Absorption spectra of some pyridine and pyridine N-oxide derivatives in oleum

The absorption spectra of a number of pyridlne and pyridine N-oxide derivatives in media of different acidity functions have been investigated. The bathochromic shift of the shortwave absorption band in oleum is interpreted as a consequence of the addition of a proton to the conjugate acid. The formation of a hydrogen bond between the 3-hydroxy derivative of the heterocyclic compounds investigated and the oleum, appearing as a hypsochromic shift of the long-wave absorption band, has been detected. This phenomenon is absent in the case of the 2-methoxy derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 963–966, July, 1973.     

Synthesis of a new series of pyridine and fused pyridine derivatives

The reaction of 4-methyl-2-phenyl-1,2-dihydro-6-oxo-5-pyridine- carbonitrile (1) with arylidene malononitrile afforded isoquinoline derivatives 2a,b. 6-Chloro-4-methyl-2-phenyl-5-pyridinecarbonitile (3) obtained by chlorination of compound 1 with phosphoryl chloride was converted into 6-amino-4-methyl-2-phenyl-5-pyridinecarbonitrile (4) and 6-hydrazido-4-methyl-2-phenyl-5-pyridinecarbonitrile (5) in good yield, through reactions with ammonium acetate and hydrazine hydrate, respectively. Treatment of 4 with ethyl acetoacetate, acetic anhydride, formic acid, urea and thiourea gave the corresponding pyrido [2,3-d] pyrimidine derivatives 7-10a,b. A new series of 6-substituted-4-methyl-2-phenyl-5-pyridine carbonitriles 11-13 has been synthesized via reaction of 4 with phenyl isothiocyanate, benzenesulphonyl chloride and acetic anhydride. Treatment of 4 with malononitrile gave 1,8-naphthyridine derivative 14. The reactivity of hydrazide 5 towards acetic acid, phenylisothiocyanate and methylacrylate to give pyrazolo-[3,4-b]-pyridine derivatives 15-17 was studied. Treatment of 5 with acetic anhydride, phthalic anhydride and carbon disulphide gave pyridine derivatives 18,19 and 1,2,4-triazolo-[3,4-a]-pyridine derivative 20.     

Synthesis of propionamide pyridine and pyridine n‐oxide ligands

A new set of pyridine and pyridine N‐oxides functionalized with N,N‐dimethylpropionamide pendant groups in the 2‐ and 2,6‐positions have been prepared from the combination of 2‐chloromethylpyridine and 2,6‐bis(chloromethyl) pyridine with α‐lithio N,N‐dimethyl acetamide. The coordination interaction between 2‐(N,N‐dimethylpropionamide) pyridine N‐oxide ( 10 ) and Tb(NO₃)₃ has been unambiguously defined via single crystal X‐ray diffraction analysis of Tb( 10 )(NO₃)₃(H₂O).     

Photodissociation dynamics of pyridine

Photodissociation of pyridine, 2,6-d2-pyridine, and d5-pyridine at 193 and 248 nm was investigated separately using multimass ion imaging techniques. Six dissociation channels were observed at 193 nm, including C5NH5 --> C5NH4 + H (10%) and five ring opening dissociation channels, C5NH5 --> C4H4 + HCN, C5NH5 --> C3H3 + C2NH2, C5NH5 --> C2H4 +C3NH, C5NH5 --> C4NH2 + CH3 (14%), and C5NH5 --> C2H2 + C3NH3. Extensive H and D atom exchanges of 2,6-d2-pyridine prior to dissociation were observed. Photofragment translational energy distributions and dissociation rates indicate that dissociation occurs in the ground electronic state after internal conversion. The dissociation rate of pyridine excited by 248-nm photons was too slow to be measured, and the upper limit of the dissociation rate was estimated to be 2x10(3) s(-1). Comparisons with potential energies obtained from ab initio calculations and dissociation rates obtained from the Rice-Ramsperger-Kassel-Marcus theory have been made.     

Electrochemistry of pyridine derivatives

Journal of Solid State Electrochemistry - The uniqueness of electrochemistry lies in the fact that it can make an unequivocal contribution to the studies of redox reaction mechanisms as well as it...     

Microwave spectra of pyridine and monodeuterated pyridines. Revised molecular structure of pyridine

The microwave spectra of pyridine and its 2-D, 3-D and 4-D substituted species were reinvestigated. Nuclear quadrupole coupling and centrifugal distortion effects were considered also for the deuterated species resulting in improved values for the rotational constants of these species. Hereby more reliable information about the hydrogen positions could be obtained.     

Reductive dimerization of pyridine N-oxide

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 133–134, January, 1988.     

Reaction of hydridohydroxodecacarbo-nyltriangulotriosmium with pyridine

Conclusions The following occurs when HOs₃(OH)(CO)₁₀ is reacted with pyridine or deuteropyridine: replacement of both bridge ligands in the osmium cluster, cleavage of the C-H or C-D bond, and migration of the H or D atom into the metal ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2793–2794, December, 1981.     

Halogenation of pyridine 1-oxides

The chlorination and bromination of α-lithiopyridine 1-oxides has been studied. Only dihalogenated pyridine 1-oxides are formed. In the case of bromination dipyridyl derivatives are also formed, and, indeed, predominate. Chloromercuration of the lithiopyridine 1-oxides gave highly insoluble, unresolvable mixtures of pyridylmercury derivatives. These could be brominated readily to give mixtures of 2-bromo- and 2,6-dibromopyridine 1-oxides.     

Magnesium hydride-promoted dearomatisation of pyridine

Reaction of pyridine with well defined magnesium hydride species results in heterocycle dearomatisation by a hydride transfer which occurs with the formation of magnesium compounds containing 1,2- and 1,4-dihydropyridide anions as the respective kinetic and thermodynamic products.     

Synthesis of dinitrochloromethyl pyridine derivatives

Reactions of 2-halo-6-methylpyridine-3,4-dicarbonitriles with nitric acid in the presence of hydrochloric acid led to the formation of 6-(chlorodinitromethyl)-2-halopyridine-3,4-dicarbonitriles.