Supramolecular aggregation in three 4‐aryl‐6‐(1H‐indol‐3‐yl)‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitriles

Both 6‐(1H‐indol‐3‐yl)‐3‐methyl‐4‐(4‐methylphenyl)‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile and 6‐(1H‐indol‐3‐yl)‐3‐methyl‐4‐(4‐methoxyphenyl)‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile crystallize from dimethylformamide solutions as stoichiometric 1:1 solvates, viz. C₂₉H₂₁N₅·C₃H₇NO, (I), and C₂₉H₂₁N₅O·C₃H₇NO, (II), respectively; however, 6‐(1H‐indol‐3‐yl)‐3‐methyl‐1‐phenyl‐4‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile, C₃₁H₂₅N₅O₃, (III), crystallizes in the unsolvated form. The heterocyclic components of (I) are linked by C—H...π(arene) hydrogen bonds to form cyclic centrosymmetric dimers, from which the solvent molecules are pendent, linked by N—H...O hydrogen bonds. In (II), the heterocyclic components are linked by a combination of C—H...N and C—H...π(arene) hydrogen bonds into chains containing two types of centrosymmetric ring, and the pendent solvent molecules are linked to these chains by N—H...O hydrogen bonds. Molecules of (III) are linked into simple C(12) chains by an N—H...O hydrogen bond, and these chains are weakly linked into pairs by an aromatic π–π stacking interaction.     

Crystal structures of functional building blocks derived from bis(benzo[b]thiophen‐2‐yl)methane

The syntheses of three bis(benzo[b]thiophen‐2‐yl)methane derivatives, namely bis(benzo[b]thiophen‐2‐yl)methanone, C₁₇H₁₀OS₂, (I), 1,1‐bis(benzo[b]thiophen‐2‐yl)‐3‐(trimethylsilyl)prop‐2‐yn‐1‐ol, C₂₂H₂₀OS₂Si, (II), and 1,1‐bis(benzo[b]thiophen‐2‐yl)prop‐2‐yn‐1‐ol, C₁₉H₁₂OS₂, (III), are described and their crystal structures discussed comparatively. The conformation of ketone (I) and the respective analogues are rather similar for most of the compounds compared. This is true for the interplanar angles, the C_aryl—C_bridge—C_aryl angles and the dihedral angles. The best resemblance is found for a bioisotere of (I), viz. 2,2′‐dinaphthyl ketone, (VII). By way of interest, the crystal packings also reveal similarities between (I) and (VII). In (I), the edge‐to‐face interactions seen between two napthyl residues in (VII) are substituted by S…π contacts between the benzo[b]thiophen‐2‐yl units in (I). In the structures of the bis(benzo[b]thiophen‐2‐yl)methanols, i.e. (II) and (III), the interplanar angles are also quite similar compared with analogues and related active pharmaceutical ingredients (APIs) containing the dithiophen‐2‐ylmethane scaffold, though the dihedral angles show a larger variability and produce unsymmetrical molecules.     

Synthesis and Structure of 3,4‐Dihydropyrido[2′,3′:3,4]pyrazolo[1,5‐a][1,3,5]triazin‐2‐amines

A new convenient synthon for heterocyclic chemistry, namely 1H‐pyrazolo[3,4‐b]pyridin‐3‐ylguanidine was successfully prepared by selective guanylation of 1H‐pyrazolo[3,4‐b]pyridin‐3‐amine. A series of 3,4‐dihydropyrido[2′,3′:3,4]pyrazolo[1,5‐a][1,3,5]triazin‐2‐amines was synthesized from 1H‐pyrazolo[3,4‐b]pyridin‐3‐ylguanidine using aldehydes or ketones as one‐carbon inserting reagents. The tautomeric preferences of the products were determined using spectroscopic (e.g., 2D NOESY NMR) and single crystal X‐ray diffraction data.     

Green One‐Pot Solvent‐Free Synthesis of Pyrazolo[1,5‐a]pyrimidines,Azolo[3,4‐d]pyridiazines,and Thieno[2,3‐b]pyridines Containing Triazole Moiety

Synthesis of pyrazolo[1,5‐a]pyrimidines, [1,2,4]triazolo[1,5‐a]pyrimidine, 8,10‐dimethyl‐2‐(5‐methyl‐1‐phenyl‐4,5‐dihydro‐1H‐1,2,3‐triazol‐4‐yl)pyrido[2′,3′:3,4]‐pyrazolo[1,5‐a]pyrimidine, benzo[4,5]imidazo[1,2‐a]pyrimidine via heterocyclic amines, and sodium 3‐hydroxy‐1‐(5‐methyl‐1‐phenyl‐1H‐1,2,3‐triazole‐4‐yl)prop‐2‐en‐1‐one were carried out. Also, synthesis of isoxazoles, and pyrazoles from sodium 3‐hydroxy‐1‐(5‐methyl‐1‐phenyl‐1H‐1,2,3‐triazole‐4‐yl)prop‐2‐en‐1‐one and hydroxymoyl chlorides and hydrazonoyl halides, respectively, were made. Analogously, (1,2,3‐triazol‐4‐yl)thieno[2,3‐b]pyridine derivatives were obtained from sodium 3‐hydroxy‐1‐(5‐methyl‐1‐phenyl‐1H‐1,2,3‐ triazole‐4‐yl)prop‐2‐en‐1‐one and cyanothioacetamide followed by its reacting with active methylene compounds. In addition to full characterization of all synthesized compounds, they were tested to evaluate their antimicrobial activities, and some compounds showed competitive activities to those of tetracycline, the typical antibacterial drug, and clotrimazole, the typical antifungal drug.     

Pyridine‐2(1H)‐thiones: Versatile Precursors for Novel Pyrazolo[3,4‐b]pyridine,Thieno[2,3‐b]pyridines,and Their Fused Azines

Pyridine‐2(1H)‐thiones were prepared and reacted with several active halogenated reagents to afford novel thieno[2,3‐b]pyridines in excellent yields. Thieno[2,3‐b]pyridine‐2‐carbohydrazide derivative was prepared by the reaction of either ethyl 2‐((3‐cyanopyridin‐2‐yl)thio)acetate derivative or thieno[2,3‐b]pyridine‐2‐carboxylate derivative with hydrazine hydrate. On the other hand, the reaction of either pyridine‐2(1H)‐thione or ethyl 2‐((pyridin‐2‐yl)thio)acetate derivative with hydrazine hydrate afforded the corresponding 1H‐pyrazolo[3,4‐b]pyridine derivative. Thieno[2,3‐b]pyridine derivatives reacted with several reagents to afford the corresponding pyrimidine‐4(3H)‐ones and [1,2,3]triazin‐4‐(3H)‐one. Moreover, 2‐carbohydrazide derivative reacted with β‐dicarbonyl reagents to give 2‐((3‐methyl‐1H‐pyrazol‐1‐yl)carbonyl)thienopyridines. The structure of the target molecules is elucidated using elemental analyses and spectral data.     

Novel Pyrano[2,3‐d]thiazole and Thiazolo[4,5‐b]pyridine Derivatives: One‐pot Three‐component Synthesis and Biological Evaluation as Anticancer Agents,c‐Met,and Pim‐1 Kinase Inhibitors

Preparation of pyrano[2,3‐d]thiazole and thiazolo[4,5‐b]pyridine derivatives through multicomponent reactions (MCRs) was achieved by the reaction of 2‐(2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophen‐3‐yl)thiazol‐4(5H)‐one with various active methylene reagents such as ethyl cyanoacetate or malononitrile in basic conditions containing diverse aromatic aldehyde. Furthermore, this study aims to evaluate the in vitro cytotoxic activity of the synthetic compounds against six cancer cell lines, and all the prepared compounds revealed valuable activity compared with the CHS‐828, which is the 2‐[6‐(4‐chlorophenoxy)hexyl]‐1‐cyano‐3‐pyridin‐4‐ylguanidine as the standard drug. Some of the pyrano[2,3‐d]thiazole and thiazolo[4,5‐b]pyridine derivatives showed the highest antitumor activity towards the six cancer cell lines. Moreover, (c‐Met) enzymatic activity of the most potent compounds showed that compounds 3b 2‐(2‐amino‐4,5,6,7 tetrahydrobenzo[b]thiophen‐3‐yl)‐5‐hydroxy‐7‐(2‐hydroxy‐phenyl)‐7H‐pyrano[2,3‐d]thiazole‐6 carbonitrile and 5e 2‐(2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophen‐3‐yl)‐5‐hydroxy‐7‐phenyl‐4,7‐dihydrothiazolo[4,5‐b]pyridine‐6‐carbonitrile were with higher activities than foretinib. Three compounds were selected to examine their Pim‐1 kinase where compounds 3b and 7b showed the highest inhibitions.     

Two similarly substituted benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐diones: supramolecular structures in two and three dimensions

The molecules of 8‐methyl‐7,10‐diphenyl‐5H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐dione, C₂₇H₁₇N₃O₂, (I), are weakly linked into chains by a single C—H...O hydrogen bond, and these chains are linked into sheets by a π–π stacking interaction involving pyridyl and aryl rings. In 8‐methyl‐7‐(4‐methylphenyl)‐10‐phenyl‐5H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,6(10H)‐dione, C₂₈H₁₉N₃O₂, (II), the molecules are linked into a three‐dimensional framework structure by a combination of C—H...N, C—H...O and C—H...π(arene) hydrogen bonds, together with a π–π stacking interaction analogous to that in (I).     

Reactions between arylhydrazinium chlorides and 2‐chloroquinoline‐3‐carbaldehydes: molecular and supramolecular structures of a hydrazone,a 4,9‐dihydro‐1H‐pyrazolo[3,4‐b]quinoline and two 1H‐pyrazolo[3,4‐b]quinolines

Hydrazone derivatives exhibit a wide range of biological activities, while pyrazolo[3,4‐b]quinoline derivatives, on the other hand, exhibit both antimicrobial and antiviral activity, so that all new derivatives in these chemical classes are potentially of value. Dry grinding of a mixture of 2‐chloroquinoline‐3‐carbaldehyde and 4‐methylphenylhydrazinium chloride gives (E)‐1‐[(2‐chloroquinolin‐3‐yl)methylidene]‐2‐(4‐methylphenyl)hydrazine, C₁₇H₁₄ClN₃, (I), while the same regents in methanol in the presence of sodium cyanoborohydride give 1‐(4‐methylphenyl)‐4,9‐dihydro‐1H‐pyrazolo[3,4‐b]quinoline, C₁₇H₁₅N₃, (II). The reactions between phenylhydrazinium chloride and either 2‐chloroquinoline‐3‐carbaldehyde or 2‐chloro‐6‐methylquinoline‐3‐carbaldehyde give, respectively, 1‐phenyl‐1H‐pyrazolo[3,4‐b]quinoline, C₁₆H₁₁N₃, (III), which crystallizes in the space group Pbcn as a nonmerohedral twin having Z′ = 3, or 6‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]quinoline, C₁₇H₁₃N₃, (IV), which crystallizes in the space group R. The molecules of compound (I) are linked into sheets by a combination of N—H…N and C—H…π(arene) hydrogen bonds, and the molecules of compound (II) are linked by a combination of N—H…N and C—H…π(arene) hydrogen bonds to form a chain of rings. In the structure of compound (III), one of the three independent molecules forms chains generated by C—H…π(arene) hydrogen bonds, with a second type of molecule linked to the chains by a second C—H…π(arene) hydrogen bond and the third type of molecule linked to the chain by multiple π–π stacking interactions. A single C—H…π(arene) hydrogen bond links the molecules of compound (IV) into cyclic centrosymmetric hexamers having (S₆) symmetry, which are themselves linked into a three‐dimensional array by π–π stacking interactions.     

Phosphorescent Cyclometalated Iridium(III) Complexes That Contain Substituted 2‐Acetylbenzo[b]thiophen‐3‐olate Ligand for Red Organic Light‐Emitting Devices

We report the synthesis of a new class of thermally stable and strongly luminescent cyclometalated iridium(III) complexes 1 – 6 , which contain the 2‐acetylbenzo[b]thiophene‐3‐olate (bt) ligand, and their application in organic light‐emitting diodes (OLEDs). These heteroleptic iridium(III) complexes with bt as the ancillary ligand have a decomposition temperature that is 10–20 % higher and lower emission self‐quenching constants than those of their corresponding complexes with acetylacetonate (acac). The luminescent color of these iridium(III) complexes could be fine‐tuned from orange (e.g., 2‐phenyl‐6‐(trifluoromethyl)benzo[d]thiazole (cf₃bta) for 4 ) to pure red (e.g., lpt (Hlpt=4‐methyl‐2‐(thiophen‐2‐yl)quinolone) for 6 ) by varying the cyclometalating ligands (C‐deprotonated C^N). In particular, highly efficient OLEDs based on 6 as dopant (emitter) and 1,3‐bis(carbazol‐9‐yl)benzene (mCP) as host that exhibit stable red emission over a wide range of brightness with CIE chromaticity coordinates of (0.67, 0.33) well matched to the National Television System Committee (NTSC) standard have been fabricated along with an external quantum efficiency (EQE) and current efficiency of 9 % and 10 cd A^?1, respectively. A further 50 % increase in EQE (>13 %) by replacing mCP with bis[4‐(6H‐indolo[2,3‐b]quinoxalin‐6‐yl)phenyl]diphenylsilane (BIQS) as host for 6 in the red OLED is demonstrated. The performance of OLEDs fabricated with 6 (i.e., [(lpt)₂Ir(bt)]) was comparable to that of the analogous iridium(III) complex that bore acac (i.e., [(lpt)₂Ir(acac)]; 6 a in this work) [Adv. Mater.­ 2011 , 23, 2981] fabricated under similar conditions. By using ntt (Hnnt=3‐hydroxynaphtho[2,3‐b]thiophen‐2‐yl)(thiophen‐2‐yl)methanone) ligand, a substituted derivative of bt, the [(cf₃bta)₂Ir(ntt)] was prepared and found to display deep red emission at around 700 nm with a quantum yield of 12 % in mCP thin film.     

Four N7‐alkoxybenzyl‐substituted 4,5,6,7‐tetrahydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐spiro‐1′‐cyclohexane‐2′,6′‐diones: hydrogen‐bonded supramolecular structures in zero,one, two or three dimensions

3‐tert‐Butyl‐7‐(4‐methoxybenzyl)‐4′,4′‐dimethyl‐1‐phenyl‐4,5,6,7‐tetrahydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐spiro‐1′‐cyclohexane‐2′,6′‐dione, C₃₁H₃₇N₃O₃, (I), 3‐tert‐butyl‐7‐(2,3‐dimethoxybenzyl)‐4′,4′‐dimethyl‐1‐phenyl‐4,5,6,7‐tetrahydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐spiro‐1′‐cyclohexane‐2′,6′‐dione, C₃₂H₃₉N₃O₄, (II), 3‐tert‐butyl‐4′,4′‐dimethyl‐7‐(3,4‐methylenedioxybenzyl)‐1‐phenyl‐4,5,6,7‐tetrahydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐spiro‐1′‐cyclohexane‐2′,6′‐dione, C₃₁H₃₅N₃O₄, (III), and 3‐tert‐butyl‐4′,4′‐dimethyl‐1‐phenyl‐7‐(3,4,5‐trimethoxybenzyl)‐4,5,6,7‐tetrahydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐spiro‐1′‐cyclohexane‐2′,6′‐dione ethanol 0.67‐solvate, C₃₃H₄₁N₃O₅·0.67C₂H₆O, (IV), all contain reduced pyridine rings having half‐chair conformations. The molecules of (I) and (II) are linked into centrosymmetric dimers and simple chains, respectively, by C—H...O hydrogen bonds, augmented only in (I) by a C—H...π hydrogen bond. The molecules of (III) are linked by a combination of C—H...O and C—H...π hydrogen bonds into a chain of edge‐fused centrosymmetric rings, further linked by weak hydrogen bonds into supramolecular arrays in two or three dimensions. The heterocyclic molecules in (IV) are linked by two independent C—H...O hydrogen bonds into sheets, from which the partial‐occupancy ethanol molecules are pendent. The significance of this study lies in its finding of a very wide range of supramolecular aggregation modes dependent on rather modest changes in the peripheral substituents remote from the main hydrogen‐bond acceptor sites.     

Synthesis of 4‐Aryl‐3‐Methyl‐1‐Phenyl‐1H‐Benzo[h]Pyrazolo[3,4‐b]Quinoline‐5,10‐diones Using Diammonium Hydrogen Phosphate as an Efficient and Versatile Catalyst in Water

A simple and efficient synthesis of 4‐aryl‐3‐methyl‐1‐phenyl‐1H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,10‐diones has been accomplished by the one‐pot condensation reaction of 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine, aldehydes and 2‐hydroxynaphthalene‐1,4‐dione in water in the presence of diammonium hydrogen phosphate.     

An Efficient One‐Pot,Four‐Component Synthesis of {[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione Derivatives

The 1‐{[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives 5 were synthesized by a simple and efficient method, i.e., by the four‐component, one‐pot condensation reaction of phthalohydrazide 4 , a (propargyloxy)benzaldehyde 1 , an active methylene compound 3 (malononitrile or ethyl cyanoacetate), and an azide 2 in the presence of Cu(OAc)₂/sodium L ‐ascorbate as catalyst and 1‐methyl‐1H‐imidazolium trifluoroacetate ([Hmim](CF₃COO)) as an ionic‐liquid medium in good to excellent yields (Scheme 1).     

Design,Synthesis, and Fungicidal Activity of Novel Imidazo[4,5‐b]pyridine Derivatives

A series of novel imidazo[4,5‐b]pyridine derivatives were designed and synthesized. The structures of all the newly synthesized compounds were identified by spectroscopic data NMR, MS, and elemental analysis. Bioassay showed that the compounds exhibited potent fungicidal activities against Erysiphe graminis, Puccinia polysora, and so forth. Particularly, 2‐chloro‐5‐((5‐methoxy‐2‐(2‐(trifluoromethyl)phenyl)‐3H‐imidazo[4,5‐b]pyridin‐3‐yl)methyl)thiazole ( 9b ) displayed fungicidal potency against P. polysora. Its EC₅₀ value: 4.00 mg/L is comparable with that of tebuconazole. The structure–activity relationship for the target compounds is discussed.     

Selective Synthesis of New Tetracyclic Coumarin‐fused Pyrazolo[3,4‐b]pyridines and Pyrazolo[3,4‐b]pyridin‐6(7H)‐ones

A three‐component reaction for the synthesis of new coumarin‐fused tetracyclic system from 4‐hydroxycoumarin, aldehydes, and 5‐aminopyrazoles/5‐aminoisoxazole is described. In the presence of acetic acid, 4,7‐dihydro‐1H‐pyrazolo[3,4‐b]pyridines ( 4 ) and pyrazolo[3,4‐b]pyridines ( 5 ) were obtained in acetonitrile and dimethylsulfoxide medium, respectively. The reaction gave rise to 4,5‐dihydro‐1H‐pyrazolo[3,4‐b]pyridin‐6(7H)‐ones ( 6 ) in acetic acid–ethanol combination system, which involved the C–O bond cleavage. 4‐Hydroxy‐6‐methyl‐2H‐pyran‐2‐one and acenaphthylene‐1,2‐dione were also examined, affording the corresponding C–O bond cleavage products. Mechanism indicates that the reaction is reversible in acetic acid–ethanol combination system.     

Three AgI,CuI and CdII coordination polymers based on the new asymmetrical ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole: syntheses,characterization and emission properties

The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C₁₇H₁₃N₅O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag^I, Cu^I and Cd^II metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF₆}_n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu₂I₂( L )₂]·C₄H₈O₂}_n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )₂(NO₃)₂]·2CH₄O·0.65H₂O}_n, were obtained. The experimental results show that ligand L coordinates easily with linear Ag^I, tetrahedral Cu^I and octahedral Cd^II metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.     

2,5‐Bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole and its one‐dimensional polymeric complex with ZnCl2

2,5‐Bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole (L), C₂₆H₂₀N₄O, forms one‐dimensional chains via two types of intermolecular π–π interactions. In catena‐poly[[dichloridozinc(II)]‐μ‐2,5‐bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole], [ZnCl₂(C₂₆H₂₀N₄O)]_n, synthesized by the combination of L with ZnCl₂, the Zn^II centres are coordinated by two Cl atoms and two N atoms from two L ligands. [ZnCl₂L]_n forms one‐dimensional P (plus) and M (minus) helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π–π and C—H...π interactions.     

A new approach for the synthesis of some pyrazolo[5,1‐c]triazines and pyrazolo[1,5‐a]pyrimidines containing naphtofuran moiety

Naphtho[2,1‐b]furan‐2‐yl)(8‐phenylpyrazolo[5,1‐c][1,2,4]triazin‐3‐yl)methanone, ([1,2,4]triazolo[3,4‐c][1,2,4]triazin‐6‐yl)(naphtho[2,1‐b]furan‐2‐yl)methanone, benzo[4,5]imidazo[2,1‐c][1,2,4]triazin‐3‐yl‐naphtho[2,1‐b]furan‐2‐yl‐methanone, 5‐(naphtho[2,1‐b]furan‐2‐yl)pyrazolo[1,5‐a]pyrimidine, 7‐(naphtho[2,1‐b]furan‐2‐yl)‐[1,2,4]triazolo[4,3‐a]pyrimidine, 2‐naphtho[2,1‐b]furan‐2‐yl‐benzo[4,5]imidazo[1,2‐a]pyrimidine, pyridine, and pyrazole derivatives are synthesized from sodium salt of 5‐hydroxy‐1‐naphtho[2,1‐b]furan‐2‐ylpropenone and various reagents. The newly synthesized compounds were elucidated by elemental analysis, spectral data, chemical transformation, and alternative synthetic route whenever possible. J. Heterocyclic Chem., (2012).     

Two one‐dimensional coordination polymers generated from a new benzimidazole bridging ligand and CdX2 (X = Br and I)

The novel asymmetric bridging ligand 1‐[(pyridin‐3‐yl)methyl]‐2‐[4‐(pyridin‐3‐yl)phenyl]‐1H‐benzimidazole (L) has been used to construct the coordination polymers catena‐poly[[[dibromidocadmium(II)]‐μ₃‐1‐[(pyridin‐3‐yl)methyl]‐2‐[4‐(pyridin‐3‐yl)phenyl]‐1H‐benzimidazole] monohydrate], {[CdBr₂(C₂₄H₁₈N₄)]·H₂O}_n, (I), and catena‐poly[[diiodidocadmium(II)]‐μ₃‐1‐[(pyridin‐3‐yl)methyl]‐2‐[4‐(pyridin‐3‐yl)phenyl]‐1H‐benzimidazole], [CdI₂(C₂₄H₁₈N₄)]_n, (II). Compounds (I) and (II) are closely related one‐dimensional polymers based on 16‐ and 20‐membered macrocycles along the chains, but they are not isomorphous. The chains are crosslinked into a two‐dimensional network via hydrogen bonds and π–π interactions in (I), and into a three‐dimensional framework through π–π interactions in (II). One well‐ordered solvent water molecule per asymmetric unit is included in (I) and forms O...Br hydrogen bonds.     

Synthesis,structure and in vitro cytotoxicity testing of some 2‐aroylbenzofuran‐3‐ols

Five 2‐aroyl‐5‐bromobenzo[b]furan‐3‐ol compounds (two of which are new) and four new 2‐aroyl‐5‐iodobenzo[b]furan‐3‐ol compounds were synthesized starting from salicylic acid. The compounds were characterized by mass spectrometry and ¹H NMR and ¹³C NMR spectroscopy. Single‐crystal X‐ray diffraction studies of four compounds, namely, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐fluorophenyl)methanone, C₁₅H₈BrFO₃, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐chlorophenyl)methanone, C₁₅H₈BrClO₃, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐bromophenyl)methanone, C₁₅H₈Br₂O₃, and (4‐bromophenyl)(3‐hydroxy‐5‐iodobenzofuran‐2‐yl)methanone, C₁₅H₈BrIO₃, were also carried out. The compounds were tested for their in vitro cytotoxicity on the four human cancer cell lines KB, Hep‐G2, Lu‐1 and MCF7. Six compounds show good inhibiting abilities on Hep‐G2 cells, with IC₅₀ values of 1.39–8.03 µM.     

Hydrogen‐bonded assembly in six closely related pyrazolo[3,4‐b]pyridine derivatives; a simple chain,three types of chains of rings and a complex sheet structure

Six closely related pyrazolo[3,4‐b]pyridine derivatives, namely 6‐chloro‐3‐methyl‐1,4‐diphenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₄ClN₃O, (I), 6‐chloro‐3‐methyl‐4‐(4‐methylphenyl)‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₁H₁₆ClN₃O, (II), 6‐chloro‐4‐(4‐chlorophenyl)‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃Cl₂N₃O, (III), 4‐(4‐bromophenyl)‐6‐chloro‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃BrClN₃O, (IV), 6‐chloro‐4‐(4‐methoxyphenyl)‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₁H₁₆ClN₃O₂, (V), and 6‐chloro‐3‐methyl‐4‐(4‐nitrophenyl)‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃ClN₄O₃, (VI), which differ only in the identity of a single small substituent on one of the aryl rings, crystallize in four different space groups spanning three crystal systems. The molecules of (I) are linked into a chain of rings by a combination of C—H...N and C—H...π(arene) hydrogen bonds; those of (II), (IV) and (V), which all crystallize in the space group P, are each linked by two independent C—H...O hydrogen bonds to form chains of edge‐fused rings running in different directions through the three unit cells; the molecules of (III) are linked into complex sheets by a combination of two C—H...O hydrogen bonds and one C—H...π(arene) hydrogen bond; finally, the molecules of (VI) are linked by a single C—H...O hydrogen bond to form a simple chain.