Halogenatedp-quinols of marine sponges. Synthesis via anodic oxidation of phenols and NHI-like rearrangement
摘要:
Oxidation of either 2,6-dibromo- (1), 2-bromo- (3), or 2-bromo-6-chloro-p-acetamidophenol (5) at a Pt anode in aq. HClO4 affords the corresponding common, 2, or rare, 4 and 6, marine halo-p-quinols in practicable yields, whereas literature recipes as to either chemical or electrochemical oxidations proved to be ineffective; these halo-p-quinols proved to be extremely alkali-labile, in part due to a NHI-like rearrangement.
Addition of functionalized organolithium reagents to p-benzoquinones and cyclohexadienones: synthesis of functionalized cyclohexadienones, dienols and dienediols
作者:Alfred Fischer、George Narayanan Henderson
DOI:10.1016/s0040-4039(00)81347-7
日期:1983.1
Low temperature addition of functionalized alkyllithium reagents to p-benzoquinones produces 4-alkyl-4-hydroxycyclohexa-2,5-dienones, and reaction of excess of the reagents with quinones yields 1,4-dialkylcyclohexa-2,5-diene-1,4-diols. With 4-acetoxy-, 4-hydroxy-, and 4-methoxy-4-methylcyclohexa-2,5-dienones the corresponding dienols are obtained. A one-step synthesis of the antibiotics 4-acetamido-
Dibromotyrosine derivatives from the ethanol extract of the marine sponge Aplysina sp.: structures, transformations, and origin
作者:E. A. Santalova、V. A. Denisenko、V. P. Glazunov、A. I. Kalinovskii、S. D. Anastyuk、V. A. Stonik
DOI:10.1007/s11172-011-0088-9
日期:2011.3
Twenty nine 3,5-dibromotyrosine derivatives were isolated from the ethanol extract of the marine sponge Aplysina sp. (South China Sea) including the earlier unknown compounds, in particular, p-hydroxycyclohexadienone and p-hydroxycyclohexenone ketals. The isolated enones, dienones, and ketals can be transformation products of aeroplysinin-1 in the course of its reactions with water and alcohols.