2‐Methyl‐1,4,5‐triphenyl‐1H‐imidazole

In 2‐methyl‐1,4,5‐tri­phenyl‐1H‐imidazole, C₂₂H₁₈N₂, the three substituent phenyl groups are not delocalized with the imidazole moiety; the dihedral angles these phenyl groups form with the imidazole ring are in the range 25.90 (5)–63.49 (6)°.     

Reactivity of Hydroxy and Amino Derivatives of 2‐Phenyl‐1H‐imidazoline and 2‐Phenyl‐1H‐imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Reactivity of 2‐(4‐hydroxyphenyl)‐1H‐imidazoline and 2‐(4‐hydroxyphenyl)‐1H‐imidazole toward substituted phenyl isocyanates was studied. When mentioned imidazoline was treated with 2.5 equiv of substituted phenyl isocyanate, three N,O‐dicarboxamides were prepared (substituents are H, 4‐NO₂, and 4‐CH₃). Subsequently, N,O‐diacetylated 2‐(4‐hydroxyphenyl)‐1H‐imidazoline was prepared and selective deprotection method was developed for preparation of 1‐acetyl‐2‐(4‐hydroxyphenyl)‐1H‐imidazoline using diethylamine in acetone. Six carbamates derived from this imidazoline were then prepared using 1.1 equiv of substituted phenyl isocyanates (substituents are H, 4‐CH₃, 4‐OCH₃, 4‐NO₂, 4‐CN, and 3‐CF₃). Finally, two carbamates were prepared from 2‐(4‐hydroxyphenyl)‐1H‐imidazole (substituents are 4‐NO₂ and 4‐CN). No reactivity to imidazole ring was observed in this case. Eight derivatives were subjected to antimycobacterial screening. Concurrently, reactivity of 2‐(2‐aminophenyl)‐ and 2‐(2‐hydroxyphenyl)‐1H‐imidazole toward aliphatic and aromatic isocyanates was studied. Eight ureas were prepared using equivalent mixture of 2‐(2‐aminophenyl)‐1H‐imidazole and isocyanate (Et, Pr, isoPr, terc‐Bu, Cy, Ph, 4‐CH₃C₆H₄, 4‐CNC₆H₄). Similar attempts to obtain related carbamates from 2‐(2‐hydroxyphenyl)‐1H‐imidazole lead only to three substituted phenyl carbamates (substituents are 4‐CH₃, 4‐NO₂, and 4‐CN). In both cases, no reactivity to imidazole ring was observed again.     

N‐{(1E)‐Amino­[3‐methyl‐5‐(4‐methyl­phenyl)‐4,5‐di­hydro‐1H‐pyrazol‐1‐yl]­methyl­ene}‐1H‐imidazole‐1‐carbox­amide

In the title compound, C₁₆H₁₈N₆O, an N‐carbonyl­imidazole derivative of pyrazoline‐1‐carboximid­amide, the π‐electron density of the N atom in the 1‐position on the pyrazoline ring is delocalized through the amidine moiety and the adjacent carbonyl group. The imidazole ring, though coplanar with the rest of the mol­ecule, is deconjugated. The pyrazoline ring adopts a flat‐envelope conformation, having the substituted phenyl ring oriented perpendicular to the mean plane of the heterocycle. Both of the two potential hydrogen‐bond donors are involved in intramolecular hydrogen‐bonding interactions.     

Investigation into Sonogashira reaction on 5-iodo-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds

Investigation into Sonogashira reaction on 5-iodo-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds had been developed by introducing an iodo atom at the C-5 position of the imidazole ring of 5-amino-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds. Specifically, 5-iodo-1-(4-iodophenyl)imidazole-4-carbonitrile compound had shown double Sonogashira coupling reactions with two differently substituted iodine along with the formation of two other compounds where an unusual coupling product with self-aggregation property was obtained. In other cases, monocoupling had been observed together with another compound where iodine atom present at C5 position of imidazole was replaced by hydrogen atom.     

Biphenyl‐ and phenylnaphthalenyl‐substituted 1H‐imidazole‐4,5‐dicarbonitrile catalysts for the coupling reaction of nucleoside methyl phosphonamidites

Crystal structures are reported for three substituted 1H‐imidazole‐4,5‐dicarbonitrile compounds used as catalysts for the coupling reaction of nucleoside methyl phosphonamidites, namely 2‐(3′,5′‐dimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C₁₉H₁₄N₄, (I), 2‐(2′,4′,6′‐trimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C₂₀H₁₆N₄, (II), and 2‐[8‐(3,5‐dimethylphenyl)naphthalen‐1‐yl]‐1H‐imidazole‐4,5‐dicarbonitrile, C₂₃H₁₆N₄, (III). The asymmetric unit of (I) contains two independent molecules with similar conformations. There is steric repulsion between the imidazole group and the terminal phenyl group in all three compounds, resulting in the nonplanarity of the molecules. The naphthalene group of (III) shows significant deviation from planarity. The C—N bond lengths in the imidazole rings range from 1.325 (2) to 1.377 (2) Å. The molecules are connected into zigzag chains by intermolecular N—H...N_imidazole [for (I)] or N—H...·N_cyano [for (II) and (III)] hydrogen bonds.     

Preparation of 2-aryl and 2-aryloxymethyl imidazo[1,2-a]pyridines and related compounds

A series of substituted 2-aryl imidazo[1,2-a]pyridines has been prepared in which a variety of substituents are introduced on the 4′-position of the phenyl ring and on the 3, 5 , 6 or 7 position of the heterocyclic ring. Most examples have acetamido, bromo, cyano, or formyl substituents at the 4′-position. Analogous imidazo-[2,1-b]fhiazoles and imidazo[1,2-a]pyrimidines have also been prepared. Another series of compounds consisting of 4′-formylphenoxymethyl derivatives of imidazole, the three positional isomers of pyridine, thiazole, benzimidazole and ring-substituted imidazo[1,2-a]pyridines has been prepared. 2-(4′-Formylphenylethenyl) derivatives of imidazole and imidazo[1,2-a]pyridine were also prepared.     

7‐Chloro‐1‐(2,6‐di­fluoro­phenyl)‐1H,3H‐thia­zolo­[3,4‐a]­benz­imidazole and 1‐(2,6‐di­fluoro­phenyl)‐6‐methyl‐1H,3H‐thia­zolo­[3,4‐a]­benz­imidazole

The title mol­ecules, C₁₅H₉ClF₂N₂S and C₁₆H₁₂F₂N₂S, respectively, display the well known butterfly‐like conformation with a flat thia­zolobenz­imidazole system. In both compounds, the mean plane through the tricyclic system is almost perpendicular to the 2,6‐di­fluoro­phenyl ring. This arrangement of the aryl group is determined by two intramolecular hydrogen bonds and by an attractive F?S interaction.     

Protonation of imidazo[2,1-b]thiazole and thiazolo[2,3-f]purine

The protonation of imidazo[2,1-b]thiazole and thiazolo[2,3-f]purine was investigated by PMR spectroscopy. In CF₃COOH and D₂SO₄ the imidazothiazole forms a monocation, the structure of which corresponds to the addition of a proton to the nitrogen atom of the imidazole ring. In aqueous D₂SO₄ solutions, the thiazolopurine forms mono- and dications. The first protonation occurs at the nitrogen atom of the pyrimidine ring, while the second protonation occurs at the nitrogen atom of the imidazole ring. The effect of delocalization of the positive charge in the cations of the investigated compounds was examined.     

2‐[2‐Methyl‐5‐nitro‐4‐(phenyl­sulfonyl­methyl)­imidazol‐1‐yl]­ethanol and 2‐methyl‐5‐nitro‐4‐phenyl­sulfonyl­methyl‐1,3‐thia­zole

The title compounds, C₁₃H₁₅N₃O₅S and C₁₁H₁₀N₂O₄S₂, respectively, both contain a phenyl­sulfonyl group connected, through a methyl­ene bridge, to either a substituted nitro­imidazole or nitro‐1,3‐thia­zole ring. In the imidazole‐containing mol­ecule, the nitro and sulfonyl groups are trans relative to the sulfonyl–methyl bond, while in the thia­zole‐containing mol­ecule, these substituents are cis. The stabilizing interactions within the crystals are also different between the two compounds.     

4‐Phenyl‐1H‐imidazole (a low‐temperature redetermination), 1‐benzyl‐1H‐imidazole and 1‐mesityl‐1H‐imidazole

Low‐temperature studies of the simple variously substituted imidazole types 4‐phenyl‐1H‐imidazole, C₉H₈N₂, 1‐benzyl‐1H‐imidazole, C₁₀H₁₀N₂, and 1‐mesityl‐1H‐imidazole, C₁₂H₁₄N₂, extend comparisons between parent imidazole species and their derivatives, the pronounced double‐bond localization opposite the substituted N atom common to simple neutral species being redistributed aromatically on protonation.     

Furopyridines. XXII. Elaboration of the C-substituents alpha to the heteronitrogen atom of furo[2,3-b] -, -[3,2-b] -, -[2,3-c]- and -[3,2-c]pyridine

The Grignard reaction of fused ring cyanopyridine derivatives 1a-d with methyl- and phenylmagnesium bromide yielded the corresponding acylpyridine compounds 2a-d and 3a-d . Furopyridine N-oxides 4a-d were converted into the compounds having a phenyl group at the α-position to the ring nitrogen 5a-d . Reduction of 1a-d and the carboxylic esters 6a-d with diisobutylaluminium hydride yielded the corresponding amines 7a-d and aldehydes 9a-d . The aldehydes were converted to nitroethanol derivatives 10a-d by condensation with nitromethane and acrylic ester compounds 11a-d by the Wittig-Horner reaction with methyl diethyl phosphonoacetate.     

2‐[(E)‐(4‐Chloro­phenyl)­methyl­ene­amino]‐N‐(X‐methyl­phenyl)‐4,5,6,7‐tetra­hydro‐1‐benzo­thio­phene‐3‐carbox­amide,where X = 2 and 3

The title compounds, both C₂₃H₂₁ClN₂OS, are isomeric, with (I) and (II) being the N‐3‐methyl­phenyl and N‐2‐methyl­phenyl derivatives, respectively. The dihedral angle between the 4‐chloro­phenyl group and the thio­phene ring in (II) [38.1 (1)°] is larger than that in (I) [7.1 (1)°], indicating steric repulsion between the chloro­phenyl and o‐toluidine groups in (II). In both compounds, an intramolecular N—H⋯N hydrogen bond forms a pseudo‐six‐membered ring, thus locking the molecular conformation. In the crystal structures, mol­ecules are connected via N—H⋯O hydrogen bonds, forming chains along the b axis in (I) and along the c axis in (II). Intermolecular C—H⋯O/S and π–π interactions are also observed in (II), but not in (I).     

Synthesis of a series of diaminobenzo[f]- and diaminobenzo[h]pyrimido[4,5-b]quinolines as 5-deaza tetracyclic nonclassical antifolates

A series of diaminobenzo[f]- and diaminobenzo[h]pyrimido[4,5-b]quinolines 1–11 were designed as 5-deaza tetracyclic nonclassical, lipophilic antifolates. The compounds were designed as conformationally semi-rigid and rigid analogs of 2,4-diamino-6-phenyl- 12 and 2,4-diamino-7-phenylpyrido[2,3-d]pyrimidines 13 and 14 . The target compounds were synthesized by cyclocondensation of chlorovinyl aldehydes obtained from appropriately substituted 1- or 2-tetralone, with 2,4,6-friaminopyrimidine. Compounds 1–11 were evaluated as inhibitors of P. carinii and T. gondii dihydrofolate reductases. These pathogens cause fatal opportunistic infections in AIDS patients. In addition, the selectivity of these agents was evaluated using rat liver dihydrofolate reductase as the mammalian source. In general the benzo[f]pyrimido[4,5-b]quinolines 1–5 were more potent than the corresponding benzo[h]pyrimido[4,5-b]quinoline analogues 6–11 against P. carinii and rat liver dihydrofolate reductase and were equipotent against T. gondii dihydrofolate reductase. Compounds 6–11 were moderately selective towards T. gondii dihydrofolate reductase with IC₅₀S in the 10⁻⁷ M range. In contrast analogues 1–5 lacked selectivity against P. carinii or T. gondii dihydrofolate reductase and were, in general, potent inhibitors of rat liver dihydrofolate reductase with IC₅₀S in the 10⁻⁸ M range. Analogues 1 and 4 were evaluated against a series of tumor cell lines in vitro and were found to have moderate antitumor activity (IC50 10⁻⁶ M). The structure activity/selectivity relationships suggest that benzo[f]pyrimido analogues 1–5 with the phenyl ring substitution in the “upper” portion of the tetracyclic ring are better accommodated within the rat liver (mammalian) dihydrofolate reductase and P. carinii dihydrofolate reductase active sites compared to the benzo[h]pyrimido analogues 6–11 which have the phenyl ring substitution in the “lower” portion of the tetracyclic ring. In contrast T. gondii dihydrofolate reductase does not discriminate between the isomers and binds to both series of compounds with similar affinities.     

Synthesis and optical behaviors of 2-(9-phenanthrenyl)-, 2-(9-anthryl)-, and 2-(1-pyrenyl)-1-alkylimidazole homologues

Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λ_amax, fluorescence emission maximum λ_em, Stokes shifts and fluorescence quantum yields (Φ_F) in ethyl acetate were determined; their fluorescent lifetimes (T₁ and T₂) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed.     

Synthesis,halogenation and structural characterization of (Z)-1-[2-(triphenylstannyl)vinyl]-1-cyclododecanol

Synthesis and characterisation of (Z)-1-[2(triphenylstannyl)vinyl]-l-cyclododecanol, c-(CH₂)₁₁C(OH)CH=CHSnPh₃, are reported, together with its halogenation by I₂, Br₂ and ICI to yield derivatives of the types c-(CH₂)₁₁C(OH)CH=CHSnPhs_?nX_n (n=1, 2; X=I, Br, Cl, respectively). The molecular structures of two compounds have been determined by X-ray diffraction analysis. The tin atom exhibits a distorted tetrahedral geometry in the crystal of (Z)-l-[2–(triphenylstannyI)vinyl]-l-cyclododecanol, but a trigonal bipyramidal geometry in the monoiodo-derivative (Z)-l-[2]-(diphenyliodo-stannyl)vinyl)-1-cyclododecanol and other derivatives, in which significant intramolecular coordinative interaction HO→Sn ia observed. And the formation of a five-membered tin containing ring is significant for their antitumour activities.     

The synthesis and transition temperatures of 5-(4-alkyl- and 4-alkoxy-phenyl)-2-cyanobenzo[b]furans and a 5-(4'-alkylbiphenyl-4-yl)-2-cyanobenzo[b]furan: a comparison with their biphenyl and terphenyl analogues

The synthesis and transition temperatures of a series of 5-(4-alkyl- and 4-alkoxy-phenyl)2-cyanobenzo[b]furans and a 5-(4'-alkylbiphenyl-4-yl)-2-cyanobenzo[b]furan are presented. The 2-cyanobenzo[b]furans show similar mesophase types to the analogous biphenyl and terphenyl compounds, which are obtained by replacing the benzo[b]furan unit with a phenyl ring. The transition temperatures for the 2-cyanobenzo[b]furan compounds are always higher than for their biphenyl and terphenyl counterparts, but they are much lower than for the corresponding phenylnaphthalenes. Five mesogenic benzo[b]furans without a cyano group were prepared as intermediates and these compounds have lower clearing points than their biphenyl analogues.     

Synthesis and activity mechanism of some novel 2-substituted benzothiazoles as hGSTP1-1 enzyme inhibitors$

Abstract

Human GSTP1-1 is one of the most important proteins, which overexpresses in a large number of human tumours and is involved in the development of resistance to several anticancer drugs. So, it has become an important target in cancer treatment. In this study, 12 benzothiazole derivatives were synthesized and screened for their in vitro inhibitory activity for hGSTP1-1. Among these compounds, two of them (compounds #2 and #5) have been found to be the leads when compared with the reference drug etoposide. In order to analyse the structure–activity relationships (SARs) and to investigate the binding side interactions of the observed lead compounds, a HipHop pharmacophore model was generated and the molecular docking studies were performed by using CDocker method. In conclusion, it is observed that the lead compounds #2 and #5 possessed inhibitory activity on the hGSTP1-1 by binding to the H-site as a substrate in which the para position of the phenyl ring of the benzamide moiety on the benzothiazole ring is important. Substitution at this position with a hydrophobic group that reduces the electron density at the phenyl ring is required for the interaction with the H side active residue Tyr108.     

A novel one‐dimensional double‐chain‐like ZnII coordination polymer: poly[bis(1‐benzyl‐1H‐imidazole‐κN3)tris(μ‐cyanido‐κ2C:N)(cyanido‐κC)disilver(I)zinc(II)]

One of most interesting systems of coordination polymers constructed from the first‐row transition metals is the porous Zn^II coordination polymer system, but the numbers of such polymers containing N‐donor linkers are still limited. The title double‐chain‐like Zn^II coordination polymer, [Ag₂Zn(CN)₄(C₁₀H₁₀N₂)₂]_n, presents a one‐dimensional linear coordination polymer structure in which Zn^II ions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographic b axis and each Zn^II ion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1‐benzyl‐1H‐imidazole (BZI) ligands, giving a five‐coordinated Zn^II ion. Interestingly, there are strong intermolecular Ag^I…Ag^I interactions between terminal and bridging dicyanidoargentate(I) units and C—H…π interactions between the phenyl rings of BZI ligands of adjacent one‐dimensional linear chains, providing a one‐dimensional linear double‐chain‐like structure. The supramolecular three‐dimensional framework is stabilized by C—H…π interactions between the phenyl rings of BZI ligands and by Ag^I…Ag^I interactions between adjacent double chains. The photoluminescence properties have been studied.     

Abundant Intramolecular Ring Rearrangements of 1-(N-Benzyloxycarbonylamino)arylmethylphosphonate Phenyl monoesters Under Electrospray Ionization Conditions

Abstract

The mass spectrometric behavior of 1-(N-benzyloxycarbonylamino)arylmethyl-phosphonate phenyl monoesters was investigated under positive ion electrospray ionization conditions. All nitrogen-protonated title compounds undergo four- and/or six-membered ring rearrangements to yield nitrogen-containing fragment ions by consecutive or simultaneous loss of a carbon dioxide and phenyl hydrogen phosphonate or phenyl benzylphosphonate or an arylmethylimine. All oxygen-protonated title compounds undergo four- to six-membered ring rearrangements to produce fragment ions by loss of a carbon dioxide plus an arylmethylimine, or phenyl benzylphosphonate, by consecutive or simultaneous loss of benzyl phenyl ether and isocyanic acid. The fragmentation is obviously different from the corresponding methyl and ethyl monoesters, which show a tendency to undergo intramolecular four-membered ring rearrangements only.

GRAPHICAL ABSTRACT