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Papers by Abir Bhattacharya

Journal of Pharmaceutical and Biomedical Analysis, 2012

Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized b... more Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized by FTIR, TG-DSC and ab initio X-ray powder structure analysis. The compound, ramipril-tris (II), crystallizes in the monoclinic space group P2(1) with a=24.3341(15), b=6.4645(5), c=9.5357(7) Å, β=96.917(3)° and V=1489.1(3) Å(3). The crystal structure has been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. A network of intermolecular OH…O, CH…N and CH…O hydrogen bonds between the ramipril-ramipril, tris-tris and ramipril-tris components in the compound generates a two-dimensional molecular assembly in (110) plane. A comparative study of solid-state stabilities of ramipril-tris (II) with that of ramipril (I) and ramipril-erbumine (III) indicates that ramipril-tris (II) is the most stable one among the three, and the conversion to impurity D after 72 h at 80 °C is only 1.5%. The solution phase analysis at different pH values also reveals a greater stability of ramipril-tris (II) over ramipril (I).

… of Pharmaceutical and …, Jan 1, 2012

Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized b... more Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized by FTIR, TG-DSC and ab initio X-ray powder structure analysis. The compound, ramipril-tris (II), crystallizes in the monoclinic space group P2 1 with a = 24.3341(15), b = 6.4645(5), c = 9.5357(7)Å, ˇ = 96.917(3) • and V = 1489.1(3)Å 3 . The crystal structure has been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. A network of intermolecular O H. . .O, C H. . .N and C H. . .O hydrogen bonds between the ramipril-ramipril, tris-tris and ramipril-tris components in the compound generates a two-dimensional molecular assembly in (1 1 0) plane. A comparative study of solid-state stabilities of ramipril-tris (II) with that of ramipril (I) and ramipril-erbumine (III) indicates that ramipril-tris (II) is the most stable one among the three, and the conversion to impurity D after 72 h at 80 • C is only 1.5%. The solution phase analysis at different pH values also reveals a greater stability of ramipril-tris (II) over ramipril (I).

J. Chem. Pharm. Res, Jan 1, 2010

Several acyl hydrazone derivatives based on naproxen and ibuprofen were synthesized via a three s... more Several acyl hydrazone derivatives based on naproxen and ibuprofen were synthesized via a three step method in good yields. All the compounds synthesized were found to exist as a mixture of two rotameric forms in solution e.g. antiperiplanar (ap) and synperiplanar (sp) as indicated by their 1 H NMR spectra. This was supported by the analysis of 1D 1 H NMR and 1 H-1 H 2D Homo COSY spectra of a representative compound. The X-ray diffraction study of the single crystal of another representative compound indicated that the molecule exists as an H-bonded symmetrical dimeric ap form in the solid state. This study also confirmed the Egeometry of the C=N bond unambiguously. Many of these compounds were found to be potent when tested against human prostate cancer (Pc-3) cell line in vitro. The ibuprofen based hydrazones showed superior cytotoxicity than that of naproxen. Sarbani Pal et al J. Chem. Pharm. Res., 2010, 2(6):393-409 ___________________________________________________________________________

Journal of Molecular …, Jan 1, 2010

A nimesulide derivative, N-[4-(2,5-dioxo-2,5-dihydropyrrol-1-yl)-2-phenoxyphenyl]methanesulfonami... more A nimesulide derivative, N-[4-(2,5-dioxo-2,5-dihydropyrrol-1-yl)-2-phenoxyphenyl]methanesulfonamide (2), was synthesized and its crystal structure has been determined from X-ray powder diffraction data following direct-space global optimization technique and refined by the Rietveld method. The molecular geometry and electronic structure of the title compound were calculated at the DFT level using the hybrid exchange-correlation functional, BLYP. The optimized molecular geometry of 2 corresponds closely to that obtained from the X-ray structure analysis. Intermolecular N-HÁÁÁO and C-HÁÁÁO hydrogen bonds in 2 form one-dimensional polymeric chains of R 2 2 (8) rings propagating along the [1 0 0] direction. Further linking between parallel chains via C-HÁÁÁp (arene) hydrogen bonds generates a two-dimensional supramolecular assembly in the (1 1 0) plane. The title compound exhibits potential anti-inflammatory activity and can induce 64% edema inhibition in rat paws.

… Section C: Crystal …, Jan 1, 2010

A new lamivudine hydrate, namely, cis-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)pyrimidin-2(... more A new lamivudine hydrate, namely, cis-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)pyrimidin-2(1H)-one hemihydrate, C(8)H(11)N(3)O(3)S.0.5H(2)O, has been synthesized and structurally characterized by both powder and single-crystal X-ray diffraction studies. The hemihydrate crystallizes in the Sohnke space group P2(1), with the asymmetric unit comprising four lamivudine and two water molecules. An extensive network of intermolecular hydrogen bonds involving both lamivudine and solvent water molecules generates a three-dimensional supramolecular architecture. The structural data and crystal packing of the present lamivudine hemihydrate are compared with those of other hydrated and anhydrous forms of lamivudine.

Chemical Physics …, Jan 1, 2010

Crystal structures of three derivatives of phenylpropionic acid, 2, 3 and 4 with hydroxyl, methyl... more Crystal structures of three derivatives of phenylpropionic acid, 2, 3 and 4 with hydroxyl, methyl and methoxy substitutions at the 2, 4 positions have been determined from X-ray powder diffraction data and their electronic structures were calculated at the DFT level. The optimized molecular geometries agree closely to that obtained from the crystallographic analysis. Intermolecular O-H. . .O hydrogen bonds generate R 2 2 (8) rings, which are further connected through O-H. . .O and C-H. . .O hydrogen bonds into two-dimensional framework in 2 and 4, and a step like architecture in 3. The HOMO-LUMO energy gap (>4.0 eV) indicates a high kinetic stability of the three compounds.

Polyhedron, Jan 1, 2010

The user has requested enhancement of the downloaded file. All in-text references underlined in b... more The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Tetrahedron, Jan 1, 2010

InCl 3 catalyzed reactions of 2-C-acetoxymethylglycal derivatives with different phenolic compoun... more InCl 3 catalyzed reactions of 2-C-acetoxymethylglycal derivatives with different phenolic compounds resulted in the formation of sugar based pyranoarenopyrans in good yields and moderate to excellent diastereoselectivity in favor of 10aR-or 12aR-or 14aR-products. One of the synthesized compounds, viz. (2R,3R,12aR)-2,3,5,12a-tetrahydro-2-methoxymethyl-3-methoxypyrano[2,3-b]naphtho[1,2-e]pyran gelated polar solvents like MeOH, EtOH and non-polar solvents like pentane, hexane, heptane, octane, pet. ether, etc. The SEM picture of the corresponding hexane xerogel exhibited a rare type of microtubular gel assembly, whereas the SEM pictures of MeOH and pet. ether xerogels showed different types of threedimensional network. Study of the MeOH gel by Fluorescence spectroscopy, 1 H NMR and X-ray powder diffraction analysis indicated that the supramolecular assembly in the MeOH gel can be attributed to p-stacking. The crystal packing of (2R,3R,10aR)-3,10a-dihydro-2-methoxymethyl-3-methoxy-7-methyl-2H, 5H-pyrano[2,3-b][1]benzopyran, a benzopyran analogue of the above organogelator was stabilized by CeH/O and CeH/p hydrogen bonds forming one-dimensional columns parallel to the [001] direction, whereas the corresponding benzopyran 3-epimer showed only CeH/O hydrogen bonds among the molecules.

Journal of Pharmaceutical and Biomedical Analysis, 2012

Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized b... more Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized by FTIR, TG-DSC and ab initio X-ray powder structure analysis. The compound, ramipril-tris (II), crystallizes in the monoclinic space group P2(1) with a=24.3341(15), b=6.4645(5), c=9.5357(7) Å, β=96.917(3)° and V=1489.1(3) Å(3). The crystal structure has been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. A network of intermolecular OH…O, CH…N and CH…O hydrogen bonds between the ramipril-ramipril, tris-tris and ramipril-tris components in the compound generates a two-dimensional molecular assembly in (110) plane. A comparative study of solid-state stabilities of ramipril-tris (II) with that of ramipril (I) and ramipril-erbumine (III) indicates that ramipril-tris (II) is the most stable one among the three, and the conversion to impurity D after 72 h at 80 °C is only 1.5%. The solution phase analysis at different pH values also reveals a greater stability of ramipril-tris (II) over ramipril (I).

… of Pharmaceutical and …, Jan 1, 2012

Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized b... more Tris(hydroxymethyl) aminomethane (tris) salt of API ramipril was synthesized, and characterized by FTIR, TG-DSC and ab initio X-ray powder structure analysis. The compound, ramipril-tris (II), crystallizes in the monoclinic space group P2 1 with a = 24.3341(15), b = 6.4645(5), c = 9.5357(7)Å, ˇ = 96.917(3) • and V = 1489.1(3)Å 3 . The crystal structure has been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. A network of intermolecular O H. . .O, C H. . .N and C H. . .O hydrogen bonds between the ramipril-ramipril, tris-tris and ramipril-tris components in the compound generates a two-dimensional molecular assembly in (1 1 0) plane. A comparative study of solid-state stabilities of ramipril-tris (II) with that of ramipril (I) and ramipril-erbumine (III) indicates that ramipril-tris (II) is the most stable one among the three, and the conversion to impurity D after 72 h at 80 • C is only 1.5%. The solution phase analysis at different pH values also reveals a greater stability of ramipril-tris (II) over ramipril (I).

J. Chem. Pharm. Res, Jan 1, 2010

Several acyl hydrazone derivatives based on naproxen and ibuprofen were synthesized via a three s... more Several acyl hydrazone derivatives based on naproxen and ibuprofen were synthesized via a three step method in good yields. All the compounds synthesized were found to exist as a mixture of two rotameric forms in solution e.g. antiperiplanar (ap) and synperiplanar (sp) as indicated by their 1 H NMR spectra. This was supported by the analysis of 1D 1 H NMR and 1 H-1 H 2D Homo COSY spectra of a representative compound. The X-ray diffraction study of the single crystal of another representative compound indicated that the molecule exists as an H-bonded symmetrical dimeric ap form in the solid state. This study also confirmed the Egeometry of the C=N bond unambiguously. Many of these compounds were found to be potent when tested against human prostate cancer (Pc-3) cell line in vitro. The ibuprofen based hydrazones showed superior cytotoxicity than that of naproxen. Sarbani Pal et al J. Chem. Pharm. Res., 2010, 2(6):393-409 ___________________________________________________________________________

Journal of Molecular …, Jan 1, 2010

A nimesulide derivative, N-[4-(2,5-dioxo-2,5-dihydropyrrol-1-yl)-2-phenoxyphenyl]methanesulfonami... more A nimesulide derivative, N-[4-(2,5-dioxo-2,5-dihydropyrrol-1-yl)-2-phenoxyphenyl]methanesulfonamide (2), was synthesized and its crystal structure has been determined from X-ray powder diffraction data following direct-space global optimization technique and refined by the Rietveld method. The molecular geometry and electronic structure of the title compound were calculated at the DFT level using the hybrid exchange-correlation functional, BLYP. The optimized molecular geometry of 2 corresponds closely to that obtained from the X-ray structure analysis. Intermolecular N-HÁÁÁO and C-HÁÁÁO hydrogen bonds in 2 form one-dimensional polymeric chains of R 2 2 (8) rings propagating along the [1 0 0] direction. Further linking between parallel chains via C-HÁÁÁp (arene) hydrogen bonds generates a two-dimensional supramolecular assembly in the (1 1 0) plane. The title compound exhibits potential anti-inflammatory activity and can induce 64% edema inhibition in rat paws.

… Section C: Crystal …, Jan 1, 2010

A new lamivudine hydrate, namely, cis-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)pyrimidin-2(... more A new lamivudine hydrate, namely, cis-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)pyrimidin-2(1H)-one hemihydrate, C(8)H(11)N(3)O(3)S.0.5H(2)O, has been synthesized and structurally characterized by both powder and single-crystal X-ray diffraction studies. The hemihydrate crystallizes in the Sohnke space group P2(1), with the asymmetric unit comprising four lamivudine and two water molecules. An extensive network of intermolecular hydrogen bonds involving both lamivudine and solvent water molecules generates a three-dimensional supramolecular architecture. The structural data and crystal packing of the present lamivudine hemihydrate are compared with those of other hydrated and anhydrous forms of lamivudine.

Chemical Physics …, Jan 1, 2010

Crystal structures of three derivatives of phenylpropionic acid, 2, 3 and 4 with hydroxyl, methyl... more Crystal structures of three derivatives of phenylpropionic acid, 2, 3 and 4 with hydroxyl, methyl and methoxy substitutions at the 2, 4 positions have been determined from X-ray powder diffraction data and their electronic structures were calculated at the DFT level. The optimized molecular geometries agree closely to that obtained from the crystallographic analysis. Intermolecular O-H. . .O hydrogen bonds generate R 2 2 (8) rings, which are further connected through O-H. . .O and C-H. . .O hydrogen bonds into two-dimensional framework in 2 and 4, and a step like architecture in 3. The HOMO-LUMO energy gap (>4.0 eV) indicates a high kinetic stability of the three compounds.

Polyhedron, Jan 1, 2010

The user has requested enhancement of the downloaded file. All in-text references underlined in b... more The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Tetrahedron, Jan 1, 2010

InCl 3 catalyzed reactions of 2-C-acetoxymethylglycal derivatives with different phenolic compoun... more InCl 3 catalyzed reactions of 2-C-acetoxymethylglycal derivatives with different phenolic compounds resulted in the formation of sugar based pyranoarenopyrans in good yields and moderate to excellent diastereoselectivity in favor of 10aR-or 12aR-or 14aR-products. One of the synthesized compounds, viz. (2R,3R,12aR)-2,3,5,12a-tetrahydro-2-methoxymethyl-3-methoxypyrano[2,3-b]naphtho[1,2-e]pyran gelated polar solvents like MeOH, EtOH and non-polar solvents like pentane, hexane, heptane, octane, pet. ether, etc. The SEM picture of the corresponding hexane xerogel exhibited a rare type of microtubular gel assembly, whereas the SEM pictures of MeOH and pet. ether xerogels showed different types of threedimensional network. Study of the MeOH gel by Fluorescence spectroscopy, 1 H NMR and X-ray powder diffraction analysis indicated that the supramolecular assembly in the MeOH gel can be attributed to p-stacking. The crystal packing of (2R,3R,10aR)-3,10a-dihydro-2-methoxymethyl-3-methoxy-7-methyl-2H, 5H-pyrano[2,3-b][1]benzopyran, a benzopyran analogue of the above organogelator was stabilized by CeH/O and CeH/p hydrogen bonds forming one-dimensional columns parallel to the [001] direction, whereas the corresponding benzopyran 3-epimer showed only CeH/O hydrogen bonds among the molecules.