Two quinazolinones: a ring conformational study

The molecules of (+/-)-2-(4-methoxyphenyl)-1-phenethyl-2,3-dihydroquinazolin-4(1H)-one, C(23)H(22)N(2)O(2), (I), and (+/-)-2-(1,3-benzodioxol-5-yl)-1-phenethyl-2,3-dihydroquinazolin-4(1H)-one, C(23)H(20)N(2)O(3), (II), have T-shaped forms in the crystal structure. The tetrahydropyrimidine ring in both structures adopts a sofa conformation. Both molecules are linked by N-H...O and C-H...O hydrogen bonds to form sheets built from alternating R(2)(2)(8) and R(4)(4)(26) [R(4)(4)(24) in (II)] edge-fused rings. Additionally, the structures are stabilized by extensive C-H...pi interactions.

3-[(E)-4-Methoxy-benzyl-idene]-1-methyl-piperidin-4-one

The piperidone ring of the title compound, C(14)H(17)NO(2), adopts a half-chair conformation. The crystal packing is stabilized by inter-molecular C-H⋯O inter-actions, which generate a C(8) chain running along the b axis.

3-[(E)-2,4-Dichloro-benzyl-idene]-1-methyl-piperidin-4-one

The piperidine ring of the title compound, C₁₃H₁₃Cl₂NO, adopts an envelope conformation. Inter­molecular C—H⋯O inter­actions link the mol­ecules into a C(7) chain running along the b axis.

4'-Amino-2,2''-dioxo-2,2'',3,3''-tetra-hydro-1H-indole-3-spiro-1'-cyclo-pent-3'-ene-2'-spiro-3''-1H-indole-3',5',5'-tricarbonitrile dihydrate

In the title compound, C(22)H(12)N(6)O(2)·2H(2)O, the cyclo-pentene ring adopts an envelope conformation, with the spiro C atom bonded to the dicyano-substituted C atom deviating by 0.437 (2) Å from the plane of the remaining four atoms in the ring. The puckering and smallest displacement asymmetry parameters for the ring are q(2) = 0.275 (2) Å, ϕ = 212.4 (4)° and Δ(s)(C(2)) = 2.7 (2). The dihedral angle between the two indole groups is 60.1 (1)°. The structure contains inter-molecular N-H⋯O hydrogen bonds involving the indole groups and O-H⋯O and O-H⋯N hydrogen bonds involving the water mol-ecules.

1'-Phenyl-6'-thia-cyclo-heptane-1-spiro-2'-perhydro-pyrrolizine-3'-spiro-3''-indoline-2,2''-dione

The thia­zolidine ring and the pyrrolidine ring in the title compound, C₂₅H₂₆N₂O₂S, both adopt an envelope conformation. The seven-membered ring has a twist-chair conformation. The crystal packing is stabilized by inter­molecular N—H⋯O hydrogen bonds.

r-2,c-6-Bis(4-fluoro-phen-yl)-t-3,t-5-dimethyl-piperidin-4-one

In the title compound, C(19)H(19)F(2)NO, the piperidinone ring adopts a chair conformation. The crystal packing is stabilized by C-H⋯O and C-H⋯F inter-molecular inter-actions, generating centrosymmetric dimers of R(2) (2)(14) and R(2) (2)(24) rings.

3-(4-Chloro-phen-yl)-7-methyl-4-(4-methyl-phen-yl)-1-oxa-2,7-diaza-spiro-[4.5]dec-2-en-10-one

In the title compound, C₂₁H₂₁ClN₂O₂, the dihydro­isoxazole ring adopts an envelope conformation and the piperidinone ring is in a chair conformation. The dihedral angle between the two benzene rings is 84.2 (1)°. The crystal used was an inversion twin.

1-{2-[(Anthracen-10-yl)methyl-ene-amino]phen-yl}-3-phenyl-thio-urea

The title compound, C(28)H(21)N(3)S, crystallizes with two mol-ecules in the asymmetric unit. There are only very slight differences in the torsion angles between the two molecules. The two mol-ecules are stabilized by intra-molecular N-H⋯N inter-actions and the crystal packing is stabilized by inter-molecular N-H⋯S inter-actions.

Intravitreal bevacizumab in the treatment of neovascular age-related macular degeneration, 6- and 9-month results

PURPOSE

To evaluate 6- and 9-month follow-up data including the effect on vision and anatomic outcome in patients treated with intravitreal bevacizumab for neovascular age-related macular degeneration (AMD).

STUDY DESIGN

Interventional consecutive retrospective case series. Patients received intravitreal bevacizumab for the treatment of neovascular AMD including choroidal neovascular membranes, pigment epithelial detachment, and macular haemorrhage. Ophthalmic evaluation included log MAR or Snellen acuity, ophthalmic examination, optical coherence tomography, and fluorescein angiography. Repeat injections were given in the presence of persistent leakage or retinal oedema. Change in vision and foveal thickness from baseline was evaluated using the paired Student's t-test.

RESULTS

A total of 112 eyes of 111 patients received injections. Median follow-up was 5 months (range: 1-12 months). Mean log MAR vision pre-injection was 0.84+/-0.03 (n=112); at 3 months was 0.69+/-0.05 (P<0.0001, n=84); at 6 months was 0.74+/-0.06 (P<0.05, n=51); and at 9 months was 0.69+/-0.08 (n=29, P=0.09). Thirteen of 17 patients who received only one injection maintained improved or stable vision at 6 months. Mean baseline foveal thickness was 291+/- 9.72 microm (n=56); at 3 months was 282.7+/-28 (P<0.05, n=31); and at 6 months was 249.7+/-10.3 (P<0.05, n=12). One case of endophthalmitis, three submacular haemorrhages, and three retinal pigment epithelial (RPE) tears occurred.

CONCLUSION

Intravitreal bevacizumab is an effective treatment for neovascular AMD, resulting in improved vision and foveal anatomy at 6 months and even up to 9 months. This treatment is well tolerated in the majority of patients but adverse events may include endophthalmitis, RPE tears, and submacular haemorrhage.

The 1:1 inclusion compounds zolmitriptan-benzene and zolmitriptan-phenol

In the benzene and phenol solvates of (S)-4-{3-[2-(dimethylamino)ethyl]-1H-indol-5-ylmethyl}oxazolidin-2-one, viz. C(16)H(21)N(3)O(2) x C(6)H(6), (I), and C(16)H(21)N(3)O(2) x C(6)H(5)OH, (II), the host molecule has three linked residues, namely a planar indole ring system, an ethylamine side chain and an oxazolidinone system. It has comparable features to that of sumatriptan, although the side-chain orientations of (I) and (II) differ from those of sumatriptan. Both (I) and (II) have host-guest-type structures. The host molecule in (I) and (II) has an L-shaped form, with the oxazolidinone ring occupying the base and the remainder of the molecule forming the upright section. In (I), each benzene guest molecule is surrounded by four host molecules, and these molecules are linked by a combination of N-H...N, N-H...O and C-H...O hydrogen bonds into chains of edge-fused R(4)(4)(33) rings. In (II), two independent molecules are present in the asymmetric unit, with similar conformations. The heterocyclic components are connected through N-H...N, N-H...O and C-H...O interactions to form chains of edge-fused R(6)(4)(38) rings, from which the phenol guest molecules are pendent, linked by O-H...O hydrogen bonds. The structures are further stabilized by extensive C-H...pi interactions.

Supramolecular hydrogen-bonded networks in adeninium phenylacetate phenylacetic acid monohydrate and adeninium 3-carboxypropionate monohydrate

In the title compounds, C(5)H(6)N(5)(+) x C(8)H(7)O(2)(-) x C(8)H(8)O(2) x H(2)O, (I), and C(5)H(6)N(5)(+) x C(4)H(3)O(4)(-) x H(2)O, (II), the adeninium cations form N-H...O hydrogen bonds with their anion counterparts and adeninium-adeninium self-association base pairs with the R(2)(2)(10) motif (Bernstein et al., 1995). A complete hydrogen-bonding motif analysis is presented. Conventional hydrogen bonds lead to layer structures in (I) and to two-dimensional infinite polymeric ribbons in (II). C-H...O interactions are found in both structures, while weak pi-pi stacking interactions are only observed in (I).

Supramolecular hydrogen-bonding networks in bis(adeninium) phthalate phthalic acid 1.45-hydrate

In the title compound, 2C(5)H(6)N(5)(+).C(8)H(4)O(4)(2-).C(8)H(6)O(4).1.45H(2)O, the asymmetric unit comprises two adeninium cations, two half phthalate anions with crystallographic C(2) symmetry, one neutral phthalic acid molecule, and one fully occupied and one partially occupied site (0.45) for water molecules. The adeninium cations form N-H...O hydrogen bonds with the phthalate anions. The cations also form infinite one-dimensional polymeric ribbons via N-H...N interactions. In the crystal packing, hydrogen-bonded columns of cations, anions and phthalate anions extend parallel to the c axis. The water molecules crosslink adjacent columns into hydrogen-bonded layers.

Assessing the burden of human rabies in India: results of a national multi-center epidemiological survey

OBJECTIVE

Human rabies has been endemic in India since time immemorial, and the true incidence of the disease and nationwide epidemiological factors have never been studied. The main objectives of the present study were to estimate the annual incidence of human rabies in India based on a community survey and to describe its salient epidemiological features.

METHODS

The Association for Prevention and Control of Rabies in India (APCRI) conducted a national multi-center survey with the help of 21 medical schools during the period February-August 2003. This community-based survey covered a representative population of 10.8 million in mainland India. Hospital-based data were also obtained from the 22 infectious diseases hospitals. A separate survey of the islands of Andaman, Nicobar, and Lakshadweep, reported to be free from rabies, was also undertaken.

RESULTS

The annual incidence of human rabies was estimated to be 17,137 (95% CI 14,109-20,165). Based on expert group advice, an additional 20% was added to this to include paralytic/atypical forms of rabies, providing an estimate of 20,565 or about 2 per 100000 population. The majority of the victims were male, adult, from rural areas, and unvaccinated. The main animals responsible for bites were dogs (96.2%), most of which were stray. The most common bite sites were the extremities. The disease incubation period ranged from two weeks to six months. Hydrophobia was the predominant clinical feature. Many of the victims had resorted to indigenous forms of treatment following animal bite, and only about half of them had sought hospital attention. Approximately 10% of these patients had taken a partial course of either Semple or a cell culture vaccine. The islands of Andaman, Nicobar, and Lakshadweep were found to be free of rabies.

CONCLUSION

Human rabies continues to be endemic in India except for the islands of Andaman, Nicobar, and Lakshadweep. Dogs continue to be the principal reservoir. The disease is taking its toll on adult men and children, the majority from rural areas, due to lack of awareness about proper post-exposure immunization. The keys to success in the further reduction of rabies in India lies in improved coverage with modern rabies vaccines, canine rabies control, and intensifying public education about the disease.

Donepezilium oxalate trihydrate, a therapeutic agent for Alzheimer's disease

Donepezil, a cholinesterase inhibitor with good central nervous system penetration, has been crystallized as a tertiary amine salt with a disordered oxalate anion to give the title compound, (R,S)-1-benzyl-4-[(5,6-dimethoxy-1-oxoindan-2-yl)methyl]piperidinium hydrogen oxalate trihydrate, C24H30NO3+.C2HO4-.3H2O. The indanone and piperidine ring planes are inclined at an angle of 33.4 (1) degrees. A comparison is made with the piperidinium cation bound in acetylcholinesterase in the solid state. The methylene units bridging the indanone-piperidine-benzyl groups determine the molecular shape and conformational features. The structure is stabilized mainly by O-H...O and N-H...O hydrogen bonds, with water molecules mediating interactions between oxalate anions and donepezilium cations.

Dimorphism in (2Z)-2-benzylidene-N,7-dimethyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thiazolo[3,2-a]pyrimidine-6-carboxamide

The title compound, C22H19N3O2S, crystallizes in two polymorphic forms having the same space group, viz. P-1, with Z' = 2 and Z' = 1. In both polymorphs, the planar thiazole ring is fused cis with the dihydropyrimidine ring, the carbamoyl group is in an extended conformation with an anticlinal orientation with respect to the pyrimidine ring, and the phenyl ring is attached to the pyrimidine ring approximately at a right angle. The two polymorphs have different interplanar angles between the phenyl and thiazole rings. The molecules are linked by N-H...O and C-H...O hydrogen bonds.

Imino Diels-Alder adducts. XII. Two pyrano[3,2-c]quinolines

The crystal structures of pyranoquinolines 9-fluoro-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline, C18H18FNO, and 9-methyl-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline, C19H21NO, are isomorphous. In both structures, the pyran ring is exo to the six-membered N-heterocyclic ring formed in the cycloaddition step. The torsion angles across the phenyl linkage for the two structures are -91.2 (1) and -88.3 (2) degrees. The striking feature in both crystal packings is that they do not contain the expected conventional hydrogen bonds, in spite of the presence of good hydrogen-bonding functionalities. Possible C-H...pi interactions are, however, observed.