S. Ya. Panchishin

Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives

A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4-dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.

Synthesis of 2-phenyl-5,6-dihydropyrano[2,3-c]pyrrole-4,7-dione derivatives

Pyrano[2,3-c]pyrroles constitute a poorly explored class of fused heterocyclic compounds. We have found only one publication where the synthesis of such compounds containing an alkoxycarbonyl or carboxy group in the 2-position has been described [1]. We have developed a new synthetic approach to pyrano [2,3-c]pyrrole-4,7-dione derivatives on the basis of methyl (E)-6-phenyl-2,4-dioxohex-5-enoate (I) [2]. By heating equimolar amounts of compound I, aromatic aldehyde IIa or IIb, and 2-aminothiazole (III) in glacial acetic acid for a short time we obtained the corresponding 5-aryl-3-hydroxy-4-(3-phenylprop-2enoyl)-1-(1,3-thiazol-2-yl)-1,5-dihydro-2H-pyrrol-2ones IVa and IVb in moderate yield. Compounds of type IV have been reported previously [3]. The structure of pyrroles IVa and IVb was confirmed by elemental analyses and IR and H NMR spectra. On heating in DMSO in the presence of a catalytic amount of iodine, compounds IVa and IVb underwent intramolecular cyclization to 5-aryl-2-phenyl-6-(1,3thiazol-2-yl)-5,6-dihydropyrano[2,3-c]pyrrole-4,7-diones Va and Vb, respectively. Such cyclization with formation of pyran ring is used in the chemistry of chromone [4, 5]. DOI: 10.1134/S1070363208080331

Alkylation of 4-(phenylthio)-1H-pyrazol-5-ols with methyl bromoacetate

Alkylation of 4-(phenylthio)-1H-pyrazol-5-ols with methyl bromoacetate has afforded a series of phenyl pyrazolyl sulfides which have been oxidized into sulfones. The resulting esters have been hydrolyzed into the corresponding acids. The synthesized compounds potentially exhibit biological activity.

Alkylation of 1-Alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with Halocarboxylic Acids Esters

A preparative method for the synthesis of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles was developed. The alkylation of the obtained compounds with halocarboxylic acid esters was also investigated. A principal possibility of creating libraries of compounds based on pyrazolo[4,3-c]pyrazole derivatives was shown.

Synthesis of 1,2-dihydrochromeno[2,3-c]pyrrole-3,9-diones spiro derivatives

Previously it was found that methyl o-hydroxybenzoylpyruvate was easily converted into 1,2-diaryl[1], 1-aryl-2-heteryl[2], or 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-diones [3]. Isatin and its N-alkyl derivatives are known to behave in many transformations like aromatic aldehydes. We found that the short-time heating of equimolar amounts of methyl ohydroxybenzoylpyruvate I, N-methylisatin II, and aliphatic amines IIIa, IIIb in methanol afford spiro derivatives of 3-hydroxy-3-pyrrolin-2-one IVa, IVb in high yield. This three-component cyclocondensation has been well studied [4], but isatin and its derivatives have not been used as carbonyl components. Pyrrole derivatives IV possess acidic properties and form adducts with aliphatic amines. Compound IVb exists as an internal salt. Similar adducts with monoethanolamine were described [5].

Phosphonium Ylides Stabilized with Cyano Group and 5-Acylamino-4-phenyl-2-thiazolyl Residue

Available ylide reagent Ph3P = C(CN)C(S)NH2 readily enters cyclocondensation with N-(chlorophenacyl)benzamide and its analogs. By this route were prepared new stabilized phosphonium ylides containing cyano group and the corresponding 5-acylamino-4-phenyl-2-thiazolyl fragment. All these compounds even under standard conditions are dephosphorylated under the action of hydrogen chloride in acetic acid to form 5-acylamino-4-phenyl-2-cyanomethylthiazoles in high yields. Their structure was proved by spectroscopic studies and independent synthesis.