Absolute configuration of (−)‐4‐(3,4‐di­chloro­phenyl)‐4‐(2‐pyridyl)­butanoic acid: essential information to determine crucial steric features of ­arpromidine‐type hist­amine H2 receptor agonists

The structural information gained from the study of the chiral building block (R)‐(?)‐4‐(3,4‐di­chloro­phenyl)‐4‐(2‐pyridyl)­butanoic acid–l ‐(?)‐ephedrine [methyl(1‐hydroxy‐1‐phenyl­prop‐2‐yl)ammon­ium 4‐(3,4‐di­chloro­phenyl)‐4‐(2‐pyrid­yl)but­an­oate], C₁₀H₁₆NO⁺·C₁₅H₁₂Cl₂NO₂^?, can be used to deduce the absolute configuration of highly potent arpromidine‐type hist­amine H₂ receptor agonists, as the chiral butanoic acid can be converted to (R)‐(?)‐3‐(3,4‐di­chloro­phenyl)‐3‐(2‐pyridyl)­propyl­amine and to the corresponding R‐configured arpromidine analogue.     

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.     

Packing considerations of bis‐dimedone derivatives

We have determined the crystal structures of 2,2′‐(4‐fluoro­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₇FO₄, (I), 2,2′‐(4‐chloro­phenyl)­methyl­enebis(3‐hy­droxy‐5,5‐dimethyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₇ClO₄, (II), 2,2′‐(4‐hydroxy­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₈O₅, (III), 2,2′‐(4‐methyl­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₄H₃₀O₄, (IV), 2,2′‐(4‐methoxy­phenyl)­methyl­enebis(3‐hy­droxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₄H₃₀O₅, (V), and 2,2′‐(4‐N,N′‐di­methyl­amino­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₅H₃₃NO₄, (VI). Structures (III) to (VI) of these bis‐dimedone derivatives show nearly the same packing pattern irrespective of the different substituent in the para position of the aromatic ring. However, (II) does not fit into this scheme, although the Cl atom is a substituent not too different from the others. The different packing of the fluoro compound, (I), can be explained by the fact that it crystallizes with two mol­ecules in the asymmetric unit, which show a different conformation of the dimedone ring. On the other hand, (I) shows a similar packing pattern to bis(2‐hydroxy‐4,4‐di­methyl‐6‐oxo‐1‐cyclo­hexenyl)­phenyl­methane, a compound containing an aromatic ring without any substituent and with Z′ = 2.     

(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.     

Racemic and chiral 1‐[N‐(chloro­acetyl)carbamoylamino]‐2,3‐dihydro‐1H‐inden‐2‐yl chloroacetate

In the racemic crystals of (1S,2R)‐ or (1R,2S)‐1‐[N‐(chloro­acetyl)­carbamoyl­amino]‐2,3‐di­hydro‐1H‐inden‐2‐yl chloro­acetate, C₁₄H₁₄Cl₂N₂O₄, (I), the enantiomeric mol­ecules form a dimeric structure via the N—H?O cyclic hydrogen bond of the carbamoyl moieties. In the chiral crystals of (—)‐(1S,2R)‐1‐[N‐(chloro­acetyl)­carbamoyl­amino]‐2,3‐di­hydro‐1H‐inden‐2‐yl chloro­acetate, C₁₄H₁₄Cl₂N₂O₄, (II), the N—­H?O intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis. The melting points and calculated densities of (I) and (II) are 446 and 396 K, and 1.481 and 1.445 Mg m^?3, respectively.     

(Z)‐2‐Methylbuten‐1‐yl(aryl)iodonium trifluoromethanesulfonates containing electron‐withdrawing groups on the aryl moiety

The crystal structures of [(Z)‐2‐methyl­but‐1‐en‐1‐yl]­[4‐(tri­fluoro­methyl)­phenyl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₂H₁₃F₃I⁺·CF₃O₃S^?, (I), (3,5‐di­chloro­phenyl)­[(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₁H₁₂­Cl₂I⁺·CF₃O₃S^?, (II), and bis{[3,5‐bis­(tri­fluoro­methyl)­phenyl][(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium} bis­(tri­fluoro­methane­sulfonate) di­chloro­methane solvate, 2C₁₃H₁₂F₆I⁺·­2CF₃­O₃S^?·CH₂Cl₂, (III), are described. Neither simple acyclic β,β‐di­alkyl‐substituted alkenyl­(aryl)­idonium salts nor a series containing electron‐deficient aryl rings have been described prior to this work. Compounds (I)–(III) were found to have distorted square‐planar geometries, with each I atom interacting with two tri­fluoro­methane­sulfonate counter‐ions.     

1:2 Complexes of chloranilic acid with pyrazole and imidazole,and the aceto­nitrile solvate of a 1:1 complex with imidazole

2,5‐Di­chloro‐3,6‐di­hydroxy‐1,4‐benzo­quinone (chloranilic acid) forms X—H?Y (X, Y = N or O) and C—H?Cl hydrogen bonds with pyrazole and imidazole to afford bis­(pyrazolium) di­chloro­anilate and bis­(imidazolium) di­chloro­anilate, (I) and (II), both 2C₃H₅N₂⁺·C₆Cl₂O₄^2?, and imidazolium chloro­anilate aceto­nitrile solvate, C₃H₅N₂⁺·­C₆HCl₂O₄^?·C₂H₃N, (III). Their crystal structures demonstrate three novel supramolecular architectures based on supramolecular synthons to build a ladder, (I), a two‐dimensional network, (II), and a flat ribbon, (III).     

Two orthopalladated chromophores

The title compounds, {5‐(di­methyl­amino)‐2‐[N‐(4‐methoxy­phenyl)­imino­methyl]­phenyl}[N‐(4‐methoxy­phenyl)‐4‐nitro­salicyl­aldiminato]­palladium(II), [Pd(C₁₄H₁₁N₂O₄)(C₁₆H₁₇N₂O)], (I), and [4‐(diethyl­amino)‐N‐(4‐methoxy­phenyl)­sali­cyl­aldiminato]{2‐[N‐(4‐methoxy­phenyl)­imino­methyl]‐5‐nitrophenyl}palladium(II) di­chloro­methane hemisolvate, [Pd(C₁₄H₁₁N₂O₃)(C₁₈H₂₁N₂O₂)]·0.5CH₂Cl₂, (II), both contain push–pull chromophores coordinated to Pd in a square‐planar arrangement. In both compounds, the five‐membered orthopalladated ring is essentially planar, while the coordinated six‐membered ring is not. Deviations from a coplanar arrangement of the phenyl­ene rings of the coordinated Schiff bases are observed in both (I) and (II) as a result of intramolecular steric interactions.     

An analysis of C—H⋯O and C—H⋯π interactions in three substituted 4‐ketotetra­hydro­indoles

The crystal and molecular structures of the three 4‐ketotetrahydro­indoles 2‐(4‐chloro­phenyl)‐1‐(4‐fluoro­phenyl)‐6,6‐dimethyl‐4,5,6,7‐tetra­hydro‐1H‐indol‐4‐one (C₂₂H₁₉ClFNO), (I), 1‐(4‐fluoro­phenyl)‐2‐(4‐methoxy­phenyl)‐6,6‐di­methyl‐4,5,6,7‐tetra­hydro‐1H‐indol‐4‐one (C₂₃H₂₂FNO₂), (II), and 6,6‐dimethyl‐1,2‐di­phenyl‐4,5,6,7‐tetra­hydro‐1H‐indol‐4‐one (C₂₂H₂₁NO), (III), have been determined via single‐crystal X‐ray diffraction in order to study the intermolecular interactions therein. All three structures are stabilized via intermolecular C—H⋯O and C—H⋯π interactions, generating different molecular motifs.     

Bis­[1‐(p‐chloro­phenyl)‐5‐iso­propyl­biguanide‐κ2N2,N4]­nickel(II) dichloride di­methyl­form­amide solvate

The asymmetric unit of the title compound, [Ni(C₁₁H₁₆ClN₅)₂]Cl₂·C₃H₇NO, contains one monomeric nickel(II) com­plex cation, two Cl⁻ anions and one di­methyl­form­amide sol­vent mol­ecule. The Ni atom is coordinated to each of two 1‐­(p‐chloro­phenyl)‐5‐iso­propyl­biguanide (proguanil) ligands via two N atoms. The complex exhibits a square‐planar coordination, with the Ni atom lying 0.021 (2) Å out of the basal plane. The crystal packing is characterized by several hydrogen bonds.     

The host–guest complex between cone‐25,26:27,28‐bis­(methyl­ene­dioxy)­calix­[4]­arene and di­chloro­methane

The title compound, 25,26:27,28‐bis­(methyl­ene­dioxy)­penta­cyclo­[19.3.1.1^3,7.1^9,13.1^15,19]­octacosa‐1(25)3,5,7(28),9,11,13(27),15,17,19(26),21,23‐dodecaene di­chloro­methane solvate, C₃₀H₂₄O₄·CH₂Cl₂, possesses crystallographic twofold sym­metry in both components. The calixarene shows a pinched cone conformation with an elliptical cavity, in which the guest di­chloro­methane solvent mol­ecule is accommodated. The contact distance between guest and host (H⋯ring centroid = 2.44 Å) is extremely short.     

Two carbamoyl‐substituted di­hydro­pyrimidines: potential mimics of di­hydro­pyridine calcium channel blockers

The structures of two conformationally similar 1,4‐di­hydro­pyrimidines with a novel carbamoyl substitution, viz. 6‐methyl‐5‐(N‐methyl­carbamoyl)‐4‐phenyl‐1,2,3,4‐tetrahydro­py­rimidine‐2‐thione monohydrate, C₁₃H₁₅N₃OS·H₂O, (I), and 4‐(4‐chloro­phenyl)‐6‐methyl‐5‐(N‐methyl­carbamoyl)‐1,2,3,4‐tetra­hydro­pyrimidine‐2‐thione monohydrate, C₁₃H₁₄ClN₃OS·H₂O, (II), exhibit the structural features of 1,4‐di­hydro­pyridine calcium channel blockers. In both structures, the pyrimidine ring adopts a flattened boat conformation and the carbamoyl side chain is in an extended conformation with an anticlinal orientation. The phenyl ring occupies a pseudo‐axial position with respect to the pyrimidine ring in these structures. Both compounds crystallize with one mol­ecule of water, which participates in a two‐dimensional hydrogen‐bonding network. The mol­ecules are linked into dimers by N—H·S hydrogen bonds in both structures.     

Isostructural or not? Adducts of some aryl­tin halides with (E)‐1,2‐bis(4‐pyridyl)­ethene

The title complexes [μ‐(E)‐4,4′‐(ethene‐1,2‐diyl)­di­pyridine‐κ²N:N′]­bis­[halotris(4‐methyl­phenyl)­tin(IV)], [Sn₂(C₇H₇)₆X₂(C₁₂H₁₀N₂)], where halo is chloro (X = Cl) and bromo (X = Br) are isostructural. In both crystals, the mol­ecules lie on inversion centers, and there are voids of ca 80 ų that could, but apparently do not, accommodate water mol­ecules. The corresponding iodo structure (X = I) is almost, but not quite, isostructural with the other two compounds; when Br is changed to I, the length of the c axis decreases by more than 1 Å and the voids are no longer large enough to accomodate any solvent mol­ecule. The related complex [μ‐(E)‐4,4′‐(ethene‐1,2‐diyl)­di­pyridine‐κ²N:N′]­bis­[chloro­tri­phenyl­tin(IV)], [Sn₂(C₆H₅)₆Cl₂(C₁₂H₁₀N₂)], crystallizes in a related structure, but the mol­ecules lie on general rather than on special positions. The molecular structures of the four complexes are similar, but the conformation of the phenyl derivative is approximately eclipsed rather than staggered.     

Two isomorphous imidazole (Him) complexes: [MCl2(Him)2(H2O)2] (M = Co and Ni)

The structures of aqua­di­chloro­bis(1H‐imidazole)­cobalt(II), [CoCl₂(Him)₂(H₂O)₂] (Him is 1H‐imidazole, C₃H₄N₂), (I), and aqua­di­chloro­bis(1H‐imidazole)­nickel(II), [NiCl₂(Him)₂(H₂O)₂], (II), are isomorphous and consist of monomers with inversion symmetry. The three monodentate ligands (imidazole, chlorine and aqua), together with their symmetry equivalents, define almost perfect octahedra. Hydro­gen‐bonding interactions via the imidazole and aqua H atoms lead to a three‐dimensional network.     

Di­cyclo­hexyl­ammonium 2,4‐di­chloro­phenoxy­acetate and (2,4‐di­chloro­phenoxy­acetato‐O,O′)bis­(tri­phenylphosphine‐P)silver(I)

The monoclinic cell of di­cyclo­hexyl­ammonium 2,4‐di­chloro­phenoxy­acetate contains four C₁₂H₂₄N⁺·C₅H₈Cl₂O₃^? ion pairs. The ammonium N atom is hydrogen bonded to the oxy­gen ends of two carboxyl groups to form a 12‐membered O—C—O?HNH?O—C—O?HNH ring. In (2,4‐di­chloro­phenoxy­lacetato)­bis­(tri­phenyl­phosphine)silver(I), [Ag(C₈H₅Cl₂O₃)(C₁₈H₁₅P)₂], the carboxyl CO₂ unit chelates to the Ag atom in an anisobidentate manner [Ag—O = 2.436 (2) and 2.517 (2) Å]; the Ag atom shows distorted tetrahedral geometry.     

Diphenyl(2‐thioxo‐1,3‐dithiole‐4,5‐di­thiolato‐S,S′)plumbane at 295 K and diphenyl(2‐thioxo‐1,3‐dithiole‐4,5‐di­thiolato‐S,S′)stannane at 150 K

Molecules of di­phenyl(2‐thio­xo‐1,3‐di­thiole‐4,5‐di­thiol­ato‐S,S′)­plumbane, [Pb(C₃S₅)(C₆H₅)₂], are linked into sheets via two intermolecular Pb?S_thione interactions of 3.322 (4) and 3.827 (4) Å; the Pb centre has a distorted octahedral geometry. In contrast, mol­ecules of ­di­phenyl(2‐thio­xo‐1,3‐di­thiole‐4,5‐di­thiol­ato‐S,S′)­stannane, [Sn(C₃S₅)(C₆H₅)₂], are linked into chains via a single intermolecular Sn—S_thione interaction of 2.8174 (9) Å; the Sn centre has a distorted trigonal‐bipy­ramidal geometry.     

Derivatives of 4‐(2‐hydro­xy­lphenyl)‐2‐phenyl‐2,3‐di­hydro‐1,5‐benzothiazepine

In the structures of 2‐(4‐chloro­phenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₁H₁₆ClNOS, 4‐(2‐hy­droxy­phenyl)‐2‐(4‐tolyl)‐2,3‐di­hydro‐1,5‐ben­zo­thia­zepine, C₂₂H₁₉NOS, and 4‐(2‐hydroxyphenyl)‐2‐(3‐methoxy­phenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₂H₁₉NO₂S, the central seven‐membered heterocyclic rings adopt twist‐boat conformations in which the N atoms are involved in strong intramolecular hydrogen bonds with the hydroxyl H atoms, resulting in six‐membered rings.     

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.     

Four bromo‐substituted pyrazoline and isoxazolinone spiro derivatives

Conformational analyses and a structural comparison of the four spiro compounds 3‐bromo‐1,9‐di­phenyl‐4‐p‐tolyl‐7‐oxa‐1,2,8‐tri­aza­spiro­[4.4]­nona‐2,8‐dien‐6‐one, (I), C₂₄H₁₈BrN₃O₂, 3‐bromo‐4‐(4‐methoxy­phenyl)‐1,9‐di­phenyl‐7‐oxa‐1,2,8‐tri­aza­spiro­[4.4]­nona‐2,8‐dien‐6‐one, (II), C₂₄H₁₈BrN₃O₃, 3‐bromo‐4‐(4‐chloro­phenyl)‐1,7,9‐tri­phenyl‐1,2,7,8‐tetra­aza­spiro­[4.4]­nona‐2,8‐dien‐6‐one, (III), C₂₉H₂₀BrClN₄O, and 3‐bromo‐1,7,9‐tri­phenyl‐4‐p‐tolyl‐1,2,7,8‐tetra­aza­spiro­[4.4]­nona‐2,8‐di­en‐6‐one, (IV), C₃₀H_22.89Br_1.11N₄O, are presented. The mol­ecular structures are rather similar, which is as expected since the compounds are all products of concerted 1,3‐dipolar attack on (Z)‐4‐aryl­idene oxazolone and pyrazolone derivatives. The observed conformations tend to favour extended π conjugation of the benzene rings and other π systems, as shown by a comparison of selected geometric parameters of the four structures.     

Two new conformationally restricted 4,5‐dihydroxynorvaline analogues with a norbornane skeleton

The structures of two conformationally restricted 4,5‐di­hydroxy­norvaline analogues with a norbornane skeleton, namely methyl (1S,2S,3R,4R)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, and methyl (1R,2S,3R,4S)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, exhibit a conformation in the helical region of the ?,ψ map but their handedness is opposite. In both cases, the torsion angles (χ^1,1) giving the relative orientation of the 1,2‐di­hydroxy­ethyl group of the amino acid side chain and the benz­amide group of the peptide chain indicate that these groups adopt a nearly eclipsed conformation. Both compounds show a complex hydrogen‐bonding pattern.