Isopropyl 4-amino-benzoate.

The title compound, C10H13NO2, crystallizes with two mol-ecules (A and B) in the asymmetric unit. For A, the dihedral angle between the plane of the phenyl ring and the i-propyl substituent is 65.4 (3)° while for B this angle is 67.8 (3)°. In the crystal, the mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds to generate double chains propagating in the [100] direction.

Synthesis and crystal structure of 2-chloro-1-(3-hy-droxy-phen-yl)ethanone.

The structure of 2-chloro-1-(3-hy-droxy-phen-yl)ethanone, C8H7ClO2, an α-halo-ketone is described. The mol-ecule is planar (r.m.s. deviation = 0.0164 Å) and in the crystal, inversion-symmetric dimers are formed as a result of pairs of strong O-H⋯O and weak C-H⋯O hydrogen bonds. A brief comparison is made with structurally related compounds deposited in the CSD. In addition, the synthesis and some spectroscopic details are presented.

Synthesis, spectroscopic and crystal structure studies of N-{3-cyano-1-[2,6-di-chloro-4-(tri-fluoro-meth-yl)phen-yl]-4-(ethyl-sulfan-yl)-1H-pyrazol-5-yl}-2,2,2-tri-fluoro-acetamide.

The structure of the title compound, C15H8N4Cl2F6OS, a phenyl-pyrazole-based insecticide related to ethiprole, fipronil, and derivatives thereof is presented. The pyrazole ring has four chemically diverse substituents, namely a nitro-gen-bound 2,6-di-chloro-4-tri-fluoro-methyl-phenyl and carbon-bound cyano, ethyl-sulfanyl, and 2,2,2-tri-fluoro-acetamide groups. The pyrazole and phenyl rings are perpendicular, subtending a dihedral angle of 89.80 (5)°. In the crystal, strong N-H⋯O hydrogen bonds link the mol-ecules into chains that extend parallel to the a-axis.

Synthesis and crystal structure of topiramate azido-sulfate at 90†K and 298†K.

The low (90 K) and room (298 K) temperature crystal structures of topiramate azido-sulfate [systematic name 2,3:4,5-bis-O-(1-methyl-ethyl-idene)-ß-d-fructo-pyran-ose azido-sulfate], C12H19N3O8S, an inter-mediate in the synthesis of the anti-convulsant drug topiramate, are described. Topiramate azido-sulfate (I) finds use as a reference impurity standard for topiramate. A modified synthesis and some spectroscopic details are also presented.

Synthesis and crystal structure of ebastinium hydrogen fumarate.

The structure of ebastinium hydrogen fumarate {systematic name: 1-[4-(4-tert-butyl-phen-yl)-4-oxobut-yl]-4-(di-phenyl-meth-oxy)piperidin-1-ium (E)-3-carb-oxy-1-hy-droxy-prop-2-en-1-olate}, C32H40NO2 +·C4H3O4 -, a 1:1 salt formed in the reaction between ebastine and fumaric acid is presented. All examined crystals were found to be twinned by pseudo-merohedry. The structure is extensively disordered, with over half (20 out of 35) its non-hydrogen atoms modelled as lying over two sets of sites. In the crystal, cation-anion pairs are linked by a strong N-H⋯O hydrogen bond [N⋯O = 2.697 (11) Å]. These units inter-act via weaker C-H⋯O and C-H⋯π contacts to form layers lying parallel to the bc plane. The hydrogen fumarate anions are linked by a very short O-H⋯O hydrogen bond [O⋯O = 2.5402 (17) Å], augmented by weak C-H⋯O contacts into pairs of R 2 2(6) ring motifs to form chains that extend parallel to the b-axis direction. Comparisons to similar crystal structures are presented.

Synthesis, Characterization, and Evaluation of Difluoropyrido[4,3-b]indoles as Potential Agents for Acetylcholinesterase and Antiamnesic Activity.

Acetylcholinesterase (AChE) inhibitors are currently the most widely prescribed drugs for Alzheimer's disease. The high potential of indole compounds in medicinal chemistry led us to discover a novel series of fluoroindole compounds. The synthesis and pharmacological analysis of the difluoropyrido[4,3-b]indoles 11-34 are described. Compounds 11-34 were tested for AChE inhibition activity using a rat brain homogenate. Compounds 25-29 display a promising in vitro profile with an IC50 value range of 46-51.6 nM and show significant protective effect on scopolamine-induced amnesia. The present data indicate that compounds 25-29 may represent attractive potent molecules for the treatment of Alzheimer's disease.

Synthesis and Anticonvulsant Activity of N-(Substituted)-1-methyl-2,4-dioxo-1,2-dihydroquinazoline-3(4H)-carboxamides.

A series of new N-(substituted)-1-methyl-2,4-dioxo-1,2-dihydroquinazoline-3(4H)-carboxamides were designed, synthesized, and evaluated for their anticonvulsant activity. Most of the synthesized compounds exhibited potent anticonvulsant activities in the maximal electroshock (MES) and pentylenetetrazol (PTZ) test. The most promising compound 4c showed significant anticonvulsant activity with a protective index value of 3.58. The compounds 4a-c were also found to have encouraging anticonvulsant activity in the MES and PTZ screen when compared with the standard drugs, valproate and methaqualone. The same compounds were found to exhibit advanced anticonvulsant activity as well as lower neurotoxicity than the reference drugs.