2,3-Dihydrospiro[1H-4- and 5-azabenzimidazole-2,1′ -cyclohexane] ( = Spiro[cyclohexane-1,2′(3′H)-1′H-imidazo[4,5-b]pyridine] and Spiro[cyclohexane-1,2′(3′H)-1′H-imidazo[4, 5-c]pyridine]): Reactions with Nucleophiles

The readily available title compounds 4a and 24 react with N-, O-, S-, and C-nucleophiles in presence of MnO₂ to give the corresponding mono- or disubstituted 2H-azabenzimidazoles ( = azaisobenzimidazoles), e.g., 11–18 and 26a–h , respectively, or 2,3-dihydro-1H-azabenzimidazoles ( = dihydro-azabenzimidazoles) such as 9 and 10 and 27 and 28 , respectively, by a 1, 4- or 1,6-Michael addition (Schemes 2 and 4). The bromo-dihydro-1H-azabenzimidazole 4b lost the Br-atom when treated with piperidine or morpholine yielding the corresponding disubstituted 2H-azabenzimidazole 21 (Scheme 3). Reductive ring opening of the substituted spiro compounds leads to mono- and disubstituted diaminopyridines which are intermediates for fused pyridine ring systems with substituents often not available by conventional routes and of potential pharmaceutical interest (see 32 – 37 ). E.g., starting from 4a , a three-step synthesis of the analgesic flupirtine maleate (= ethyl {2-amino-6-[(4-fluorobenzyl)amino]pyridin-3-yl}carbamate maleate = Katadolon®; 39 ) and of its non-fluorinated derivative D-7195 is described. Its analogue 40 was similarly made from the spiro compound 24 .     

Synthesis of 1,2′,3,3′,5′,6′-hexahydro-3-phenylspiro[isobenzofuran-1,4′-thiopyrans] and 1,2′,3,3′,5′,6′-hexahydro-3-phenylspiro-[isobenzofuran-1,4′-pyrans]

The 1,2′,3,3′,5′,6′-hexahydro-3-phenylspiro[isobenzofuran-1,4′-thiopyran] ring system ( 2a ) has been prepared from o-bromobenzoic acid. The 1,2′,3,3′,5′,6′-hexahydro-3-phenylspiro[isobenzofuran-1,4′-pyran] ring system ( 3a ) has been prepared from 2-bromobenzhydrol methyl ether. Several 3-(dimethylaminoalkyl) derivatives of both 2a and 3a were prepared by lithiation followed by alkylation.     

Hydrogen bis[tris(4‐fluorophenyl)phosphane oxide] triiodide

In the title compound, C₃₆H₂₅F₆O₂P₂⁺·I₃⁻, hydrogen‐bonded [{(p‐FC₆H₄)₃PO}₂H]⁺ dimers assemble along the crystallographic c axis to form channels that house extended chains of triiodide anions. Although the I—I bond lengths of 2.9452 (14) and 2.9023 (15) Å are typical, the inter‐ion I...I distance of 3.5774 (10) Å is unusually short. A posteriori modelling of nonmerohedral twinning about (100) has been only partially successful, achieving a reduction in the maximum residual electron density from 5.28 to 3.24 e Å⁻³. The inclusion of two low‐occupancy I‐atom sites (total 1.7%), which can be interpreted as translational disorder of the triiodide anions along the channels, reduced the maximum residual electron density to 2.03 e Å⁻³. The minor fractional contribution volume of the nonmerohedral twin domains refined to 0.24 and simultaneous refinement of the inversion twin domains showed the crystal to be a 0.5:0.5 inversion twin.     

Poly[aqua[μ4‐3,3′‐(diazenediyl)dibenzoato]zinc]

The solvothermal reaction of Zn(OAc)₂·2H₂O with 3,3′‐(diazenediyl)dibenzoic acid (H₂ADB) in H₂O at 393 K afforded the title complex, [Zn(C₁₄H₈N₂O₄)(H₂O)]_n. The asymmetric unit contains half a Zn^II cation, half an ADB ligand and half a water molecule. Each Zn^II centre lies on a crystallographic twofold rotation axis and is five‐coordinated by four O atoms of bridging carboxylate groups from four ADB ligands and one O atom from a water molecule, forming a distorted trigonal–bipyramidal coordination geometry. The [Zn(H₂O)] subunits are bridged by carboxylate groups to give one‐dimensional [Zn(μ‐COO)₄(H₂O)]_n chains. The chains are linked by ADB ligands into two‐dimensional sheets, and these sheets are further connected to neighbouring sheets via hydrogen bonds (OW—HW...O), forming a three‐dimensional hydrogen‐bond‐stabilized structure with an unprecedented 3⁷4¹⁷5²6² topology.     

trans‐Bis[3‐(2‐fluorophenyl)‐1‐(4‐nitrophenyl)triazenido‐κN3]bis(pyridine‐κN)palladium(II)

In the title complex, [Pd(C₁₂H₈FN₄O₂)₂(C₅H₅N)₂] or trans‐[Pd(FC₆H₄N=N—NC₆H₄NO₂)(C₅H₅N)₂], the Pd atom lies on a centre of inversion in space group P. The coordination geometry about the Pd²⁺ ion is square planar, with two deprotonated 3‐(2‐fluoro­phenyl)‐1‐(4‐nitro­phenyl)­triazenide ions, FC₆H₄N=N—NC₆H₄NO₂^?, acting as monodentate ligands (two‐electron donors), while two neutral pyridine mol­ecules complete the metal coordination sphere. The whole triazenide ligand is not planar, with the largest interplanar angle being 16.8 (5)° between the phenyl ring of the 2‐­fluorophenyl group and the plane defined by the N=N—N moiety. The Pd—N(triazenide) and Pd—N(pyridine) distances are 2.021 (3) and 2.039 (3) Å, respectively.     

Bis[μ‐1,2‐bis(2‐pyridyl)ethyne‐κ2N:N′]bis[aquadinitratocadmium(II)]

Two twisted 1,2‐bis(2‐pyridyl)­ethyne ligands bridge two Cd²⁺ centers in the C₂‐symmetric title complex, [Cd₂(NO₃)₄(μ‐C₁₂H₈N₂)₂(H₂O)₂]. The bridging ligands arch across one another creating a `zigzag loop' molecular geometry. Two nitrate ions and a water mol­ecule complete the irregular seven‐coordinate Cd‐atom environment. The dihedral angles between the equivalent pyridyl ring planes of the two independent ligands are 67.2 (1)°. O_water—H⃛O_nitrate hydrogen bonding creates two‐dimensional layers parallel to the ab plane.     

2,2′‐(1,2‐Ethanediyldithio)bis(1,3‐benzothiazole)

In the title compound, C₁₆H₁₂N₂S₄, which is the result of the S‐alkyl­ation reaction of 2‐mercapto­benzo­thia­zole with ethyl­ene dibromide, the planes of the two benzo­thia­zole moieties form a dihedral angle of 3.84 (14)°. The bridging chain moiety, –SCH₂CH₂S–, adopts an antiperiplanar conformation. There are intermolecular S⃛S non‐bonded contacts of 3.6471 (9) Å, which stabilize the crystal packing.     

New Synthetic Approach to Naphtho[1,2‐b]furan and 4′‐Oxo‐Substituted Spiro[cyclopropane‐1,1′(4′H)‐naphthalene] Derivatives

A one‐step synthesis of ethyl 2,3‐dihydronaphtho[1,2‐b]furan‐2‐carboxylate and/or ethyl 4′‐oxospiro[cyclopropane‐1,1′(4′H)‐naphthalene]‐2′‐carboxylate derivatives 2 and 3 , respectively, from substituted naphthalen‐1‐ols and ethyl 2,3‐dibromopropanoate is described (Scheme 1). Compounds 2 were easily aromatized (Scheme 2). In the same way, 3,4‐dibromobutan‐2‐one afforded the corresponding 1‐(2,3‐dihydronaphtho[1,2‐b]furan‐2‐yl)ethanone and/or spiro derivatives 8 and 9 , respectively (Scheme 6). A mechanism for the formation of the dihydronaphtho[1,2‐b]furan ring and of the spiro compounds 3 is proposed (Schemes 3 and 4). The structures of spiro compounds 3a and 3f were established by X‐ray structural analysis. The reactivity of compound 3a was also briefly examined (Scheme 9).     

Poly[bis[μ2‐3‐(pyridin‐4‐yl)benzoato‐κ3N:O,O′]lead(II)]

In the title compound, [Pb(C₁₂H₈NO₂)₂]_n, the Pb atom sits on a crystallographic C₂ axis and is six‐coordinate, ligated by two chelating carboxylate groups from two 3‐(pyridin‐4‐yl)benzoate (L) ligands and by two N atoms from another two ligands. Each ligand bridges two Pb^II centres, extending the structure into a corrugated two‐dimensional (4,4) net. The ligand L is conformationally chiral, with a torsion angle of 27.9 (12)° between the planes of its two rings. The torsion angle has the same sense throughout the structure, so that the extended two‐dimensional polymer is homochiral. Investigation of the thermal stability shows that the network is stable up to 613 K. In the absence of any stereoselective factor in the preparation of the compound, the enantiomeric purity of the crystal studied, based only on the torsional conformation of the ligand, implies that the bulk sample is a racemic conglomerate.     

Bis[S‐6‐(2,2:6′,2′′‐terpyridin‐4′‐yloxy)hexyl thioacetate]manganese(II) bis(hexafluorophosphate)

The structure of a manganese(II) complex of terpyridine functionalized with acetylsulfanyl‐terminated hexyloxy chains, [Mn(C₂₃H₂₅N₃O₂S)₂](PF₆)₂, is described. This type of complex is of interest in the study of single‐molecule transport properties in open‐shell systems. The manganese coordination environment is distorted octahedral but, importantly, with no larger deviations from the idealized geometry than those observed for other metal–terpyridine complexes. The Mn—N bond lengths range from 2.192 (2) to 2.272 (3) Å. The title compound crystallizes with the cation and anions all on general positions, with the hexafluorophosphate anions exhibiting orientational disorder. When compared with other bis‐terpyridine complexes, this structure demonstrates that manganese(II) is no more prone to undergo low‐symmetry distortions than systems with ligand field stabilization energy contributions.     

The three‐dimensional coordination polymer poly[[aqua[μ4‐2,2′‐(diazene‐1,2‐diyl)dibenzoato]lead(II)] 1,2‐bis(pyridin‐4‐yl)ethylene hemisolvate]

A novel three‐dimensional coordination polymer, {[Pb(C₁₄H₈N₂O₄)(H₂O)]·0.5C₁₂H₁₀N₂}_n, has been synthesized by hydrothermal reaction of Pb(OAc)₂·3H₂O (OAc is acetate), 2,2′‐(diazene‐1,2‐diyl)dibenzoic acid (H₂L) and 1,2‐bis(pyridin‐4‐yl)ethylene (bpe). The asymmetric unit contains a crystallographically independent Pb^II cation, one L²⁻ ligand, an aqua ligand and half a bpe molecule. Each Pb^II centre is seven‐coordinated by six O atoms of bridging–chelating carboxylate groups from L²⁻ ligands and by one O atom from a coordinated water molecule. The Pb^II cations are bridged by L²⁻ ligands, forming [PbO₂]_n chains along the a axis. These chains are further connected by L²⁻ ligands along the b and c axes to give a three‐dimensional framework with a 4¹²6³ topology. The channel voids are occupied by bpe molecules.     

Poly[(μ4‐biphenyl‐3,3′,4,4′‐tetracarboxylato)bis[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene]dicobalt(II)]

The asymmetric unit of the title two‐dimensional coordination polymer, [Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]_n, contains one Co²⁺ ion, half of a biphenyl‐3,3′,4,4′‐tetracarboxylate (bptc) anion lying about an inversion centre and one 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligand. The Co^II atom is coordinated by three carboxylate O atoms from two different bptc ligands and two N atoms from two bix ligands constructing a distorted square pyramid. Each Co²⁺ ion is interlinked by two bptc anions, while each bptc anion coordinates to four Co atoms as a hexadentate ligand so that four Co^II atoms and four bptc anions afford a larger 38‐membered ring. These inorganic rings are further extended into a two‐dimensional undulated network in the (10) plane. Two Co^II atoms in adjacent 38‐membered rings are joined together by pairs of bix ligands forming a 26‐membered [Co₂(bix)₂] ring that is penetrated by a bptc anion; these components share a common inversion centre.     

Two mononuclear Tc complexes: [2,2′‐(3‐phenylpropylimino)‐ and [2,2′‐(propylimino)bis(ethanethiolato)](4‐methoxybenzenethiolato)oxidotechnate(V)

The molecular structures of the two mononuclear title complexes, namely (4‐methoxybenzenethiolato‐κS)oxido[2,2′‐(3‐phenylpropylimino)bis(ethanethiolato)‐κ³S,N,S′]technetium(V), [Tc(C₁₄H₂₁NS₂)(C₇H₇OS)O], (I), and (4‐methoxybenzenethiolato‐κS)oxido[2,2′‐(propylimino)bis(ethanethiolato)‐κ³S,N,S′]technetium(V), [Tc(C₇H₁₅NS₂)(C₇H₇OS)O], (II), exhibit the same coordination environment for the central Tc atoms. The atoms are five‐coordinated (TcNOS₃) with a square‐pyramidal geometry comprising a tridentate 2,2′‐(3‐phenylpropylimino)bis(ethanethiolate) or 2,2′‐(propylimino)bis(ethanethiolate) ligand, a 4‐methoxybenzenethiolate ligand and an additional oxide O atom. Intermolecular C—H...O and C—H...S hydrogen bonds between the monomeric units result in two‐dimensional layers with a parallel arrangement.     

Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas

Substituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.     

2′‐(4‐Fluoro­phenyl)‐[1,2,3]­triazolo[4′,5′:16,17]­androst‐5‐en‐3β‐ol methanol hemisolvate

The asymmetric unit of the title compound, C₂₅H₃₀FN₃O·0.5CH₃OH, contains four symmetry‐independent steroid and two methanol mol­ecules. The conformations of the independent steroid mol­ecules are very similar. Intermolecular O—H⋯O hydrogen bonds create two independent chains, each of which links two of the independent steroid mol­ecules plus one methanol mol­ecule via a co‐operative O—H⋯O—H⋯O—H pattern. Intermolecular C—H⋯O and C—H⋯F interactions are also observed.     

Tris[N‐(4‐fluorophenyl)pyridine‐2‐carboxamidato‐κ2N,N′]cobalt(III) trihydrate: a novel meridional complex

The title complex, [Co(C₁₂H₈FN₂O)₃]·3H₂O, has been synthesized for the first time. The complex comprises three bidentate ligands containing the pyridine‐2‐carbox­amide stem. The distorted octahedral coordination around the Co atom is formed via the pyridine (py) N atom and the deprotonated amide N atom of each ligand, with the three pyridine rings in a meridional arrangement. For each ligand, the pyridine ring and the carbonyl group are nearly coplanar, with torsion angles in the range 0.4 (3)–4.8 (4)°. The Co—N_py distances [1.9258 (16)–1.9656 (17) Å] are shorter than the corresponding Co—N_amide distances [1.9372 (17)–1.9873 (15) Å]. In addition, the Co—N_py distances are closely related to the magnitudes of the chelate angles, a shorter Co—N_py distance corresponding to a larger angle. Five intermolecular hydrogen bonds, involving carbonyl O atoms of the ligands and lattice water mol­ecules, lead to the formation of a mesh structure.     

Synthesis of [3,3′‐Di‐sec‐butyl‐4′‐(2‐dimethylaminoethoxy)biphenyl‐4‐yl‐oxy]acetic Acid

A modified synthetic route of [3,3′‐di‐sec‐butyl‐4′‐(2‐dimethylaminoethoxy)biphenyl‐4‐yloxy]acetic acid ( 1 ) with high total yield of 44% from biphenyl‐4,4′‐diol ( 2 ) is described.     

Synthesis and characterization of novel polyimides with 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein‐3′,5′‐bis(trifluoromethyl)anilide

2,2‐Bis[4(4‐aminophenoxy)phenyl]phthalein‐3′,5′‐bis(trifluoromethyl)anilide (6FADAP), containing fluorine and phthalimide moieties, was synthesized via the Williamson ether condensation reaction from 1‐chloro‐4‐nitrobenzene and phenolphthalein‐3′,5′‐bis(trifluoromethyl)anilide, which was followed by hydrogenation. Monomers such as 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein‐anilide containing phthalimide groups and 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein containing only phthalein moieties were also synthesized for comparison. The monomers were first characterized by Fourier transform infrared (FTIR), ¹H NMR, ¹⁹F NMR, elemental analysis, and titration and were then used to prepare polyimides with 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride. The polyimides were designed to have molecular weights of 20,000 g/mol via off‐stoichiometry and were characterized by FTIR, NMR, gel permeation chromatography (GPC), differential scanning calorimetry, and thermogravimetric analysis. Their solubility, water absorption, dielectric constant, and refractive index were also evaluated. The polyimides prepared with 6FADAP, containing fluorine and phthalimide moieties, had excellent solubility in N‐methylpyrrolidinone, N,N‐dimethylacetamide, tetrahydrofuran, CHCl₃, tetrachloroethane, and acetone, and GPC analysis showed a molecular weight of 18,700 g/mol. The polyimides also exhibited a high glass‐transition temperature (290 °C), good thermal stability (～500 °C in air), low water absorption (1.9 wt %), a low dielectric constant (2.81), a low refractive index, and low birefringence (0.0041). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3361–3374, 2003     

Helical supramolecular assembly of N2,N2′‐bis[3‐(morpholin‐4‐yl)propyl]‐N1,N1′‐(1,2‐phenylene)dioxalamide dimethyl sulfoxide monosolvate

In the title compound, C₂₄H₃₆N₆O₆·C₂H₆OS, the carbonyl groups are in an antiperiplanar conformation, with O=C—C=O torsion angles of 178.59 (15) and −172.08 (16)°. An intramolecular hydrogen‐bonding pattern is depicted by four N—H...O interactions, which form two adjacent S(5)S(5) motifs, and an N—H...N interaction, which forms an S(6) ring motif. Intermolecular N—H...O hydrogen bonding and C—H...O soft interactions allow the formation of a meso‐helix. The title compound is the first example of a helical 1,2‐phenylenedioxalamide. The oxalamide traps one molecule of dimethyl sulfoxide through N—H...O hydrogen bonding. C—H...O soft interactions give rise to the two‐dimensional structure.