Palmer, Rex A., Potter, Brian S., Leach, Michael J. ORCID: https://orcid.org/0000-0002-9859-1325 and Chowdhry, Babur Z. (2008) X-ray crystallographic 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. Journal of Chemical Crystallography, 38 (5). pp. 387-392. ISSN 1074-1542 (Print), 1572-8854 (Online) (doi:10.1007/s10870-008-9320-3)

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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) angstrom, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) angstrom, beta = 111.59(1)degrees, 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 degrees 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.

Item Type:	Article
Uncontrolled Keywords:	central nervous system drugs, triazines, lamotrigines, voltage gated Na+ channel inhibitors, crystal structures and drug design
Subjects:	Q Science > QD Chemistry R Medicine > RM Therapeutics. Pharmacology
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Education, Health & Human Sciences > School of Human Sciences (HUM)
Related URLs:	Publisher
Last Modified:	09 Oct 2021 04:46
URI:	http://gala.gre.ac.uk/id/eprint/2210

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