - chemistry , ring (chemistry) , yield (engineering) , nitrogen atom , catalysis , stereochemistry , derivative (finance) , medicinal chemistry , organic chemistry , materials science , economics , financial economics , metallurgy
Transamidation Reactions with Cyclic Amino‐amides Lactames which are substituted at the nitrogen atom by a 3‐aminopropyl residue are transformed under base catalysis to cyclic amino‐amides enlarged by 4 ring atoms. The formed ring must be at minimum 12‐membered. Scheme 2 illustrates this result: the 8‐membered 7 is transamidated in 96% yield to the 12‐membered ring 8 (in the presence of potassium 3‐aminopropylamid in 1, 3‐propanediamine), the 9‐membered 10 to the 13‐membered ring 11 (97%) and the 11‐membered 14 to the 15‐membered ring 15 . Furthermore, the 13‐membered ring 27 ( Scheme 5 ) is transformed to the 17‐membered 28 . In the case of the 15‐membered lactame 15 it is demonstrated that 14 is not formed back under the conditions of the transamidation. Large ring lactames which are substituted at the nitrogen atom by a 3‐(alkylamino) propyl group lead under base catalysis to an equilibrium mixture, e.g. the 17‐membered 26 is in equilibrium with the 21‐membered 29 . This result is similar to the behavior of the corresponding open‐chain amino‐amides [2]. Because of transannular interactions, the 11‐membered ring 2 is not stable: transamidation of the 7‐membered 1 ( Scheme 1 ) doesn't give the expected 2 , but its water elimination product 3 in small yield. The N ‐tosyl derivative of 2 , namely 20 , is synthesized by an independent route ( Scheme 3 ). Detosylation of 20 yields the 7‐membered 1 instead of 2 . Concerning the mechanism of this interesting reaction see Scheme 4 .