Investigation of the Interaction of 5-Aryl-2,3-dihydro-2,3-furandiones with Compounds Containing C=N and C≡N Bonds Simultaneously

Aroylketenes, generated by the thermolysis of 5-aryl-2,3-dihydro-2,3-furandiones, react with S-methyl-N-cyano-N′-phenylisothiourea, N-cyano-N′,N′-dimethylformamidine, and N,N-bis(β-cyanoethyl)-cyanamide with the formation of 6-aryl-2-[(methylthio)(phenylamino)methylene]amino-, 6-aryl-2-dimethylaminomethyleneamino-, and 6-aryl-2-[N,N-bis(β-cyanoethyl)amino]-4H-1,3-oxazin-4-ones respectively. Modeling has been carried out of the interaction of benzoylketene with the indicated cyano compounds by the SSP MO LCAO semiempirical method using the MNDO-PM3 approach. A mechanism is proposed for the formation of substituted 4H-1,3-oxazin-4-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1490–1501, October, 2005.     

Chemistry of oxalyl derivatives of methyl ketones. 40. Reaction of 5-aryl-2,3-dihydro-2,3-furandiones with aryl and aroyl cyanamides

Starting from 5-aryl-2,3-dihydro-2,3-furandiones and benzoyl cyanamide, 2-benzoylamino-6-aryl-1,3-oxazin-4-ones were obtained. It was shown that on reaction of o-chlorophenyl cyanamide with furandiones, 2-imino-3-(o-chlorophenyl)-5-phenacyliden-4-oxazolidones are formed which in acid medium rearrange to 3-(o-chlorophenyl)-5-phenacylideneimidazolidin-2,4-diones and on thermolysis in acid medium they form 2-(o-chloroanilino)-6-aryl-1,3-oxazin-4-ones.For Communication 39, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 166–169, February, 1985.     

Novel salicylaldehyde-based mineral-supported expeditious synthesis of benzoxazin-2-ones

One-pot montmorillonite K-10 clay supported reactions of either salicylaldehyde/2-hydroxyacetophenone hydrazones and aryl-/alkylureas or salicylaldehydes/2-hydroxyacetophenone and 4-aryl-/alkylsemicarbazides expeditiously yield 3,4-dihydro-4-hydrazino-2H-benz[e]-1,3-oxazin-2-ones (9) via cycloisomerization of the intermediate salicylaldehyde/2-hydroxyacetophenone 4-aryl-/alkylsemicarbazones (5) under solvent-free microwave irradiation. Under the same conditions, hydrazines (9) readily underwent reductive dehydrazination on alumina-supported copper(II) sulfate to furnish 2H-benz[e]-1,3-oxazin-2-ones (10).     

5-Acyl-4-amino-2-phenyl-1,3-oxazin-6-ones

Intramolecular cyclization of acyl(ethoxycarbonyl)keteneN-benzoylaminals in boiling Ph₂O gives 5-acyl-4-amino-2-phenyl-1,3-oxazin-6-ones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1322–1323, July, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08964).     

Optically active 4-amino-4-aryl-5,5,5-trifluoropentan-2-ones: Versatile reagents for synthesis of chiral 4-trifluoromethyl-3,4-dihydroazin-2-ones

A cyclocondensation of disubstituted (thio)ureas and isocyanates derived from enantiomerically enriched 4-amino-4-aryl-5,5,5-trifluoropentan-2-ones affords a novel synthetic access to chiral 4-trifluoromethyl-substituted 3,4-dihydropyrimidin-2(1H)-(thi)ones and 3,4-dihydro-1,3-oxazin-2-ones, respectively.     

Reaction of 6-aryl-2,2-dimethyl-1,3-dioxin-4-ones with cyanoamino compounds

Aroylketenes have been generated by thermolysis of 6-aryl-2,2-dimethyl-1,3-dioxin-4-ones. They take part in a 1,4-cycloaddition reaction at the CN bond of N-aryl or N,N-dialkyl-N-cyanoamines and of N'-phenyl-N-cyanoguanidine to form the corresponding 2-N-aryl-amino, 2-N,N-dialkylamino, and 2-N-phenylguanidino-6-aryl-1,3-oxazin-4-ones. p-Aminobenzonitrile and cyanoacetamide are acylated by aroylketenes to form the p-cyanophenylamide of p-toluylacetic acid and the cyano-acetamide of benzoylacetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1265–1268, September, 1989.     

Novel Synthesis of Acylaminomethylene Meldrum's Acids and Their Thermolysis to 4-Methylthio-and 4-Amino-2-aryl-6H-1,3-oxazin-6-ones

Bismethylthiomethylene Meldrum's acid reacts with amides in the presence of potassium hydroxide to afford methylthioacylaminomethylene Meldrum's acid 5. Aminolysis of 5 gives aminoacylaminomethylene Meldrum's acids 7. Thermolysis of 5 and 7 supplies a novel synthetic method of 4-methylthio- and 4-amino-2-aryl-6H-1,3-oxazin-6-ones.     

Cycloacylation of 3-oxo-3-R1-N-R2-propanethioamides by 3-aryl-2-propenoyl chlorides

The products of cyclocondensation of 3-oxo-3-R¹-N-R²-propanethioamides with 3-aryl-2-propenoyl chlorides in acetone in the presence of potassium carbonate are 5-acyl-1-aryl(alkyl)-4-aryl-6-thioxopiperidin-2-ones, 5-acyl-2-aryl-6-aryl(alkyl)amino-2,3-dihydro-4H-thiopyran-4-ones, and 2-acetonylidene-3,6-diaryl-5,6-dihydro-4H-1,3-thiazin-4-ones, the structure of which is proven by both spectral methods and chemical conversions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 623–628, April, 2006     

Five-Membered 2,3-Dioxo Heterocycles: XLVII. Reaction of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones with Compounds Containing C = N and C≡N Bonds

Thermal decarbonylation of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones gives rise to intermediate aroyl(phenyl)ketenes which react with nonactivated Schiff bases, N,N'-dicyclohexylcarbodiimide, and p-di-methylaminobenzonitrile according to the [4 + 2]-cycloaddition pattern with formation of 6-aryl-5-phenyl-4H-1,3-oxazin-4-ones. Reactions of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones with activated Schiff bases at a temperature below the thermolysis temperature lead to 4-aroyl-4-phenyltetrahydropyrrole-2,3-diones.     

Five-membered 2,3-dioxoheterocycles 3. The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with aliphatic and aromatic nitriles

On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with -aminoisobutyronitrile, o-aminobenzonitrile, and -anilinopropiononitrile, we obtained aroylpyruvic acid N-(1-methyl-1-cyanoethyl)-, N-(o-cyanophenyl)-, and N-phenyl-N-(cyanoethyl)-amides, respectively. On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with cyanoacetamide we obtained aroylacetic acid N-(cyanoacetyl)amides, while in the case of methyleneaminoacetonitrile and p-dimethylaminobenzonitrile we obtained (6-aryl-4-oxo-2,3-dihydro-1,3-oxazin-3-yl)acetonitriles and 2-(p-dimethylaminophenyl)-6-aryl-1,3-oxazine-4-ones, respectively.For Communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 740–743, June, 1987.     

Novel cobalt-catalyzed carbonylation of 2-aryl-2-oxazolines

Catalytic ring-expanding carbonylation of 2-aryl-2-oxazolines is reported as a novel method for the synthesis of 4,5-dihydro-1,3-oxazin-6-ones. Various observations suggest the involvement of cobalt radicals as the catalytically active species. [reaction: see text]     

Reactions of β-aroylacrylic acids with 2-aminophenols

3,4-Dihydrobenzo-1,4-oxazin-2-ones were obtained from the corresponding β-aroylacrylic acids and 2-aminophenols. With 2-amino-4(5)-nitrophenols, stable intermediate β-amino adducts (4-aryl-4-oxobutyric acid derivatives) were isolated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1018–1021, June, 2006.     

Reactions of 2-alkylsulfanyl- and 2-alkoxy-4-hydroxy-6<Emphasis Type="Italic">H</Emphasis>-1,3-oxazin-6-ones with O-nucleophiles

Reactions of 2-alkylsulfanyl- and 2-alkoxy-4-hydroxy-6H-1,3-oxazin-6-ones with oxygen-centered nucleophiles were studied. 2-Alkoxy-4-hydroxy-6H-1,3-oxazin-6-ones reacted with water and alcohols to give the corresponding alkyl 3-amino-3-oxopropanoates as a result of opening of the oxazine ring at the C⁶-O bond, whereas their 2-alkylsulfanyl analogs turned out to be stable toward O-nucleophiles. The different reactivities of the title compounds were interpreted in terms of quantum-chemical calculations of their electronic structure.     

Potentiometric study on acid properties of some 4-hydroxy-6H-1,3-oxazin-6-ones. Structure-biological activity relationship

4-Hydroxy-6H-1,3oxazin-6-ones exhibit properties of weak OH acids. These compounds are readily methylated with diazomethane to give the corresponding 4-methoxy derivatives. According to the potentiometric titration data, the pK _a values of 2-methoxy-and 2-methylsulfanyl-substituted 4-hydroxy-6H-1,3-oxazin-6-ones range from 7.45 to 8.42, depending on the substituent in position 5 of the heteroring. 4-Hydroxy-6H-1,3-oxazin-6-ones in biological media exist mainly in the neutral form.     

Reaction of 2,3-Dihydro-1,5-benzothiazepines and Phenylacetyl Chloride in the Presence of Triethylamine： A New Aspect on the Formation Mechanism of Dihydro-1,3-oxazin-4-one Derivatives

2a,4-Disubstituted 2,2a,3,4-tetrahydro-2-phenyl-1H-azeto[2,1-d][ 1,5]benzothiazepin-1-ones, as well as 2-substi-tuted 2,3-dihydro-3-phenylacetyl-2-styryl-benzothiazoles and 4a,6-disubstituted 3- .benzyl-4a,5-d/hydro-2-phenyl-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, were obtained from the reaction of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines with phenylacetyl chloride in the presence of triethylamine. The mechanism for the formation of 4a,5-dihydro-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, 2,3-dihydro-1,3-oxazin-4-one derivatives, was suggested.     

Facile and convenient synthesis of 2,6-disubstituted 4H-1,3-oxazin-4-one derivatives

Facile and convenient methods for the preparation of a variety of 2,6-disubstituted 4H-1,3-oxazin-4-ones 3 by three complementary methods are described. Treatment of the branched aliphatic imidate 2c,d with diketene 1 in the presence of a catalytic amount of acetic acid affords 2-substituted 6-methyl-1,3-oxazin-4-ones 3c,d , whereas the unbranched imidate 2b,e gave oxazines 3b,e and pyrimidines 4b,e (Method A). The reaction of acyl Meldrum's acid 5 with imidate 2 afford 2,6-disubstituted oxazine 3, though the alkylimidate with acetyl Meldrum's acid yielded 3 and 5-acetyl-1,3-oxazine-4,6-dione 8 (Method B). The cylodehydration of acylacetylcarboxamide 13 with acid, such as 70% perchloric acid or fluorosulfonic acid, afforded 1,3-oxazines 3 (Method C).     

Azoles and azines. 62. Structure of 2-aryl-1,3-oxazine-4,6-diones

¹H,¹³C NMR, IR, and UV spectra have been studied for solutions of a number of potentially tautomeric 2-aryl-1,3-oxazine-4,6-diones and their 5-methyl substituted analogs with variation of substituent at the para position of the benzene ring, as well as compounds with a fixed structure that simulates possible tautomeric forms. The data have been compared with the results of quantum chemical calculations carried out in SSO MO LCAO approximation by the CNO, CNDO/2, and MPNDO/3 methods. In DMSO and THF solution the test compounds exist predominantly as 2-aryl-4-hydroxy-6H-1,3-oxazin-6-ones. The para substituent in the benzene ring does not affect the composition of the tautomer mixture significantly.For Communication 61, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 386–394, March, 1987.     

Stereochemical studies — 79 synthesis and kinetic study on the retrodiene decomposition of norbornene-condensed 1,3-oxazin-4-ones

The $\text{cis}$-$\text{cxo}$- amino acid $\text{c}$ with norbornene skeleton was converted into 2-aryvl-$\text{cis}$-$\text{cxo}$-1,3-oxazin-4-ones $\text{5a}$-$\text{d}$. These compounds, similarly to the $\text{diendo}$ isomers $\text{1a}$-$\text{d}$ studied by us earlier, undergo retrodiene decomposition under mild conditions to give 2-aryl-6$\text{2}$-l,3-oxazin-6-ones ($\text{2}$$\text{a}$-$\text{d}$) in 50-60% yield. The ratio of the decomposition rate constants of the tricyclic $\text{diendo}$ and $\text{diexo}$-1,3-oxazin-4-ones, measured in toluene solution, is about 2.     

Five-Membered 2,3-Dioxo Heterocycles: XLV. Thermolysis of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the Absence of Other Partners and in the Presence of Carbonyl Compounds

Aroyl(phenyl)ketenes generated by thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones undergo [4+2]-cyclodimerization to 3-aroyl-6-aryl-3,5-diphenyl-3,4-dihydro-2H-pyran-2,4-diones. Heating of the latter leads to rearrangement with formation of 4-aroyloxy-6-aryl-3,5-diphenyl-2H-pyran-2-ones. Thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the presence of carbonyl compounds yields 6-aryl-5-phenyl-4H-1,3-dioxin-4-ones.     

Preparation of fused 1,3-oxazine-2,4-diones as potential antitumor agents

A series of indole, thiophene and pyrrole-fused 1,3-oxazine-2,4-diones, 2-methyl-1,3-oxazin-4-ones and 2-dimethylamino-1,3-oxazin-4-ones were synthesized and evaluated as antitumor agents.