4‐Ethoxycarbonyl‐3‐hydroxy‐3‐phenylcyclohexanone

The title compound, ethyl 2‐hydroxy‐4‐oxo‐2‐phenyl­cyclo­hexane­carboxyl­ate, C₁₅H₁₈O₄, was obtained by a Michael–Aldol condensation and has the cyclo­hexanone in a chair conformation. The attached hydroxy, ethoxy­carbonyl and phenyl groups are disposed in β‐axial, β‐equatorial and α‐­equatorial configurations, respectively. An intermolecular hydrogen bond, with an O?O distance of 2.874 (2) Å, links the OH group and the ring carbonyl. Weak intermolecular C—H?O=C (ester and ketone), O—H?O=C (ketone) and C—H?OH hydrogen bonds exist.     

5‐(2‐Pyridyl)‐1,3‐di­thia­ne‐2‐thione

The title compound, C₉H₉NS₃, crystallizes with two mol­ecules in the asymmetric unit. In both mol­ecules, the di­thia­ne‐2‐thione rings adopt a symmetric half‐boat conformation with the C atom opposite the C—S_thione bond out of the plane. The pyridine ring is in an equatorial position and is twisted out of the plane of the half‐boat by 82.7 (2) and 84.5 (2)° in the two mol­ecules, so that the N atom is trans to the axial C—H bond in both cases.     

Cyclo­decyl 4‐nitro­phenyl­acetate

Cyclodecyl 4‐nitrophenylacetate, C₁₈H₂₅NO₄, has its ten‐membered ring in the expected diamond‐lattice boat–chair–boat [2323] conformation, with the substituent 4‐nitro­phenyl­acet­oxy group in the BCB IIIe position. The ester unit has the expected Z conformation, with an O=C—O—C torsion angle of −0.3 (3)°, and the connection to the benzene ring is nearly perpendicular to the ester, with an O=C—C—C torsion angle of 85.5 (2)°. An inter­molecular contact exists between the ester C atom and a nitro O atom, having a C⋯O distance of 2.909 (2) Å.     

2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.     

3,5‐Di­fluoro‐4‐nitro­pyridine N‐oxide and 3,5‐di­amino‐4‐nitro­pyridine N‐oxide monohydrate

The mol­ecule of 3,5‐di­fluoro‐4‐nitro­pyridine N‐oxide, C₅H₂F₂N₂O₃, is twisted around the C—NO₂ bond by 38.5 (1)°, while the 3,5‐di­amino analogue, 3,5‐di­amino‐4‐nitro­pyridine N‐oxide monohydrate, C₅H₆N₄O₃·H₂O, adopts a planar conformation stabilized by intramolecular hydrogen bonds, with a significant redistribution of π electrons.     

Charge‐transfer complexes of 4‐(di­methyl­amino)­pyridine with 2,4‐, 3,4‐ and 3,5‐di­nitro­benzoic acid

In the three title crystal structures 4‐(di­methyl­amino)­pyridinium 2,4‐di­nitro­benzoate, (I), 4‐(di­methyl­amino)­pyri­dinium 3,4‐di­nitro­benzo­ate, (II), and 4‐(di­methyl­amino)pyri­din­ium 3,5‐di­nitro­benzo­ate, (III), all C₇H₁₁N₂⁺·C₇H₃N₂O₆^?, the ions are connected by an N—H?O hydrogen bond. Dihedral angles between the pyridine and phenyl rings are 69.9 (1), 26.7 (1) and 56.2 (1)° in (I), (II) and (III), respectively. Donor–acceptor π–π stacking is observed in (II) and (III), but not in (I).     

(E)‐1‐(2′‐Deoxy‐β‐d‐ribo­furan­osyl)‐2,4‐di­fluoro‐5‐(2‐iodo­vinyl)­benzene

This analysis of the title compound, C₁₃H₁₃F₂IO₃, establishes the orientation of (E)‐5‐(CH=CH—I) as antiperiplanar (ap) to the C—C bond (5–6 position) of the 2,4‐di­fluoro­phenyl ring system, with the (E)‐5‐(CH=CH—I) H atom located in close proximity (2.17 Å) to the F4 atom of the 2,4‐di­fluoro­phenyl moiety.     

Methyl 4‐(2‐chloro‐5‐nitro­phenyl)‐2,7,7‐tri­methyl‐5‐oxo‐1,4,5,6,7,8‐hexa­hydro­quinoline‐3‐carboxyl­ate

The title compound, C₂₀H₂₁ClN₂O₅, has potential calcium modulatory properties. The 1,4‐di­hydro­pyridine ring has the usual shallow boat conformation. The 2‐chloro‐5‐nitro­phenyl ring is oriented such that the chloro substituent is in a synperiplanar orientation with respect to the 1,4‐di­hydro­pyridine ring plane, while the nitro substituent sits over the 1,4‐di­hydro­pyridine ring. The cyclo­hexenone ring has a conformation that is approximately half‐way between that of an envelope and that of a half‐chair. The mol­ecules are linked into chains by intermolecular N—H⋯O hydrogen bonds.     

Hydrogen bonding in nitroaniline analogues: hydrogen‐bonded sheets in 2‐amino‐4,6‐dimethoxy‐5‐nitropyrimidine and π‐stacked hydrogen‐bonded sheets in 4‐amino‐2,6‐dimethoxy‐5‐nitropyrimidine

In 2‐amino‐4,6‐di­methoxy‐5‐nitro­pyrimidine, C₆H₈N₄O₄, the mol­ecules are linked by one N—H⋯N and one N—H⋯O hydrogen bond to form sheets built from alternating R(8) and R(32) rings. In isomeric 4‐amino‐2,6‐di­methoxy‐5‐nitro­pyrimidine, C₆H₈N₄O₄, which crystallizes with Z′ = 2 in P, the two independent mol­ecules are linked into a dimer by two independent N—H⋯N hydrogen bonds. These dimers are linked into sheets by a combination of two‐centre C—H⋯O and three‐centre C—H⋯(O)₂ hydrogen bonds, and the sheets are further linked by two independent aromatic π–π‐stacking interactions to form a three‐dimensional structure.     

Two intermediates in the synthesis of deca­hydro­iso­quinolines with NMDA and AMPA receptor antagonist activity

In 6‐methyl‐N‐(4‐nitro­benzoyl)‐5,6‐di­hydropyridin‐2(1H)‐one, C₁₃H₁₂N₂O₄, (I), the piperidone ring is in a distorted half‐chair conformation. In 8‐methoxy‐3‐methyl‐N‐(4‐nitro­benzoyl)‐1,2,3,4,5,6,7,8‐octa­hydro­iso­quinoline‐1,6‐dione, C₁₈H₂₀N₂O₆, (II), the heterocyclic ring is in a slightly distorted half‐boat conformation, while the other six‐membered ring is in a distorted chair conformation. Compound (II) presents a strong intramolecular C—H?O hydrogen bond. In both (I) and (II), the mol­ecules interact through C—H?O interactions.     

2,6‐Diiodo‐4‐nitrophenol, 2,6‐diiodo‐4‐nitrophenyl acetate and 2,6‐diiodo‐4‐nitroanisole: interplay of hydrogen bonds,iodo–nitro interactions and aromatic π–π‐stacking interactions to give supramolecular structures in one,two and three dimensions

In 2,6‐di­iodo‐4‐nitro­phenol, C₆H₃I₂NO₃, the mol­ecules are linked, by an O—H?O hydrogen bond and two iodo–nitro interactions, into sheets, which are further linked into a three‐dimensional framework by aromatic π–π‐stacking interactions. The mol­ecules of 2,6‐di­iodo‐4‐nitro­phenyl acetate, C₈H₅I₂NO₄, lie across a mirror plane in space group Pnma, with the acetyl group on the mirror, and they are linked by a single iodo–nitro interaction to form isolated sheets. The mol­ecules of 2,6‐di­iodo‐4‐nitro­anisole, C₇H₅I₂NO₃, are linked into isolated chains by a single two‐centre iodo–nitro interaction.     

5,5‐Di­methoxy‐2‐phenoxy‐1,3,2‐dioxaphosphorinane 2‐oxide

In the title compound, C₁₁H₁₅O₆P, the six‐membered dioxa­phospho­rinane ring of the cyclic phosphate triester exists in a distorted chair conformation, with the phenoxy group in an axial position. The phenyl ring and both methoxy groups are in a trans–gauche orientation with respect to the 1,3,2‐di­oxa­phospho­rinane ring. In the phosphate group, a significant deformation from the ideal tetrahedral shape is observed. The crystal structure is stabilized by a three‐dimensional network of C—H⋯O interactions.     

1,4,4‐Tri­methyl‐9‐phenyl‐8‐oxa‐9‐aza­bi­cyclo­[3.2.2]­non‐6‐en‐2‐one

The structure of the adduct of eucarvone with nitro­so­benzene, C₁₆H₁₉NO₂, is reported. The [3.2.2] bicyclic system corresponds to two seven‐membered rings in boat and distorted chair conformations and a six‐membered ring that adopts a distorted boat conformation. No conjugation is observed between the phenyl group and the N—O system. The packing is directed mainly by a C?O hydrogen bond, C—H?O‐(1 ? x, ?y, z) and by intermolecular C—H?π interactions.     

Di­propyl 3,6‐di­phenyl‐1,2‐di­hydro‐1,2,4,5‐tetrazine‐1,2‐di­carboxyl­ate

The title compound, C₂₂H₂₄N₄O₄, was prepared from propyl chloro­formate and 3,6‐di­phenyl‐1,2‐di­hydro‐s‐tetrazine. This reaction yields the title compound rather than di­propyl 3,6‐di­phenyl‐1,4‐di­hydro‐s‐tetrazine‐1,4‐di­carboxyl­ate. The 2,3‐di­aza­buta­diene group in the central six‐membered ring is not planar; the C=N double‐bond length is 1.285 (2) Å, and the average N—N single‐bond length is 1.401 (3) Å, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie 0.3268 (17) Å from the plane of the ring. The mol­ecule has twofold crystallographic symmetry.     

2‐Chloro­phenyl 3‐nitro­benzene­sulfonate and 2,4‐di­chloro­phenyl 3‐nitro­benzene­sulfonate: supramole­cular aggregation through C–H⋯O, π–π and van der Waals interactions

In 2‐chloro­phenyl 3‐nitro­benzene­sulfonate, C₁₂H₈ClNO₅S, and 2,4‐di­chloro­phenyl 3‐nitro­benzene­sulfonate, C₁₂H₇Cl₂NO₅S, weak C—H⋯O interactions generate S(5), S(6) and (7) rings. The supramolecular aggregation is completed by the presence of π–π interactions and intermolecular van der Waals short contacts.     

1‐Chloro‐3,6‐di­methoxy‐2,5‐di­methyl­benzene and 1‐chloro‐3,6‐di­methoxy‐2,4‐di­methyl­benzene

The title compounds, 1‐chloro‐3,6‐di­methoxy‐2,5‐di­methyl­benzene, (IIIa), and 1‐­chloro‐3,6‐di­methoxy‐2,4‐di­methyl­benzene, (IIIb), both C₁₀H₁₃ClO₂, were obtained from 2,5‐ and 2,6‐di­methyl‐1,4‐benzo­quinone, respectively, and are intermediates in the synthesis of ammonium quinone derivatives. The isomers have different substituents around the methoxy groups and crystallize in different space groups. In both mol­ecules, the methoxy groups each have different orientations with respect to the benzene ring. In both cases, one methoxy group lies in the plane of the ring and can participate in conjugation with the aromatic system, while the second is almost perpendicular to the plane of the aromatic ring. The C—O—C bond angles around these substituents are also different: 117.5 (4) and 118.2 (3)° in (IIIa) and (IIIb), respectively, when the methoxy groups lie in the plane of the ring, and 114.7 (3) and 113.6 (3)° in (IIIa) and (IIIb), respectively, when they are out of the plane of the ring.     

Three‐dimensional aggregation in 2‐hydroxy‐3‐iodo‐5‐nitrobenzaldehyde involving C—H⋯O,iodo–nitro and aromatic π–π stacking interactions,and isolated dimers in disordered 2,4‐diiodo‐6‐nitroanisole

In 2‐hydroxy‐3‐iodo‐5‐nitro­benz­aldehyde, C₇H₄INO₄, the mol­ecules are linked into sheets by a combination of C—H⋯O hydrogen bonds and two‐centre iodo–nitro interactions, and these sheets are linked by aromatic π–π stacking interactions. Molecules of 2,4‐di­iodo‐6‐nitro­anisole, C₇H₅I₂NO₃, are disordered, with the nitro group and one of the I substituents each occupying common sets of sites with 0.5 occupancy. The mol­ecules are linked into isolated centrosymmetric dimeric units by a single iodo–nitro interaction.     

Azole. 45.

The three title compounds, namely (Z)‐1‐(4,5‐di­nitro­imidazol‐1‐yl)‐3‐morpholinopropan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₁₆H₁₇N₉O₉, (IV), (Z)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₂₀H₂₅N₉O₈, (Va), and (E)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenylhydra­zone tetra­hydro­furan solvate, C₂₀H₂₅N₉O₈·C₄H₈O, (Vb), have been prepared and their structures determined. In (IV), the C‐4 nitro group is nearly perpendicular to the imidazole ring and the C‐4—NO₂ bond length is comparable to the value for a normal single Csp²—NO₂ bond. In (IV), (Va) and (Vb), the C‐­5 nitro group deviates insignificantly from the imidazole plane and the C‐5—NO₂ bond length is far shorter in all three compounds than C‐4—NO₂ in (IV). In consequence, the C‐4 nitro group in (IV) is easily replaced by morpholine, while the C‐5 nitro group in (IV), (Va) and (Vb) shows an extraordinary stability on treatment with the amine. The E configuration in (Vb) is stabilized by a three‐centre hydrogen bond.     

2‐Nitroso‐1,3‐diphenyl‐1,2,3,4‐tetrahydrobenzo[b][1,6]naphthyridine

The title compound, C₂₄H₁₉N₃O, crystallizes in the centrosymmetric space group P2₁/a with one mol­ecule in the asymmetric unit. The tetra­hydro­pyridine ring has a boat conformation. The dihedral angle between the fused pyridine rings is 16.2 (1)°. The equatorial and axial orientations of the two phenyl groups with respect to the tetra­hydro­pyridine ring are confirmed. The nitroso group is coplanar with the attached C—N—C group. The interplanar angle formed between the fused tetra­hydro­pyridine and benzene planes is 13.4 (1)°. The crystal packing is stabilized by an intermolecular C—H⃛O hydrogen bond, which forms a C(9) graph‐set chain running along the [001] direction.     

Calcium(II) meso‐2,3‐di­phenyl­succinate heptahydrate

The title compound, [Ca(C₁₆H₁₂O₄)(H₂O)₆]·H₂O, adopts a conformation about the central C—C bond that places the two carboxylate groups in an anti orientation. The crystal consists of layers of two‐dimensional arrays of 2,3‐di­phenyl­succinate dianions which are linked by bridging Ca²⁺ cations. The unit cell contains two Ca²⁺ cations in an unusual four‐membered Ca—O—Ca—O ring in which the bridging O atoms belong to water mol­ecules rather than carboxyl­ates, i.e. poly­[[[di‐μ‐aqua‐bis­[penta­aqua­calcium(II)]]‐μ‐(meso‐2,3‐di­phenyl­succinato‐O:O′)] succinate dihydrate].