Розглянуто праці, які стосуються способів одержання похідних ізокумарину та їхніх 3,4-дигідроаналогів. Обговорено синтетичні можливості і практичне застосування різних методів.
Ключові слова: ізокумарини, 3,4-дигідроізокумарини, синтез.
The paper reviews methods of isocoumarins and 3,4-dihydroisocoumarins synthesis. These compounds are
important class of organic compounds that are widespread in nature and exhibit a wide spectrum of biological
activity. Isocoumarins often are synthetic precursors of isoquinoline alkaloids. Analysis of literature data
shows that there are several basic approaches to designing of isocoumarins skeleton. The most of them are
based on using of homophthalic acid derivatives in various types of condensation reactions. Diene synthesis
and different catalytic reactions (transition metal catalysis, organometalic reagents, etc.) are also useful to the
isocoumarins rings construction.
Condensation of homophthalic acid derivatives, such as esters, nitriles, anhydride, with carbonyl
compounds were used in various types of the reactions (e.g. Shtobbe, Claisen, Perkin, types), due to the reactivity
of the CH2 group. Carbonyl components in this synthesis were aldehydes, ketones, esters of formic and
oxalic acids, aromatic anhydrides. Acylation of homophthalic acid derivatives by the various acyl chloride are
general synthetical method of isocoumarins ring constraction. Homophthalic acid are also utilized for the
synthesis of 3,4-dyhidroisocoumarins through oxidation to isochromans. Oxidants utilized in this reaction are
CrO3, HNO3, O2, dymethyldioxyran (DMD), systems of SeO2/xylene and KMnO4/acetone.
In addition, spontaneous or initiated by various reagents cyclizations of 2-carboxybenzyl ketones are
convenient method for synthesis of a 3-isocoumarins. Mineral acids, Lewis acids, sodium acetate, LDA in THF
are catalysts of in these reactions. If ketogroup was reduced to the hydroxyl, the substituted 3,4-dyhidroisocoumarins
may be obtained by the intramolecular etherification.
2-Vinylbenzoic acid under the action of concentrated mineral acids, peroxide compounds or reactions
halolactonization gives either γ-lactones or δ-lactones. Formation of different lactones, or its mixtures are determined by steric and electronic factors. Direction of lactonization depends on the center of the lowest
electronic density.
Using of organometalic reagents and transition metal complexes are a convenient method of synthesis of
acyclic isocoumarins precursors. Although organometalic reagents and catalysts are effective in this synthesis,
but using of special conditions (low temperature, high purity solvents, etc.) causes some complications.
Diels-Alder [4+2]-cycloaddition are convenient method for obtaining of isocoumarin precursors. This
reaction is especially often used when it is necessary to reproduce the natural structure of isocoumarins.
We also described the utilizing of diazonium salts, obtained from anthranylic acid derivatives in synthesis
of isocoumarins.
Keywords: isocoumarins, 3,4-dihydroisocoumarins, synthesis.
Рассмотрено работы, касающиеся способов получения производных изокумарина и их 3,4-дигидроаналогов. Обсуждено синтетические возможности и практическое применение различных методов.
Ключевые слова: изокумарины, 3,4-дигидроизокумарины, синтез.
