Aryl Derivatives Research Articles

Diethynyl Aryl Derivatives for P-Channel and N-Channel Organic Field-Effect Transistors

AbstractOrganic field-effect transistors (OFETs) consisted of vacuum-evaporated diethynyl aryl derivatives were prepared and the device characteristics were evaluated. The fabricated OFETs showed typical p-type characteristics for diethynyl naphthalene derivative with two end naphthyl groups. By optimizing the fabrication process, the device exhibited a high field-effect hole mobility up to 0.12 cm2V−1s−1 and a high on/off current ratio of 3.3×105. On the other hand, OFETs showed typical n-type characteristics for diethynyl aryl derivative with two end heptafluoronaphthyl groups. We have observed clear changes from p-channel to n-channel conductions in OFETs by chemically modifying diethynyl aryl derivatives.

Microcontact Printing Using the Spontaneous Reduction of Aryldiazonium Salts

Patterning of aryl derivatives on graphitic carbon surfaces by printing with poly(dimethylsiloxane) stamps is described. The printing ink contained aryldiazonium salts which react spontaneously with the carbon substrate (pyrolyzed photoresist film) resulting in covalently attached modifiers. Printed surfaces were characterized using electrochemistry and scanning electron microscopy, and by generating water condensation figures. The method is very simple and versatile: both aqueous acid and DMF were shown to be suitable ink solvents and the diazonium salt could be printed directly from its synthesis solution. Surfaces patterned with nitrophenyl, aminophenyl, and caboxyphenyl groups were successfully prepared. Extension of the method to patterning other conducting and semiconducting substrates should be straightforward.

Suzuki reaction on pyridinium N-haloheteroarylaminides: regioselective synthesis of 3,5-disubstituted 2-aminopyrazines

An extensive study of Suzuki–Miyaura cross-coupling processes on N-pyridinium bromoazinyl aminides has been performed. Mono- and disubstitution on 5- and 3,5-bromo derivatives produced the corresponding aryl derivatives. In the disubstituted compounds regioselective substitution at the 3-position occurred, vicinal to the aminide nitrogen, and this was more evident in pyrazine derivatives. The commonly used strategy involving N-alkylation and reduction of the N–N bond gave rise to a series of 2-alkylamino-3,5-disubstituted-pyrazines.

Structure of cyclic dihydroxyacetone phosphate dimethyl acetal, a cyclic DHAP precursor, in the crystalline state

The six-membered cyclic phosphate diester, 5,5-dimethoxy-2-oxo-1,3,2-dioxaphosphorinane-2-ol, the dimethyl acetal of cyclic dihydroxyacetone phosphate, (MeO) 2cDHAP, was obtained by the isolation of an intermediate in the basic hydrolysis of the cyclic triester derivative. The compound had been isolated in the form of the crystalline cyclohexylammonium (cha) salts: (cha)[(MeO) 2cDHAP]·3H 2O ( 5a) and (cha)[(MeO) 2cDHAP]·H 2O ( 5b), which were then converted into the free acid: (H 5O 2)[(MeO) 2cDHAP] ( 5c) and then into a series of different salts: Na[(MeO) 2cDHAP]·2H 2O ( 5d), K[(MeO) 2cDHAP]·1.5H 2O ( 5e), K[(MeO) 2cDHAP]·0.5H 2O ( 5e′), Ca[(MeO) 2cDHAP] 2·2H 2O ( 5f), CaK[(MeO) 2cDHAP] 3·2H 2O ( 5g) and NH 4[(MeO) 2cDHAP] ( 5h). The synthesis of the compounds, their crystallization and crystal structures determined by X-ray crystallography are described. The most interesting structural feature observed in 5a– g anions in the crystalline state is the chair conformation of the P/O/C/C/C/O 1,3,2-dioxaphosphorinane ring, which is generally not flattened, in contrast to the deformations often observed in the analogous aryl derivatives (also in (MeO) 2cDHAP(Ph); Ślepokura, K.; Lis, T. Acta Crystallogr. Sect. C 2004, 60, o315–o317). However, the anion in crystal 5h is disordered and exists in two conformations, 76% of which is the skew, S, conformation, not observed so far in the compounds of related structure.

Fluorine-containing Diethynyl Aryl Derivatives for n-Channel Organic Field-effect Transistors

Abstract Fluorine-containing diethynyl aryl derivatives (1–5), in which three aromatic rings were connected together with rigid acetylenic linkages, were synthesized for n-channel organic field-effect transistors. The field-effect electron mobility of the thin film of 2 exhibited 3.4×10−3 cm2 V−1 s−1.

Stereoselective Synthesis of α-Phosphorylated Spiranes

α-Oxospiranes have been converted into vinyl triflates for phosphorylation and arylation by palladium-catalyzed cross-coupling reactions. With diethyl phosphite, the coupling provided olefinic mono- and diphosphonated spiranes. Saturation of conjugated aryl and phosphonyl alkene bonds was stereoselective when effected by catalytic hydrogenation. The double bond in conjugated alkenylphosphonates was in general more difficult to reduce than conjugated aryl derivatives. In mixed substrates, regioselectivity in the saturation of conjugated olefinic bonds was obtained.

Synthesis, structure elucidation and identification of antitumoural properties of novel fused 1,2,4-triazine aryl derivatives

Synthesis, structure elucidation and anticancer activities of novel fused 1,2,4-triazine aryl derivatives containing the ethoxycarbonyl ( 6– 10) and carbohydrazide formations ( 11– 15) are presented. Molecular structures of the synthesized compounds were confirmed by IR, 1H NMR, 13C NMR, EI-MS spectra and elemental analyses. Antitumour activities in vitro for heterobicyclic hydrazides of the type 11– 14 were evaluated by BrdU method for human LS180, SiHa and T47D carcinoma cells. Amongst them, hydrazide 14 has exhibited remarkable inhibitory effect against SiHa and LS180 tumour cells, and simultaneously was found to be non-toxic towards the human normal cell line – HSF cells. Furthermore, the pulse field gel electrophoresis experiment was performed for characterizing DNA-cleaving activity of heterobicycle 14. The DNA fragments of 2500, 2000 and 500 kilobase pairs (kbp) were commonly detected in the cancer cell lines (SiHa, LS180 and T47D) treated with compound 14. DNA fragmentation pattern, since three types of fragments induced by the tested hydrazide of the type 14 were detected, suggesting a way of interaction with DNA. It is worth pointing out, that DNA strand breaks were also produced in human breast cancer (T47D) cells, a cell line where the induction of DNA fragmentation is very difficult. Moreover, the statistically significant apoptotic activity in T47D human breast cancer cells for the tested heterobicycle 14 was proved using the annexin V – binding assay. The antiproliferative properties in vitro for compounds 6– 14 were evaluated by MTT method for human leukaemic Jurkat cells. Significant viability decreases in Jurkat cells treated with different concentrations of compounds 10 and 11 were observed, suggesting that these derivatives have antiproliferative activities. Their acute toxicities were established. For these compounds the influence on the central nervous system of mice in behavioural tests was examined. Molecular structure for free base of the intermediate 4 was confirmed by 1H– 1H COSY, HMBC and HMQC correlations.

Novel azolyl-(phenylmethyl)]aryl/heteroarylamines: Potent CYP26 inhibitors and enhancers of all- trans retinoic acid activity in neuroblastoma cells

The synthesis and potent inhibitory activity of novel 4-[(imidazol-1-yl and triazol-1-yl)(phenyl)methyl]aryl-and heteroaryl amines versus a MCF-7 CYP26A1 cell assay is described. Biaryl imidazole ([4-(imidazol-1-yl-phenyl-methyl)-phenyl]-naphthalen-2-yl-amine ( 8), IC 50 = 0.5 μM; [4-(imidazol-1-yl-phenyl-methyl)-phenyl]-indan-5-yl-amine ( 9), IC 50 = 1.0 μM) and heteroaryl imidazole derivatives ((1 H-benzoimidazol-2-yl)-{4-[(5 H-imidazol-1-yl)-phenyl-methyl]-phenyl}-amine ( 15), IC 50 = 2.5 μM; benzooxazol-2-yl-{4-[(5 H-imidazol-1-yl)-phenyl-methyl]-phenyl}-amine ( 16), IC 50 = 0.9 μM; benzothiazol-2-yl-{4-[(5 H-imidazol-1-yl)-phenyl-methyl]-phenyl}-amine ( 17), IC 50 = 1.5 μM) were the most potent CYP26 inhibitors. Using a CYP26A1 homology model differences in activity were investigated. Incubation of SH-SY5Y human neuroblastoma cells with the imidazole aryl derivative 8, and the imidazole heteroaryl derivatives 16 and 17 potentiated the atRA-induced expression of CYP26B1. These data suggest that further structure–function studies leading to clinical development are warranted.

Heck Reaction on 1‐Alkoxy‐1,3‐dienes in Ionic Liquids: A Superior Medium for the Regioselective Arylation of the Conjugated Dienic System.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

First Comprehensive Investigation of Suzuki Couplings of Alkenyl Nonaflates with Aryl and Alkenyl Boronic Acid Derivatives by Using Classical Conditions and Microwave Heating

Alkenyl nonaflates (nonafluorobutanesulfonates) are excellent substrates in a variety of palladium-catalysed coupling reactions. We herein demonstrate that bicyclic nonaflates generated from 8-heterobicyclo[3.2.1]octan-3-one derivatives can be coupled with aryl or alkenyl boronic acids in a very efficient manner. The resulting densely functionalised bicyclic skeletons are highly suitable for further synthetic elaboration. The thermal Suzuki couplings provided the expected products in moderate to good yields. Microwave (MW) irradiation dramatically shortened reaction times and gave superior results. Bisboronic ester 19 was also coupled with bicyclic nonaflates, for example, with 14, and double Suzuki-coupling products, such as 22, were isolated in good yields. We demonstrated the great synthetic potential of aryl-substituted 8-heterobicyclo[3.2.1]octene derivatives, such as 15, by the stereoselective conversion of this compound into highly substituted furanose 31 or substituted pyran derivative 33, which were obtained in short and efficient reaction sequences.

Comparative Studies on Conventional and Microwave Assisted Synthesis of Benzimidazole and Their 2-Substituted Derivative with the Effect of Salt Form of Reactant

Benzimidazole and their derivative were reported to have wide biological activities and were synthesized by using different solvents and ring closing agents. The present work deals with the comparative synthesis of 2-alkyl and aryl substituted benzimidazole derivative in the presence of polyphosphoric acid through microwave and conventional methods and also studied the effect of salt form of reactant for completion of the reaction. The 2-substituted aryl and alkyl benzimidazole derivative were synthesized via microwave and was observed to be more beneficial, in respect of yield (increases up to 10 to 50%) and time (96 to 98% was reduced) than conventional method of synthesis. This study was concluded that the salt form of reactant (o-phenylenediamine dihydrochloride) gave reduced colour impurities, homogenous mixing and reduced time for completion of reaction.

Pd(II)-Catalyzed Addition of Boronic Acids to Nitriles

There are rather few reports, concerning the catalytic reaction of organoboron compounds with carbon-heteroatom multiple bonds. Herein, a simple and synthetically useful method for the preparation of ketones from nitriles and arylboronic acids is reported. Several types of nitriles, including alkyl, aryl and heteroaryl derivatives were used in the reaction. Beside arylboronic acids, boroxines and aryltrifluoroborates can also be used with slightly lower product yields. The reaction proceeds under relatively mild conditions and should possess a good functional group compatibility.

Synthesis of Novel Dipyrido-1,4-thiazines

An efficient synthesis of novel type of dipyrido-1,4-thiazine (4) was elaborated in the reactions of two pairs of 3,4-disubstituted pyridines in DMF. The reactions proceeded through the S→N type of the Smiles rearrangement of the resulting 4,4'-dipyridinyl sulfide. In the case of formation of 10-(3'-nitro-4'- pyridinyl)-2,7-diazaphenothiazine (5) double rearrangement was observed. 10H- 2,7-diazaphenothiazine (4) was N-alkylated, N-arylated and N-heteroarylated to give 10-substituted (alkyl, arylalkyl, aryl, heteroaryl and dialkylaminoalkyl) derivatives (5) and (17-29). The NMR spectra were assigned with the help of the 1 H- 1 H correlation (COSY) and NOE experiment of the methyl derivative (17). The crucial 10H-2,7-diazaphenothiazine (4) showed promising anticancer activity.

A Thermoanaerobacter ethanolicus secondary alcohol dehydrogenase mutant derivative highly active and stereoselective on phenylacetone and benzylacetone

The secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus 39E (TeSADH) is highly thermostable and solvent-stable, and it is active on a broad range of substrates. These properties make TeSADH an excellent template to engineer an industrial catalyst for chiral chemical synthesis. (S)-1-Phenyl-2-propanol was our target product because it is a precursor to major pharmaceuticals containing secondary alcohol groups. TeSADH has no detectable activity on this alcohol, but it is highly active on 2-butanol. The structural model we used to plan our mutagenesis strategy was based on the substrate's orientation in a horse liver alcohol dehydrogenase*p-bromobenzyl alcohol*NAD(+) ternary complex (PDB entry 1HLD). The W110A TeSADH mutant now uses (S)-1-phenyl-2-propanol, (S)-4-phenyl-2-butanol and the corresponding ketones as substrates. W110A TeSADH's kinetic parameters on these substrates are in the same range as those of TeSADH on 2-butanol, making W110A TeSADH an excellent catalyst. In particular, W110A TeSADH is twice as efficient on benzylacetone as TeSADH is on 2-butanol, and it produces (S)-4-phenyl-2-butanol from benzylacetone with an enantiomeric excess above 99%. W110A TeSADH is optimally active at 87.5 degrees C and remains highly thermostable. W110A TeSADH is active on aryl derivatives of phenylacetone and benzylacetone, making this enzyme a potentially useful catalyst for the chiral synthesis of aryl derivatives of alcohols. As a control in our engineering approach, we used the TbSADH*(S)-2-butanol binary complex (PDB entry 1BXZ) as the template to model a mutation that would make TeSADH active on (S)-1-phenyl-2-propanol. Mutant Y267G TeSADH did not have the substrate specificity predicted in this modeling study. Our results suggest that (S)-2-butanol's orientation in the TbSADH*(S)-2-butanol binary complex does not reflect its orientation in the ternary enzyme-substrate-cofactor complex.

Simultaneous detection of ascorbate and uric acid using a selectively catalytic surface

The direct and selective detection of ascorbate at conventional carbon or metal electrodes is difficult due to its large overpotential and fouling by oxidation products. Electrode modification by electrochemical reduction of diazonium salts of different aryl derivatives is useful for catalytic, analytical and biotechnological applications. A monolayer of o-aminophenol ( o-AP) was grafted on a glassy carbon electrode (GCE) via the electrochemical reduction of its in situ prepared diazonium salts in aqueous solution. The o-aminophenol confined surface was characterized by cyclic voltammetry. The grafted film demonstrated an excellent electrocatalytic activity towards the oxidation of ascorbate in phosphate buffer of pH 7.0 shifting the overpotential from +462 to +263 mV versus Ag/AgCl. Cyclic voltammetry and d.c. amperometric measurements were carried out for the quantitative determination of ascorbate and uric acid. The catalytic oxidation peak current was linearly dependent on the ascorbate concentration and a linear calibration curve was obtained using d.c. amperometry in the range of 2–20 μM of ascorbate with a correlation coefficient 0.9998, and limit of detection 0.3 μM. The effect of H 2O 2 on the electrocatalytic oxidation of ascorbate at o-aminophenol modified GC electrode has been studied, the half-life time and rate constant was estimated as 270 s, and 2.57 × 10 −3 s −1, respectively. The catalytically selective electrode was applied to the simultaneous detection of ascorbate and uric acid, and used for their determination in real urine samples. This o-AP/GCE showed high stability with time, and was used as a simple and precise amperometric sensor for the selective determination of ascorbate.

Trans‐1‐Sulfonylamino‐2‐isoborneolsulfonylaminocyclohexane Derivatives: Excellent Chiral Ligands for the Catalytic Enantioselective Addition of Organozinc Reagents to Ketones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Electrochemically reduced titanocene dichloride as a catalyst of reductive dehalogenation of organic halides

We have studied a reaction between the reduced form of titanocene dichloride (Cp 2TiCl 2) and a group of organic halides: benzyl derivatives (4-X C 6H 4CH 2Cl, X = H, NO 2, CH 3; 4-X C 6H 4CH 2Br, X = H, NO 2, PhC(O); 4-X C 6H 4CH 2SCN, X = H, NO 2) as well as three aryl halides (4-NO 2C 6H 4Hal, Hal = Cl, Br; 4-CH 3O-C 6H 4Cl). It has been shown that the electrochemical reduction of Cp 2TiCl 2 in the presence of these benzyl halides leads to a catalytic cycle resulting in the reductive dehalogenation of these organic substrates to yield mostly corresponding toluene derivatives as the main product. No dehalogenation has been observed for aryl derivatives. Based on electrochemical data and digital simulation, possible schemes of the catalytic process have been outlined. For non-substituted benzyl halides halogen atom abstraction is a key step. For the reaction of nitrobenzyl halides the complexation of Ti(III) species with the nitro group takes place, with the electron transfer from Ti(III) to this group (owing to its highest coefficient in LUMO of the nitro benzyl halide) followed by an intramolecular dissociative electron redistribution in the course of the heterolytic C Hal bond cleavage. The results for reduced titanocene dichloride centers immobilized inside a polymer film showed that the catalytic reductive dehalogenation of the p-nitrobenzyl chloride does occur but with a low efficiency because of the partial deactivation of the film due to the blocking of the electron charge transport between the electrode and catalytic centers.

Heck Reaction on 1-Alkoxy-1,3-dienes in Ionic Liquids: A Superior Medium for the Regioselective Arylation of the Conjugated Dienic System

α,β-Unsaturated acetals afford, in the presence of the LIC-KOR superbase and of a suitable electrophile, 1-functionalized-1-alkoxybuta-1,3-dienes. These substrates cross couple with aryl derivatives in the presence of a Pd catalyst (Heck conditions) in a regio- and stereoselective mode using different ionic liquids as a solvent.

Cross-Coupling of Organoindium Reagents with Propargylic Esters

The chemistry of organoindium compounds is becoming a useful tool in modern organic synthesis. The method presented herein allows a simple preparation of various allenes, including chiral ones, starting from readily available propargylic esters. Organoindium compounds tolerate a variety of functional groups, therefore the method can be useful for the preparation of functionalized allenes. Aryl, alkenyl and alkynyl indium derivatives are suitable reagents. The process is highly anti-stereoselective, and a good degree of chirality transfer was observed for enantiopure substrates. The reaction proceeds smoothly at room temperature.

Trans‐1‐Sulfonylamino‐2‐isoborneolsulfonylaminocyclohexane Derivatives: Excellent Chiral Ligands for the Catalytic Enantioselective Addition of Organozinc Reagents to Ketones

The catalytic enantioselective addition of different organozinc reagents (such as alkyl and aryl derivatives or in situ generated aryl, allyl alkenyl, and alkynyl derivatives obtained through different transmetallation processes) to simple ketones has been accomplished by using titanium tetraisopropoxide and chiral ligands derived from substituted trans-1-sulfonylamino-2-isoborneolsulfonylaminocyclohexane, producing the corresponding tertiary alcohols with enantiomeric excesses (ee) up to >99 %. A simple and efficient procedure for the synthesis of the chiral ligands used in these reactions is described.