Chemical constituents of Avicennia alba. Isolation and structural elucidation of new naphthoquinones and their analogues.
Three new naphthoquinones and their analogues, named avicequinone-A (1), -B (2), -C (3), and avicenol-A (4), -B (5), -C (6), respectively, were isolated from the stem bark of Avicennia alba (Avicenniaceae) collected in Singapore, and their structures were elucidated by means of spectral methods. Gillan and co-workers have proposed that the structures of the new phytoalexins isolated from Avicennia marina are 1,2-naphthoquinones 8 and 9. Our synthetic and spectrometric studies showed that these structures should be revised respectively to 1,4-naphthoquinones 2 and 3, named avicequinone-B and -C by us.
Ito
C
C
Faculty of Pharmacy, Meijo University, Nagoya, Japan.
Katsuno
S
S
Kondo
Y
Y
Tan
H T
HT
Furukawa
H
H
D009682:Magnetic Resonance Spectroscopy; D009285:Naphthoquinones / Q000737:chemistry / Q000302:isolation & purification*; D019441:Plant Epidermis / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
D009285:Naphthoquinones; C008252:lapachol