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Synthesis of the Macrocyclic Spermidine Alkaloid (±)‐(2 R *,3 R *)‐3‐Hydroxycelacinnine
Author(s) -
Khanjin Nikolai A.,
Hesse Manfred
Publication year - 2001
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 - 10.1002/1522-2675(20010613)84:6<1253::aid-hlca1253>3.0.co;2-u
Subject(s) - chemistry , stereochemistry , moiety , azide , epimer , heteronuclear single quantum coherence spectroscopy , stereoselectivity , carbon 13 nmr , alkaloid , proton nmr , nuclear magnetic resonance spectroscopy , organic chemistry , catalysis
The macrocyclic lactam alkaloid (±)‐(2 R *,3 R *)‐3‐hydroxycelacinnine ( 1 ) derived from spermidine was synthesized via stereoselective epoxide‐ring opening with magnesium azide and cesium carbonate promoted macrocyclization of the ditosylated diamino precursor 12 with 1,4‐dibromobutane in the two key steps ( Scheme 2 ). 1 H‐ and 13 C‐NMR Signal assignments from COSY, HSQC, and HMBC 2D NMR data of the synthesized 1 were compared with the earlier‐described data of the natural 3‐hydroxycelacinnine. The similarity of their 13 C‐NMR spectra point to the correctness of the proposed constitutional formula for natural 3‐hydroxycelacinnine; however, different 1 H‐NMR chemical shifts and coupling constants ( J (2,3)=9.0 vs . 1.2 Hz, resp.) in the α ‐hydroxy‐ β ‐amino lactam moiety suggest that natural 3‐hydroxycelacinnine is the 2,3‐ cis ‐epimer of one synthetic (±)‐ 1 .