Chiroptical Properties of the Protoverbine Class of Macrocyclic Spermine Alkaloids
作者:Konstantin Drandarov、Armin Guggisberg、Anthony Linden、Manfred Hesse
DOI:10.1002/(sici)1522-2675(19981007)81:10<1773::aid-hlca1773>3.0.co;2-x
日期:1998.10.7
The chiroptical properties (circular dichroism, CD) of the 17-membered macrocyclic spermine lactam alkaloids (-)-protoverbine (16), its N,N'-methylene-bridged natural analogue (+)-protomethine (17), their natural derivatives (-)-verbacine (1), (-)-verballocine (2), (-)-verbascenine (3), (-)-verballoscenine (4), (+) verbamethine (5), (+)-incasine C (6), (+)-verdoline (incasine B', 30), (+)-incasine B (31), and some of their isosteric analogues were studied. By chemical and chiroptical correlation, it was confirmed that an amidically bonded (S)-beta-phenyl-beta-alanine fragment forms the chiral moiety in all of these natural compounds The signs of the registered Cotton effects (CEs) are interpreted in terms of the Smith's quadrant rule for the L-1(b) CEs of chiral a-substituted benzylamines and the Ogura's sign rule for n --> pi* CEs of lactams. Some of the conclusions regarding configuration are supported for the rigid bicyclic compound (-)-(9S)-9-phenyl-1,6-diazabicyclo[4.3.1]decan-7-one (15) by the X-ray crystal structure of the racemate.