Spyros Spyroudis

Hydroxyquinones: Synthesis and Reactivity

Quinones having hydroxy groups directly attached to the quinone ring constitute a very interesting class of quinoid compounds. A great number of hydroxyquinones are found in nature and the majority of them exhibit unique biological activity. Their syntheses and their main reactivity patterns are reviewed in this paper.

A Convenient Approach to Fused Indeno-1,4-diazepinones through Hypervalent Iodine Chemistry

Indenocarboxamides, resulting from the sequential addition of two arylamine equivalents to indanedione ketene dimer, are oxidized by [bis(trifluoroacetoxy)iodobenzene] to fused indeno-1,4-diazepinones in yields depending on the substituents on both aromatic rings. A plausible reaction pathway explaining the formation of the title compounds, as well as the formation of the two other minor products of the reaction, through a common intermediate, is suggested.

The chemistry of 2-oxido-3-phenyliodonio-1,4-benzoquinones: Transformation to 2-cyclopentene-1,4-diones and cycloadditions

The conversion of substituted 2-hydroxy-1,4-benzoquinones, 1, to 2-cyclopentene-1,4-diones, 3, is effected by thermolysis of their iodonium zwitterions, 2. Some cycloadditions through 2 are also described.

Phenyliodoniophenolates from 1,3-dihydroxybenzene derivatives

Abstract A new type of phenyliodonio phenolates resulting from the reaction of 1,3-dihydroxy benzene derivatives and (diacetoxyiodo)benzene were isolated and characterized. The new phenolates afforded cyclization products from their photochemical reaction with alkenes and alkynes and phenyl ethers from their thermal rearrangement. A possible reaction pathway is proposed in order to explain the regioselectivity of these reactions.

Novel trifluoroethyliodonium salts from cyclic enaminones and their thermal decomposition

Abstract Upon reaction of 1-[hydroxy(tosyloxy)iodo]-2,2,2-trifluoroethane with cyclic enaminones, stable iodonium tosylates are obtained. Their mild thermolysis provides iodoenaminones and 2,2,2-trifluoroethyl tosylate.

ARYLIODONIUM DERIVATIVES OF 2-AMINO-1,4-QUINONES : PREPARATION AND REACTIVITY

Abstract The reaction of 2-amino-1,4-quinones with [(hydroxy)(tosyloxy)iodo]arenes affords stable 2-amino-3-aryliodonio-1,4-quinones in high yields. The latter, upon treatment with alkali, are converted to the corresponding zwitterionic 3-aryliodonio-1,4-quinone-2-imides. This new class of compounds exhibits an interesting reactivity: upon heating, aryl migration from iodine to nitrogen is observed, while photochemical reaction with aromatic compounds and 2,3-dihydrofuran leads to substitution products. Nucleophilic attack of sodium alkoxides on these zwitterions results in opening of the quinone ring affording synthetically interesting multifunctional products.

3-Aryliodonio-1,4-naphthoquinone-2-imides: A new class of aryliodonium 1,4 dipoles

Abstract The synthesis of a new class of zwitterionic aryliodonium compounds from 2-amino-1,4-naphthoquinone and [(hydroxy) (tosyloxy)iodo]arenes is described. These dipoles exhibit an interesting reactivity under thermal and photochemical conditions.

Reactivity of a new alkenyl phenyliodonium tosylate derived from methyl 3-aminocrotonate

Abstract Methyl 3-aminocrotonate reacts with [hydroxy(tosyloxy)iodo]benzene to afford the corresponding E-2-phenyliodonio tosylate in good yield. This new alkenyl iodonium salt upon reaction with various nucleophiles offers an easy access to substituted enamine derivatives of crotonic acid. The reaction can be also extended to N-substituted crotonates.

Cyclisation of tryptamine enaminones to functionalised tetrahydro-β-carbolines induced by [bis(trifluoroacetoxy)iodo] benzene

The reaction of enamino carbonyl derivatives of tryptamine with [bis(trifluoroacetoxy)iodo]benzene provides an easy route to 1,1-bis-functionalised-N-trifluoroacetylated-β-carbolines. The reaction proceeds through Pictet-Spengler-type cyclisation, trifluoroacetylation and oxidation steps.

The reaction of triptycene haloquinones with alkoxides. An unusual route to pentiptycene quinones

Abstract Triptycene haloquinones 3 react with sodium alkoxides in refluxing alcohol to afford, besides the expected substitution products, pentiptycene quinone 4 . This approach to 4 is compared with a Diels–Alder strategy to the same compound.