Rajeshwar R A O Bojja | National Institute of Technology, Warangal (original) (raw)
Papers by Rajeshwar R A O Bojja
SN Applied Sciences, 2020
(E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol (1) has been synthesized and its... more (E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol (1) has been synthesized and its computational investigations have been carried out through semi-empirical Austin Model-1 (AM1), SCF-MM2 and DFT/B3LYP methods in relation to its solid state molecular structure determined by single-crystal X-ray diffraction to correlate structural parameters in the gaseous state under vacuum to empirical those of the molecule in its crystalline solid state. The compound is reported to crystallize in monoclinic system in space group P21/n with crystal data as a = 15.1589(12) Å, b = 7.4349(5) Å, c = 15.4287(13) Å, β = 98.340(4), V = 1720.5(2) Å 3 , Z = 4, density = 1.353 Mg/m 3 , F (000) = 736, T = 296(2) K, obtained through reflections collected/unique = 13,631/4112. The shifts in various relevant bond lengths, bond angles, dihedral angles, etc. under AM1, B3LYP and MM2 treatments are discussed. Graphic abstract (E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol has been synthesized and its structural aspects in its solid state obtained by single crystal XRD have been compared with those in its gas phase evaluated by Austin Model-1 under AM1, DFT/B3LYP and ChemSoft's ChemDraw Pro under MM2 Calculations.
Research Square (Research Square), Jan 17, 2023
Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesi... more Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesis of DNA and RNA to participate in energy transfer processes, intracellular signalling, and the regulation of proteins' biological activity. The changing of the base sequence is to cause chromosomal mutations which are sometimes useful and occasionally harmful. Phosphorylation of Nucleosides and Nucleotides have been optimized and evaluated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (∆H f o), dipole moment (µ), energies of frontier molecular orbitals (E HOMO and E LUMO) and quantum chemical descriptors have been performed. It is observed that stability of nucleosides in DNA (deoxythymidin > deoxycytidine > deoxyguanosine > deoxyadenosine) as per heats of formation (∆H f o) data. The dipole moment (µ) of nucleosides are investigated in DNA (deoxythymidin > deoxycytidine > deoxyadenosine > deoxyguanosine). Furthermore, the dipole-dipole interactions take part a critical role during the sequencing and replication of DNA has been discussed.
World Journal of Pharmaceutical Research , 2023
Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesi... more Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesis of DNA and RNA to participate in energy transfer processes, intracellular signalling, and the regulation of proteins' biological activity. The changing of the base sequence is to
3081-3088The geometry and electronic structure of cytosine and cytidine involving [1, 3]sigmatrop... more 3081-3088The geometry and electronic structure of cytosine and cytidine involving [1, 3]sigmatropic hydrogen migration in the formation of tautomers have been fully optimized and calculated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (ΔHfo), dipole moments (μ), full atomic charges, and energies of frontier molecular orbital (EHOMO and ELUMO) have been calculated and discussed. The conformational analyses and the mechanism of [1,3]sigmatropic rearrangement in cytosine and cytidine has also been studied by the comparison of net charges of atoms in the different positions of the molecule. All tautomers are existed within the change of energy of 20.390 kcal/mol. Furthermore, it is predicted the type of dipole-dipole attraction for making hydrogen bonding which is responsible for self-duplication of molecule to exist as stable conformations
terapeuticamente efficace e conseguentemente lo sviluppo come farmaco anticancro. Al fine di supe... more terapeuticamente efficace e conseguentemente lo sviluppo come farmaco anticancro. Al fine di superare i problemi derivanti dall'uso nei pazienti delle citochine (e dell'IL12 in particolare), e' stato proposto l'impiego di immunocitochine (citochine fuse ad anticorpi o frammenti anticorpali) con lo scopo di concentrare l'attivita' del sistema immunitario esclusivamente nella regione interessata dalla malattia. In questa tesi descrivo il disegno e la costruzione di F8-IL12, una immunocitochina eterodimerica, composta da scFv(F8) (un frammento anticorpale, specifico per l'extra-dominio A della fibronectina, regione soggetta a splicing alternativo) fuso alle due subunita' dell'interleuchina 12 umana. Tale immunocitochina e' stata stabilmente espressa in cellule di mammifero e purificata all'omogeneita' mantenendo l'attivita' biologica. In experimenti preclinici in topi, questo nuovo prodotto farmaceutico ha mostrato di possedere straordinarie capacita' di accumulo selettivo a livello tumorale.
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2006
The geometry and electronic Structure of zwitterions of 6-aminopenicillanic acid (6-APA) have bee... more The geometry and electronic Structure of zwitterions of 6-aminopenicillanic acid (6-APA) have been optimized and calculated by semi-empirical molecular orbital AMI method. The mechanism of formation of zwitterions of 6-APA has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (ΔΗ° f ), dipole moments (μ), ionization potentials (IP), full atomic charges, and energies of frontier molecular orbital (E HOMO and E LUMO ) have been performed and discussed. The effect of conformational changes and electronic properties of stable conformations have been determined.
Book, 0
Compilation research publications in the form of book on Computational study of medicinally impor... more Compilation research publications in the form of book on Computational study of medicinally important antibiotics. It consists of tautomerism, protonation, zwitterion formation, mass spectral fragmentation, kinetic study,
The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimize... more The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule surrounded by vacuum. Further, the mechanism of protonation in phenoxymethylpenicillin has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and discussed. The conformational analyses of mono-and di-protonated species and their stable conformations have also been performed. Introduction Penicillin derivatives have been studied extensively because of their broad anti-microbial spectra, more favourable absorption patterns and reduced undesirable side effects 1 . Significance of β-Lactam ring of penicillin has been kno...
World Journal of Pharmaceutical Research, 2019
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimize... more The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule surrounded by vacuum. Further, the mechanism of protonation in phenoxymethylpenicillin has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and ELUMO) have been performed and discussed. The conformational analyses of mono- and di-protonated species and their stable conformations have also been performed.
The electronic structure of adenine and guanine are involved in [1, 3] sigmatropic hydrogen migra... more The electronic structure of adenine and guanine are involved in [1, 3] sigmatropic hydrogen migration in the formation of tautomers, which have been optimized and evaluated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), full atomic charges and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The mechanistic investigation of [1,3] sigmatropic rearrangement in adenine and guanine have been studied by the comparison of net charges of hetero atoms in different positions of the molecule. It has found that all tautomers of adenine and guanine exist with in the energy of 13.572 kcal/mol and 14.203kcal/mol respectively. Furthermore, dipole moment and atomic charges of all tautomers indicated that the dipole-dipole interactions play a vital role during the synthesis of proteins and enzymes. The effect of changes and electronic properties of stable tautomers have been determined.
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2002
The geometry and electronic structure of 6-aminopenicillanic acid (6-APA) molecule having various... more The geometry and electronic structure of 6-aminopenicillanic acid (6-APA) molecule having various reaction centers have been fully optimized and calculated by semi-empirical molecular orbital AMI method. Furthermore, the effect of conformational changes on the electronic properties has been studied. In this connection, the heats of formation, dipole moments, ionization potentials, full atomic charges, and energies of frontier molecular orbital (E H O M O and E L U M O ) have been calculated and discussed. The mechanism of protonation in 6-APA has been studied by comparison of net charges on nitrogen atoms in the different positions of the molecule. The conformational analyses of mono- and di-protonated species have also been performed by AM1 and their stable conformations determined.
The electronic structure, conformation and keto-enol tautomerism in cephapirin have been optimize... more The electronic structure, conformation and keto-enol tautomerism in cephapirin have been optimized and calculated by semi-empirical molecular orbital AM1 method. The formation of zwitterions of cephapirin enol-form has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), full atomic charges and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The effects of tautomeric and conformational changes of stable conformers have been evaluated.
The geometry and electronic structure of 7-aminodeacetoxycephalosporanic acid (7-ADCA) have been ... more The geometry and electronic structure of 7-aminodeacetoxycephalosporanic acid (7-ADCA) have been fully optimized and calculated by semi-empirical molecular orbital AM1 method. The mechanism of protonation at nitrogen atoms of the molecule has been studied by the comparison of net charges in the different positions. Further, the effect of conformational changes on the electronic properties has been studied. In this connection, the heats of formation (∆Hf°), dipole moments (μ), full atomic charges, and energies of frontier molecular orbitals (EHOMO and ELUMO) have been calculated and discussed. The conformational analyses of monoand di-protonated species have also been performed by AM1 method and their stable conformations determined.
SN Applied Sciences, 2020
(E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol (1) has been synthesized and its... more (E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol (1) has been synthesized and its computational investigations have been carried out through semi-empirical Austin Model-1 (AM1), SCF-MM2 and DFT/B3LYP methods in relation to its solid state molecular structure determined by single-crystal X-ray diffraction to correlate structural parameters in the gaseous state under vacuum to empirical those of the molecule in its crystalline solid state. The compound is reported to crystallize in monoclinic system in space group P21/n with crystal data as a = 15.1589(12) Å, b = 7.4349(5) Å, c = 15.4287(13) Å, β = 98.340(4), V = 1720.5(2) Å 3 , Z = 4, density = 1.353 Mg/m 3 , F (000) = 736, T = 296(2) K, obtained through reflections collected/unique = 13,631/4112. The shifts in various relevant bond lengths, bond angles, dihedral angles, etc. under AM1, B3LYP and MM2 treatments are discussed. Graphic abstract (E)-1-(((3-fluoro-4-morpholinophenyl)imino)methyl)napthalen-2-ol has been synthesized and its structural aspects in its solid state obtained by single crystal XRD have been compared with those in its gas phase evaluated by Austin Model-1 under AM1, DFT/B3LYP and ChemSoft's ChemDraw Pro under MM2 Calculations.
Research Square (Research Square), Jan 17, 2023
Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesi... more Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesis of DNA and RNA to participate in energy transfer processes, intracellular signalling, and the regulation of proteins' biological activity. The changing of the base sequence is to cause chromosomal mutations which are sometimes useful and occasionally harmful. Phosphorylation of Nucleosides and Nucleotides have been optimized and evaluated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (∆H f o), dipole moment (µ), energies of frontier molecular orbitals (E HOMO and E LUMO) and quantum chemical descriptors have been performed. It is observed that stability of nucleosides in DNA (deoxythymidin > deoxycytidine > deoxyguanosine > deoxyadenosine) as per heats of formation (∆H f o) data. The dipole moment (µ) of nucleosides are investigated in DNA (deoxythymidin > deoxycytidine > deoxyadenosine > deoxyguanosine). Furthermore, the dipole-dipole interactions take part a critical role during the sequencing and replication of DNA has been discussed.
World Journal of Pharmaceutical Research , 2023
Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesi... more Phosphorylation of Nucleosides and Nucleotides play essential function for the enzymatic synthesis of DNA and RNA to participate in energy transfer processes, intracellular signalling, and the regulation of proteins' biological activity. The changing of the base sequence is to
3081-3088The geometry and electronic structure of cytosine and cytidine involving [1, 3]sigmatrop... more 3081-3088The geometry and electronic structure of cytosine and cytidine involving [1, 3]sigmatropic hydrogen migration in the formation of tautomers have been fully optimized and calculated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (ΔHfo), dipole moments (μ), full atomic charges, and energies of frontier molecular orbital (EHOMO and ELUMO) have been calculated and discussed. The conformational analyses and the mechanism of [1,3]sigmatropic rearrangement in cytosine and cytidine has also been studied by the comparison of net charges of atoms in the different positions of the molecule. All tautomers are existed within the change of energy of 20.390 kcal/mol. Furthermore, it is predicted the type of dipole-dipole attraction for making hydrogen bonding which is responsible for self-duplication of molecule to exist as stable conformations
terapeuticamente efficace e conseguentemente lo sviluppo come farmaco anticancro. Al fine di supe... more terapeuticamente efficace e conseguentemente lo sviluppo come farmaco anticancro. Al fine di superare i problemi derivanti dall'uso nei pazienti delle citochine (e dell'IL12 in particolare), e' stato proposto l'impiego di immunocitochine (citochine fuse ad anticorpi o frammenti anticorpali) con lo scopo di concentrare l'attivita' del sistema immunitario esclusivamente nella regione interessata dalla malattia. In questa tesi descrivo il disegno e la costruzione di F8-IL12, una immunocitochina eterodimerica, composta da scFv(F8) (un frammento anticorpale, specifico per l'extra-dominio A della fibronectina, regione soggetta a splicing alternativo) fuso alle due subunita' dell'interleuchina 12 umana. Tale immunocitochina e' stata stabilmente espressa in cellule di mammifero e purificata all'omogeneita' mantenendo l'attivita' biologica. In experimenti preclinici in topi, questo nuovo prodotto farmaceutico ha mostrato di possedere straordinarie capacita' di accumulo selettivo a livello tumorale.
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2006
The geometry and electronic Structure of zwitterions of 6-aminopenicillanic acid (6-APA) have bee... more The geometry and electronic Structure of zwitterions of 6-aminopenicillanic acid (6-APA) have been optimized and calculated by semi-empirical molecular orbital AMI method. The mechanism of formation of zwitterions of 6-APA has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (ΔΗ° f ), dipole moments (μ), ionization potentials (IP), full atomic charges, and energies of frontier molecular orbital (E HOMO and E LUMO ) have been performed and discussed. The effect of conformational changes and electronic properties of stable conformations have been determined.
Book, 0
Compilation research publications in the form of book on Computational study of medicinally impor... more Compilation research publications in the form of book on Computational study of medicinally important antibiotics. It consists of tautomerism, protonation, zwitterion formation, mass spectral fragmentation, kinetic study,
The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimize... more The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule surrounded by vacuum. Further, the mechanism of protonation in phenoxymethylpenicillin has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and discussed. The conformational analyses of mono-and di-protonated species and their stable conformations have also been performed. Introduction Penicillin derivatives have been studied extensively because of their broad anti-microbial spectra, more favourable absorption patterns and reduced undesirable side effects 1 . Significance of β-Lactam ring of penicillin has been kno...
World Journal of Pharmaceutical Research, 2019
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin... more The geometry, conformation, electronic structure of beta-lactam antibiotics i.e. benzylpenicillin, methicillin, phenethicillin, cephapirin and their tautomers have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule, which is surrounded by vacuum. The mechanism of tautomerism in beta-lactam antibiotics have been studied by comparison of the different positions of net charges at hetero-atoms in the molecule. Further, the heats of formation (∆H f o), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and E LUMO) have been performed and their stable conformations have also been evaluated.
The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimize... more The geometry, conformation and electronic structure of phenoxymethylpenicillin have been optimized and calculated in the gas phase by semi-empirical molecular orbital AM1 method usually considering an isolated molecule surrounded by vacuum. Further, the mechanism of protonation in phenoxymethylpenicillin has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E HOMO and ELUMO) have been performed and discussed. The conformational analyses of mono- and di-protonated species and their stable conformations have also been performed.
The electronic structure of adenine and guanine are involved in [1, 3] sigmatropic hydrogen migra... more The electronic structure of adenine and guanine are involved in [1, 3] sigmatropic hydrogen migration in the formation of tautomers, which have been optimized and evaluated by semi-empirical molecular orbital AM1 method. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), full atomic charges and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The mechanistic investigation of [1,3] sigmatropic rearrangement in adenine and guanine have been studied by the comparison of net charges of hetero atoms in different positions of the molecule. It has found that all tautomers of adenine and guanine exist with in the energy of 13.572 kcal/mol and 14.203kcal/mol respectively. Furthermore, dipole moment and atomic charges of all tautomers indicated that the dipole-dipole interactions play a vital role during the synthesis of proteins and enzymes. The effect of changes and electronic properties of stable tautomers have been determined.
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2002
The geometry and electronic structure of 6-aminopenicillanic acid (6-APA) molecule having various... more The geometry and electronic structure of 6-aminopenicillanic acid (6-APA) molecule having various reaction centers have been fully optimized and calculated by semi-empirical molecular orbital AMI method. Furthermore, the effect of conformational changes on the electronic properties has been studied. In this connection, the heats of formation, dipole moments, ionization potentials, full atomic charges, and energies of frontier molecular orbital (E H O M O and E L U M O ) have been calculated and discussed. The mechanism of protonation in 6-APA has been studied by comparison of net charges on nitrogen atoms in the different positions of the molecule. The conformational analyses of mono- and di-protonated species have also been performed by AM1 and their stable conformations determined.
The electronic structure, conformation and keto-enol tautomerism in cephapirin have been optimize... more The electronic structure, conformation and keto-enol tautomerism in cephapirin have been optimized and calculated by semi-empirical molecular orbital AM1 method. The formation of zwitterions of cephapirin enol-form has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆Hf o ), dipole moment (µ), full atomic charges and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The effects of tautomeric and conformational changes of stable conformers have been evaluated.
The geometry and electronic structure of 7-aminodeacetoxycephalosporanic acid (7-ADCA) have been ... more The geometry and electronic structure of 7-aminodeacetoxycephalosporanic acid (7-ADCA) have been fully optimized and calculated by semi-empirical molecular orbital AM1 method. The mechanism of protonation at nitrogen atoms of the molecule has been studied by the comparison of net charges in the different positions. Further, the effect of conformational changes on the electronic properties has been studied. In this connection, the heats of formation (∆Hf°), dipole moments (μ), full atomic charges, and energies of frontier molecular orbitals (EHOMO and ELUMO) have been calculated and discussed. The conformational analyses of monoand di-protonated species have also been performed by AM1 method and their stable conformations determined.
Book, 2022
This book is designed with the essentials of the subject for the research students as well as the... more This book is designed with the essentials of the subject for the research students as well as the post-graduates with quantum chemistry backgrounds. Thus, the computational chemistry aspects of the fundamental organic processes of antibiotics, such as tautomerism, protonation, formation of zwitterions, mass spectral fragmentation, kinetic study and X-ray diffraction have been included. [1,3]sigmatropic hydrogen migration in nucleic acids and Conformational analysis have led to the systematic interpretation of stable conformers to the prediction of new facts.
Ph.D thesis, 1984
Oxazoles and fused oxazoles are gaining considerable importance in medicine and industry. These i... more Oxazoles and fused oxazoles are gaining considerable importance in medicine and industry. These include compounds of diverse structures both aromatic and heterocyclic. They are widely used as pharmaceuticals, fluorescent whitening agents for cotton and pollster fibers, scintillators for detection of radiations, ion-exchangers, detergents and they also find application in photography. It is a well known fact that many of the natural products containing benzopyran moiety exhibit versatile physiological activities like antifungal, anticoagulant, and antifertility. Some of them have been recognized as highly carcinogenic and also found to be responsible for psoriasis.
Benzopyrano[3,4-d]oxazol-4(H)-one (which was isolated by the degradation of antibiotic Novobiocin) and its analogues were found to possess bacteriostatic and fungistatic activities. It is also interesting to note that 2-mercapto-oxazoles and their silver salts have been used in the photoconductive layer of electro photographic materials, and also as additives to polyphosphate detergents to reduce the tarnishing of metals by the detergents. 2-mercaptooxazole derivatives are also used as drugs.
In the course of present work, a number of 2-mercaptopyranobenzoxazoles have been prepared, and an investigation of the microbial activity of most of the compounds has also been carried out. At this juncture a brief review of general methods of synthesis of 2-mercaptooxazoles has been presented.