Synthesis of 4-Vinylmorpholine Based on Acetylene

It has been shown that from the possible methods for the synthesis of 4-vinylmorpholine, the vinylation of morpholine with acetylene remains acceptable. A technologically accessible method for vinylation of morpholine with acetylene at atmospheric pressure was developed.

     

Synthesis of 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane) derivatives

The reaction of4-acylamino-3-cyano-1,2-dihydrospiro(naphthalene-2,1-cyclohexanes) with hydrogen chloride yields 2-substituted 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes). It was found that when the latter are condensed with methyl iodide, N-alkylation takes place exclusively. Alkylation with ethyl iodide in analogous conditions yields a mixture of O- and N-substituted products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 658–661, May, 1992.     

Dimroth rearrangement in the row of new pyrano[3,4-c][1,2,4]triazolo[4,3-a][1,5-a]pyridines and synthesis of new heterocyclic systems: Pyranopyrazolo[4,3-e][1,2,4]triazolopyridines

New and effective methods for the synthesis of derivatives of pyrano[3,4-c][1,2,4]triazolo[4,3-a][1,5-a]pyridines were developed. Synthesized new tetracyclic heterocyclic systems containing pyrano[3,4-c]pyridine ring unknown in the literature were obtained for the first time. The rearrangement of Dimroth in the triazolo[4,3-a]pyridine systems for the first time was studied. The possibility of rearrangement of Dimroth in the new heterocyclic system has been investigated.     

Palladium-catalysed synthesis of allyl acetates from allenes

Allyl acetates were synthesised from allenes utilising methodology based on the general reactivity of π-allyl palladium intermediates which participate efficiently in transformations involving nucleophiles. Reactions of allenes and aryl iodides in the presence of AcONa and Pd(OAc)₂/PPh₃ as the catalytic system afforded allyl acetates in moderate to good yields. Monosubstituted allenes, depending on their structure, produced either a separable mixture of two regioisomeric products or a single regioisomer. As allylic acetates can be easily hydrolysed, the methodology is applicable for the synthesis of allyl alcohols as well.     

Synthesis of 2-alkyl thio-substituted 4-oxo-3-p-tolyl-3,4,5,6-tetrahydrospiros-(Benzo[h]quinazoline-5,1′-cycloalkanes)

Reaction of 4-amino-3-carbethoxy-1,2-dihydrospiro(naphthalene-2,1-cycloalkanes) with p-tolylisothio-cyanate gave 4-oxo-2-thioxo-3-p-tolyl-1,2,3,4,5,6-hexahydro(benzo[h]quinazoline-5,1-cycloalkanes) which could be alkylated using various halo compounds to yield the corresponding S-alkyl derivatives.A. L. Mndzhoyan Institute of Fine Organic Chemistry, Armenian Academy of Sciences, Yerevan 375014; e-mail:msrc@ipia.sci.am. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1655–1658, December, 1999.     

Quantum-chemical investigation of 4-oxo-2-thioxospiro(benzo[h]quinazoline-5,1'-cycloalkanes) in alkylation reactions

The method of CMC was used to study the electronic and steric structure of 3-substituted 4-oxo-2-thioxospiro(benzo[h]quinazoline-5,l'-cycloalkanes) and the corresponding deprotonated forms, as well as their indexes of reactivity in alkylation reactions. The calculated values of charges on the atoms and of -orbital partial densities on the HOMO and LFMO enabled a quantum-chemical explanation for the formation of S-alkylated products to be given.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences (NAN) of the Republic of American, Yerevan 375014 Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1531–1536, November, 1999.     

Rotational excitation cross sections of para-H2 + para-H2 collisions. A full-dimensional wave-packet propagation study using an exact form of the kinetic energy

A full-dimensional quantum dynamical study of the rotational excitation in para-para H2 + H2 collisions using the potential-energy surface of Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] is reported. The multiconfiguration time-dependent Hartree algorithm is utilized to propagate wave packets and the cross sections for collision energies up to 1.2 eV are determined by a flux analysis through the interaction of the wave packet with a complex absorbing potential. Calculations for a collection of total angular momenta up to J = 70 are performed; the missing channels are obtained with a J-interpolation algorithm.     

Quantum dissipative chaos in the statistics of excitation numbers

A quantum manifestation of chaotic classical dynamics is found in the framework of oscillatory number statistics for the model of a nonlinear dissipative oscillator. It is shown that the probability distributions and variances of oscillatory number states are strongly transformed in the order-to-chaos transition. A nonclassical, sub-Poissonian statistics of oscillatory excitation numbers is established for chaotic dissipative dynamics in the framework of the Fano factor and Wigner functions. It is proposed to use these results in experimental studies of the quantum dissipative chaos.     

Annulations of isoquinoline and β-carboline ring systems: synthesis of 8-oxoprotoberberine derivatives

Annulation processes of isoquinoline and β-carboline compounds have been investigated leading to synthetic routes for the preparation of 8-oxoprotoberberine derivatives. The key steps combined a diene formation/Diels-Alder cycloaddition reaction to afford the targeted polycyclic skeletons. Further oxidative transformations of the cycloadducts produced the 8-oxoprotoberberine type products. The alkaloids of this class are important natural products with a wide range of biological activity and the synthethic methodology described in this paper could prove to be useful for the preparation of the D-ring functionalised derivatives.     

Microsecond simulations of DNA and ion transport in nanopores with novel ion–ion and ion–nucleotides effective potentials

We developed a novel scheme based on the grand‐canonical Monte Carlo/Brownian dynamics simulations and have extended it to studies of ion currents across three nanopores with the potential for single‐stranded DNA (ssDNA) sequencing: solid‐state nanopore Si₃N₄, α‐hemolysin, and E111N/M113Y/K147N mutant. To describe nucleotide‐specific ion dynamics compatible with ssDNA coarse‐grained model, we used the inverse Monte Carlo protocol, which maps the relevant ion–nucleotide distribution functions from all‐atom molecular dynamics (MD) simulations. Combined with the previously developed simulation platform for Brownian dynamics simulations of ion transport, it allows for microsecond‐ and millisecond‐long simulations of ssDNA dynamics in the nanopore with a conductance computation accuracy that equals or exceeds that of all‐atom MD simulations. In spite of the simplifications, the protocol produces results that agree with the results of previous studies on ion conductance across open channels and provide direct correlations with experimentally measured blockade currents and ion conductances that have been estimated from all‐atom MD simulations. © 2014 Wiley Periodicals, Inc.