Methylamination of some 3,6-dinitro-1,8-naphthyridines with liquid methylamine – potassium permanganate

2000 ◽  
Vol 78 (7) ◽  
pp. 950-956
Author(s):  
Marian Wozniak ◽  
Maria Grzegozek ◽  
Piotr Surylo
Keyword(s):  
Quantum Chemical Calculations ◽  
Potassium Permanganate ◽  
Satisfactory Agreement ◽  
Quantum Chemical ◽  
Transition States ◽  
Molecular Orbitals ◽  
Heats Of Formation ◽  
Convenient Synthesis

3,6-Dinitro-1,8-naphthyridine and its 2-substituted derivatives are dehydro-methylaminated with the solution of potassium permanganate in liquid methylamine (LMA–PP) to the corresponding mono- or mono- and bis(methylamino)-3,6-dinitro-1,8-naphthyridines. In the case of 2-chloro- and 2-methoxy-3,6-dinitro-1,8-naphthyridine the replacement of chloro and methoxy substituents by the NHCH3 group occurs as well. Quantum-chemical calculations indicate the reactions to be controlled by the interaction of the frontal molecular orbitals (FMO) of the reagents. Moreover the heats of formation of intermediary methylamino-σ-adducts and transition states are calculated for the reaction studied. The calculations show satisfactory agreement between calculated and observed results. A convenient synthesis of some 2-substituted-3,6-dinitro-1,8-naphthyridines is reported.Key words: methylaminations, calculations PM3, nitro-1,8-naphthyridines, oxidation.

Strukturen ladungsgestörter oder räumlich überfüllter Moleküle, 80 [1 - 3] Strukturänderungen von p-Benzochinon durch Donator- und Akzeptor-Substituenten

1996 ◽  
Vol 51 (2) ◽  
pp. 153-171 ◽  
Author(s):  
Hans Bock ◽  
Sabine Nick ◽  
Wolfgang Seitz ◽  
Christian Näther ◽  
Jan W. Bats
Keyword(s):  
Charge Distribution ◽  
Quantum Chemical Calculations ◽  
Satisfactory Agreement ◽  
Quantum Chemical ◽  
Structural Changes ◽  
Structural Data ◽  
Semiempirical Calculations ◽  
Reduction Potentials ◽  
Donor Acceptor ◽  
Structural Summary

Abstract The structures of seven di- or tetrasubstituted p-benzoquinone derivatives O=C(XC=CH )2C=O and O=C(XC=CX)2C=O with substituents X = -OCH3, -N(CH2)5, - N(CH2CH2)2O, -Cl, -CN and -⊕N(HC=CH)2C-N(CH3)2 are presented and discussed in comparison with published ones substituted by X = -Si(CH3)3, -C6H5, -N(CH3)2, -⊕N(HC=CH)2CN(CH3)2, -O⊖ , and - NO2. Based on the introduction, in which halfwave-reduction potentials, geometry-optimized quantum-chemical calculations on substituent perturbation and known structural data of p-benzoquinone derivatives are used to characterize their molecular ground states. The structural changes indicate how substituent perturbations might be rationalized. Of the categories defined - imperturbed, donor, donor/acceptor and acceptor perturbed - the donorsubstituted p-benzoquinones do exhibit the largest differences, often called cyanine distorsion. In very satisfactory agreement with extensive semiempirical calculations, all effects determined experimentally are discussed in terms of varying charge distribution. With respect to the biochemical importance of p-benzoquinone derivatives, this first structural summary points out important facets.

scholarly journals Combined Graph/relational Database Management System for Calculated Chemical Reaction Pathway Data

2020 ◽  
Author(s):  
Timur Gimadiev ◽  
Ramil Nugmanov ◽  
Dinar Batyrshin ◽  
Timur Madzhidov ◽  
Satoshi Maeda ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Chemical Reaction ◽  
Relational Database ◽  
Quantum Chemical ◽  
Reaction Pathway ◽  
Transition States ◽  
Structural Data ◽  
Database Management System ◽  
Pathway Data ◽  
Machine Learning Applications

Nowadays quantum chemical calculations are widely used to generate extensive datasets for machine learning applications, however, generally these sets only include information on equilibrium structures and some close conformers. Exploration of potential energy surface provides an important information on ground and transition states, but analysis of such data is complicated due to the number of possible reaction pathways. Here, we present RePathDB, a database system for managing 3D structural data for both ground and transition states resulted from quantum chemical calculations. Our tool allows to store, to assemble and to analyze reaction pathway data. It combines relational database CGR DB for handling compounds and reactions as molecular graphs with a graph database architecture for the pathway analysis by graph algorithms. Original Condensed Graph of Reaction Technology is used to store any chemical reaction as a single graph.

HEATS OF FORMATION FOR BORON COMPOUNDS BASED ON QUANTUM CHEMICAL CALCULATIONS

2010 ◽  
Vol 09 (06) ◽  
pp. 1009-1019
Author(s):  
JIAHENG ZHANG ◽  
SHIQIAN WEI ◽  
CHAOZHU MAO ◽  
LIANG CHEN ◽  
HAIXIANG GAO ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Excellent Agreement ◽  
Quantum Chemical ◽  
Good Accuracy ◽  
Heats Of Formation ◽  
Boron Compounds ◽  
Light Atoms ◽  
Cl Atoms

We have calculated the heats of formation at 298.15 K of series of boron compounds including H , N , O , F , Cl atoms using the atomization enthalpies analysis based on eleven quantum chemical calculations. The majority of calculated values are in excellent agreement with available experiment values and Gaussian-n methods perform more accurate evaluations than other approaches. As with the existing literature, the following calculations of the heats of formation of borides containing light atoms are recommended as accurate values: ΔfHG2,298 (BH) = 442.731 kJ·mol-1, ΔfHG2,298 (BF3) = -1135.749 kJ·mol-1, the deviations are respectively 0.031 kJ·mol-1 and 0.251 kJ·mol-1. Furthermore, ab initio calculations of heats of formation of chlorinated boron compounds also show good accuracy and comparisons with previous thermodynamics data are made.

scholarly journals Combined Graph/relational Database Management System for Calculated Chemical Reaction Pathway Data

2020 ◽  
Author(s):  
Timur Gimadiev ◽  
Ramil Nugmanov ◽  
Dinar Batyrshin ◽  
Timur Madzhidov ◽  
Satoshi Maeda ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Chemical Reaction ◽  
Relational Database ◽  
Quantum Chemical ◽  
Reaction Pathway ◽  
Transition States ◽  
Structural Data ◽  
Database Management System ◽  
Pathway Data ◽  
Machine Learning Applications

Nowadays quantum chemical calculations are widely used to generate extensive datasets for machine learning applications, however, generally these sets only include information on equilibrium structures and some close conformers. Exploration of potential energy surface provides an important information on ground and transition states, but analysis of such data is complicated due to the number of possible reaction pathways. Here, we present RePathDB, a database system for managing 3D structural data for both ground and transition states resulted from quantum chemical calculations. Our tool allows to store, to assemble and to analyze reaction pathway data. It combines relational database CGR DB for handling compounds and reactions as molecular graphs with a graph database architecture for the pathway analysis by graph algorithms. Original Condensed Graph of Reaction Technology is used to store any chemical reaction as a single graph.

COMPARISON OF PHOTOELECTRON SPECTRA OF ${\rm Cu}_n^-$, ${\rm Ag}_n^-$, AND ${\rm Na}_n^-$: MOLECULAR ORBITALS VERSUS ELECTRONIC SHELLS

1996 ◽  
Vol 03 (01) ◽  
pp. 399-403 ◽  
Author(s):  
G. GANTEFÖR ◽  
H. HANDSCHUH ◽  
H. MÖLLER ◽  
CHIA-YEN CHA ◽  
P.S. BECHTHOLD ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Shell Model ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Electronic States ◽  
Molecular Orbitals ◽  
Photoelectron Spectra

The photoelectron spectra of [Formula: see text] clusters are compared to the results of quantmn-chemical ab-initio calculations (n=2-9) and to the predictions of the shell model. The shell model yields qualitative assignments of the dominant features in the spectra to photoemission from occupied electronic shells. These correspond to the exact quantitative assignments to transitions into various electronic states of the neutral clusters according to the quantum-chemical calculations. The photoelectron spectra of [Formula: see text] and [Formula: see text] clusters exhibit certain similarities to the Ag data in agreement with the basic idea of the shell model.

scholarly journals Structure and stereochemistry of electrochemically synthesized poly-(l-naphthylamine) from neutral aceto- nitrile solution

2002 ◽  
Vol 67 (12) ◽  
pp. 867-877 ◽  
Author(s):  
Gordana Ciric-Marjanovic ◽  
Budimir Marjanovic ◽  
Vojislav Stamenkovic ◽  
Zeljko Vitnik ◽  
Vesna Antic ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Polymer Films ◽  
Quantum Chemical ◽  
Platinum Electrode ◽  
Heats Of Formation ◽  
Stereochemical Analysis ◽  
Acetonitrile Medium ◽  
Semiempirical Quantum Chemical Calculations

Poly-(1-naphthylamine) films were synthesized potentiodinamically and potentiostatically from 1-naphthylamine in neutral acetonitrile medium using a platinum electrode. These polymer films were investigated by infrared spectroscopy. Contrary to earlier published results neglecting the stereochemistry of the poly-(1-naphthylamine), we predict on the basis of quantum stereochemical analysis of the possible structural subunits of the polymer, that the ordinary N?C(4) coupled product is not predominant in the polymer because it is far removed from the expected planarity. Based on the results of IR investigations and semiempirical quantum chemical calculations, it is proposed that the polymer products are formed via mixed N?C(4), N?C(5) and N?C(7) coupling routes. The heats of formation of the oxidized 1-naphthylamine dimers and hexamers were calculated.

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

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