Tautomerism and Stereodynamics of Indophenols,Amidines, and Their Derivatives and Analogs: XV.1 Cyclization of N-Benzylidene-N'-R-sulfonyl-o-phenylenediamines to Tetrahydroquinoxalines

Alkylation of N-benzylidene-N'-R-sulfonyl-o-phenylenediamines with phenacyl bromides is accompanied by diastereoselective cyclization to afford tetrahydroquinoxaline derivatives. No cyclization occurs in the alkylation of the same compounds with p-nitrobenzyl bromide or chloroacetamide derivatives because of reduced reactivity of the N-methylene protons.     

Tautomerism and Stereodynamics of Indophenols,Amidines, Their Derivatives,and Analogs: XIV. New Methods of Synthesis of Spiro-Fused Quinoxalines

A new procedure was proposed for synthesis of quinoxaline derivatives by N-alkylation of 2,6-di-tert-butyl-4-(o-R-sulfonylaminophenylimino)-2,5-cyclohexadienones and subsequent intramolecular spirocyclization. A necessary condition for the reaction to occur is high mobility of hydrogen in the N-methylene group, which is activated by electron-acceptor aroyl or two ethoxycarbonyl groups.     

Tautomerism and Stereodynamics of Indophenols,Amidines, and Their Derivatives and Analogs: XVI. Synthesis of Tetrahydroquinoxalines Having Spiro-Fused Oxoindole and Cyclohepta[c]furan Fragments

Alkylation of o-(N-sulfonylamino)phenylimino derivatives of indol-2-one and cyclohepta[c]furan with phenacyl bromides is accompanied by cyclization to previously unknown tetrahydroquinoxalines having spiro-fused oxoindole and cyclohepta[c]furan fragments. The structure of the latter includes a nitrogen-oxygen triangular system typical of most natural cytotoxic compounds.     

Synthesis,Intramolecular Cyclization,and Antinociceptive Activity of Substituted 2-[2-(4-Nitrobenzoyl)hydrazinylidene]-4-oxobut-2-enoic Acids

Russian Journal of Organic Chemistry - New substituted 2-[2-(4-nitrobenzoyl)hydrazinylidene]-4-oxobut-2-enoic acids have been synthe­sized by condensation of 4-nitrobenzohydrazide with...     

Synthesis of 4-(Hydroxymethyl)dihydroisoindolium Salts and Their Intramolecular Recyclization

The review discusses intramolecular cyclization of ammonium salts containing a 4-hydroxybut-2- yn-1-yl group in combination with various π⁴-fragments, as well as mechanisms of cyclization and intramolecular recyclization of the resulting 4-(hydroxymethyl)dihydroisoindolium salts and their fused analogs. The process is accompanied by neither ring expansion nor contraction, and a pharmacophoric 1,3-dihydrofuran ring is formed instead of dihydroisoindolium fragment. The effects of electronic and structural factors on the intramolecular cyclization and recyclization processes are considered.     

Synthesis,Intramolecular Cyclization,and Analgesic Activity of Substituted 2-[2-(Furancarbonyl)hydrazinylydene]-4-oxobutanoic Acids

Russian Journal of General Chemistry - A method was proposed for the synthesis of substituted 2-[2-(furan-2-carbonyl)hydrazinylidene]-4-oxobutanoic acids by the reaction of...     

2-[4-(2,6-二氟苯基)噻唑-2-基]-3-羟基丙烯腈衍生物的合成及生物活性

为了寻找生物活性良好的噻唑基丙烯腈类化合物, 利用2-[4-(2,6-二氟苯基)噻唑-2-基]乙腈(3)分别与取代氯甲酸酯4和取代苯基异氰酸酯6在碱存在下反应, 合成了8个2-[4-(2,6-二氟苯基)噻唑-2-基]-3-羟基-3-烃氧基丙烯腈化合物5和7个2-[4-(2,6-二氟苯基)噻唑-2-基]-3-羟基-3-取代苯胺基丙烯腈化合物7, 均为首次报道的丙烯腈类化合物. 化合物结构经1H NMR, IR, MS和元素分析表征. 初步生物活性测定结果表明, 在试验浓度下, 目标化合物均具有一定的杀虫和抑菌活性, 其中化合物5f和5h在100 mg/L浓度下对炭疽病菌的抑制率达95%; 化合物5g和7d在250 mg/L浓度下对棉红蜘蛛的致死率达85%.     

Synthesis of Pyrano,Pyrido, Oxazino,and Spiro Pyrazole Derivatives and Their Antimicrobial Activity

Russian Journal of Organic Chemistry - Condensation of 5-methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one with 4-hydroxybenzaldhyde in alcoholic sodium hydroxide yielded...     

Studies Directed Towards Stereospecific Synthesis of Oxybiotin,Biotin, and Their Analogs. III. Preparation of Some New 2,5-Anhydro-Xylitol Derivatives

Abstract

Some new partially or fully tosylated and/or mesylated 2, 5-anhydro-xylitol derivatives have been prepared in this work. Some of them represent the real optically active intermediates in an attempted synthesis of selected (+)-oxybiotin analogs, while the others, being racemic, serve only as easily available model-intermediates.     

Reaction of Barbituric, 2-Thiobarbituric Acids and Their Derivatives with 2-Carboxybenzaldehyde and Opianic Acid: Synthesis and Tautomerism of 5-(3'-Oxo-1',3'-dihydroisobenzofuran-1'-yl)barbituric Acids and Their 2-Thio Analogs

The reaction of barbituric, N-alkylbarbituric acids, and their 2-thio analogs with carboxybenzaldehyde and 2-carboxy-3,4-dimethoxybenzaldehyde leads to the formation of the corresponding 5-(3'-oxo-1',3'-dihydroisobenzofuran-1'-yl)barbituric and 2-thiobarbituric acids, the structures of which were studied by ¹H and ¹³C NMR spectroscopy and mass spectrometry. In DMSO the derivatives of barbituric acid exist in the form of mixtures of the ketone and enol tautomers, while their 2-thio analogs exist in the enol form. In chloroform the tautomeric equilibrium is displaced fully toward the ketone form.     

1-(嘧啶基-4)-3-(2,6-二氟苯甲酰基)脲衍生物的合成与生物活性

为了寻找高效、低毒、低残留的环境友好杀虫剂, 设计并合成了12个新的1-(嘧啶基-4)-3-(2,6-二氟苯甲酰基)脲衍生物6a～6l, 其结构经IR, ¹H NMR, LC/MS和元素分析确证. 初步生物活性测试结果表明, 部分化合物具有明显的杀虫活性, 如6g在100 mg/L浓度下, 对粘虫(Mythimna sepatara)具有100%的杀虫活性.     

Synthesis of 4-Aminopyrazol-5-ols as Edaravone Analogs and Their Antioxidant Activity

One of the powerful antioxidants used clinically is Edaravone (EDA). We synthesized a series of new EDA analogs, 4-aminopyrazol-5-ol hydrochlorides, including polyfluoroalkyl derivatives, via the reduction of 4-hydroxyiminopyrazol-5-ones. The primary antioxidant activity of the compounds in comparison with EDA was investigated in vitro using ABTS, FRAP, and ORAC tests. In all tests, 4-Amino-3-pyrazol-5-ols were effective. The lead compound, 4-amino-3-methyl-1-phenylpyrazol-5-ol hydrochloride (APH), showed the following activities: ABTS, 0.93 TEAC; FRAP, 0.98 TE; and ORAC, 4.39 TE. APH and its NH-analog were not cytotoxic against cultured normal human fibroblasts even at 100 μM, in contrast to EDA. According to QM calculations, 4-aminopyrazolols were characterized by lower gaps, IP, and η compared to 4-hydroxyiminopyrazol-5-ones, consistent with their higher antioxidant activities in ABTS and FRAP tests, realized by the SET mechanism. The radical-scavenging action evaluated in the ORAC test occurred by the HAT mechanism through OH bond breaking in all compounds, directly dependent on the dissociation energy of the OH bond. All the studied compounds demonstrated the absence of anticholinesterase activity and moderate inhibition of CES by some 4-aminopyrazolols. Thus, the lead compound APH was found to be a good antioxidant with the potential to be developed as a novel therapeutic drug candidate in the treatment of diseases associated with oxidative stress.     

微波促进下1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基硫脲及其衍生物的合成

微波辐射条件下，首先由2-苯并呋喃甲酰氯在相转移条件下依次与硫氰酸铵和 芳甲酰肼反应合成了一系列1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基硫脲，进 一步在微波辐射的条件下由这些氨基硫脲分别与碘酸钾、醋酸或醋酸汞等试剂作用 高产率地制得了1-芳甲酰基-4-（2’-苯并呋喃甲酰基）氨基脲、2-芳基-5-（2’- 苯并呋喃甲酰胺基）-1，3，4-噻二唑和2-芳基-5-（2’-苯并呋喃甲酰胺基）-1， 3，4-（口恶）二唑。     

Synthesis and reactions of 4-(benzothiazol-2-yl)-2,6-dimethylpyrylium perchlorate

A new method has been developed for the synthesis of 4-(benzothiazol-2-yl)-2,6-dimethylpyrylium perchlorate from 2,6-dimethyl--pyrone and 2-lithiobenzothiazole. The reaction of this salt with ammonia and with primary and secondary amines, hydrazine, phenylhydrazine. and hydroxylamine leads to the formation of difficultly accessible hetaryl-substituted benzothiazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1016–1019, August, 1973.     

Synthesis of benzoates of 1,4-bis(2,5-dimethyl-4-hydroxypiperidino)-2-butene and 1,4-bis-(2,5-dimethyl-4-hydroxypiperidino)-2-butyne

1,4-Bis(2,5-dimethyl-4-hydroxypiperidino)-2-butene and 1,4-bis(2,5-dimethyl-4-hydroxypiperidino)-2-butyne (II and III) were obtained by the action of 1,4-dibromo-2-butene and 1,4-dibromo-2-butyne on the form of 2,5-dimethyl-4-piperidol (I). The benzoates (IV and V) were obtained by acylation of II and III with benzoyl chloride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 352–353, March, 1971.     

Mild and Efficient Synthesis of 1-（6-Chloroquinoxalin-2-yl）-2- [4-（trifluoromethyl）-2,6-dinitrophenyl] Hydrazine Derivatives by Microwave Irradiation

Some 1-（6-chloroquinoxalin-2-yl）-2-[4-（trifluoromethyl）-2,6-dinitrophenyl] hydrazine derivatives have been synthesized via both conventional and microwave assisted organic synthesis（MAOS） methods. The MAOS method is more effective on synthesizing these compounds than the conventional method in regard to the higher chemical yields of products（76%-98%） and the shorter reaction time（1-15 min）.     

Synthesis and configuration of diastereomeric 2,4-, 2,5-, and 2,6-piperidinedicarboxylic acids and their dimethyl esters

The reduction in an acidic medium over a platinum catalysts of 2,4-, 2,5-, and 2.6-pyridinedicarboxylic acids gave cis-2,4-, -2,5-, and -2,6-piperidinedicarboxylic acids, heating of which in an alkaline medium led to thermodynamically equilibrium mixtures of diastereomers. Individual trans-2,5-piperidinecarboxylic acid was isolated. The configurations of the 2,4-, 2,5-, and 2,6-piperidinedicarboxylic acids and their methyl esters were established by means of the PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 367–371, March, 1985.     

Synthesis and crystal structure of thermochroic 2,6-di-tert-butyl-4-dimethylamino-4-(2-hydroxyphenyl) cyclohexadien-2,5-one

The compound 2,6-di-tert-butyl-4-dimethylamino-4-(2-hydroxyphenyl)cyclohexadien-2,5-one is synthesized and its structure is studied. The thermochromism of the compound is due to cleavage on excitation of the C_spiro-N bond, which is lengthened to 1.512 Å under normal conditions, and O N proton transfer. A deeply colored diphenoquinone and dimethylamine are formed. The C_spiro-N bond is lengthened due to mutual steric repulsion of the atoms bound to C⁴ and N.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1808–1813, August, 1991.     

Derivatives of 5-(Dimethylamino)-4-tosyl-1,3-oxazole-2-carbaldehyde and Its Analogs

Treatment of N-(2,2,2-trichloro-1-tosylethyl)dichloroacetamide with excess dimethylamine, piperidine, or morpholine gave substituted aminals of the oxazole series, whose facile acid hydrolysis provided 5-(dimethylamino)-4-tosyl-1,3-oxazol-2-carbaldehyde and its analogs having the piperidino and morpholino group in the 5 position of the oxazole ring. The resulting aldehydes and their aminals were condensed with phenylhydrazine, thiosemicarbazide, N-alkylrhodanines, and 1,3-dimethylbarbituric acid to obtain 2,5-disubstituted derivatives of 4-tosyl-1,3-oxazole.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 1002–1006.Original Russian Text Copyright © 2005 by Vyzhdak, Danielova, Kiselev, Drach.