Synthesis and Absolute Configuration of Zonarol. A Fungitoxic Hydroquinone from the Brown Seaweed Dictyoptfris Zonarioides⁽¹⁾

Abstract

A total synthesis of both the enantiomers of zonarol 1 was accomplished. Measurements of the ORD-CD spectra of two bicyclic intermediates coupled with direct comparison of the natural and synthetic zonarol 1 established the absolute configuration of the naturally occurring (+)-zonarol 1 as Ig, 4ag, 8aR.In 1973, Fenical, g &. reported the isolation of fungitoxic hydroquinones zonarol 1 and isozonarol 2 from the brown seaweed Dictyopteris zonarioides (Fig.

Zonarol, a sesquiterpene from the brown algae Dictyopteris undulata , provides neuroprotection by activating the Nrf2/ARE pathway

“…Originally, this sesquiterpene hydroquinone from Dictyopteris undulata had been reported to be a fungitoxic compound by Fenical and Cimino in the 1970's [5]. Subsequently, the chemical structure of the hydroquinone was elucidated in 1986 [6]. In a prior study, we described the protective role of ZO against dextran sodium sulfate-induced colon injury in young male Slc:ICR mice, representing a murine model of the inflammatory bowel disease, ulcerative colitis [7].…”

Marine Hydroquinone Zonarol Prevents Inflammation and Apoptosis in Dextran Sulfate Sodium-Induced Mice Ulcerative Colitis

“…Originally, this sesquiterpene hydroquinone had been reported as a fungitoxic compound by Fenical and Cimino in the 1970's, and had been derived from Dictyopteris zonarioides (synonymous with Dictyopteris undulata ) [14] , [15] . The absolute chemical structure of the sesquiterpene was elucidated in 1986 [16] . Other pharmacological actions of zonarol have been reported, such as antioxidant effects [17] , phospholipase inhibition [18] , feeding deterrents against abalone [19] and algicidal effects [20] .…”

Recent Advances in the Syntheses of Decalin Type Natural Products

“…Wittig reaction of (10R)-57 with phosphonium salt in the presence of n-BuLi afforded the exo-olefin (10R)-58 (73% yield) whose spectral data were identical with those of the reported olefin (10R)-58. 19 Total synthesis of (+)-zonarol (59) from (10R)-58 has been already achieved. 19 …”

“…The former type natural products could be synthesized from natural source such as l-abietic acid (3) or (+)-sclareolide (4), while the latter type natural products could be derived from natural source such as (-)-copalic acid (5). In the course of our studies on the chemical conversion of l-abietic acid (3) to optically active natural products, 3 ozonolysis of phenolic compounds [11,12-dihydroxy dehydroabietane (7), 4 ferruginol (8), 4 13-hydroxy-13-deisopropyldehydroabietane (9), 4 14-hydroxydehydroabietane (10), 4 and 6,14dihydroxydehydroabietane (11) 5 ] derived from dehydroabietic acid (6) followed by reduction or/and oxidation with the appropriate reagent afforded (+)-isodrimenin (12), 5,6 pentanorlabdane type compound (13), 5,6 (+)-pallescensin A (14), 5,6 (+)-confertifolin (15), 5,6 (+)-valdiviolide (16), 5,6 (+)-winterin (17), 5,6 (+)-fragrolide (18), 5,7 and (+)-bemadienolide (19), 5,7 respectively, as shown in Scheme 2. (+)-isodrimenin (12) pentanorlabdane type compound (13) (+)-pallescensin A (14) (+)-confertifolin (15) (+)-validiviolide (16) (+)-winterin (17) (+)-fragrolide (18) (+)-bemadienolide (19) l-abietic acid (3) H CO 2 H (-)-copalic acid …”