6a,6b,12a,12b‐Tetra­hydro­cyclo­octa­[3,4]­cyclo­buta­[1,2][8]­annulene

The cis,syn,cis‐tricyclic [2+2]‐dimer of cyclo­octatetraene, C₁₆H₁₆, crystallizes in space group Pca2₁ with two mol­ecules in the asymmetric unit. An extensive network of weak C—H⋯π(Czdbnd;C) interactions between the two independent mol­ecules, A and B, as well as A⋯A and B⋯B interactions, are observed in the supramolecular assembly. The C—H groups point more towards one C atom than to the centre of the Czdbnd;C bond. Notable among the interactions are bifurcated (cyclo­butane)C—H⋯Czdbnd;C contacts that span transannularly the eight‐membered ring.     

8‐Chloro‐6‐phenyl‐4H‐[1,2,4]­triazolo­[4,3‐a][1,5]­benzodiazepin‐5(6H)‐one

The title compound, C₁₆H₁₁ClN₄O, is an anticonvulsant agent. In the crystal, a particularly short C—H?N intermolecular hydrogen bond is noted [H?N 2.22 (2) Å]. The diazepine ring has a boat conformation.     

Tri­carbonyl­[(6a,7,8,9,10a‐η)‐3,3‐di­methyl‐3H‐benzo­[f]­chromene]chromium

The title compound, [Cr(C₁₅H₁₄O)(CO)₃], is a chromene complexed with tri­carbonyl­chromium and it exhibits photochromic properties. The molecular geometry is compared to that of two similar complexes. The analysis results indicate that complexation has minor effects on the chromene structure.     

Benzo­[i]­naphtho­[c,d]­bi­cyclo­[5.4.1]dodecan‐12‐one

In the title compound, penta­cyclo­[11.8.1.1^3,11.0^7,23.0^15,20]­tricosa‐3,5,7,9,11(23),15,17,19‐octaen‐22‐one, C₂₃H₂₀O, the bi­cyclo­[5.4.1]­dodecan‐12‐one moiety takes a rigid conformation in which the seven‐ and eight‐membered rings take chair and boat–boat forms, respectively. The mol­ecule has a non‐crystallographic mirror symmetry perpendicular to the benzene and naphthalene planes.     

1,4‐Methano‐11a‐methyl‐4,4a,11,11a‐tetrahydro‐1H‐benzo­[b]­fluoren‐11‐one

The title compound, C₁₉H₁₆O, crystallizes with two mol­ecules of opposite chirality in the asymmetric unit. In both mol­ecules, the naphthalene and cyclo­pentanone moieties are individually planar. The two cyclo­pentane rings adopt envelope conformations, while the cyclo­hexane ring adopts a boat conformation.     

A novel class of fused heterocycles,benzo­[b]­furo­[2,3‐c]­pyrroles

In the isomeric compounds 2‐benzyl‐3‐methyl‐1‐phenyl­benzo­[b]­furo­[2,3‐c]­pyrrole and 2‐benzyl‐1‐methyl‐3‐phenyl­benzo­[b]­furo­[2,3‐c]­pyrrole, both C₂₄H₁₉NO, the pyrrole ring, although presumably somewhat strained, does not differ appreciably from N‐methyl­pyrrole except for a relatively short C—C single bond in the pyrrole ring.     

3,3‐Bis(2‐methoxy­phenyl)‐3H‐benzo­[f]­chromene

The substituent methoxy group at the phenyl ortho position in the title compound, C₂₇H₂₂O₃, has an insignificant effect on the length of the Csp³—O bond and on the non‐planarity of the pyran ring. The cause of the changes in the photochemical properties is discussed.     

A dimeric layered structure of a 4‐oxo‐4,5‐di­hydro‐1H‐pyrazolo­[3,4‐d]­pyrimidine compound

The title compound, 6‐methyl­sulfanyl‐1‐(3‐phenyl­propyl)‐4,5‐di­hydro‐1H‐pyrazolo­[3,4‐d]­pyrimidin‐4‐one, C₁₅H₁₆N₄OS, crystallizes in space group Pbca, with two mol­ecules of similar structure in the asymmetric unit. The molecular structure shows the absence of intramolecular stacking in the crystalline state, as indicated by earlier ¹H NMR analysis in solution. In addition, the crystal packing reveals the formation of a layered structure, due mainly to intermolecular N—H?O=C hydrogen bonding and arene–arene interactions.     

13,13a‐Di­hydro‐13‐methoxy‐9‐methyl‐1‐benzo­pyrano­[4,3‐i]­dinaphtho­[2,1‐c;1′,2′‐f]‐2,8‐dioxa­bicyclo­[3.3.1]­nonane

The crystal structure of the title compound, C₃₂H₂₄O₄, contains three fused di­hydro­pyran rings (A, B and C); ring A is fused with a benzene ring while the other two rings, B and C, are fused with naphthalene rings. Ring A adopts a half‐chair conformation with an equatorial methoxy group, whereas ring B assumes a distorted half‐chair conformation, the A/B ring junction being trans. Ring C adopts a distorted half‐boat conformation and is nearly orthogonal to ring B. Ring C is inclined to the best plane of ring A at an angle of 112.1 (1)°.     

An unusual acid: (±)‐3‐benzoyl‐1,2‐dimethyl‐8a‐phenyl‐2‐benzo­thieno­[2,3‐b]pyrrole‐1,2‐dicarboxylic anhydride

The title compound, C₂₇H₂₁NO₄S, is a 2‐benzothieno[2,3‐b]pyrrole derivative with several substituents, present in the crystal as a racemate. The tetra­cyclic fused‐ring system shows a `U‐shaped' mol­ecular architecture, since the two rings flanking the central pyrrolidine ring both point in the same direction.     

11‐Methyl‐12a‐phenyl‐9a,12a‐di­hydro­phenanthro­[9′,10:5,6][1,4]­dioxino­[2,3‐d]­thia­zole

In the title compound, C₂₄H₁₇NO₂S, the dioxine and thia­zoline rings are distorted from planarity towards a half‐chair and an envelope conformation, respectively. The configurations of the dioxine ring, the thiazoline ring and the attached phenyl ring are conditioned by the sp³ state of the two bridgehead C atoms. The phenanthrene system is nearly coplanar with the dioxine ring, while the attached phenyl ring is orthogonal to the thia­zoline ring.     

(RS)‐6‐Ethyl 2‐carboxy‐1,2,3,4‐tetra­hydro­azulene‐6‐carboxylate

The title compound, C₁₄H₁₆O₄, was obtained during the synthesis of 2,6‐disubstituted azulene derivatives. In the partially reduced azulene skeleton, the absence of a H atom at the ester substitutent position of the seven‐membered ring, as well as lengthened double bonds, indicate a conjugative stabilized system with two overlaid tautomers.     

3,3′‐Dimesityl‐7‐methyl‐9a‐phenyl‐4,4′,5,5′,6,8,9,9a‐octa­hydro‐7H‐1,2,4‐oxa­diazo­lo­[4,5‐d][1,4]­diazepine‐8‐spiro‐5′‐isoxazole

Condensation of mesito­nitrile oxide with 1,7‐di­methyl‐5‐phenyl‐2,3‐di­hydro‐1H‐1,4‐diazepine leads to two cycloadducts (I) and (II). The structure and stereochemistry of the dicyclo­adduct (II) was established by X‐ray crystallographic analysis.     

1‐[4‐(Methyl­sulfonyl)­phenyl]‐5‐phenyl‐1H‐pyrazole derivatives

Three related compounds containing a pyrazole moiety with vicinal phenyl rings featuring a methyl­sulfonyl substituent are described, namely 3‐methyl‐1‐[4‐(methyl­sulfonyl)­phenyl]‐5‐phenyl‐1H‐pyrazole, C₁₇H₁₆N₂O₂S, ethyl 1‐[4‐(methyl­sul­fonyl)­phenyl]‐5‐phenyl‐1H‐pyrazole‐3‐carboxyl­ate, C₁₉H₁₈N₂O₄S, and 1‐[4‐(methyl­sulfonyl)­phenyl]‐3‐[3‐(morpholino)­phenoxy­methyl]‐5‐phenyl‐1H‐pyrazole, C₂₇H₂₇N₃O₄S. The design of these compounds was based on celecoxib, a selective cyclo­oxy­genase‐2 (COX‐2) inhibitor, in order to study the influence of various substituents on COX‐2 and 5‐lipoxy­genase (5‐LOX) inhibition.     

Dicyano(7‐methyl‐6‐oxo‐6H‐dibenzo[b,d]pyran‐9‐yl)methanide Salts via a Multicomponent Reaction

Dialkylammonium dicyano(7‐methyl‐6‐oxo‐6H‐dibenzo[b,d]pyran‐9‐yl)methanides 4a – 4j are obtained in good yields via a simple reaction between 3‐acetylcoumarins (=3‐acetyl‐2H‐1‐benzopyran‐2‐ones) 1 and malononitrile ( 2 ) in EtOH (Table 1). In this reaction, a charge‐separated zwitterionic salt is formed.     

1‐(2‐{4‐[6‐Hydro­xy‐2‐(4‐hydroxy­phenyl)­benzo­[b]­thiol‐3‐yl­carbonyl]­phenoxy}ethyl)­piperidinium chloride

The title compound, raloxifene hydro­chloride, C₂₈H₂₈NO₄S⁺·Cl^?, belongs to the benzo­thio­phene class of antiosteoporotic drugs. In the molecular cation, the 2‐phenol ring sustains a dihedral angle of 45.3 (1)° relative to the benzo­[b]­thio­phene system. The benzo­[b]­thio­phene and phenyl ring planes are twisted with respect to the carbonyl plane, with the smallest twist component occurring between the phenyl and carbonyl planes. The N atom bears the positive charge in the molecular cation and the piperidine ring adopts an almost perfect chair conformation. The Cl^? anion is involved in the formation of N—H?Cl and O—H?Cl intermolecular hydrogen bonds, which lead to the formation of a layer of molecular cations.     

A pair of epimeric 13‐hydroxy‐2,3,6,7‐tetra­methoxy‐8b,11,12,12a,13,13a‐hexa­hydro‐9H‐9a‐aza­cyclo­penta­[b]tri­phenyl­ene‐10‐ones

The structures of two compounds which are intermediates in the synthesis of phenanthroindolizidine alkaloids have been determined. (8bS,13aS,14R,14aR)‐8b,9,11,12,13,13a,14,14a‐Octa­hydro‐14‐hydroxy‐2,3,6,7‐tetra­methoxy­dibenzo­[f,h]pyrrolo[1,2‐b]­isoquinolin‐11‐one acetone solvate, C₂₄H₂₇NO₆·C₃H₆O, (II), crystallizes in a chiral space group with one solvent mol­ecule (acetone) present in the asymmetric unit. On the other hand, (8bS,13aS,14S,14aR)‐8b,9,11,12,13,13a,14,14a‐octa­hydro‐14‐hydroxy‐2,3,6,7‐tetra­methoxy­dibenzo­[f,h]pyrrolo[1,2‐b]­isoquinolin‐11‐one, C₂₄H₂₇NO₆, (III), crystallizes in a centrosymmetric space group with two mol­ecules in the asymmetric unit and with no solvent present. The two mol­ecules in the asymmetric unit of (III) are structurally the same. Compounds (II) and (III) are epimers at the C atom carrying the OH group; otherwise they are very similar in structure.     

2‐Hydro­xy‐3‐(4,5,6,7‐tetra­hydro‐1H‐imidazo­[4,5‐c]­pyridin‐5‐ium‐4‐yl)­benzoate monohydrate

The title mol­ecule, C₁₃H₁₃N₃O₃·H₂O, is in the form of a mono­hydrated zwitterion. The tetra­hydro­pyridinium ring adopts an envelope conformation and is nearly coplanar with the plane of the imidazoline ring. The water solvate mol­ecule plays an important role as a bridge between zwitterions, forming molecular chains running along the c direction, which are interconnected by N—H?O hydrogen bonds into molecular ribbons. The crystal packing is further stabilized by another N—H?O and one O—H?N hydrogen bond, which interconnect the molecular ribbons.     

Ethyl 3,5‐dimethyl‐4‐phenyl‐1H‐pyrrole‐2‐carboxylate

In the title compound, C₁₅H₁₇NO₂, the ethoxy­carbonyl group is anti with respect to the pyrrole N atom. The angle between the planes of the phenyl and pyrrole rings is 48.26 (9)°. The mol­ecules are joined into dimeric units by a strong hydrogen bonds between pyrrole N—H groups and carbonyl O atoms. The geometry of the isolated mol­ecule was studied by ab initio quantum mechanical calculations, employing both molecular orbital Hartree–Fock (MO–HF) and density functional theory (DFT) methods. The minimum energy was achieved for a conformation where the angle between the planes of the phenyl and pyrrole rings is larger, and that between the ethoxy­carbonyl and pyrrole planes is smaller than in the solid‐state mol­ecule.     

(1SR,2SR,3SR,4RS,5RS,6RS,7SR,8RS)‐7,8‐Dichloro­bicyclo­[4.2.0]octa‐2,3,4,5‐tetrayl tetra­acetate

In the title compound, C₁₆H₂₀Cl₂O₈, the bicyclic system contains a central non‐planar cyclo­hexane ring which is fused to a cyclo­butane moiety. The cyclo­hexane ring has a chair conformation and the whole system adopts a syn conformation. The structure provides information on the stereochemical course of the chlorination, photo‐oxidation and hydrox­ylation steps of the reaction.