Ramachandra Hosmane - Academia.edu (original) (raw)
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Papers by Ramachandra Hosmane
J Am Chem Soc, 1982
... triazine ( 1),4 for the first time and have determined its physical and spectroscopic propert... more ... triazine ( 1),4 for the first time and have determined its physical and spectroscopic properties and its structure by X-ray crystallography. This compound has been the subject of numerous theoretical calculations and prediction^^,^ as (1) Liebig, J. Ann. Pharm. (Lemgo, Ger.) 1834 ...
![Research paper thumbnail of ChemInform Abstract: An Efficient, Short Synthesis and Potent Anti-Hepatitis B Viral Activity of a Novel Ring-Expanded Purine Nucleoside Analogue Containing a 5:7-Fused, Planar, Aromatic, Imidazo[4,5-e][1,3]diazepine Ring System](https://attachments.academia-assets.com/48479839/thumbnails/1.jpg)
](Journal of Medicinal Chemistry, Mar 1, 2004
As part of a program to explore structure-activity relationships for the extremely tight binding ... more As part of a program to explore structure-activity relationships for the extremely tight binding inhibition characteristics of coformycins to adenosine deaminase, a series of analogues (1a-1h) containing the imidazo[4,5-e][1,2,4]triazepine ring system has been synthesized and screened in vitro against a mammalian adenosine deaminase for inhibitory activity. While compounds 1a and 1b were synthesized in five steps starting from 4-nitroimidazole, others were derived from 1a through simple exchange reactions with the appropriate alcohols. The observed kinetics profiles and K(i) values suggest that the target compounds are competitive inhibitors that bind 6-9 orders of magnitude less tightly to the enzyme. Compounds 1c and 1d were the most active in the series with K(i)'s ranging from 12 to 15 microM.
Synthesis Stuttgart, 1981
Tetrahedron Letters, Aug 1, 1991
Journal of Heterocyclic Chemistry, 1984
Acta Chemica Scandinavica, Sep 1, 1998
Numerous models have been suggested for the important concept of aromaticity. In the current stud... more Numerous models have been suggested for the important concept of aromaticity. In the current study, a set of recently suggested models of aromaticity/homoaromaticity/anti-aromaticity for one-ring species [e.g. pyridazine, oxazole, tropilidene (cycloheptatriene), 1,4-dithiin, [8]-annulene (cyclooctatetraene)] is shown to have a common mathematical framework from which a new, unifying quantitative equation has been derived. Calculational and conceptual application is made to a well defined set of one-ring carbocycles.
Nucleos Nucleot Nucleic Acids, 1997
Coformycin analogues 1–6 were synthesized and biochemically screened against adenosine deaminase ... more Coformycin analogues 1–6 were synthesized and biochemically screened against adenosine deaminase in order to assess the relative contributions of N-4, N-6, and the N-3 sugar moiety to the mode of enzyme inhibition. Our results indicate that N-4 plays a relatively greater role than N-6 in enzyme tight-binding, and that a benzyl group can substitute for the sugar moiety at N-3. The absence of a sugar or benzyl group at N-3, however, leads to loss of activity. The hydroxyl group at C-8, while crucial for activity, does not alone confer the tight-binding characteristics to coformycins.
Journal of Physical Chemistry, 1984
Structural Chemistry, May 2, 2009
An explanation for the reported lower basicity of quinoline as compared with pyridine or isoquino... more An explanation for the reported lower basicity of quinoline as compared with pyridine or isoquinoline has been provided. The competing roles of steric hindrance and solvation effects are discussed along with resonance stabilization of neutral molecules and related ions.
RESEARCH COMMUNICATION 0892-6638/95/0009-1 085/$01 .50. © FASEB 1085 ABs'rRAcr Central to the stu... more RESEARCH COMMUNICATION 0892-6638/95/0009-1 085/$01 .50. © FASEB 1085 ABs'rRAcr Central to the study of free radical processes is the ability to identify and localize their cellular site of formation. Under the best of experimental conditions, spin trappinglESR spectroscopy can only characterize intracellular production of specific free radicals and confocal microsocopy can only localize the site of their formation.
Progress in Heterocyclic Chemistry, 2009
Http Dx Doi Org 10 1081 Ncn 100105250, Aug 17, 2006
Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an ... more Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an imidazole ring have been reported. These analogues include methyl 1-(2-hydroxyethoxymethyl)imidazole-4, 5-dicarbo-xylate (1), 4,5-dicarbamoyl-1-(2-hydroxyethoxymethyl)imidazole (2), 4,5-dicyano-1-(2-hydroxyethoxymethyl)imidazole (4), Methyl 1-(2-bromoethoxymethyl)imidazole-4,5-dicarboxylate (7), 4,5-dicyano-(2-bromoethoxymethyl)imidazole (8), and Methyl 1-(2-phosphonomethoxyethyl)imidazole (10). Also reported are a few potential prodrugs of the above compounds, including the acetyl derivatives 5 and 6 (of 1 and 4, respectively), and the diethyl phosphonate ester 9 (of 10). In addition, the corresponding benzyl-protected precursors 11 and 12 (of 1 and 4, respectively), along with their common hydrolysis product, 1-(2-benzyloxy-ethoxymethyl)-4,5-imidazoledicarboxylic acid (3), are reported. Another potential prodrug included in the list is 1-(2-acetoxyethyl)-4,5-dicyanoimidazole (15). The compounds were screened for in vitro antiviral activity against a wide variety of herpes and respiratory viruses. The most active compound was the phosphonate analogue 9 which exhibited an anti-measles virus activity with an EC50 of <2.5 microg/mL and an SI value of > 176.
Http Dx Doi Org 10 1080 15257779908041573, Oct 4, 2006
In an effort to biochemical mode of guanase inhibition as well as the structure-activity relation... more In an effort to biochemical mode of guanase inhibition as well as the structure-activity relationships of azepinomycin, five analogues (I-V) of azepinomycin were synthesized and screened against guanase from rabbit liver. Our results suggest that while the 6-hydroxy group of azepinomycin is crucial for activity, its putative transition state mode of inhibition of guanase is questionable. The additional H-bonding sites at position 5, and hydrophobic groups in and around position 3 of azepinomycin appear to be tolerated, and may in fact enhance the potency of inhibition.
J Am Chem Soc, 1982
... triazine ( 1),4 for the first time and have determined its physical and spectroscopic propert... more ... triazine ( 1),4 for the first time and have determined its physical and spectroscopic properties and its structure by X-ray crystallography. This compound has been the subject of numerous theoretical calculations and prediction^^,^ as (1) Liebig, J. Ann. Pharm. (Lemgo, Ger.) 1834 ...
Journal of Medicinal Chemistry, Mar 1, 2004
As part of a program to explore structure-activity relationships for the extremely tight binding ... more As part of a program to explore structure-activity relationships for the extremely tight binding inhibition characteristics of coformycins to adenosine deaminase, a series of analogues (1a-1h) containing the imidazo[4,5-e][1,2,4]triazepine ring system has been synthesized and screened in vitro against a mammalian adenosine deaminase for inhibitory activity. While compounds 1a and 1b were synthesized in five steps starting from 4-nitroimidazole, others were derived from 1a through simple exchange reactions with the appropriate alcohols. The observed kinetics profiles and K(i) values suggest that the target compounds are competitive inhibitors that bind 6-9 orders of magnitude less tightly to the enzyme. Compounds 1c and 1d were the most active in the series with K(i)&amp;amp;amp;amp;amp;#39;s ranging from 12 to 15 microM.
Synthesis Stuttgart, 1981
Tetrahedron Letters, Aug 1, 1991
Journal of Heterocyclic Chemistry, 1984
Acta Chemica Scandinavica, Sep 1, 1998
Numerous models have been suggested for the important concept of aromaticity. In the current stud... more Numerous models have been suggested for the important concept of aromaticity. In the current study, a set of recently suggested models of aromaticity/homoaromaticity/anti-aromaticity for one-ring species [e.g. pyridazine, oxazole, tropilidene (cycloheptatriene), 1,4-dithiin, [8]-annulene (cyclooctatetraene)] is shown to have a common mathematical framework from which a new, unifying quantitative equation has been derived. Calculational and conceptual application is made to a well defined set of one-ring carbocycles.
Nucleos Nucleot Nucleic Acids, 1997
Coformycin analogues 1–6 were synthesized and biochemically screened against adenosine deaminase ... more Coformycin analogues 1–6 were synthesized and biochemically screened against adenosine deaminase in order to assess the relative contributions of N-4, N-6, and the N-3 sugar moiety to the mode of enzyme inhibition. Our results indicate that N-4 plays a relatively greater role than N-6 in enzyme tight-binding, and that a benzyl group can substitute for the sugar moiety at N-3. The absence of a sugar or benzyl group at N-3, however, leads to loss of activity. The hydroxyl group at C-8, while crucial for activity, does not alone confer the tight-binding characteristics to coformycins.
Journal of Physical Chemistry, 1984
Structural Chemistry, May 2, 2009
An explanation for the reported lower basicity of quinoline as compared with pyridine or isoquino... more An explanation for the reported lower basicity of quinoline as compared with pyridine or isoquinoline has been provided. The competing roles of steric hindrance and solvation effects are discussed along with resonance stabilization of neutral molecules and related ions.
RESEARCH COMMUNICATION 0892-6638/95/0009-1 085/$01 .50. © FASEB 1085 ABs'rRAcr Central to the stu... more RESEARCH COMMUNICATION 0892-6638/95/0009-1 085/$01 .50. © FASEB 1085 ABs'rRAcr Central to the study of free radical processes is the ability to identify and localize their cellular site of formation. Under the best of experimental conditions, spin trappinglESR spectroscopy can only characterize intracellular production of specific free radicals and confocal microsocopy can only localize the site of their formation.
Progress in Heterocyclic Chemistry, 2009
Http Dx Doi Org 10 1081 Ncn 100105250, Aug 17, 2006
Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an ... more Syntheses of a few acyclic nucleoside and acyclic nucleoside phosphonate analogues containing an imidazole ring have been reported. These analogues include methyl 1-(2-hydroxyethoxymethyl)imidazole-4, 5-dicarbo-xylate (1), 4,5-dicarbamoyl-1-(2-hydroxyethoxymethyl)imidazole (2), 4,5-dicyano-1-(2-hydroxyethoxymethyl)imidazole (4), Methyl 1-(2-bromoethoxymethyl)imidazole-4,5-dicarboxylate (7), 4,5-dicyano-(2-bromoethoxymethyl)imidazole (8), and Methyl 1-(2-phosphonomethoxyethyl)imidazole (10). Also reported are a few potential prodrugs of the above compounds, including the acetyl derivatives 5 and 6 (of 1 and 4, respectively), and the diethyl phosphonate ester 9 (of 10). In addition, the corresponding benzyl-protected precursors 11 and 12 (of 1 and 4, respectively), along with their common hydrolysis product, 1-(2-benzyloxy-ethoxymethyl)-4,5-imidazoledicarboxylic acid (3), are reported. Another potential prodrug included in the list is 1-(2-acetoxyethyl)-4,5-dicyanoimidazole (15). The compounds were screened for in vitro antiviral activity against a wide variety of herpes and respiratory viruses. The most active compound was the phosphonate analogue 9 which exhibited an anti-measles virus activity with an EC50 of <2.5 microg/mL and an SI value of > 176.
Http Dx Doi Org 10 1080 15257779908041573, Oct 4, 2006
In an effort to biochemical mode of guanase inhibition as well as the structure-activity relation... more In an effort to biochemical mode of guanase inhibition as well as the structure-activity relationships of azepinomycin, five analogues (I-V) of azepinomycin were synthesized and screened against guanase from rabbit liver. Our results suggest that while the 6-hydroxy group of azepinomycin is crucial for activity, its putative transition state mode of inhibition of guanase is questionable. The additional H-bonding sites at position 5, and hydrophobic groups in and around position 3 of azepinomycin appear to be tolerated, and may in fact enhance the potency of inhibition.