Methyl (SR)‐10‐chloro‐1,2,3,4,5,6‐hexahydro‐6‐hydroxy‐8‐methoxy‐1‐methyl‐1,9‐phenanthroline‐6‐carboxylate

In the title compound, C₁₆H₁₉ClN₂O₄, the pyridine ring is nearly planar, the piperidine ring is non‐planar and the cyclo­hexane ring adopts a screw‐boat conformation. The carboxyl­ate group makes a dihedral angle of 80.9 (2)° with the least‐squares plane through the cyclo­hexane ring.     

3‐Methyl 5‐isopropyl 2‐methoxy­imino­methyl‐6‐methyl‐4‐(3‐nitro­phenyl)‐1,4‐di­hydro­pyridine‐3,5‐di­carboxyl­ate

The crystal structure of the title compound, C₂₀H₂₃N₃O₇, consists of relatively isolated mol­ecules. The substituted 1,4‐di­hydro­pyridine ring adopts a flattened boat conformation. Both ester groups, at positions 3 and 5, have cis,cis geometry. The phenyl ring is nearly planar and is approximately perpendicular to the 1,4‐di­hydro­pyridine ring (dihedral angle 87.70°).     

N,N‐Diethyl‐2,6,6‐trimethyl‐4‐(3‐nitrophenyl)‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐3‐carboxamide

The title compound, C₂₃H₂₉N₃O₄, has potential calcium modulatory properties. The conformation of the 1,4‐di­hydro­pyridine ring is unusual in that it is planar, instead of the usual shallow boat. The 3‐nitro­phenyl substituent is in the synperiplanar orientation with respect to the di­hydro­pyridine ring plane. The oxo­cyclo­hexene ring has a distorted envelope conformation, with the out‐of‐plane atom being disordered on opposite sides of the ring plane. The mol­ecules are linked into chains by intermolecular hydrogen bonds.     

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.     

4′,4′,6′,6′‐Tetra­chloro‐3,4‐di­hydro‐3‐(6‐methyl­pyridin‐2‐yl)­spiro­[1,3,2‐benzox­aza­phosphinine‐2,2′‐(2λ5,4λ5,6λ5‐cyclo­triphosphazene)]

The title compound, C₁₃H₁₂Cl₄N₅OP₃, is a phosphazene derivative with a bulky substituted spiro­cyclic ring. The C₃NPO spiro­cyclic ring has a twist‐boat conformation, while the phosphazene ring has a very flattened boat conformation.     

(Z)‐2‐(1‐Benzyl‐5‐nitro‐1H‐indol‐3‐ylmethyl­ene)‐1‐aza­bicyclo­[2.2.2]octan‐3‐one

In the title compound, C₂₃H₂₁N₃O₃, the indole ring is planar and the phenyl ring of the benzyl group makes a dihedral angle with the best plane of the indole ring of 73.77 (4)°. The double bond connecting the aza­bicyclic and indole moieties has Z geometry.     

Anomeric effect and hydrogen‐bonded supramolecular motif in 5‐(3‐fluoro‐4‐methoxyphenyl)‐1‐[(3‐fluoro‐4‐methoxyphenyl)aminomethyl]‐1,3,5‐triazinane‐2‐thione

In the title compound, C₁₈H₂₀F₂N₄O₂S, the triazinane‐2‐thione ring adopts an envelope conformation, the ring substituents lie on the same side of the mean plane of the heterocyclic ring and the exo lp—N—C—N_triaz unit (lp is a lone pair and triaz is the triazinane ring) exhibits an antiperiplanar orientation, which is shown to be governed by strong anomeric effects. Molecules are linked into a complex three‐dimensional framework by a combination of two N—H...S hydrogen bonds, three C—H...F hydrogen bonds and a π–π stacking interaction.     

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, 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.     

20‐Hydroxy­imino‐5α‐pregna‐9(11),16‐dien‐3β‐yl acetate and 17‐oxo‐5α‐androst‐9(11)‐en‐3β‐yl acetate

In the title compounds, C₂₃H₃₃NO₃ and C₂₁H₃₀O₃, respectively, the ester linkage in ring A is equatorial. In these steroids, the six‐membered rings A and B have chair conformations, but ring C can be better described as a half‐chair. The five‐membered ring D adopts a 14α‐envelop conformation. The A/B, B/C and C/D ring junctions are trans.     

4‐Acetonyl­idene‐1‐ethyl‐2,3,4,5‐tetra­hydro‐1H‐1,5‐benzodiazepin‐2‐one

The title compound, C₁₄H₁₆N₂O₂, contains a diazepine ring, which appears in a boat conformation. An intramolecular hydrogen bond is formed between the NH group of the diazepine ring and a carbonyl O atom of one of the side chains.     

(Z)‐7‐Chloro‐3‐[(3‐chloro­phenyl)­methyl­idene]‐4‐p‐tosyl‐3,4‐di­hydro‐2H‐1,4‐benzoxazine

In the title compound, C₂₂H₁₇Cl₂NO₃S, the mol­ecule is a substituted 3,4‐di­hydro‐2H‐1,4‐benzoxazine compound which has three phenyl rings which are essentially planar. The 3,4‐di­hydro‐2H‐oxazine part of the mol­ecule is fused to the benzo ring and has a half‐boat conformation; the dihedral angle between the planar part of the oxazine ring and the benzo ring is 10.2 (2)°. The (3‐chloro­phenyl)­methyl­idene substituent has a Z configuration in relation to the ring N atom of the oxazine moiety. Interestingly, the p‐toluenesulfonyl (p‐tosyl) substituent on the ring N atom protrudes away from the 3‐­chloro­phenyl substituent thus avoiding any steric interaction.     

Two atropisomers of tri­carbonyl­[η6‐7‐chloro‐3‐(3‐chloro‐2‐methyl­phenyl)‐2,4,8‐tri­methyl‐1,2,3,4‐tetra­hydro‐2,4‐dibora‐1,3‐di­aza­naphthalene]­chromium(0)

The structures of two atropisomers of the title compound, [Cr(C₁₆H₁₈B₂Cl₂N₂)(CO)₃], are reported. For both compounds, the Cr(CO)₃ moiety is bound to the C₆ aromatic ring of the mol­ecule; the existence of atropisomers resulting from the non‐equivalence of both faces of the C₆ aromatic ring is a consequence of the 3‐chloro‐2‐methylphenyl ring being nearly perpendicular to the mean plane of the 2,4‐dibora‐1,3‐di­aza­naphthalene ring. The orientation of the Cr(CO)₃ tripod relative to the C₆ aromatic ring is such that it is nearly eclipsed in one isomer (2.4° rotation from being eclipsed with C—N, C—Cl and C—H) and slightly twisted (16.2°) from an eclipsed conformation in the other.     

5‐Acetyl‐2‐amino‐6‐methyl‐4‐phenyl‐4H‐pyran‐3‐carbonitrile and 2‐amino‐5‐benzoyl‐6‐methyl‐4‐phenyl‐4H‐pyran‐3‐carbonitrile acetonitrile solvate

The syntheses, X‐ray structural investigations and calculations of the conformational preferences of the carbonyl substituent with respect to the pyran ring have been carried out for the two title compounds, viz. C₁₅H₁₄N₂O₂, (II), and C₂₀H₁₆N₂O₂·C₂H₃N, (III), respectively. In both mol­ecules, the heterocyclic ring adopts a flattened boat conformation. In (II), the carbonyl group and a double bond of the heterocyclic ring are syn, but in (III) they are anti. The carbonyl group forms a short contact with a methyl group H atom in (II). The dihedral angles between the pseudo‐axial phenyl substituent and the flat part of the pyran ring are 92.7 (1) and 93.2 (1)° in (II) and (III), respectively. In the crystal structure of (II), inter­molecular N—H⋯N and N—H⋯O hydrogen bonds link the mol­ecules into a sheet along the (103) plane, while in (III), they link the mol­ecules into ribbons along the a axis.     

2,4‐Diamino‐5‐(1‐naphthyl)‐3,5‐diaza‐1‐azoniaspiro[5.5]undeca‐1,3‐diene chloride

The title salt, C₁₈H₂₂N₅⁺·Cl^?, is a member of a new series of lipophilic 4,6‐di­amino spiro‐s‐triazines which are potent in­hib­itors of di­hydro­folate reductase. The protonated triazine ring deviates from planarity, whereas the cyclo­hexane ring adopts a chair conformation. A rather unusual hydrogen‐bonding scheme exists in the crystal. There is a centrosymmetric arrangement involving two amino groups and two triazine ring N atoms, with graph‐set R(8) and an N?N distance of 3.098 (3) Å, flanked by two additional R(8) systems, involving two amino groups, a triazine ring N atom and a Cl^? anion, with N?Cl distances in the range 3.179 (2)–3.278 (2) Å. Furthermore, the Cl^? anion, the protonated triazine ring N atom and an amino group form a hydrogen‐bonding system with graph‐set R(6).     

4‐Hydroxy‐7‐methoxy‐2‐methyl‐5H‐1‐benzopyrano[4,3‐b]pyridin‐5‐one

The title compound, C₁₄H₁₁NO₄, consists of a methoxy‐substituted coumarin skeleton fused to a 2‐methyl‐4‐pyridone ring. The ring system of the mol­ecule is approximately planar and the methoxy group is roughly coplanar with the ring plane. The 4‐pyridone ring exists in a 4‐hydroxy tautomeric form and is stabilized by an intramolecular hydrogen bond between the O—H and C=O groups. Comparison of the results with those found for other structures containing the 4‐pyridone substructure reveals a substantial effect of the nature of the substituents bonded to the pyridine ring on the keto–enol tautomerism.     

(±)‐Methyl and (±)‐ethyl 4‐(2,3‐di­fluoro­phen­yl)‐2,6,6‐trimethyl‐5‐oxo‐1,4,5,6,7,8‐hexa­hydro­quinoline‐3‐carboxyl­ate

The title compounds, C₂₀H₂₁F₂NO₃ and C₂₁H₂₃F₂NO₃, respectively, belong to a class of 1,4‐dihydro­pyridines whose members sometimes display calcium modulatory properties. The 1,4‐dihydro­pyridine rings have the usual shallow boat conformation. In each structure, the 2,3‐difluoro­phenyl ring is oriented such that the fluoro substituents are in a synperi­planar orientation with respect to the 1,4‐dihydro­pyridine ring plane and the oxocyclo­hexene ring has a slightly distorted envelope conformation. Both structures exhibit the same inter­molecular N—H⋯O hydrogen‐bonding motif, in which the mol­ecules are linked into chains by inter­actions involving the carbonyl O atom of the oxocyclo­hexene ring.     

5‐Amino‐4‐(4‐diethyl­amino­phenyl)‐2‐(4‐hydroxy­phenyl)‐7‐(pyrrolidin‐1‐yl)‐1,6‐naphthyridine‐8‐carbo­nitrile

In the title compound, C₂₉H₃₀N₆O, the naphthyridine moiety is planar with a dihedral angle between the fused rings of 1.9 (1)°. The phenol ring is nearly coplanar, while the diethyl­amino­phenyl substituent is orthogonal to the central naphthyridine ring and the pyrrolidine ring makes an angle of 11.2 (1)° with it. The O atom of the hydroxy substituent is coplanar with the phenyl ring to which it is attached. The molecular structure is stabilized by a C—H?N‐type intramolecular hydrogen bond and the packing is stabilized by intermolecular C—H?π, O—H?N and N—H?O hydrogen bonds.     

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.     

Hydrogen‐bonding and C—H⋯π interactions in 7‐hydroxy‐3‐methoxy‐4‐methyl‐5,6,7,8‐tetrahydro­pyrido­[1,2‐c]pyrimidin‐1(9H)‐one

In the title compound, C₁₀H₁₄N₂O₃, a pyrimidine ring is fused with a piperidine ring. The pyrimidine ring is planar, whereas the piperidine ring adopts a half‐chair conformation. The molecules of the title compound are connected via O—H⋯O intermolecular hydrogen bonds into infinite zigzag chains. The pyrimidine ring is involved in three C—H⋯π interactions, which link the hydrogen‐bonded chains into a three‐dimensional framework.     

()‐9‐(2‐Bromophenyl)‐7,7‐dimethyl‐1,3,4,5,6,7,8,9‐octahydrofuro[3,4‐b]quinoline‐1,8‐dione

The title compound, C₁₉H₁₈BrNO₃, has potential calcium modulatory properties. The 1,4‐di­hydro­pyridine ring has a very shallow boat conformation and is one of the most planar examples of this moiety. The 2‐bromo­phenyl substituent is in the axial synperiplanar orientation. The quinoline ring has a half‐chair conformation, with the unusual arrangement of the out‐of‐plane atom being on the opposite side of the ring plane to the bromo­phenyl substituent. The mol­ecules are linked into chains by intermolecular hydrogen bonds.