Heteroaromatization with 4-phenyldiazenyl-1-naphthol. Part III: One-pot synthesis and DFT study of 4H-naphthopyran derivatives

A one pot three component reaction of 4-phenyldiazenyl-1-naphthol (1), p-chloro benzaldehyde (2) and malononitrile or ethyl cyanoacetate (3) in ethanol/piperidine under reflux afforded 2-amino-4-(p-chlorophenyl)-6-phenyldiazenyl-4H-naphtho[1,2-b]pyrano-3-carbonitrile (4a) and ethyl 2-amino-4-(p-chlorophenyl)-6-phenyldiazenyl-4H-naphtho[1,2-b]pyrano -3-carboxylate (4b). Structure of these compounds was established on the basis of IR, 1H NMR, 13C NMR, Mass and UV-Vis spectra. Molecular geometry of compounds 4a and b was obtained at B3LYP/6-31+G(d) level. Two tautomers and two conformers were geometrically optimized. The tautomers are separated by about 7.942 kcal/mol while rotational conformers are only separated by 0.511 kcal/mol. Molecular reactivity descriptors including global electrophilicity, hardness, softness and local condensed Fukui functions were computed and discussed. Frontier molecular orbitals (HOMO and LUMO) were also computed

Computational Studies on the Thermodynamic and Kinetic Parameters of Oxidation of 2-Methoxyethanol Biofuel via H-Atom Abstraction by Methyl Radical

In this work, a theoretical investigation of thermochemistry and kinetics of the oxidation of bifunctional 2-Methoxyethanol (2ME) biofuel using methyl radical was introduced. Potential-energy surface for various channels for the oxidation of 2ME was studied at density function theory (M06-2X) and ab initio CBS-QB3 levels of theory. H-atom abstraction reactions, which are essential processes occurring in the initial stages of the combustion or oxidation of organic compounds, from different sites of 2ME were examined. A similar study was conducted for the isoelectronic n-butanol to highlight the consequences of replacing the ϒ CH2 group by an oxygen atom on the thermodynamic and kinetic parameters of the oxidation processes. Rate coefficients were calculated from the transition state theory. Our calculations show that energy barriers for n-butanol oxidation increase in the order of α ‹ O ‹ ϒ ‹ β ‹ ξ, which are consistent with previous data. However, for 2ME the energy barriers increase in the order α ‹ β ‹ ξ ‹ O. At elevated temperatures, a slightly high total abstraction rate is observed for the bifunctional 2ME (4 abstraction positions) over n-butanol (5 abstraction positions). © 2019, The Author(s).Scopu

Theoretical and experimental studies on anticancer drug mitoxantrone

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Mitoxantrone (MX) is an important antineoplastic drug used for treatment of different types of cancer with lower side effects. The purpose of this study is to shade more light on the mechanism of interaction between MX and biological molecules. This study would result in drug design and development. Molecular structure was computed at the B3LYP/6-31 + G(d) level. All possible intramolecular hydrogen bonding interactions were considered and calculated at the same level. Five conformers of MX were located and computed to lie in the energy range 0.000–48.495 kcal/mol. Molecular reactivity of MX towards biological systems was explored using condensed molecular descriptors, Fukui functions of electrophilic, nucleophilic and free radical attack. Molecular docking studies for the inhibition of CDK2 and DNA binding were carried out to explore the anticancer potency of MX. The role of charge transfer binding in the interaction of MX with biological molecules was investigated via studying the ability of MX to act as a charge transfer acceptor with known donors using NMR spectroscopy. Charge transfer complex formation was confirmed by proton chemical shift and stability constants were measured from the NMR chemical shift data. Stability constants of MX with donors, phenylene diamine, hexamethyl benzene and pyrene are 4.178, 2.527 and 1.240 M-1 respectively

Atmospheric Oxidation of Methyl Propanoate by the OH radical

The file attached to this record is the author's final peer reviewed version.Atmospheric oxidation of methyl propanoate (MP) by the OH radical has been performed using density functional theory (BMK, BBIK) and ab initio (MP2, CBS-QB3) calculations. The thermodynamic and kinetic parameters are calculated. Three channels have been discussed. These reactions occur through low energy barriers of 3.2–4.3 kcal/mol. The energy barriers increase in the order α < μ < β at CBS–QB3. However, BMK shows slightly different order. Rate constants and branching ratios reveal that the H-abstraction from Cα is as the dominant reaction over the whole temperature range of 200–300 K, with a competition from Cβ channel at lower temperature. The BB1K data reproduce the available experimental rate constant

A thermochemistry and kinetic study on the thermal decomposition of ethoxyquinoline and ethoxyisoquinoline

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Quantum chemical calculations were used to study the production of ethylene and keto/enol tautomers from ethoxyquinoline (2‐EQ) and ethoxyisoquinoline (1‐EisoQ and 3‐EisoQ) in the gas phase and ethanol at the MP2/6‐311++G(2d,2p)//BMK/6‐31+G(d,p) level. The obtained data indicate that the elimination of ethylene from 1‐EisoQ and 2‐EQ is slightly more favorable than from 3‐EisoQ. Formation of quinolone and isoquinolone (2‐EQO, 1‐EisoQO, and 3‐EisoQO) is kinetically favored compared to their enols. Decomposition of 2‐EQ and 1‐EisoQ to ethylene and keto forms is thermodynamically and kinetically preferable more stable than the corresponding enols. However, the hydroxy form of 3‐EisoQ is more stable than its keto tautomer in the gas phase and ethanol. The enol tautomers cost less energy when formed from their keto forms rather than from the parent ethoxyquinolone and ethoxyisoquinoline

Monte Carlo integration in Glauber model analysis of reactions of halo nuclei

Reaction and elastic differential cross sections are calculated for light nuclei in the framework of the Glauber theory. The optical phase-shift function is evaluated by Monte Carlo integration. This enables us to use the most accurate wave functions and calculate the phase-shift functions without approximation. Examples of proton nucleus (e.g. p-$^6$He, p-$^6$Li) and nucleus-nucleus (e.g. $^6$He$-^{12}$C) scatterings illustrate the effectiveness of the method. This approach gives us a possibility of a more stringent analysis of the high-energy reactions of halo nuclei.Comment: 20 pages, 8 figure

A novel class of peptide pheromone precursors in ascomycetous fungi

Recently, sexual development in the heterothallic ascomycete Trichoderma reesei (anamorph of Hypocrea jecorina) has been achieved and thus initiated attempts to elucidate regulation and determinants of this process. While the α-type pheromone of this fungus fits the consensus known from other fungi, the assumed a-type peptide pheromone precursor shows remarkably unusual characteristics: it comprises three copies of the motif (LI)GC(TS)VM thus constituting a CAAX domain at the C-terminus and two Kex2-protease sites. This structure shares characteristics of both a- and α-type peptide pheromone precursors. Presence of hybrid-type peptide pheromone precursor 1 (hpp1) is essential for male fertility, thus indicating its functionality as a peptide pheromone precursor, while its phosphorylation site is not relevant for this process. However, sexual development in a female fertile background is not perturbed in the absence of hpp1, which rules out a higher order function in this process. Open reading frames encoding proteins with similar characteristics to HPP1 were also found in Fusarium spp., of which Fusarium solani still retains a putative a-factor-like protein, but so far in no other fungal genome available. We therefore propose the novel class of h-type (hybrid) peptide pheromone precursors with H. jecorina HPP1 as the first member of this class

Biology and biotechnology of Trichoderma

Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications