2,2′-Di­propyl­malonic acid: intermolecular association via strong O—H...O hydrogen bonds

The molecular structure of the title compound, C₉H₁₆O₄, is described by a trans-planar configuration of the propyl chains. The mol­ecule has an approximate pseudo-twofold rotation axis in the crystal structure. The mol­ecules are interconnected by strong O—H...O hydrogen bonds and form an R₂²(8) ring structure.

N-Amino-3-methyl-2,3-di­hydro-1,3-benzo­thia­zoliminium chloride monohydrate

The title compound, C₈H₁₀N₃S⁺·Cl^-·H₂O, is extensively used as a spectrophotometric reagent for the determination of pharmaceutical compounds, vitamins and environmental samples.

A pseudopolymorph of valdecoxib

Valdecoxib, C₁₆H₁₄N₂O₃S, is a non-steroidal anti-inflammatory drug containing a planar isoxazole heterocycle which is substituted at the C atoms with two aromatic rings and a methyl group. In addition to one mol­ecule of valdecoxib, there is half a mol­ecule of ethyl methyl ketone in the asymmetric unit of the title compound [systematic name: 4-(5-methyl-3-phenyl­isoxazol-4-yl)­benzene­sulfon­amide ethyl methyl ketone hemisolvate], viz. C₁₆H₁₄N₂O₃S·0.5C₄H₈O. The crystal packing is stabilized by N—H...O hydrogen bonds. Apart from the orientation of the sulfon­amide group, the conformation of the title compound agrees well with that of the recently published orthorhombic polymorph which does not contain any solvent.

3-(p-Nitro­benzyl)-1,3-thia­zolidine-2,4-dione

The title compound, C₁₀H₈N₂O₄S, serves as a starting material for the synthesis of antihyperglycemic pharmaceuticals. The nearly planar thia­zolidine-2,4-dione ring is almost perpendic­ular to the nitro­phenyl ring.

5-Amino-3H-isobenzo­furan-1-one (5-amino­phthalide)

The title compound, C₈H₇NO₂, serves as an intermediate for the synthesis of citalopram. The packing of the planar mol­ecules is stabilized by N—H...O and N—H...N hydrogen bonds.

5-Bromo-3H-isobenzo­furan-1-one (5-bromo­phthalide)

The title compound, C₈H₅BrO₂, serves as a starting material for the synthesis of citalopram. It crystallizes with two almost identical mol­ecules in the asymmetric unit.

N—H⁺...Cl⁻ and C—H...O interactions in 6-fluoro-3-(4-piperidinio)benz[d]isoxazole chloride

Supramolecular assembly of the title compound, C₁₂H₁₄ClFN₂O, is primarily governed by N—H⁺...Cl⁻ and C—H...O interactions, and a putative C—H...F interaction. The piperidine ring assumes a chair conformation, with the substituted benzisoxazole ring in an equatorial position.

4′-[2-Butyl-4-chloro-5-(hydroxy­imino­methyl)-1H-imidazol-3-yl­methyl]­bi­phenyl-2-carbo­nitrile

The title compound, C₂₂H₂₁ClN₄O, is used as an intermediate for the synthesis of biologically active compounds. Geometric parameters are in the usual ranges. The packing is stabilized by O—H...N hydrogen bonding.

Nipecotic acid hydro­chloride

The title compound (3-carboxy­piperidinium chloride), C₆H₁₂NO₂⁺·Cl⁻, is the hydro­chloride of nipecotic acid and is used as a drug inter­mediate and in the synthesis of γ-amino­butyric acid (GABA) uptake inhibitors. The geometric parameters are in the normal ranges. The crystal packing is stabilized by O—H...Cl and N—H...Cl hydrogen bonds.

5-[4'-(Bromo­meth­yl)biphen­yl-2-yl]-2-trit­yl-2H-tetra­zole

The title compound, C₃₃H₂₅BrN₄, belongs to the class of substituted tetrazoles. This type of compound is an important starting material for the synthesis of pharmaceutically active materials.

2,2'-Diamino­dibenzyl: a rare case of crystallographically non-compliant mol­ecular symmetry

The title compound, C₁₄H₁₆N₂, adopts a trans-planar conformation. However, the mol­ecule, which possesses C_i point group symmetry, crystallizes in the non-centrosymmetric space group P2₁2₁2₁. In the crystal structure, the mol­ecular symmetry is only approximately retained. The crystal packing is predominantly stabilized by N—H...N hydrogen bonds. Weak C—H...π inter­actions also contribute to the stability.

4-(2-Chloro­ethyl)­morpholinium chloride

The structure of the title compound, C₆H₁₃ClNO⁺·Cl^-, comprises a cation with the morpholine ring in the chair conformation, and a single hydrogen-bonding association between the morpholinium NH group and the Cl^- anion.

4'-Methyl­bi­phenyl-2-carboxyl­ic acid

The title compound, C₁₄H₁₂O₂, is used as an intermediate for the synthesis of various biologically active and pharmaceutical compounds. Bond lengths and angles adopt usual values. The dihedral angles between the two aromatic rings [53.39 (3)°] and between the carboxyl group and adjacent ring [42.37 (10)°] lie in the expected ranges. The crystal structure is characterized by centrosymmetric hydrogen-bonded dimers.

4'-(2-But­yl-4-chloro-5-formyl­imidazol-1-ylmeth­yl)biphen­yl-2-carbonitrile

The title compound, C₂₂H₂₀ClN₃O, (I), is used as an inter­mediate for the synthesis of the antihypertensive drug losartan. Bond lengths and angles are unexceptional. The crystal packing is stabilized by one C—H...O and one C—H...N contact. It is noteworthy that (I) is isomorphous with a closely related compound which differs in having a but-2-en­yl chain instead of a but­yl chain on the imidazole ring.

10-Methoxy­dibenz­[b,f]­azepine-5-carbox­amide

The structure of the title compound, C₁₆H₁₄N₂O₂, contains a seven-membered ring that adopts a boat conformation, and the overall molecular shape is that of a butterfly. In the packing, the mol­ecules form a convoluted hydrogen-bonded polymer via a typical R₂²(8) graph-set dimer, between carbox­amide groups, and an R₂²(16) graph-set dimer formed through an interaction between the second carbox­amide NH group and an adjacent methoxy O atom (in each mol­ecule). The dihedral angle between the benzene rings is 56.09 (5)°.

Thio­nordazepam: strong inter­molecular N—H...N hydrogen-bonded chains

In the title compound, 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-thione, C₁₅H₁₁ClN₂S, the central seven-membered diazepinethione ring adopts a boat conformation. The dihedral angle between the planes of the aromatic rings is 63.7 (1)°. The crystal packing is determined by strong N—H...N hydrogen bonds, generating a one-dimensional chain along [001].