Quinoxalino[2,3-b]-1,4-thiazines

Quinoxalino[2,3-b]-1,4-thiazines were obtained by the reaction of 2-aminoquinoxaline-3-thione and its 6,7-dimethyl derivative with -halocarbonyl compounds. Hydrolysis of these compounds in alkaline and acid media gave 2-amino-3-quinoxalone and quinoxaline-2,3-dione. The IR and UV spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 853–856, June, 1971.     

Synthesis of substituted 2-arylimino-2,3-dihydro-4H-1,3-thiazines

The synthesis of 3,4,4,6-tetramethyl-2-arylimino-2,3-dihydro-4H-1,3-thiazines, which have a fixed imino structure, was accomplished by two methods: by intramolecular rearrangement of 1,4,6,6-tetramethyl-3-aryl-1,2,3,6-tetrahydropyrimidine-2-thiones and by amination of 3,4,4,6-tetramethyl-2,3-dihydro-4H-1,3-thiazine-2-thione methiodide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 941–943, July, 1972.     

Synthesis of 2-substituted-2,3- dihydro-1,4-dioxino[2,3-b]pyridine derivatives

[reaction--see text] A variety of 2-substituted-2,3-dihydro-1,4-dioxino[2,3-b]pyridines B have been synthesized from the readily available 2-nitro-3-oxiranylmethoxypyridine 1 via a Smiles rearrangement. We demonstrate how variations of reaction conditions affect the product distribution of A and B.     

Facile deacylation of N-acyl-2,3-dihydrobenzo-1,4-thiazine 1-oxide and 1,1 dioxide

The title amides react easily with methanolic sodium methoxide at room temperature affording 2,3-dihydrobenzo-1,4-thiazine 1-oxide and 1,1-dioxide and methylacetate. An unusual mechanism of deacylation is proposed.     

Synthesis of 4-acyl-2,3-dihydro-4H-1,4-oxazines

The synthesis of 4-acyl-2,3-dihydro-4H-1,4-oxazines ( 6a-h ) via acid dehydration of 4-acyl 2- and 3-morpholinols is described. During dehydration of 2-morpholinols 3d,e , N-alkylisoquinolones 7a-e were also isolated.     

Synthesis of 2,3-diaryl-1,4-diazolyl-2,3-epoxybutanes

2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity.     

Synthesis of substituted 2-amino-5,6-dihydro-4H-1,3-thiazines and 2-iminotetrahydro-1,3-thiazines

N-Aryl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas are cyclized in acidic media to 4,4,6-trimethyl-2-arylimino-5,6-dihydro-4H-1,3-thiazines, the methylation of which with methyl iodide gives 4,4,6-trimethyl-2-methylarylamino-5,6-dihydro-4H-1,3-thiazines. 3,4,4,6-Tetramethyl-2-aryliminotetrahydro-1,3-thiazines were synthesized by cyclization of Naryl-N′-methyl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas.     

2,3-二取代-1,4-萘醌的合成

常温下, 在丙酮与水的混合介质中(V∶V＝1∶1), 4-羟基香豆素类化合物与1,4-萘醌进行Michael加成反应, 生成6个未见文献报道的2,3-二取代-1,4-萘醌. 产物经MS, 1H NMR, 元素分析表征, 确定了其化学结构.     

1,4-二硝基-2,3-二硝胺基哌嗪的合成

本文以乙二胺, 乙二醛和脲为原料, 通过Mannich反应, 合成出2,5,7,9-四氮杂双环[4.3.0]壬-8-酮盐酸盐(1); 化合物1 亚硝化给出2,5-二亚硝基-2,5,7,9-四氮杂双环[4.3.0]壬-8-酮(2); 硝化化合物2制得2,5,7,9-四硝基-2,5,7,9-四氮杂双环[4.3.0]壬-8-酮(3); 化合物3水解制得1,4-二硝基-2,3-二硝胺基哌嗪(4).     

Synthesis of 2-methylthio-4H-1,3-thiazines

2-Methylthio-4H-1,3-thiazines or their mixtures with 5-alkylidene-4H-5,6-dihydro-1,3-thiazines were obtained by cyclization of methyl N-3-oxoalkyldithiocarbamates in sulfuric acid. The regiospecificity of the reaction is determined by the structures of the starting compounds. The structures of the synthesized thiazines were confirmed by spectral methods of analysis (IR and ¹H and ¹³C spectroscopy).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–993, July, 1992.     

Synthesis of novel aza analogues of 2-substituted-2,3-dihydro-1,4-benzodioxins as potential new scaffolds for drug discovery

New synthesis approaches that have led to a series of novel aza analogues of the 2-substituted-2,3-dihydro-1,4-benzodioxin core, bearing versatile bromomethyl group on the non aromatic oxygenated ring, are described. According to their structures these novel scaffolds can be useful intermediates for the preparation of potential new therapeutic agents.     

Synthesis and reactivity of a 1,4-dihydropyrazine derivative

N,N-Bis-(tert-butoxycarbonyl)-2,5-bis-methoxycarbonyl-1,4-dihydropyrazine can be obtained in high yield by treatment of the methyl ester of N-(4-toluenesulfonyl)-N-(tert-butoxycarbonyl)-α,β-didehydroalanine with dimethylaminopyridine and potassium carbonate. This compound was used as substrate in Michael addition reactions with several types of nucleophiles. The electrochemical behaviour of this pyrazine derivative was also studied by cyclic voltammetry and by controlled potential electrolysis.     

Nitrogen and sulfur heterocycles. 45. Dual reactivity of 1,2-dioxo-3a-alkyl-7-chloroimidazolidino[3,2-f]-pyrido[2,3-b]-1,4-thiazines

1,2-Dioxo-3a-alkyl-7-chloroimidazolidino[3,2-f]pyrido[2,3-b]-1,4-thiazines react with o- and p-nitroanilines, alkyl and acyl halides, and heterocyclic amines to give C₍₂₎- and N₍₃₎-substituted 3a-alkyl-7-chloroimidazolidino[3,2-f]pyridol[2,3-b]-1,4-thiazines.For Communication 44, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1688–1693, December, 1987.     

Synthesis of Mixed Aryl 2,3-Diarylsulphanyl-1,4-naphthoquinones

The reaction of 2-arylsulphanyl-1,4-napththoquinone with aromatic thiols and sodium dithionate leads to bis-2,3-(arylsulphanyl)naphthalene-1,4-diols in high yield. Corresponding oxidized products, namely 2,3-diarylsulphanyl-1,4-naphthoquinones, are prepared in near quantitative yield by a copper(II)-catalyzed aerial oxidation reaction of bis-2,3-(arylsulphanyl)naphthalene-1,4-diols under mild condition.     

Synthesis of 4-(2-chloroethyl)-2,3-dihydro[1,4]oxazino[2,3-b]quinoline and 4-(2-chloroethyl)2,3-dihydropyrido[2,3-b][1,4]oxazine

The title compounds were synthesized from 3-[bis(2-hydroxyethyl)amino]quinolin-2(1H)-one 11a and 3-[bis(2-hydroxyethyl)amino]pyridin-2(1H)-one 18 respectively. The preparation involved a tandem chlorination/cyclization reaction.     

Mass spectra of 4-substituted-1,2,6-trimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridines

The mass spectra of 4-substituted-1,2,6-trimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridines have been studied. The detailed fragmentation mechanisms, supported by high resolution measurements, the study of metastable ions and the use of deuterium labelling, are discussed.     

Studies on chemotherapeutics I. Synthesis of 5-substituted-4-oxo-1,4-dihydro-3-pyridinecarboxylic acid derivatives

Ethyl 5-substituted-4-oxo-1,4-dihydro-3-pyridinecarboxylates were synthetized by reacting 1,3,5-triazine with 4-substituted ethyl acetoacetate derivatives in ethanol, in the presence of sodium ethoxide. The l-alkyl-5-substituted-4-oxo-1,4-dihydro-3-pyridinecarboxylic acids required for the antimicrobial studies were prepared by N-alkylation (with triethyl phosphate or alkyl halides) and alkaline hydrolysis of the pyridone esters.     

Synthesis of the four stereoisomers of 2,3-epoxy-4-hydroxynonanal and their reactivity with deoxyguanosine

2,3-Epoxy-4-hydroxynonanal (EHN) is a potential product of lipid peroxidation that gives rise to genotoxic etheno adducts. We have synthesized all four stereoisomers of EHN and individually reacted them with 2'-deoxyguanosine. In addition to 1,N(2)-etheno-2'-deoxyguanosine, 12 stereoisomeric products were isolated and characterized by (1)H NMR and circular dichroism spectroscopy. The stereochemical assignments were consistent with selective NOE spectra, vicinal coupling constants, and molecular mechanics calculations. Reversed-phase HPLC conditions were developed that could separate most of the adduct mixture.