2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶的CI-MS-MS分析

二氨基-3-硝基吡啶和2_氨基-5-硝基吡啶的EI—MS质谱图接近，单纯通过Ⅱ-MS质谱图较难区分这两种异构体，作者以甲烷为反应气对2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶进行化学电离，并利用离子阱质谱的串联质谱技术在离子阱内以He作碰撞气进行碰撞诱导裂解，所得的CI—MS—MS质谱图表明，两者之间存在明显的差别，可用于2-氨基-3-硝基吡啶和2-氨基一5一硝基吡啶的鉴别。     

The Mannich reaction with 2-methyl-5-vinylpyridine

1,3-Bis(dimethylamino)-2-(5-vinyl-2-pyridyl)propane and 2-(-dimethylaminoethyl)-5-vinylpyridine were prepared by the aminomethylation of 2-methyl-5-vinylpyridine. These Mannich bases have been transformed into 1-dimethylamino-2-(5-vinyl-2-pyridyl)-1-propene and 2,5-divinylpyridine by the decomposition of their quaternary salts.     

Anodic oxidation of sodium 2-mercaptobenztiazolate anion in the presence of 5-methyl-2-hexanol

The anodic oxidation of the sodium 2-mercaptobenztiazolate anion in alkaline solution yields a finely dispersed difficultly filterable form of di-(2-benztiazolyl)disulfide, an accelerant of the rubber sulfur vulcanization. A crucial problem in the establishing of the continuous di-(2-benztiazolyl)disulfide electrosynthesis is the choice of reaction mixture, which ensures easy filtration of the target product. It was found by using oscillographic voltammetry at platinum microelectrode that the sodium 2-mercaptobenztiazolate anion in aqueous alkaline solution in the presence of 5-methyl-2-hexanol is oxidized to a radical that undergoes dimerization, thus yielding easily filterable form of di-(2-benztiazolyl)disulfide. The obtained result is explained by assuming that the dimer formation occurs in the 5-methyl-2-hexanol adsorption layer at the electrode surface. A reaction scheme of the process is suggested.     

2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶的EI/MS/MS分析

2 氨基 3 硝基吡啶和2 氨基 5 硝基吡啶的一级质谱图接近,单纯通过一级质谱图较难区分这两种异构体,利用离子阱质谱的串联质谱技术对2 氨基 3 硝基吡啶和2 氨基 5 硝基吡啶在离子阱内以He作碰撞气进行碰撞诱导裂解,所得的二级质谱图表明,两者之间存在明显的差别,可用于2 氨基 3 硝基吡啶和2 氨基 5 硝基吡啶的鉴别。     

Structures of the intermediates formed in the ring-opening reaction of 2-chloro-3-nitropyridine

The reaction of 2-chloro-3-nitropyridine with two equivalents of hydroxide ion was studied by NMR and X-ray crystallography. On the basis of NMR coupling constants, the originally formed ring-opened intermediate is the pseudo-cis form, as predicted by the SN(ANRORC) mechanism. However, the first intermediate is unstable and isomerizes to a second intermediate, which was isolated. The pseudo-trans geometry of the second intermediate [3-pentenenitrile, 2-nitro-5-oxo, ion(-1), sodium] explains why additional base does not lead to the ring-closing reaction as observed with 2-chloro-5-nitropyridine.     

Femtosecond studies of charge-transfer mediated proton transfer in 2-butylamino-6-methyl-4-nitropyridine N-oxide

We have unraveled the effects of an amino substituent in the ortho position on the excited-state dynamics of 4-nitropyridine N-oxide by studying the picosecond fluorescence kinetics and femtosecond transient absorption of a newly synthesized compound, 2-butylamino-6-methyl-4-nitropyridine N-oxide, and by quantum chemical calculations. Similar to the parent compound, the S(1) state of the target molecule has significant charge-transfer character and shows a large (approximately 8000 cm(-1)) static Stokes shift in acetonitrile. Analysis of the experimental and the theoretical results leads, however, to a new scenario in which this intramolecular charge transfer triggers in polar, aprotic solvents an ultrafast (around 100 fs) intramolecular proton transfer between the amino and the N-O group. The electronically excited N-OH tautomer is subsequently subject to solvent relaxation and decays with a lifetime of approximately 150 ps to the ground state.     

Successive electron transfer reaction of the lithium salt of 5-methyl-5,10-dihydrophenazine anion with 4-nitrophenethyl bromide via 4-nitrostyrene

The reaction of lithium salt of 5-methyl-5,10-dihydrophenazine anion with 4-nitrophenethyl bromide in 1,2-dimethoxyethane gave unexpected compounds, 1,2-bis[5-(10-methyl-5,10-dihydrophenazinyl)]-1-(4-nitrophenyl)ethane and 1,4-bis(4-nitrophenyl)-1,4-bis[5-(10-methyl-5,10-dihydrophenazinyl)]butane, while the reaction in dimethyl sulfoxide brought about the formation of 5-methyl-10-(4-nitrophenethyl)-5,10-dihydrophenazine. The successive electron transfer mechanism is proposed for the former reaction via 4-nitrostyrene.     

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.     

Crystal structure of 2-nitropyridine

The crystal structure of 2-nitropyridine has been determined by x-ray diffraction analysis. The influence of the nitro group on the geometric parameters of the molecule was evaluated, as well as its influence on the molecular parameters of other nitropyridines, depending on the position of this group in the pyridine ring. Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090. E-mail: gatilov@nioch.nsc.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1371, October, 1998.     

Synthesis and Chemical Conversions of 2-Chloro-3-cyano-4-methylamino-5-nitropyridine

5-Cyano-6-(-dimethylamino)vinyl-1-methyl-4-pyrimidinone was synthesized by the interaction of -cyano--(N-methylamino)crotonamide with N,N-dimethylformamide diethylacetal. Recyclization of the product in alkaline medium leads to 3-cyano-4-methylamino-2-pyridone. Nitration of the latter and transformation of the nitropyridone by boiling in POCl₃ gave 2-chloro-3-cyano-4-methylamino-5-nitropyridine. This is a key compound for various transformations including the synthesis of derivatives of dipyrido[1,2-a:3,2-e]pyrimidine, thieno[2,3-b]pyridine, and (2-pyridylamino)polyene derivatives.     

Conformational analysis of the complex of 2-methyl-1,3,2-dioxaborinane with hydroxyl anion

Studies of the conformationsl transformations of the complex of 2-methyl-1,3,2-dioxaborinane with the hydroxyl anion performed by the quantum-chemical method HF/6-31+G(d) showed that they are more versatile than those in the initial boric ester, include the existence of six minima, five transition states, and are close to the conformational behavior of 1,3-dioxanes.     

Demjanov reaction with 1-methyl-2-aminomethylpiperidine

The Demjanov rearrangement with ring expansion proceeds to a slight degree (9%) during the deamination of 1-methyl-2-aminomethylpiperidine with nitrous acid, and the major reaction products are 1-methyl-2-hydroxymethylpiperidine and 6-methylamino-2-hexanone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1654–1658, December, 1970.     

Stereochemistry of the Horner-Emmons reaction of 3-functionalized 2-methyl-2-propenylphosphonates with aliphatic aldehydes 5. Effects of base anion,temperature, solvent,and addition of a crown ether

Taking the reaction of diethyl 3-ethoxycarbonyl-2-methyl-2-propenylphosphonate with 3-methylbutanal as an example, it has been shown that the composition of the equilibrium mixture of the E- and Z-isomers of the starting phosphonate formed in the presence of bases is independent of the base anion (KOH or K₂CO₃) and the solvent (benzene or DMSO). In the mixture of 2E,4E- and 2Z,4E-isomers of ethyl 3, 7-dimethyl-2, 4-octadienoate formed in this reaction, the proportion of the 2E, 4E-ester falls as the temperature is reduced from +40 to –40C; the proportion of the 2E, 4E-ester in the heterophase system base/aprotic solvent increases with increasing polarity; and in the presence of 10 mole % of 18-crown-6 ether the proportion of the 2E, 4E-isomer is increased, being greater than 50% in all solvents. These findings indicate that the stereochemical outcome of the reaction depends on the balance between the phase systems and the chemical equilibria, including the formation, dissociation, and reactions of the intermediate products.For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2544–2550, November, 1990.     

5-Benzopyridyl-substituted 2-methyl- and 2-methyleneindolines

A method of synthesis of 5-(isoquinol-l-yl)- and 5-(quinol-2-yl)-1,3,3-trimethyl-2-methyleneindolines has been developed consisting of hetarylation of 1,2,3,3-tetra-methylindoline with isoquinoline and quinoline in the presence of benzoyl chloride, followed by oxidation and aromatization of N-benzoyl-1,2-dihydrobenzopyridine derivatives of 1,2,3,3-tetramethylindoline formed at the first stage to 5-benzopyridyl-substituted 2-methylene-indolines.For a preliminary communication on this subject, see [15].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1372, October, 1989.     

5-Substituted 2-methyl- and 2-methyleneindolines

A method for the synthesis of 5-substituted 1,3,3-trimethyl-2-methyleneindolines has been developed, in which the substituents are introduced into the benzene ring of 1,2,3,3-tetramethylindolines, followed by oxidation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1474–1477, November, 1986.