Synthesis of 3-arylazo-1H-pyridazin-4-ones from difluoroboron chelates of 1,3-diketones

A convenient method for the synthesis of 6-R-3-arylazo-1H-pyridazin-4-ones from difluoroboron chelates of acetylacetone and aroylacetones was developed. The method is based on the ability of the methyl group of the chelates to react with two equivalents of a diazonium salt. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1502–1506, August, 2007.     

Instanton effects in quark form factor and quark-quark scattering at high energy

The nonperturbative effects in the high-energy processes involving strongly interacting particles are studied within the instanton liquid model of the QCD vacuum (ILM) by using the Wilson integral framework. The detailed analysis of nonperturbative contributions to the electromagnetic quark form factor is presented considering the structure of the instanton-induced effects in the evolution equation describing the high energy behavior of the form factor. It is shown that the instantons yield in high energy limit the logarithmic corrections to the amplitudes which are exponentiated in small instanton density parameter. By using the Gaussian interpolation of the constrained instanton solution, we show that the all-order multi-instanton contribution is well approximated by the weak field limit result. The role of the instantons in high energy diffractive quark-quark scattering, in particular, in formation of the soft Pomeron, is also considered. We show that within the ILM the C-odd diffractive amplitude is suppressed as 1/s compared to the C-even one. The further applications of the developed approach in studying the nonperturbative effects in high energy hadronic processes are briefly discussed.     

Acetyl ketene aminals in Nenitzescu reaction

Nenitzescu reaction of acetyl ketene aminals (N,N-acetals) was investigated. The interaction of 2-acetyl-1-amino-1-anilinoethene with benzoquinone gave 3-acetyl-2-amino-7a-hydroxy-1-phenyl-5,7a-dihydro-1H-indol-5-one, which was then transformed into 3-acetyl-2-amino-6-chloro-5-hydroxy-1-phenylindole. The reaction of benzoquinone with 2-acetyl-1-amino-1-benzoylaminoethene led to the corresponding hydroquinone-adduct which was oxidized to 4-acetylamino-5-(2,5-dihydroxyphenyl)-2-phenyloxazole. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 160–165, January, 1999.     

Kinetics of the liquid-phase catalytic hydrogenation of chlorine-containing aromatic nitro compounds in the presence of pyridine

We have analyzed experimental kinetic data for nitro compound consumption, for the formation of the corresponding amino product, and for the accumulation of intermediate products and by-products in the hydrogenation of chlorine-containing aromatic nitro compounds. The reaction has been carried out under static conditions over a platinum catalyst on a porous support in the presence of pyridine. The effect of the admixture on different hydrogenation steps of a chlorine-containing aromatic nitro compound has been quantitatively interpreted.     

Synthesis of Tris(ɣ-oximinoalkyl)amines,New Tripodal N4 Ligands

An original approach to the synthesis of tris(γ-oximinoalkyl)amines was proposed. The suggested synthetic sequence is based on aza-Michael addition of ammonia to methyl vinyl ketone and oximation of obtained products with hydroxylamine or O-alkhylhydroxylamines. The tris(γ-oximinoalkyl)amines may be considered as prospective N4 tripodal ligands.     

Synthesis of quinolizin-2-one and pyrido[1,2-a]azepin-2-one derivatives from difluoroboron complexes of aroylacetones and O-methyllactims

O-Methyllactims react at the methyl group of difluoroboron complexes of aroylacetones with the formation of condensation products, novel difluoroboron chelates of 1-aryl-4-(piperi-din-2-ylidene)butane-1,3-diones and 1-aryl-4-(azepan-2-ylidene)butane-1,3-diones, which upon the action of concentrated HCl in ethanol are transformed into the corresponding quino-lizin-2-one and pyrido[1,2-a]azepin-2-one derivatives.     

The pseudoscalar hadronic channel contribution of the light-by-light process to the muon (<Emphasis Type="Italic">g</Emphasis>−2)<Subscript><Emphasis Type="Italic">μ</Emphasis></Subscript> within the nonlocal chiral quark model

The light-by-light contribution to the anomalous magnetic moment of muon (g−2) _μ from the hadronic exchanges in the neutral pseudoscalar meson channel is calculated in the nonlocal chiral quark model. The full kinematic dependence of the meson two-photon vertices from the virtualities of the mesons and photons is taken into account. It is demonstrated that the effect of the full kinematic dependence in the meson–photon vertices is to reduce the contribution of pseudoscalar exchanges comparing with the most of previous estimates and the result is a_m^PS,LbL=(5.85±0.87)·10^-10a_{\mu}^{\mathrm{PS,LbL}}=(5.85\pm0.87)\cdot10^{-10}. The status of various phenomenological and QCD short-distance constraints is discussed and the comparison with the predictions of other models is performed.     

Single spin asymmetries in high energy reactions and nonperturbative QCD effects

We discuss some experimental and theoretical results on single spin asymmetries (SSA) in high energy lepton-hadron and hadron-hadron reactions. In particular, recent results on meson SSA obtained by HERMES are considered in detail. We also discuss the SSA results obtained recently by COMPASS, as well as those from BRAHMS, PHENIX and STAR. Special attention is paid to a possible nonperturbative QCD mechanism that might be responsible for the observed meson SSA. This mechanism originates from the spin-flip quark-gluon chromomagnetic interaction induced by the complex topological structure of the QCD vacuum. We argue that in semi-inclusive deep-inelastic scattering a large SSA is expected not only for mesons but also for baryons due to strong nonperturbative final state interactions between ud-diquark and u-quark in the fragmenting proton.