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11.
Withnall R Chowdhry BZ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(8):1721-1729
Raman and infrared spectra of four substituted 3,5-diamino-6-(ortho-substituted phenyl)-1,2,4-triazines, having ortho-fluoro, -chloro, -bromo and -methyl groups on the phenyl ring, are reported and discussed. Bands due to substituent sensitive phenyl vibrations are observed in both the Raman and infrared spectra. The Raman spectra of all four compounds have strong bands near 770 and 1330 cm(-1) which are assigned to the ring breathing vibration of the 1,2,4-triazine ring and an asymmetric triazine C-NH2 stretching vibration, respectively. A medium/strong band near 800 cm(-1) in the infrared spectra is attributed to an out-of-plane bending vibration of the substituted 1,2,4-triazine ring. 相似文献
12.
The dye nuclear fast red has been detected and determined semi-quantitatively by means of surface enhanced resonance Raman scattering (SERRS) and surface enhanced Raman scattering (SERS), using laser exciting wavelengths of 514.5 and 632.8 nm, respectively, by employing a citrate-reduced silver colloid. A good linear correlation is observed for the dependence of the intensities of the SERRS bands at 989 cm−1 (R=0.9897) and 1278 cm−1 (R=0.9872) on dye concentration over the range 10−9 to 10−7 M, when using an exciting wavelength of 514.5 nm. At dye concentrations above 10−7 M, the concentration dependence of the SERRS signals is non-linear. This is almost certainly due to the coverage of the colloidal silver particles being in excess of a full monolayer of the dye. A linear correlation is also observed for the dependence of the intensities of the SERS bands at 989 cm−1 (R=0.9739) and 1278 cm−1 (R=0.9838) on the dye concentration over the range 10−8 to 10−6 M when using an exciting wavelength of 632.8 nm. Strong fluorescence prevented collection of resonance Raman scattering (RRS) spectra from powdered samples or aqueous solutions of the dye using an exciting wavelength of 514.5 nm, but weak bands were observed in the spectra obtained from both powdered and aqueous samples of the dye using an exciting wavelength of 632.8 nm. A study of the pH dependence of SERRS/SERS and UV–VIS absorption spectra revealed the presence of different ionisation states of the dye. The limits of detection for nuclear fast red by SERRS (514.5 nm), SERS (632.8 nm) and visible spectroscopy (535 nm) are 9, 89 and 1000 ng ml−1, respectively. 相似文献
13.
Rex A. Palmer Brian S. Potter Michael J. Leach Babur Z. Chowdhry 《Journal of chemical crystallography》2007,37(11):771-777
Abstract Drugs based on 5-phenyl-2,4 diamino pyrimidine and 6-phenyl-1,2,4 triazine derivatives are well known for their effects on
the central nervous system. The study presented here provides detailed crystal structures of two pyrimidine derivatives which
have neuroprotective properties in models of both grey and white matter ischemia. Recently published studies suggest that
the compounds lamotrigine (a triazine derivative), and the two pyrimidines BW1003C87 (I) and sipatrigine (II) mediate their primary in vivo mode of action by inhibiting voltage-gated Na+ channels. The X-ray crystal structures will contribute valuable data for applications involving binding and modelling studies
of the biological actions of these drugs.
Graphical Abstract
X-ray crystallographic structures of neuroprotective pyrimidine derivatives: (I) the mesylate salt of BW1003C87 and (II) sipatrigine
base
Rex A. Palmer*, Brian S. Potter, Michael J. Leach and Babur Z. Chowdhry
Surface representations, [20] are a useful tool with respect to considerations employed for the purposes of drug design. Shown here are the neuroprotective
drug molecules (a) BW1003C87 and (b) Sipatrigine Base (BW619C89) derived from their solid state structures reported in this
paper. The molecules are viewed edge on to ring B with the two adjacent Cl atoms uppermost on the left.
相似文献
14.
Andrew P. Mendham Trevor J. Dines Martin J. Snowden Babur Z. Chowdhry Robert Withnall 《Journal of Raman spectroscopy : JRS》2009,40(11):1478-1497
Investigations of the vibrational spectra of cyclo(Gly‐Gly), cyclo(L‐Ala‐L ‐Ala) and cyclo(L ‐Ala‐Gly) are reported. Raman scattering and Fourier transform infrared (FTIR) spectra of solid‐state and aqueous protonated samples, as well as their corresponding N‐deuterated isotopomers, have been examined. In addition, density functional theory (DFT) (B3‐LYP/cc‐pVDZ) calculations of molecular structures and their associated vibrational modes were carried out. In each case, the calculated structures of lowest energy for the isolated gas‐phase molecules have boat conformations. Assignments have been made for the observed Raman and FTIR vibrational bands of the cyclic di‐amino acid peptides (CDAPs) examined. Raman polarization studies of aqueous phase samples are consistent with C2 and C1 symmetries for the six‐membered rings of cyclo(L‐Ala‐L‐Ala) and cyclo(L‐Ala‐Gly), respectively. There is a good correlation between experimental and calculated vibrational bands for the three CDAPs. These data are in keeping with boat conformations for cyclo(L‐Ala‐L‐Ala) and cyclo(L‐Ala‐Gly) molecules, predicted by the ab initio calculations, in both the solid and aqueous solution states. However, Raman spectroscopic results might infer that cyclo(L‐Ala‐Gly) deviates only slightly from planarity in the solid state. The potential energy distributions of the amide I and II modes of a cis‐peptide linkage are shown to be significantly different from those of the trans‐peptides. For example, deuterium shifts have shown that the cis‐amide I vibrations found in cyclo(Gly‐Gly), cyclo(L‐Ala‐L‐Ala), and cyclo(L‐Ala‐Gly) have larger N‐H contributions compared to their trans‐amide counterparts. Compared to trans‐amide II vibrations, cis‐amide II vibrations show a considerable decrease in N H character. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
15.
Rex A. Palmer Brian S. Potter Michael J. Leach Babur Z. Chowdhry 《Journal of chemical crystallography》2008,38(5):387-392
Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine, C9H8ClN5, (465BL) as a hydrate, and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine, C9H7Cl2N5, (469BR) as a methanol solvate, have been carried out at liquid nitrogen temperature and room temperature, respectively.
A detailed comparison of the two structures is given. Both are centrosymmetric with (I) in the orthorhombic space group Pbca, a = 12.2507(3), b = 15.7160(6), c = 21.71496(9) ?, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) ?, β = 111.59(1)°, Z = 8. Final R indices
[I > 2sigma(I)] for (I) are R1 = 0.0670, wR2 = 0.1515 and for (II) R1 = 0.0434, wR2 = 0.1185. Structure (I) has water of crystallization in the lattice and (II) includes a solvated CH3OH. Structure (I) is characterized by having two crystallographically independent molecules, A and B, of 465BL, per asymmetric unit. Molecule
B has a very unusual feature in that the 2-chlorophenyl ring is statistically disordered, occupying site (1) in 87.5% of the
structure and site (2) in 12.5% of the structure. Sites (1) and (2) are related by an exact 180° pivot of the phenyl ring
about the ring linkage bond. The presence of two independent molecules per asymmetric unit provides an ideal opportunity for
the conformational flexibility of the molecule 465BL to be studied. Structure (I) also includes a further unusual feature in that the lattice contains one fully occupied water molecule and an additional
solvated water which is only 33% occupied.
Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry
The crystal structures of two lamotrigine analogues: (I) 3, 5-diamino-6-(2-chlorophenyl)-1, 2, 4-triazine, water solvate and (II) 3, 5-diamino-6-(3,6-dichlorophenyl)-1, 2, 4-triazine methanol solvate are presented. Structure (I) includes two molecules per asymmetric unit labeled A and B where molecule B is unusually disordered having Cl in either
position 2 (87.5% occupied) or position 6 of the phenyl ring (12.5% occupied), the two sites being related by 180deg rotation
about the ring linkage bond. Molecule I(A) on the other hand shows no disorder. The relative orientations of the two rings
in I(A and B) and in II is shown to be different. Lamotrigine and analogues have been investigated for some time for their
effects on the central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code
name BW 1003C87) are voltage-gated sodium channel blockers as well as blocking the release of the
neurotransmitter glutamate. BW 1003C87 has also been shown to reduce the release of glutamate evoked by veratrine in brain
tissue, providing a therapeutic approach in both cerebral ischemia and epilepsy [B. S. Meldrum, J. H. Swan, M. J. Leach, M.
H. Millan, R. Gwinn, K. Kadota, S. H Graham, J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.]. This is one of a series of papers on the structures of lamotrigine analogues.
相似文献
16.
Rex A. Palmer Brian S. Potter Michael J. Leach Babur Z. Chowdhry 《Journal of chemical crystallography》2008,38(6):407-411
Abstract The X-ray crystal structures of two crystalline forms of 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine, C10H7Cl3N4 (code name BW1003C87) (I) and (II), have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are centrosymmetric,
with structure (I) in the triclinic space group P unit cell a = 6.4870(10), b = 9.216(2), c = 12.016(2) ?, α = 75.78(3)°, β = 89.95(3)°, γ = 83.45(3)°, V = 691.5(2) ?3, Z = 2 and density (calculated) = 1.544 Mg/m3; and (II) in the monoclinic space group P21/c, unit cell a = 12.000(2), b = 7.518(2), c = 13.450(3) ?, β = 97.87(3)°, V = 1202.0(5) ?3, Z = 4, Density (calculated) = 1.600 Mg/m3. Structure (I) includes a solvated CH3OH in the lattice. Final R indices [I > 2sigma(I)] are R1 = 0.0427, wR2 = 0.1075 for (I) and R1 = 0.0487, wR2 = 0.1222 for (II). R indices (all data) are R1 = 0.0470, wR2 = 0.1118 for (I) and R1 = 0.0623, wR2 = 0.1299 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine),
have been investigated for some time for their effects on the central nervous system. Both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine
(code name BW1003C87), the subject of the present study, are anticonvulsant as well as neuroprotective in models of brain
ischaemia and in a model of white matter ischaemia. BW1003C87 is a sodium channel blocker which also reduces the release of
the neurotransmitter glutamate. The three dimensional structures reported here form part of a newly developed data base for
the detailed investigation of members of this drug family and their biological activities.
Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry
5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine occurs in two crystalline forms whose X-ray structures are described here.
The molecular conformations in (I) and (II) are quite distinct as illustrated, the ring linkage torsion angle differing by 23.5 deg. (I) has a methanol solvate molecule in the lattice.
相似文献
17.
Rex A. Palmer Brian S. Potter Michael J. Leach Babur Z. Chowdhry 《Journal of chemical crystallography》2008,38(4):255-260
Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 2-methyl, 3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1,2,4-triazine, C10H9Cl2N5, as the hemi hydrate and (II) 2-methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, C10H10Cl2N5, as the isethionate-water solvate, have been carried out at liquid nitrogen temperature. A detailed comparison of the two
structures is given. Both are monoclinic and centrosymmetric, with (I) in space group C2/c, and (II) in space group P21/n. For (I) the unit cell dimensions are a = 19.5466(10), b = 7.5483(4), c = 15.7861(8) ?, β = 91.458(3)°, volume = 2328.4(2) ?3, Z = 8, density = 1.590 Mg/m3; for (II). For (II) the unit cell dimensions are a = 6.0566(2), b = 11.0084(4) c = 23.9973(9) ?, β = 92.587(3)°, volume = 1598.35(10) ?3, Z = 4, density = 1.597 Mg/m3. For (I) final R indices [I > 2sigma(I)] are R1 = 0.0356, wR2 = 0.0782 and R indices (all data) are R1 = 0.0424, wR2 = 0.0817. For
(II) final R indices [I > 2sigma(I)] are R1 = 0.0380, wR2 = 0.0871 and R indices (all data) R1 = 0.0558, wR2 = 0.0949. Both structures
have a molecule of water of crystallization and (II) also includes a solvated CH3SO3. Comparisons are made between the two structures. Structure (I) is very unusual in having a = NH group at position C5′ on the triazine ring. No other examples of this particular substitution,
which is usually −NH2, have been reported.
Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry
The crystal structures of (I) 2-methyl,3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine, water solvate and (II) 2-methyl,3, 5-diamino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine isethionate water solvate are presented. The relative orientation
of the two rings is shown to vary. Lamotrigine and analogues have been investigated for some time for their effects on the
central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW 1003C87)
are voltage-gated sodium channel blockers as well as blocking the release of the neurotransmitter glutamate [D. R. Riddall,
M. J. Leach, J. Garthwaite, Mol. Pharmacol. 2006, 69 (1), 278.3], BW10003C87 (like lamotrigine) has been shown to exhibit excitatory amino acid antagonist activity similar to that
of three conventional antiepileptic drugs phenytoin, carbamazepine and phenobarbital [R. Lingamaneni, H. C. Hemmings Jr.,
Epilepsy Res.
1993,
15, 101.]. BW 1003C87 has also been shown [B. S. Meldrum, J. H. Swan, M. J. Leach, M. H. Millan, R. Gwinn, K. Kadota, S. H Graham,
J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.] to reduce the release of glutamate evoked by veratrine in brain tissue, providing a therapeutic approach in both cerebral
ischemia and epilepsy. This is one of a series of papers on the structures of lamotrigine analogues.
相似文献
18.
Rex A. Palmer Brian S. Potter Madeleine Helliwell Michael J. Leach Babur Z. Chowdhry 《Journal of chemical crystallography》2009,39(1):36-41
Abstract The X-ray crystal structures of (I), the base 4030W92, 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine, C11H9Cl2FN4, and (II) 227C89, the methanesulphonic acid salt of 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine, C11H11Cl2N4 · CH3O3S, have been carried out at low temperature. A detailed comparison of the two structures is given. Structure (I) is non-centrosymmetric, crystallizing in space group P21 with unit cell a = 10.821(3), b = 8.290(3), c = 13.819(4) ?, β = 105.980(6)°, V = 1191.8(6) ?3, Z = 4 (two molecules per asymmetric unit) and density (calculated) = 1.600 mg/m3. Structure (II) crystallizes in the triclinic space group with unit cell a = 7.686(2), b = 8.233(2), c = 12.234(2) ?, α = 78.379(4), β = 87.195(4), γ = 86.811(4)°, V = 756.6(2) ?3, Z = 2, density (calculated) = 1.603 mg/m3. Final R indices [I > 2sigma(I)] are R1 = 0.0572, wR2 = 0.1003 for (I) and R1 = 0.0558, wR2 = 0.0982 for (II). R indices (all data) are R1 = 0.0983, wR2 = 0.1116 for (I) and R1 = 0.1009, wR2 = 0.1117 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine),
have been investigated for some time for their effects on the central nervous system. The three dimensional structures reported
here form part of a newly developed data base for the detailed investigation of members of this structural series and their
biological activities.
Index Abstract Low temperature X-ray structures of (I): the base 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine (4030W92); and (II): 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine methanesulphonic acid salt (227C89) are presented. Both drugs
act on the central nervous system. (I) crystallizes in non-centrosymmetric space group P21 with two molecules A and B per asymmetric unit cell and (II) is triclinic in space group . The absolute configuration of (I) is determined.
相似文献
19.
20.