Reactions of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with Electrophiles

Summary.  Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives. Received May 9, 2001. Accepted (revised) August 17, 2001     

Nucleophilic ring-opening of the azole and azine moieties in 6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-ones

The effects of the nature of the nucleophile and the structure of 6-nitrotriazolo[1,5-a]pyrimidinones on the direction of the ring opening were investigated. The triazole ring is opened under the action of strong bases, such as alkoxides or alkalis, to form 2-cyanoaminopyrimidinones and then 2-aminopyrimidinones. The results of the reactions with N-nucleophiles depend on the accessibility of position 5 of the heterocycle. Thus, sterically hindered secondary amines react with 5-methyltriazolopyrimidinones to give 2-guanidinopyrimidinones and then 2-aminopyrimidinones. In the absence of a substituent at position 5, the azine ring is opened to form 4-alkyl-3-amino-1,2,4-triazoles and 3-amino-2-nitroacrylamides. Under the action of primary amines, only the pyrimidine fragment is cleaved.     

Synthesis and Crystal Structure of 4-Salicyli deneamino-3-methyl-1,2,4-triazol-5-thione

1 INTRODUCTION 3-Substituted-4-amino-1,2,4-triazol-5-thione is the key synthon in the formation of heterocyclic compound. As a bifunctional agent, it can react with various electrophilic reagents and its derivatives have been reported to show various biological activities to be employed as fungicide[1], micro- biocide[2, 3], bactericide[4], herbicides[5] and anti in- flammatory agents[6]. Furthermore, 3-substituted-4- amino-1,2,4-triazol-5-thione has potential electron donors. Though ma…     

1,1-二取代炔丙醇氯代产物与4-甲基-7-羟基香豆素的异常缩合产物

报道了一类1,1-二取代炔丙醇(1)氯代产物与4-甲基-7-羟基香豆素反应的异常缩合产物. 一些实验数据表明1,1-二取代炔丙醇(1)的氯代反应中有一类未见报道的2,4-二氯-2-烯化合物(5)生成.     

Synthesis and spectral properties of n-alkyl-4-methyl-7(8)-nitro-2,3,4,5-tetrahydro-(1h)-1,5-benzodiazepin-2-ones

Alkylation of 4-methyl-7(8)-nitro-2,3,4,5-tetrahydrobenzodiazepin-2-ones under phase transfer catalytic conditions or in dry acetone occurs only at position 1. The 5-alkyl isomers are obtained by reductive alkylation of 4-methyl-7(8)-nitro-2,3-dihydro-1,5-benzodiazepin-2-ones. The UV, IR, PMR, and mass spectra of the isomeric compounds are reported.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 959–963, July, 1992.     

(2R,4S)-4-甲基-2-哌啶甲酸乙酯的合成

以S-(-)-α-苯乙胺为原料,经一锅法制得1-(1-苄基)-6-乙氧羰基-4-甲基-3,4-二氢哌啶(3),收率58.7%。以10%Pd/C为催化剂,3经催化氢化脱苄合成了4-甲基-2-哌啶甲酸乙酯(4),收率96%;4通过减压分馏得(2R,4S)-4,含量95%,其结构经1H NMR,IR和MS确证。     

Electrochemical Conversions of 2-Methyl-3-nitro-4-phenylquinoline, Its Quinolinium Salts, and Hydrogenated Derivatives

Classical polarography, cyclic voltammetry, and EPR spectroscopy was used to study electrochemical reduction and oxidation of 3-nitro derivatives of 2-methyl-4-phenylquinoline, the corresponding quinolinium perchlorates, and 1,2- and 1,4-dihydroquinolines. The nitro derivatives of quinoline and 1,2-dihydroquinoline are reduced in the first step at the nitro group; the quinolinium cations are reduced at the heterocycle followed by reduction of the nitro group; and in 1,4-dihydroquinolines, the nitro group is not reduced. Electrochemical reduction processes associated with electron transfer in the heterocycle mainly display the same behavior as established for pyridine derivatives. But important differences were observed in electrochemical oxidation: the N-methyl derivative of 1,4-dihydroquinoline is oxidized significantly more easily than the corresponding N-unsubstituted derivative of 1,4-dihydroquinoline (in the 1,4-dihydropyridine series, the difference in pot! enti als is fairly small), and even more easily than the corresponding N-methyl derivative of 1,2-dihydroquinoline.     

(R)-2-甲基-7-炔-辛酸的合成

以1,5-戊二醇为起始原料,用Evans手性助剂诱导的烷基化反应构造了C-2手性中心,用Ohira-Bestmann试剂制备了末端炔基,通过13步反应,合成了(R)-2-甲基-7-炔-辛酸,总收率为17.1%,e.e.值大于99%.     

5-Methyl-2-furylglyoxal, 5-Methyl-4-nitro-2-furylglyoxal, and Their Derivatives. Nitration of 2-(5-Methyl-2-furyl)quinoxaline

The oxidation of 2-acetyl-5-methyl-4-R-furans (R = H, NO₂) by selenious acid was studied. Derivatives substituted at the C=O groups of the corresponding glyoxals were obtained. The nitration of 2-(5-methyl-2-furyl)quinoxaline was carried out at C_(4'). Oxidative splitting of the -nitrofuryl group occurs at the C₍₄₎-C₍₅₎ and C₍₅₎-O bonds.     

7—[（4—甲基2—胂酸基苯）偶氮]—8—羟基喹啉—5—磺酸荧光光度法测定氟

本文介绍了７－［（４－甲基－２－胂酸基苯）偶氮］－８－羟基喹啉－５－磺酸的合成方法以及性能，详细研究了氟对该试剂与铝形成的荧光的熄灭作用，建立了荧光法测定微量氟的新方法。应用于水样和牙膏中的氟的测定，效果良好。     

14N and 15N NMR Spectroscopy of 2-Methyl-4,5-dinitro-1,2,3-triazole and of Substituted 2-Methyl-4(5)-nitro-1,2,3-triazole 1-Oxides

Analysis of the ¹⁴N and ¹⁵N NMR spectroscopic data of 2-methyl-4,5-dinitro-1,2,3-triazole and of substituted 2-methyl-4(5)-nitro-1,2,3-triazole 1-oxides has shown the possibility of applying them for confirmation of the structures of the studied compounds.     

Functionalization of 2,3,4,5-Tetrahydro-1,5-benzodiazepin-2(1<Emphasis Type="Italic">H</Emphasis>)-ones by Electrophilic Aromatic Substitution

Summary. Highly substituted, novel, 8- and 9-nitro-2,3,4,5-tetrahydro-1,5-benzodiazepin-2(1H)-ones were obtained by direct nitration of the 7-bromo-5-trifluoroacetyl (or formyl)-substituted tetrahydrobenzodiazepinones. Alkaline and acidic hydrolysis of the novel mononitro derivatives was examined. Semiempirical AM1 calculations of aromatic substituents orientation in the nitration products are presented.     

The absence of nitrone form in re-determined crystal structure of 2-hydroxyimino-3-methyl-4-nitro-2,5-dihydrothiophene 1,1-dioxide

Crystal and molecular structures of 2-hydroxyimino-3-methyl-4-nitro-2,5-dihydrothiophene-1,1-dioxide C₅H₆N₂O₅S (I) have been re-determined by single crystal X-ray diffraction analysis. The structure of I (space group P2₁2₁2₁, a = 6.124(1) Å, b = 9.205(2) Å, c = 14.884(3) Å, Z = 4) was solved by the direct method and refined anisotropically in the full-matrix approximation to R = 0.064 using all 1756 measured independent reflections (automated diffractometer CAD-4, λCuK_α, anomalous scattering taken into account). This study proves that the compound I contains a disordered group H-O-N=C, but not the isomeric nitrone group O←N(H)=C, as it has been concluded by the workers who pioneered single crystal X-ray diffraction study of I and erroneously took the second low-occupied oxygen position of the disordered hydroxyimine group for H at N atom.     

2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷与丙烯腈、丙烯酸甲酯的共聚合反应及竞聚率的测定

用高效液相色谱跟踪2-甲基-7-亚甲基-1,4,6-三氧螺[4,4]壬烷(MMTN)与丙烯腈(AN),丙烯酸甲酯(MA)的共聚合反应。根据Lowry-Meyer共聚积分方程式,采用插值法进行数据拟合测定单体的竞聚率。对于体系MMTN(M_1)-AN(M_2),r_1=0.048;r_2=0.213;MMTN(M_1)-MA(M_2)r_1=0.025,r_2=0.764。说明两组共聚体系均有较强的交替共聚趋势。     

Fluorescent detection of peptides and amino acids for capillary electrophoresis via on-line derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole

An in-capillary derivatization of amino acids and peptides with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed for their subsequent capillary electrophoretic analysis with laser-induced fluorescence detection (λ _ex=488 nm). The in-capillary derivatization was achieved in zone-passing mode by introducing successive plugs of sample and NBD-F into a fused silica capillary previously equilibrated with an alkaline borate buffer. To prevent NBD-F hydrolysis and to achieve a reliable derivatization, NBD-F was prepared daily in absolute ethanol and a plug of absolute ethanol was introduced between the sample and NBD-F reagent plugs. Various parameters influencing the derivatization efficiency were investigated and the optimum conditions were as follows: background electrolyte (BGE), 20 mM borate buffer (pH 8.8); introduction time, 4 s for sample and 2 s for NBD-F; molar ratio of NBD-F/sample, above 215; temperature, 45 °C for amino acids and 35 °C for peptides; applied voltage, +15 kV. The validation of the in-capillary derivatization method under optimal conditions showed a good linearity between the heights of the derivative peaks and the concentrations of the amino acids. The intra-day relative standard deviations of the migration times and the peak heights were less than 1.3% and 4.6%, respectively. The efficient derivatization and separation of a mixture of valine, alanine, glutamic acid and aspartic acid were achieved using this technique. Peptides such as buccaline and β-protein fragment 1–42 could also be derivatized using the developed in-capillary derivatization procedure. In‑capillary derivatization and separation of amino acids with different concentrations. From the top to bottom the concentrations are 1.11×10⁻⁵ M, 5.55×10⁻⁶ M, 2.78×10⁻⁶ M, 6.95×10⁻⁷ M. for valine; 1.26×10⁻⁵ M, 6.30×10⁻⁶ M, 3.15×10⁻⁶ M, 7.88×10⁻⁷ M for alanine; 3.78×10⁻⁵ M, 1.89×10⁻⁵ M, 9.45×10⁻⁶ M, 2.36×10⁻⁶ M for glutamic acid;, 4.27×10⁻⁵ M, 2.14×10⁻⁵ M, 1.07×10⁻⁵ M, 2.68×10⁻⁶ M for aspartic acid. Experiment conditions: injection order: 4s for sample, 1s for absolute ethanol, and then 2s for 5.24×10⁻² M NBD‑F; BGE: 20 mM borate pH 8.77; Applied voltage: 15 kV.     

IR spectra of 2-alkylamino-and alkylnitramino-3-or 5-nitro-4-methylpyridine derivatives

IR spectra of some N-substituted 2-amino-3-nitro- and 2-amino-4-methyl-5-nitropyridines were measured and interpreted. Assignments and the influence of substituents on the vibration of the pyridine ring were established.Department of Organic Chemistry, Academy of Economics, Pl-53 342 Wroclaw, Poland Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 908–913, July, 2000.     

2,3-Benzodiazepine-1-thione in the synthesis of substituted and hetero-annelated 2,3-benzodiazepines

A series of S-substituted and 1,2-annelated derivatives of 2,3-benzodiazepine has been obtained on the basis of 2,3-benzodiazepine-1-thione. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 594-601, April, 2009.