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[3+2]-Dipolar cycloaddition of diarylnitrones to substituted pyrroloquinoxalinetriones afforded (2aS*,3R*,5aS*)-2a-acyl-3,4-diaryl-3,4-dihydro-1H-[1,2]oxazolo[5′,4′:2,3]pyrrolo[1,2-a]quinoxaline-1,2,6(2aH,7H)-triones that attract interest for medicinal chemistry. [ABSTRACT FROM AUTHOR]

Thermally induced [4 + 2]-cycloaddition of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones with alkyl vinyl ethers afforded mixtures of diastereoisomeric (5S*,6aR*)- and (5R*,6aR*)-5-alkoxy-3-aryl-5,6-dihydropyrano[ 4′,3′: 2,3]pyrrolo[1,2-a]quinoxaline-1,2,7(8H)-triones. [ABSTRACT FROM AUTHOR]

[4 + 2]-Cycloaddition of vinyl acetate to 3-aroylpyrrolo[2,1- c][1,4]benzoxazine-1,2,4-triones afforded (10 R*,11a R*)-8-aryl-6,7,12-trioxo-6,7,10,11-tetrahydropyrano[4′,3′:2,3]pyrrolo[2,1- c][1,4]benzoxazin-10-yl acetates with high diastereoselectivity. [ABSTRACT FROM AUTHOR]

Methyl 3-aroyl-1-aryl-4,5-dioxo-4,5-dihydro-1 H-pyrrole-2-carboxylates reacted with styrene and butyl vinyl ether to give 6-substituted methyl (6 R*,7a R*)-1,4-diaryl-2,3-dioxo-1,2,3,6,7,7a-hexahydropyrano-[4,3- b]pyrrole-7a-carboxylates whose structure was confirmed by X-ray analysis. [ABSTRACT FROM AUTHOR]

3-Aroyl-1 H-pyrrolo[2,1- c][1,4]benzoxazine-1,2,4-triones reacted with alkyl vinyl ethers according to the [4 + 2]-cycloaddition pattern with formation of substituted (1 S*,16 R*)- and (1 R*,16 R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadeca-4,6,8,13-tetraene-2,11,12-triones. The structure of (1 S*,16 R*)-7-chloro-16-ethoxy-14-phenyl-3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadeca-4,6,8,13-tetraene-2,11,12-trione was determined by X-ray analysis. A new synthetic approach was developed to heteroanalogs of 13(14→8)-abeo steroids, substituted 3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadecanes. [ABSTRACT FROM AUTHOR]

[4 + 2]-Cycloaddition of 3-aroylpyrrolo[2,1- c][1,4]benzoxazine-1,2,4(4 H)-triones to alkyl vinyl ethers gave substituted stereoisomeric (1 R*,16 R*)- and (1 S*,16 R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetracyclo[8.7.0.0.0]heptadeca-4,6,8,13-tetraene-2,11,12-triones. [ABSTRACT FROM AUTHOR]

The article discusses butyl vinyl ether [4 + 2]- cycloaddition with 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones. Topics include formation of cycloadducts through thermally initiated [4 + 2]-cycloaddition, synthesis of 16-butoxy-14-(4-chlorophenyl)-15-oxa-3,10-diazatetracyclo[ 8.7.0.01,13.04,9]heptadeca-4,6,8,13- tetraene-2,11,12-trione (2b), and measuring of proton nuclear magnetic resonance (H NMR) spectra using tetramethylsilane.

The article discusses a study of two concurrent pathways in 3-benzoylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-trione reaction with 3,4-dihydro-2H-pyran. Topics include formation of the compounds through thermally induced pyran [4 + 2]-cycloaddition to triketone conjugated bond sequence, measuring the proton nuclear magnetic resonance (H NMR) spectra using tetramethylsilane, and elemental analyses.

The article presents a study on the cycloaddition of styrene to aroylpyrrolo benzoxazine triones and its reactions. The reaction of styrene to aroylpyrrolo benzoxazine triones as heterodienes with alkyl vinyl ethers is reported. The isolated compounds' purity are examined on Silufol plates with benzene-ethyl acetate as eluent.

The article reports on the findings a study which examined the reaction of 3-aroylpyrrolo [2,1-c][1,4] benzoxazine-1,2,4-triones Ia and Ib with alkyl vinyl ethers IIa and IIb at a ratio of 1:5 in boiling benzene. The study, which was performed under financial support by the Russian Foundation for Basic Research, revealed the formation of compounds IIIa and IIIb via thermally induced [4 + 2]-cycloaddition involving the O=C-C3=C3a conjugated bond system.