Bosentan monohydrate

In the title compound, C₂₇H₂₉N₅O₆S·H₂O {systematic name: 4-tert-butyl-N-[6-(2-hy­droxy­eth­oxy)-5-(2-meth­oxy­phen­oxy)-2-(pyrimidin-2-yl)pyrimidin-4-yl]benzene-1-sulfonamide monohydrate], the dihedral angle between the mean planes of the pyrimidine rings is 27.0 (1)°. The dihedral angle between the mean planes of the benzene rings is 47.7 (8)°, forming a U-shaped channel around the chain of twisted pyrimidine rings. The crystal packing is stabilized by O—H...O, O—H...N and N—H...O hydrogen bonds with a single water mol­ecule, and weak O—H...N inter­molecular inter­actions between the hy­droxy group and one of the pyrimidine rings producing an two-dimensional supra­molecular array in the bc plane. The title compound studied was a merohedral twin with the major component being approximately 57%.

catena-Poly[[[O,O′-bis­(2-methyl­phen­yl) dithio­phosphato-κ²S,S]lead(II)]-μ-O,O′-bis­(2-methyl­phen­yl) dithio­phosphato-κ³S,S′:S]

In the title compound, [Pb(C₁₄H₁₄O₂PS₂)₂]_n, the metal atom is surrounded by two O,O′-bis­(2-methyl­phen­yl) dithio­phosphate ligands bonding through the S-donor atoms. Three of the Pb—S bond lengths are are close to each other at 2.7710 (18), 2.8104 (16) and 2.8205 (16) Å, while the fourth Pb—S bond is elongated at 3.0910 (18) Å and reflects the fact that this atom is involved in inter­molecular bridging to an adjacent Pb^II atom [Pb—S = 3.145 (2) Å]. The bond angles demonstrate that the Pb^II atom contains a stereochemically active lone pair with a distorted octa­hedral geometry about the Pb^II atom. This distortion is shown by the S—Pb—S bite angles of 73.63 (4) and 69.50 (4)°, while the remaining S—Pb—S angles range from 81.03 (5) to 143.66 (5)°. One of the benzene rings shows positional disorder over two orientations with occupancy factors of 0.747 (11) and 0.253 (11).

2-(2,4-Dichloro­phen­yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide

In the crystal structure of the title compound, C₁₉H₁₇Cl₂N₃O₂, the mol­ecules form dimers of the R₂²(10) type through N—H...O hydrogen bonding. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 80.70 (13) and 64.82 (12)°, respectively. The dihedral angle between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings is 48.45 (5)° while that between the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings is 56.33 (6)°.

Ethyl 2,7,7-trimethyl-4-(1-methyl-1H-indol-3-yl)-5-oxo-1,4,5,6,7,8-hexa­hydro­quinoline-3-carboxyl­ate

In the title mol­ecule, C₂₄H₂₈N₂O₃, the cyclo­hexene ring is in a sofa conformation and the 1,4-dihydro­pyridine ring is in a slight boat conformation. In the indole ring system, the pyrrole and benzene rings form a dihedral angle of 2.63 (7)°. In the crystal, N—H...O hydrogen bonds connect the mol­ecules into C(6) chains parallel to the b axis and pairs of weak C—H...O hydrogen bonds link inversion-related chains into a ladder motif through R₂²(18) rings. A weak intra­molecular C—H...O hydrogen bond is also observed.

2-(2,6-Dichloro­phen­yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide

In the title compound, C₁₉H₁₇Cl₂N₃O₂, the amide group is planar and, through N—H...O hydrogen bonding to an adjoining mol­ecule, forms dimers of the R₂²(10) type. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 71.63 (11) and 57.93 (10)°, respectively. The dihedral angle between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings is 76.60 (10)° while that between the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings is 49.29 (7)°. The crystal structure also features weak C—H...O inter­actions.

2-(1-Phenyl-1H-benzimidazol-2-yl)phenol

In the title mol­ecule, C₁₉H₁₄N₂O, the benzimidazole unit is close to being planar [maximum deviation = 0.0253 (11) Å] and forms dihedral angles of 68.98 (6) and 20.38 (7)° with the adjacent phenyl and benzene rings; the dihedral angle between the latter two planes is 64.30 (7)°. An intra­molecular O—H...N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by C—H...N and C—H...O hydrogen bonds, and consolidated into a three-dimensional architecture by π–π stacking inter­actions, with a centroid–centroid distance of 3.8428 (12) Å.

2,2,7,7-Tetra­methyl-1,2,3,4,5,6,7,8-octa­hydro­acridine-1,8-dione

The whole molecule of the title compound, C₁₇H₂₁NO₂, is generated by twofold rotational symmetry. The N atom and the C and H atoms in position 4 of the pyridine ring lie on the twofold axis. The cyclohexene ring has a sofa conformation with the CH₂ C atom adjacent to the dimethyl-substituted C atom displaced by 0.5949 (16) Å from the mean plane of the other five C atoms. In the crystal, weak C—H...O inter­actions link the mol­ecules into chains parallel to the a axis. In addition, π–π stacking inter­actions [centroid–centroid distance = 3.8444 (7) Å] contribute to the stabilization of the crystal structure.

Cinnarizinium fumarate

In the title salt {systematic name: 4-diphenyl­methyl-1-[(E)-3-phenyl­prop-2-en-1-yl]piperazin-1-ium (2Z)-3-carb­oxy­prop-2-enoate}, C₂₆H₂₉N₂⁺·C₄H₃O₄⁻, the piperazine ring in the cation adopts a distorted chair conformation and contains a positively charged N atom with quaternary character. The dihedral angle between the mean planes of the phenyl rings of the diphenyl­methyl group is 74.2 (7)° and those between these rings and the phenyl ring of the 3-phenyl­prop-2-en-1-yl group are 12.7 (9) and 80.6 (8)°. In the crystal, N—H...O and O—H...O hydrogen bonds form chains along [001]. Weak C—H...O inter­actions connect parallel chains along [010], forming layers perpendicular to the a-axis direction.

(E)-2-[(Furan-2-yl)methyl­idene]-7-methyl-2,3,4,9-tetra­hydro-1H-carbazol-1-one

In the title mol­ecule, C₁₈H₁₅NO₂, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1317 (12) Å]. The pyrrole ring makes dihedral angles of 1.01 (8) and 18.56 (10)° with the benzene and furan rings, respectively. The cyclo­hexene ring adopts a half-chair conformation. In the crystal, pairs of N—H...O hydrogen bonds form an R₂²(10) ring. Mol­ecules are further linked by C—H...O and C—H...π inter­actions, forming a three-dimensional network.

9-[3-(Dimethyl­amino)­prop­yl]-10,10-dimethyl-9,10-dihydro­anthracen-9-ol

The asymmetric unit of the title compound, C₂₁H₂₇NO, contains two mol­ecules (A and B). In mol­ecule A, the central ring of the anthrone unit adopts a shallow boat conformation and the dihedral angle between the benzene rings is 18.96 (7)°. In mol­ecule B, the central ring is close to being planar (r.m.s. deviation = 0.078 Å) and the dihedral angle between the aromatic rings is 7.82 (7)°. In the crystal, mol­ecules are linked by O—H...N hydrogen bonds, forming zigzag C(7) chains of alternating A and B mol­ecules running parallel to [100]. The structure also features weak C—H...O and C—H...π inter­actions.

Methyl 2-bromo-3-(4-chloro­benzene­sulfonamido)­benzoate

In the crystal structure of the title compound, C₁₄H₁₁BrClNO₄S, the mol­ecules form inversion dimers with R₂²(8) motifs through pairs of N—H...O hydrogen bonds. The benzene rings are not coplanar and subtend a dihedral angle of 66.27 (8)°. The carbomethoxy group makes a dihedral angle of 75.1 (1)° with the ring to which it is attached.

1-(2-Furo­yl)-3-(2-meth­oxy-4-nitro­phen­yl)thio­urea

The asymmetric unit of the title compound, C₁₃H₁₁N₃O₅S, contains two independent mol­ecules, which are linked by a pair of inter­molecular N—H...S hydrogen bonds, forming an R₂²(8) ring motif. The central thio­urea core forms dihedral angles of 3.02 (12) and 14.00 (10)° with the essentially planar furoyl groups [maximum deviations = 0.030 (2) and 0.057 (2) Å] in the two mol­ecules and dihedral angles of 2.43 (13) and 8.03 (12)° with the benzene rings. The dihedral angles between the furoyl and benzene rings in the two mol­ecules are 3.97 (10) and 5.98 (9)°. The trans–cis geometry of the thio­urea group is stabilized by three intra­molecular N—H...O hydrogen bonds involving carbonyl and meth­oxy O atoms with the H atom of the cis-thio­amide group and between furan O atom and the other thio­amide H atom. There is also a weak intra­molecular C—H...S inter­action in each mol­ecule.

3,3′-(1-Oxopropane-1,3-di­yl)bis­(1,3-thia­zolidine-2-thione) chloro­benzene hemisolvate

The title compound, C₉H₁₂N₂OS₄·0.5C₆H₅Cl, which contains two 1,3-thia­zolidine-2-thione rings, is a by-product of the synthesis of 3-acryloyl-1,3-thia­zolidine-2-thione. The dihedral angle between these rings is 79.95 (9)°, with both rings displaying a twisted conformation. The twist angle of the amide group is 5.6 (1)°. In the crystal, the molecules are linked into [001] chains by C—H...O interactions. The chloro­benzene solvent mol­ecule was found to show unresolvable disorder about a centre of inversion and its contribution to the scattering was removed with the SQUEEZE option in PLATON [Spek (2009). Acta Cryst. D65, 148–155].

2-(3,4-Dichloro­phen­yl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide

In the title compound, C₁₉H₁₇Cl₂N₃O₂, there are three mol­ecules (A, B and C) in the asymmetric unit and each differs in the conformation adopted. As a result of steric repulsion, the amide group is rotated with respect to both the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 44.5 (2) and 56.2 (2)°, respectively in A, 51.1 (2) and 54.1 (2)° in B, and 53.8 (2) and 54.6 (2)° in C. The dihedral angles between the dichloro­phenyl and 2,3-dihydro-1H-pyrazol-4-yl rings are 54.8 (2), 76.2 (2) and 77.5 (2)° in mol­ecules A, B and C, respectively, while the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings make dihedral angles of 45.3 (2), 51.2 (2) and 42.8 (2)°, respectively. In the crystal, two of the mol­ecules are linked through N—H...O hydrogen bonding to an adjoining mol­ecule, forming dimers of the R₂²(10) type, while the third mol­ecule forms such dimers with itself. C—H...O inter­actions link the dimers.

Cinnarizinium bis­(p-toluene­sulfonate) dihydrate

The asymmetric unit of the title salt [systematic name: 1-benzhydryl-4-cinnamylpiperazine-1,4-diium bis­(p-toluene­sulfonate) dihydrate], C₂₆H₃₀N₂²⁺·2C₇H₇O₃S⁻·2H₂O, consists of a diprotonated cinnarizinium cation hydrogen bonded through two water mol­ecules to two independent p-toluene­sulfonate anions, one which is disordered over two sets of sites in a 0.793 (3):0.207 (3) ratio. In the cation, the piperazine ring adopts a chair configuration and contains two positively charged N atoms with quarternery character. The dihedral angle between the two benzene rings in the benzhydr­yl group is 71.8 (1)°. The benzene ring flanked opposite the piperazine ring is twisted by 75.9 (9) and 8.8 (3)° from these two benzene rings. In the crystal, the [N—H...O_water—H...O([pdbond]S)]₂ hydrogen-bonded asymmetric unit is connected by further O—H...O hydrogen bonds linking the components into chains along [100].

2-(2,6-Dichloro­phen­yl)-N-(1,3-thia­zol-2-yl)acetamide

In the title compound, C₁₁H₈Cl₂N₂OS, the mean plane of the dichloro­phenyl ring is twisted by 79.7 (7)° from that of the thia­zole ring. In the crystal, molecules are linked via pairs of N—H...N hydrogen bonds, forming inversion dimers which stack along the a-axis direction.

(Z)-4-[2-(2,4-Dimethyl­phen­yl)hydrazinyl­idene]-3-methyl­pyrazol-5(1H)-one

The mol­ecule of the title compound, C₁₂H₁₄N₄O, is roughly planar, with a dihedral angle of 8.0 (8)° between the benzene and pyrazole rings, and an intra­molecular N—H...O hydrogen bond forms an S(6) ring motif. In the crystal, mol­ecules are linked into an inversion dimer by a pair of N—H...O hydrogen bonds, which form an R₂²(8) ring motif.

Amicarbazone

Three independent mol­ecules comprise the asymmetric unit of the title compound, C₁₀H₁₉N₅O₂, (systematic name: 4-amino-N-tert-butyl-3-isopropyl-5-oxo-4,5-dihydro-1H-1,2,4-triazole-1-carboxamide) . In all three mol­ecules, the triazole ring and the carboxamide group are almost coplanar [within 4.0–5.9 (9)°], particularly because of the formation of an intra­molecular N—H...O hydrogen bond. On other hand, the orientation of the isopropyl group varies significantly from mol­ecule to mol­ecule. The crystal packing is dominated by N—H...O and N—H...N hydrogen bonds, which connect the mol­ecules into infinite chains along [010].

2-(3,4-Dichloro­phen­yl)-N-(1,3-thia­zol-2-yl)acetamide

In the title compound, C₁₁H₈Cl₂N₂OS, the mean plane of the dichloro­phenyl ring is twisted by 61.8 (1)° from that of the thia­zole ring. In the crystal, mol­ecules are linked via pairs of N—H...N hydrogen bonds with an R₂²(8) graph-set motif, forming inversion dimers which stack along the a-axis direction.

[meso-5,10,15,20-Tetra­kis(3-methyl­thio­phen-2-yl)porphyrinato-κ⁴N,N′,N′′,N′′′]nickel(II) benzene hemisolvate

In the title compound, [Ni(C₄₀H₂₈N₄S₄)]·0.5C₆H₆, the Ni^II atom is in a square-planar geometry defined by four pyrrole N atoms. There is considerable buckling in the porphyrin ring with the dihedral angles between the N₄ donor set and the pyrrole rings being in the range 16.24 (5)–22.47 (5)°. Each of the six-membered chelate rings is twisted about an Ni—N bond and the dihedral angles between diagonally opposite chelate rings are 21.36 (4) and 23.87 (4)°; each pair of rings is oriented in opposite directions. The methyl­thienyl rings are twisted out of the plane of the central N₄ core with dihedral angles in the range 75.98 (2)–88.70 (5)°. All four methyl­thienyl groups are disordered over two sets of sites, as is commonly found with such groups, with occupancies of 0.553 (8):0.447 (8), 0.579 (7):0.421 (7), 0.796 (6):0.204 (6) and 0.956 (7):0.044 (7). The benzene solvent mol­ecule was found to be present in half-occupancy.

2-(2,4-Di­chloro­phen­yl)-N-(1,3-thia­zol-2-yl)acetamide

In the title compound, C₁₁H₈Cl₂N₂OS, the mean plane of the di­chloro­phenyl ring is twisted by 72.4 (1)° from that of the thia­zole ring. In the crystal, mol­ecules are linked via pairs of N—H...N hydrogen bonds with an R₂²(8) graph-set motif and weak C—H...O inter­actions, forming inversion dimers which stack along the c-axis direction.

Methyl 2-{2-[(2-methyl­phen­oxy)meth­yl]phen­yl}-2-oxoacetate

In the title compound, C₁₇H₁₆O₄, the dihedral angle between the benzene rings is 4.4 (2)°. In the crystal, weak C—H...O hydrogen bonds connect mol­ecules along [001].

4-Hy­droxy-N-methyl­benzamide

Three independent mol­ecules comprise the asymmetric unit of the title compound, C₈H₉NO₂, in which the dihedral angles between the amide group and the benzene ring are 3.0 (2), 4.0 (3) and 3.3 (9)°. In the crystal, O—H...O hydrogen bonds and weak C—H...N inter­actions are observed, forming infinite chains along [101].

7-Methyl-1-phenyl-1,10-di­hydro­pyrazolo­[3,4-a]carbazole

In the title mol­ecule, C₂₀H₁₅N₃, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1082 (15) Å]. The pyrrole ring makes dihedral angles of 3.17 (8)/4.10 (9), 7.20 (9) and 44.62 (9)° with the fused benzene, pyrazole and phenyl rings, respectively. In the crystal, mol­ecules are linked via N—H...N hydrogen bonds, forming an infinite chain along [010]. Mol­ecules are further linked by nine π–π [centroid–centroid distances vary from 3.6864 (11) to 3.9802 (11) Å] and one C—H...π inter­action, forming a three-dimensional network.

10-Methyl-2-oxo-4-phenyl-2,11-di­hydro­pyrano[2,3-a]carbazole-3-carbo­nitrile

In the title mol­ecule, C₂₃H₁₄N₂O₂, the atoms in the carbazole unit deviate from planarity [maximum deviation from mean plane = 0.1018 (8) Å]. The pyrrole ring makes dihedral angles of 4.44 (5), 3.84 (5), 2.18 (5) and 56.44 (5)° with the pyran, fused benzene rings and phenyl ring, respectively. In the crystal, pairs of N—H...O hydrogen bonds generate R₂²(14) loops and a C—H...N inter­action is also found. Mol­ecules are further linked by a number of π–π interactions [centroid–centroid distances vary from 3.5702 (5) to 3.7068 (6) Å], forming a three-dimensional network.

Calixarene-based mol­ecular capsule from olefin metathesis

The reaction of tetra­kis­(all­yloxy)calix[4]arene with the first-generation Grubbs catalyst, followed by catalytic hydrogenation, gave the novel bis-calixarene 15,20,46,51,64,69,74,79-octa­oxatridecacyclo[32.28.8.8^3,28.1^13,53.1^22,44.0^9,14.0^21,26.0^38,70.0^40,45.0^52,57.0^59,63.0^7,80.0^32,73]octa­conta-1(63),3,5,7(80),9(14),10,12,21,23,25,28(73),29,31,34,36,38(70),40,42,44,52,54,56,59,61-tetra­cosa­ene benzene monosolvate, C₇₂H₇₂O₈·C₆H₆. The structure consists of two calix[4]arene units connected by four-carbon chains at each of the four O atoms on their narrow rims, to form a cage. Each of the calix[4]arene units has a flattened cone conformation in which two of the opposite aryl groups are closer together and nearly parallel [dihedral angle between planes = 7.35 (16)°], and the other two aryl groups are splayed outward [dihedral angle between planes = 72.20 (8)°]. While the cavity contains no solvent or other guest mol­ecule, there is benzene solvent mol­ecule in the lattice. Two of the alkyl linking arms were disordered over two conformations with occupancies of 0.582 (3)/0.418 (3) and 0.33 (4)/0.467 (4). They were constrained to have similar metrical and thermal parameters.

N-Butanoyl-N-(3-chloro-1,4-dioxonaph­thalen-2-yl)butanamide

In the title compound, C₁₈H₁₈ClNO₄, the imide group with its two alkyl substituents is approximately perpendicular to the plane of the naphtho­quinone ring system [dihedral angle = 78.5 (1)°]. Further, the imide carbonyl groups are oriented in an anti sense. In the crystal, the substituted naphtho­quinone rings form π–π stacks in the a-axis direction [perpendicular centroid–centroid distance = 3.209 (2) Å and slippage = 4.401 Å].

1,5-Bis(4-chloro­phen­yl)-3-(4-methyl­phen­yl)pentane-1,5-dione

In the title mol­ecule, C₂₄H₂₀Cl₂O₂, the central methyl­benzene ring forms dihedral angles of 42.47 (10) and 34.34 (10)° with the terminal 4-chloro­phenyl fragments. The dihedral angle between the chloro­benzene rings is 34.45 (11)°. A weak intra­molecular C—H...O inter­action generates an S(6) ring motif. The crystal packing exhibits weak C—H...O hydrogen bonds and C—H...π inter­actions.

Desvenlafaxinium chloranilate ethyl acetate solvate

In the cation of the title compound, C₁₆H₂₆NO₂⁺·C₆HCl₂O₄⁻·C₄H₈O₂, the 1-hy­droxy-cyclo­hexyl ring adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the 1-hy­droxy­cyclo­hexyl and 4-hy­droxy­phenyl rings is 84.0 (8)°. In the anion, the hydroxyl H atom is twisted slightly out of the ring plane with a C—C—O—H torsion angle of −171.9°. Disorder was modeled for the methyl group of the acetate group in the solvate with an occupancy ratio of 0.583 (15): 0.417 (15). In the crystal, O—H...O hydrogen bonds are observed between cations and between cations and anions, while bifuricated N—H...(O,O) cation–anion hydrogen bonds are also present, forming chains along [010] and [100]. In addition weak cation–anion and cation–solvate C—H...O inter­actions occur.

2-(Phenyl­selenon­yl)pyridine

In the title compound, C₁₁H₉NO₂Se, the pyridine and phenyl rings are almost perpendicular, with the dihedral angle between their mean planes being 79.16 (7)°. In the crystal, the mol­ecules pack so as to form ruffled sheets in the (110) plane connected by weak C—H...O inter­actions. In addition, there are weak π–π inter­actions between the mean planes of both the phenyl [centroid–centroid perpendicular distance of 3.591 (2) Å and slippage of 1.854 (2) Å] and pyridine rings [centroid–centroid perpendicular distance of 3.348 (2) Å and slippage of 1.854 (2) Å].

3-[1-(4-Bromo­phen­yl)eth­oxy]-2,2,5-trimethyl-4-phenyl-3-aza­hexa­ne

The title compound, C₂₂H₃₀BrNO, is an alk­oxy­amine compound, an effective initiator in nitroxide-mediated free radical polymerization. It was prepared as a mixture of two diasteromers; the crystal for the X-ray analysis showed one of these as a pair of R,S and S,R enanti­omers. The tert-butyl and isopropyl groups are in an almost anti conformation in the crystal [C—N—C—C torsion angle = −168.8 (1)°], and the methyl group of the ethoxy group is in an approximate anti relationship to the tert-butyl group. The dihedral angle between the phenyl and benzene rings is 33.12 (7)°. The Br atom is disordered over two positions, with occupancies of 0.9139 (16) and 0.0861 (16). In the crystal, weak C—H...Br contacts link the mol­ecules into chains along [-110].

Isovaline monohydrate

The title compound, C₅H₁₁NO₂·H₂O, is an isomer of the α-amino acid valine that crystallizes from water in its zwitterion form as a monohydrate. It is not one of the 20 proteinogenic amino acids that are used in living systems and differs from the natural amino acids in that it has no α-H atom. The compound exhibits hydrogen bonding between the water mol­ecule and the carboxyl­ate O atoms and an amine H atom. In addition, there are inter­molecular hydrogen-bonding inter­actions between the carboxyl­ate O atoms and amine H atoms. In the crystal, these extensive N—H...O and O—H...O hydrogen bonds lead to the formation of a three-dimensional network.

Ethyl 6-(4-chloro­phen­yl)-4-(4-fluoro­phen­yl)-2-oxo­cyclo­hex-3-ene-1-carboxyl­ate

The asymmetric unit of the title compound, C₂₁H₁₈ClFO₃, contains two independent mol­ecules. In one mol­ecule (A), the 4-chloro­phenyl, oxo­cyclo­hex-3-ene, carboxyl­ate, and ethyl groups were refined as disordered over two sets of sites with a 0.684 (5):0.316 (5) ratio. The cyclo­hexene ring in the disordered mol­ecule is in a slightly distorted envelope conformation for the major component (with the C atom bound to the carboxylate group being the flap atom) and in a screw-boat conformation for the minor component. In the ordered mol­ecule (B), the cyclo­hexene ring is in a half-chair conformation. The dihedral angles between the mean planes of the fluoro- and chloro-substituted benzene rings are 89.9 (7) (only the major component is considered for A) and 76.4 (7)° (B). In the crystal, inversion dimers are observed along with weak C—H...O hydrogen bonds, which form chains along [100].

2-Methyl­aspartic acid monohydrate

The title compound, C₅H₉NO₄·H₂O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O—H...O hydrogen bond is present between the acid and water mol­ecules while extensive N—H...O and O—H...O hydrogen bonds link the components into a three-dimensional array.