Synthesis of 2-carbethoxy-3-methyl-4-hydroxy-6-phenylbenzofuran derivatives

4-Hydroxybenzofuran derivatives were synthesized, and their reactions with bromine and nitric acid were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 879–882, July, 1976.     

Synthesis of 2-phenyl-4-hydroxybenzofuran derivatives

2-Phenyl-4-hydroxybenzofuran was obtained by dehydrogenation of 2-phenyl-4-oxo-4,5,6,7-tetrahydrobenzofuran under the influence of sulfur. The transformations of 2-phenyl-4-hydroxybenzofuran and its derivatives were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1036–1039, August, 1977.     

Synthesis and stereochemistry of 2-benzylidene-4-carbethoxy-5-methyl-3-(2H)-furanones

The title products were obtained by Knoevenagel condensation between 4-carbethoxy-5-methyl-3-(2H)furanone and substituted benzaldehydes (or 4-chloroacetophenone). The configuration of the resulting compounds was investigated by ¹H nmr using the lanthanide shift reagent.     

Vilsmeier formylation of 2-methyl-3 -carbethoxy-5-methoxy- and 2-methyl-5-methoxyindoles

The corresponding 6- and 3-formyl derivatives were obtained by formylation of 2-methyl-3-carbethoxy-5-methoxy- and 2-methyl-5-methoxyindole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–341, March, 1971.     

Synthesis of benzene-ring-substituted 2-methyl-3-acetylquinoxaline derivatives

2-Methyl-4-acetylquinoxaline derivatives were obtained by the condensation of pentane-2,3,4-trione with 4-substituted o-phenylenediamines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1423–1424, October, 1971     

Formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives

The Vilsmeier formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives was studied. It is shown that 2-phenyl-5-methoxybenzofuran is formylated in the 4 position, whereas 3-phenyl-5-methoxybenzofuran is formylated in the 2 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1023–1024, August, 1976.     

Synthesis of 2-acetyl-3-methyl-4H-1,4-benzothiazine and its derivatives

Summary 2-Aminothiophenol (1) reacts with 3-chloro-2,4-pentanedione (2) in the presence of pyridine to form 2-acetyl-3-methyl-4H-1,4-benzothiazine (3) in high yields. Reaction of3 with hydrazine gives 4-(2-aminophenylthio)-3,5-dimethylpyrazole (5). Condensation of3 with 4-nitrobenzaldehyde yields the corresponding Schiff base7. Hydroxylamine with benzothiazine3 affords 3,9a-dimethyl-3a, 9a-dihydro-9H-isoxazolo[4,5-b][1,4]benzothiazine (8).

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Synthese von 2-Acetyl-3-methyl-4H-1, 4-benzothiazin und seinen Derivaten

Zusammenfassung 2-Aminothiophenol (1) reagiert mit 3-Chlor-2,4-pentandion (2) in Anwesenheit von Pyridin unter Bildung von 2-Acetyl-3-methyl-4H-1,4-benzothiazin (3) in sehr hoher Ausbeute. Benzothiazin3 kondensiert mit Hydrazin zu 4-(2-Aminophenylthio)-3,5-dimethylpyrazol (5), dessen Aminogruppe reagiert mit 4-Nitrobenzaldehyd zu einer Schiffschen Base (7), die spektroskopisch charakterisiert wurde. Benzothiazin3 mit Hydroxylamin ergibt 3,9a-Dimethyl-3a,9a-dihydro-9H-isoxazolo[4,5-b][1,4]benzothiazin (8). Die Stereochemie der letztgenannten Verbindung wurde ermittelt.

     

Use of two-dimensional spectroscopy for the determination of the stereochemical structure of 3-carbethoxy-2-methyl-7a-(4-carbethoxy-5-methyl-2-furyl)-3a,4,5,6,7,7a-hexahydrobenzofuran

Homo- and heteronuclear two-dimensional correlation spectra, as well as J-resolved spectra with selective excitation, were used to analyze in detail the stereochemical structure of 3-carbethoxy-2-methyl-7a-(4-carbethoxy-5-methyl-2-furyl)-3a,4,5,6,7,7a-hexahydrobenzofuran, obtained by the reaction of cyclohexenyl-acetylene with acetoacetic ester in the presence of a manganese(III) salt. It was shown that the use of the long-range ¹³C-¹H coupling constants is a very effective method for the determination of the conformation of the molecule. The stereochemical aspects of the reaction of cyclohexenylacetylene with acetoacetic ester is discussed.cis-Configuration has an axial-equatorial arrangement of the C_(7a)-O and C_(3a) bonds, trans-configuration has a diequatorial (diaxial) arrangements of these bonds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 167–171, February, 1991.     

Synthesis of 2-hydroxy-3-carbethoxy-5,6-dialkylpyrazines

Conclusions Some 2-hydroxy-3-carbethoxy-5,6-dialkylpyrazines were synthesized by reacting the hydrochlorides of -amino ketones with carbethoxyacetyl chloride in the presence of N,N-di-ethylaniline, azo-coupling the obtained N-(carbethoxyacetyl)--amino ketones with phenyldiazonium salt, and reduction of the intermediate N-(phenylhydrazonocarbethoxyacetyl)--amino ketones with zinc.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1067–1070, May, 1980.     

Synthesis of unsaturated derivatives of 2,5-dimethyl-4-phenylpyridine and 3-methyl-2-azafluorene

A substituted butadiene — 1-phenyl-4-(5-methyl-4-phenyl-2-pyridyl)buta-1,3-diene with a trans, trans configuration — was obtained by condensation of 2,5-dimethyl-4-phenylpyridine with cinnamaldehyde. Two 3-methyl-9-cinnamylidene-2-azafluorene isomers are formed as a result of condensation of the same aldehyde with 3-methyl-2-azafluorene. Data from the PMR and IR spectra were used to prove the configuration of the compounds obtained. It was established that the condensation of 3-methyl-2-azafluorene with salicylaldehyde gives 3-methyl-9-(2-hydroxybenzylidene)-2-azafluorene, which has a zwitterionic structure, and 1,2-bis(3-methyl-2-aza-9-fluorenylidene)ethane. Ideas regarding the chemical mechanism of the formation of the latter are presented. The preparation of an unsaturated alcohol — 3-methyl-9-allyl-2-aza-9-fluorenol — is described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 82–86, January, 1978.     

Synthesis of 2-amino-3-carbethoxy-1-hydroxyindoles

A general method is described for the synthesis of 2-amino-3-carbethoxy-l-hydroxyindoles by the reductive cyclization of 2-nitrophenylcyanoacetates using zinc and acetic acid at temperatures of 15–28°.     

Preparation of 1-aryl-2-methyl-3-carbethoxy-4,5-dioxo-6-bromoindoles

1-Aryl-2-methyl-3-carbethoxy-5-hydroxy-6-bromoindoles are oxidized by nitric acid to 1-aryl-2-methyl-3-carbethoxy-4,5-dioxo-6-bromoindoles, while 1,2-dimethyl-3-carbethoxy-5-hydroxy-6-bromoindole is converted to the 4,6-dinitro derivative under similar conditions.     

Synthesis of 2-ethoxy-2-carbethoxy-δ5 -dihydropyrans and their derivatives

Acrolein and methyl vinyl ketone undergo diene condensation with ethyl -ethoxyacrylate to give the corresponding 2-ethoxy-2-carbethoxy-⁵-dihydropyrans in 50–60% yields. The reduction of the latter with lithium aluminum hydride gave the hydroxymethyl derivatives of dihydropyrans, while ammonolysis gave amides of 2-ethoxy-⁵-dihydropyran-2-carboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 452–453, April, 1972.     

Synthesis of 3-acylamino- and 3-carbethoxy-2-benzopyrylium salts

High yields of 3-acylamino-2-benzopyrylium salts are formed in the acylation of 3,4-dimethoxy- and 3,4-methylenedioxyphenylacetonitrile. The salts are converted to 4-isoquinolones on treatment with ammonia. The acylation of ethyl 3,4-dimethoxyphenylglycidate ester also results in heterocyclization to 3-carbethoxy-2-benzopyrylium salts, which are converted to high yields of the corresponding 3-carbethoxyisoquinolines by treatment with ammonium hydroxide. The mechanisms of these transformations are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 730–732, June, 1971.     

Synthesis and structure of anils of 2-formyl-3-hydroxybenzofuran

A number of anils of 2-formyl-3-hydroxybenzofuran (I) and their derivatives, which are models of the individual tautomeric forms II and III, were synthesized. A ketoamine structure (Ic) was assigned to compounds I as a result of a study of the electronic, vibrational, and PMR spectra.Communication XIV from the series Benzenoid-Quinoid Tautomerism of Azomethines and Their Structural Analogs; see [1] for communication XIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 154–157, February, 1973.     

4-Hydroxy-2-quinolones. 3. Synthesis and physicochemical properties of 1-R-3-carbethoxy-4-hydroxy-2-quinolones

1-R-3-Carbethoxy-4-hydroxy-2-quinolones were synthesized by intramolecular cyclization of N-R-2-carbalkoxymalonanilic acids by the Dieckmann reaction. The possibility and advantages of conducting this reaction in aqueous medium were demonstrated. The mutually perpendicular orientation of the heterocyclic and aryl fragments was demonstrated for the 1-phenyl derivative by ESR spectroscopy.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 636–639, May, 1992.     

6位取代的2-甲基-3-乙氧羰基-4-喹啉酮的微波合成及晶体结构

用微波技术在无溶剂条件下合成了4个6-位取代的2-甲基-3-乙氧羰基-4-喹啉酮类化合物,其结构经红外光谱和元素分析表征,并用X-射线衍射法测定了取代基为甲氧基的标题化合物的晶体结构,其晶体属单斜晶系,P21/n空间群,a=0.67780(14)nm,b=O.68990(14)nm,c=2.7329(6)nm,β=92.34(3).,V=1.2769(5)nm3,Z=4,M r=261.27,D c=1.359g/cm3,μ=0.100mm-1,S=1.097.F(000)=552,最终偏离因子为R1=0.087,wR2=0.200.分子间氢键N-H…O和π-π堆积作用使该化合物分子形成稳定的三维结构.     

4-甲基-3-硝基苯甲腈和2-甲基-5-硝基苯甲腈的合成与表征

4-甲基-3-硝基苯甲腈和2-甲基-5-硝基苯甲腈是重要的有机合成中间体[1,2],因其芳环上具有硝基和氰基两个第二类取代基,同时又有一个可参与反应的甲基而使得这两个化合物在有机合成领域有着广泛的应用前景.芳环上的甲基可以氧化为酸,也可进一步反应形成酰氯、酯等功能基;芳环上的氰基可水解成羧基,也可以与叠氮钠在Lewis酸催化下形成具有生物活性的四唑衍生物;芳环上的硝基经还原可形成氨基,如4-甲基-3-硝基苯甲腈通过化学反应可环合形成药物中间体6-氰基吲哚[2～4].