Natural diaryl ethers
In this review, on the basis of an analysis of voluminous literature material on natural phenolic compounds belonging to various structural types, the interrelationship between the dimeric molecules formed as the result of the oxidative coupling of the corresponding monomeric compounds is considered.
Structure of the lichen depsidone gangaleoidin
As a result of degradative, spectroscopic, and synthetic evidence the structure of the lichen depsidone gangaleoidin is revised to methyl 2,4-dichloro-3-hydroxy-8-methoxy-1,6-dimethyl-11-oxo-11H-dibenzo [b,e][1,4]dioxepin-7-carboxylate. Gangaleoidin was degraded to methyl 3-(2-methoxycarbonyl-5-methoxy-3-methylphenoxy)-4,6-dimethoxy-2-methylbenzoate (10), which was synthesised in 70% yield by Ullmann reaction between methyl 2-bromo-4-methoxy-6-methylbenzoate (22) and methyl 3-hydroxy-4,6-dimethoxy-2-methylbenzoate (30). The bromination of methyl dihydro-orsellinate(23) was studied.
Reaktionen cyclischer Oxonium‐Ionen mit nucleophilen Partnern
Es werden Flavylium-, Xanthylium- und 2.6-Diphenyl-pyryliumkationen mit CH-aciden Verbindungen umgesetzt. Die Konstitution der entstehenden Produkte wird erortert. Sie haben kaum salzartigen Charakter und lassen sich zu farbigen Dehydrobasen dehydrieren.