Aromatic alkaloids from the marine sponge Chelonaplysilla sp
摘要:
Four novel alkaloids derived from tryptophan and tyrosine subunits have been isolated from the marine sponge Chelonaplysilla sp. collected from a marine lake in Palau. The structures of chelonin A (3), chelonin B (4), bromochelonin B (5), and chelonin C (6) were determined by interpretation of spectral data and chemical conversions. Chelonin A (3) and C (6) are the first natural products incorporating a 2,6-disubstituted morpholine ring. Chelonin A (3), chelonin B (4), and bromochelonin B (5) exhibited antimicrobial activity against Bacillus subtilis, while chelonin A (3) showed in vivo antiinflammatory activity.
The asymmetric synthesis and stereochemical assignment of chelonin B
摘要:
The first total synthesis of the marine natural product (S)-(+)-chelonin B is described. The key reactions employed include Sharpless asymmetric dihydroxylation of a styrene derivative, catalytic ring-opening of an epoxide and sequential deprotection-rearrangement of a phthalimido indole acetate. (C) 2001 Elsevier Science Ltd. All rights reserved.