3a 3f Research Articles

Synthesis and characterization of optically active poly(amide-imide)s based on [N,N′-(4,4′-carbonyldiphtaloyl)-bis-lamino diacid]s and 1,5-bis(4-aminophenyl)penta-1,4-dien-3-one

Six dicarboxylic acids 3a–3f were synthesized by the reaction of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride 1 with L-aminoacids 2a–2f in a solution of glacial acetic acid/pyridine (Py) at refluxing temperature. Then six new poly(amide-imide)s PAIs were synthesized from the direct polycondensation reaction of [N,N′-(4,4′-carbonyldiphtaloyl)-bis-L-amino diacid]s with 1,5-bis(4-aminophenyl)penta-1,4-dien-3-one (APPD). The polymerization reactions produced a series of new optically active PAIs with high yield and good inherent viscosity. Also these PAIs are optically active and soluble in various organic solvents. These resulting new polymers can be used in column chromatography for the separation of enantiomeric mixtures. The resulted polymers were fully characterized by means of FTIR and 1H-NMR spectroscopy, elemental analyses, inherent viscosity measurements, solubility tests and thermogravimetric analysis (TGA).

Thiosemicarbazone platinacycles with tertiary phosphines. Preparation of novel heterodinuclear platinum–tungsten complexes

Treatment of thiosemicarbazones (R1C6H4)C(H)NN(H)C(S)NHR2 [R1,R2: 4-Me,H (a); 4-Me,Me (b); 4-Me,Et (c); 2-Me,H (d); 2-Me,Me (e); 2-Me,Et (f)] with cis-[PtMe2(cod)] afforded the tetranuclear platinum(II) compounds [Pt{(R1C6H3)C(H)NNC(S)NHR2}]4 (1a–1f) with the ligand as terdentate [C,N,S] after C–H activation and NH deprotonation. The reaction of 1a–1f with PPh3 in 1:4M ratio gave the mononuclear compounds [Pt{(R1C6H3)C(H)NNC(S)NHR2}(PPh3)] (2a–2f). Treatment of 1a–1f with large-bite diphosphines Ph2P(CH2)nPPh2 (n=2, dppe; n=3, dppp; n=4, dppb) afforded the dinuclear compounds [{Pt[(R1C6H3)C(H)N–N=C(S)NHR2]}2{μ-Ph2P(CH2)nPPh2}], (3a–3f, 4a–4f, 5a–5f), with the diphosphine in a bridging mode. Similar reactions with the short-bite diphosphines Ph2PCH2PPh2 (dppm) and Ph2PC(CH2)PPh2 (vdpp) yielded the mononuclear compounds [Pt{(R1C6H3)C(H)NNC(S)NHR2}(Ph2PR3PPh2-P)] (R3=CH2, 6a–6f; R3=C=CH2, 7a–7f) with the diphosphine in a monodentate coordination. Treatment of 1a–1f with [W(CO)5(Ph2CH2PPh2)] gave the heterodinuclear species [{Pt[(R1C6H3)C(H)NNC(S)NHR2]}{Ph2CH2PPh2W(CO)5}] (8a–8f). The molecular structures of compounds 3e and 5c have been determined by X-ray crystal structure analysis.

Synthesis and evaluation of fluoroethyl cyclofenil analogs: Models for potential estrogen receptor imaging agent

Cyclofenil analogs (2a–2f) and their fluorine-containing derivatives (3a–3f) were synthesized and evaluated as candidate ligands for positron emission tomography (PET) imaging of estrogen receptors. Most of them show relatively high binding affinities comparable with estradiol (E2). (4-Fluoroethoxyphenyl)-(4-hydroxyphenyl) methylenecyclopentane (3a) showed both the highest binding affinity for ERs (88.6 for ERβ, 13.8 for ERα) and highest β/α ratio (β/α for 6.4-fold). The radioactive compound [18F]3a was prepared via displacement of the corresponding mesylate precursor 4 with [18F]fluoride (18F: β+; 96.7%, T1/2=109.8min). The biodistribution studies in immature female SD rats demonstrated that the uptake in the uterus and ovaries were 1.358±0.089%ID/g, 1.439±0.214%ID/g, respectively, both of the ratios of uterus/blood and ovaries/blood was less than 2:1. Micro-PET imaging of immature female SD rats has also been reported.

Antimicrobial and anticancer effects of some 2-(substitutedsulfanyl)-N-(5-methyl-isoxazol-3-yl)acetamide derivatives

In the present study, some isoxazole-(benz)azole derivatives (3a–3j) were synthesized by considering antimicrobial and anticancer potencies of azole compounds. Chemical structures of obtained compounds (3a–3j) were confirmed by the data of spectral and elemental analyses. Anticancer activity evaluation was performed at two steps. Initially, cytotoxic effects of the compounds (3a–3j) on HT-29 (colon carcinoma) and C-6 (melanoma) cell lines were determined by MTT assay. Secondly, the compounds 3g–3i, which indicated significant cytotoxicity were selected and analysed for their inhibitory activity on DNA synthesis of carcinogenic cells. The compounds 3g and 3h showed notable DNA synthesis inhibition on both cancer cell lines. Antibacterial and antifungal activities of the synthesized compounds (3a–3j) were also examined. All of the compounds exhibited very poor antibacterial activity against gram negative and gram positive bacterial strains, whereas antifungal activity of the compounds 3a–3f was equal to that of Ketoconazole.

Synthesis and structure elucidation of novel fused 1,2,4-triazine derivatives as potent inhibitors targeting CYP1A1 activity

Synthesis and structure elucidation of new series of novel fused 1,2,4-triazine derivatives 3a–3f, 4a–4i and 6a–6b and their inhibitory activities are presented. Molecular structures of the synthesized compounds were confirmed by 1H NMR, 13C NMR, MS spectra and elemental analyses. X-ray crystallographic analysis was performed on 2-acetyl-8-(N,N-diacetylamino)-6-(4-methoxybenzyl)-3-(4-methoxy-phenyl)-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 3d and 2-acetyl-8-(N-acetylamino)-6-benzyl-3-(4-chlorophenyl)-3-methyl-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 4e to secure their structures. The inhibitory effect of these compounds toward the CPY1A1 activity was screened to determine their potential as promising anticancer drugs. Our data showed that compounds 4e, 5a, 5b and 6b possess the highest inhibitory effects among all tested compounds. Furthermore, analysis of triazolotriazine derivatives docking showed that these compounds bind only at the interface of substrate recognition site 2 (SRS2) and (SRS6) at the outer surface of the protein. Amino-acids ASN214, SER216 and ILE462 participate in the binding of these compounds through H-bonds.

Fundamental study of (ferrocenylethynyl)phosphines: Correlation of steric and electronic effects in C,C cross-coupling reactions

Complexes [Pd(Cl)(μ-Cl)(P(CCFc)R2)]2 (Fc = (η5-C5H4)(η5-C5H5); 6e, R = tBu; 6f, R = cC6H11) and [PdCl2(P(CCFc)R2)2] (7a, R = C6H5; 7b, R = 2-MeC6H4; 7c, R = 2,4,6-Me3C6H2; 7d, R = cC4H3O; 7e, R = tBu; 7f, R = cC6H11) are accessible by the reaction of P(CCFc)R2 (3a–f) with either [PdCl2(cod)] (5) (cod = cyclo-1,5-octadiene) or [PdCl2(SEt2)2] (8). The spectroscopic, mass-spectrometric and cyclovoltammetric data of 6 and 7 were investigated and the structures of four complexes (6e, 6f, 7b, 7c) in the solid state determined. Complexes 7a–f are mononuclear with palladium in a square-planar environment and show a cis- (7b) or trans-configuration (7c) with linear FcCCP moieties in the solid state. In contrast, 6e and 6f are forming dimers with a planar Pd2P2Cl2(μ-Cl)2 core with the ferrocenylethynyl ligands positioned above and below this plane. Electrochemical studies of phosphines 3a–3f and the appropriate seleno phosphines 4a–4f show after oxidation follow-up reactions, while a reversible behavior is found for the corresponding palladium complexes 6 and 7. UV–Vis/NIR and IR spectro–electrochemical measurements of 7f indicate moderate electronic interactions between the ferrocenyl units. All complexes are catalytically active in Heck (reaction of iodo benzene with tert-butyl acrylate) and Suzuki (2-bromo toluene or 4′-chloro acetophenone with phenyl boronic acid) C,C cross-couplings. The influence of the electronic (1J(31P–77Se)) and the steric (Tolman cone angle) properties of the phosphine ligands on the activity of the respective palladium catalysts will be discussed.

Designing nickel phthalocyanine periphery by alkyl chain via [1,3,4]-oxadiazole

Nickel phthalocyanine (NiPc, 1) periphery has been decorated by alkyl chains of varying chain length via [1,3,4]-oxadiazole moiety (NiPcs 3a–3f). All the newly synthesized compounds NiPcs 3a–3d have been completely characterized by elemental analysis, FT-IR, solid-state UV-Vis, and solid-state 13C NMR spectroscopy, in addition to X-ray diffraction, scanning electron microscopy, and thermal analysis. The effect of chain length in the NiPc periphery on electronic absorption and DC electrical conductivity has been investigated.

Synthesis and Spectral Characterization of Some Novel Thiazolyl-Pyrazoline Derivatives Containing 1,2,3-Triazole Moiety

A series of novel 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-(4-aryl-2-thiazoyl)-pyrazolines 6a–6r were synthesized using 2-aryl-4-formyl-1,2,3-triazoles 1a,b as the starting materials. Thus, reacting 1a,b with 1-arylethanones 2a–2c gave 1-aryl-3-(2-aryl-1,2,3-triazol-4-yl)-2-propen-1-ones 3a–3f. The reaction of the latter with thiosemicarbazide afforded 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-thiocarbamoyl-pyrazolines 4a–4f, which condensed with 2-bromo-1-arylethanones 5a–5c to afford the target compounds 6a–6r. The chemical structures of the compounds were verified by means of their IR, 1H NMR, ESI-MS spectroscopic data, and elemental analysis.Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.GRAPHICAL ABSTRACT

Novel Disubstituted Phenylene‐Linked Bis‐imidazole Derivatives: Facile Synthesis and Optical Properties

AbstractSix novel disubstituted phenylene‐linked bis‐imidazole derivatives, 3a–3f, were prepared by a one‐pot, microwave‐assisted method under solvent‐free conditions, in yields ranging from 61.6 to 85.6%. The new compounds were characterized by 1H‐ and 13C‐NMR, UV/VIS, and fluorescence spectroscopy, and mass spectrometry, as well as by elemental analyses. The influence of substituents and solvents on the optical properties of 3a–3f was investigated. It was found that there is little influence on absorption and excitation spectra in contrast to emission spectra. Compounds 3a–3f exhibit strong fluorescence in solution, their fluorescence quantum yields ranging from 0.27 to 0.96.

Synthesis, Cytotoxicity and Antibacterial Studies of Novel Symmetrically and Nonsymmetrically 4‐(Methoxycarbonyl)benzyl‐Substituted N‐Heterocyclic Carbene–Silver Acetate Complexes

AbstractFrom the reaction of 1H‐imidazole (1a), 4,5‐dichloro‐1H‐imidazole (1b), 1H‐benzimidazole (1c), 1‐methyl‐1H‐imidazole (1d), and 1‐methyl‐1H‐benzimidazole (1f) with methyl 4‐(bromomethyl)benzoate (2), symmetrically and nonsymmetrically 4‐(methoxycarbonyl)benzyl‐substituted N‐heterocyclic carbene (NHC) precursors, 3a–3f, were synthesized. These NHC precursors were then reacted with silver(I) acetate (AgOAc) to yield the NHC–silver acetate complexes (acetato‐κO){1,3‐bis[4‐(methoxycarbonyl)benzyl]imidazol‐2‐ylidene}silver (4a), (acetato‐κO){4,5‐dichloro‐1,3‐bis[4‐(methoxycarbonyl)benzyl]‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver (4b), (acetato‐κO){1,3‐bis[4‐(methoxycarbonyl)benzyl]‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl}silver (4c), (acetato‐κO){1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver (4d), (acetato‐κO){4,5‐dichloro‐1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver (4e), and (acetato‐κO){1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl}silver (4f), respectively. The three NHC–AgOAc complexes 4a, 4c, and 4d were characterized by single‐crystal X‐ray diffraction. All compounds studied in this work were preliminarily screened for their antimicrobial activities in vitro against Gram‐positive bacteria Staphylococcus aureus, and Gram‐negative bacteria Escherichia coli using the qualitative disk‐diffusion method. All NHC–AgOAc complexes exhibited weak‐to‐medium antibacterial activity with areas of clearance ranging from 4 to 7 mm at the highest amount used, while the NHC precursors showed significantly lower activity. In addition, NHC–AgOAc complexes 4a and 4b, and 4d–4f exhibited in preliminary cytotoxicity tests on the human renal‐cancer cell line Caki‐1 medium‐to‐high cytotoxicities with IC50 values ranging from 3.3±0.4 to 68.3±1 μM.

Synthesis of 5‐(6‐Pyridazinone‐3‐yl)‐2‐glycosylamino‐1,3,4‐thiadiazoles

AbstractN‐Glycosyl‐2‐(1,4,5,6‐tetrahydropyridazin‐6‐one‐3‐carbonyl)‐hydrazinecarbothioamides (3a‐3f) and N‐glycosyl‐2‐(1,6‐dihydropyridazin‐6‐one‐3‐carbonyl)‐hydrazinecarbothioamides (5a‐5f) were prepared by the reaction of glycosyl isothiocyanates with the compounds 1,4,5,6‐tetrahydro‐3‐hydrozinecarbonyl‐6‐pyridazinone (1) and 1,6‐dihydro‐3‐hydrozinecarbonyl‐6‐pyridazinone (2). The terminal heterocyclic compounds 1,3,4‐thiadiazoles derivatives were obtained from cyclization of compounds 3a–3f and 5a–5f by phosphoric acid. The structures of all the compounds were confirmed by elemental analysis and IR, 1H NMR, LC‐MS (ESI) spectral data.

Synthesis and property of 9,9′-spirobifluorene-containing aromatic polyesters as optical polymers with high refractive index and low birefringence

C2-Symmetric 9,9′-spirobifluorene-containing polyesters (PEs) were synthesized by polycondensation of 2,2′-dihydroxy-9,9′-spirobifluorene (1) with bis(acyl chloride)s (2) at 230 °C in diphenylether. The molecular weights of PEs 3a–3f were sufficiently high (Mw 13,400–41,600). PEs displayed high thermal stability. The glass transition temperatures (Tg) estimated by differential scanning calorimetry analysis appeared in a range 177–352 °C depending on the spacer structure, while the 5% decomposition temperatures (Td5) measured by thermogravimetric analysis were over 416 °C both under nitrogen atmosphere and in air. PEs showed good solubility in typical organic solvents such as CHCl3 and THF easily to afford the tough, transparent, and flexible cast films. The transmittance of the polymer films reached over 90% in the wavelength range from ca. 410–900 nm. In addition, PEs exhibited higher refractive index rather than that of commercially available 9,9-diarylfluorene-containing PE, in addition to very low degree of birefringence presumably due to the C2-symmetric structure.

Synthesis and calming activity of helicid derivatives containing the 3,4-dihydropyrimidin-2(H)-one and 3,4-dihydropyrimidine-2(H)-thione moiety

A series of novel helicid derivatives containing 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidine2(1H)-thione moiety (3a–3f and 4a–4f) were synthesized starting from helicid. The structure of the new compounds were characterized by 1H NMR, IR and HR-MS spectra. The sedative-hypnotic activities of the target compounds were evaluated using the test of spontaneous locomotor activity in mice. All of the derivatives produced moderate to high activities; in particular, compound 4a presented the most potent sedative-hypnotic effect in comparison to the other derivatives, and derivatives 3a, 3c, 3d, 3e and 3f also showed potent activities.

Better Performance of Monodentate P‐Stereogenic Phosphanes Compared to Bidentate Analogues in Pd‐Catalyzed Asymmetric Allylic Alkylations

AbstractThe cationic allylpalladium complexes 3a–3f, 4a, 4e, 5e of type [Pd(η3‐2‐Me‐C3H4)P2]PF6 were synthesized using a group of monodentate P‐stereogenic phosphanes, P=PPhRR′ (a–f) and diphosphanes (PhRPCH2)2 (1a, 1e) or PhRPCH2Si(Me)2CH2PPhR (2e). The analogous cationic complexes with the disubstituted allyl group (η3‐1,3‐Ph2‐C3H3) and monodentate phosphanes were not isolated as stable solids; only [PdCl(η3‐1,3‐Ph2‐C3H3)P] (6a, 6d) were obtained. Palladium allyl complexes were screened as precatalysts in the allylic substitution of rac‐3‐acetoxy‐1,3‐diphenyl‐1‐propene (I) and (E)‐3‐acetoxy‐1‐phenyl‐1‐propene (III) with dimethyl malonate as the nucleophile. The various catalytic precursors showed a wide range of activity and selectivity. The bismonodentate phosphane complexes 3 are more active than the bidentate analogues. With regard to the regioselectivity, precursors containing monodentate phosphanes favour the formation of the linear product in the allylic substitution of cinnamyl acetate (III) compared with those containing bidentate phosphanes. With substrate I, compounds with the diphosphanes 1a and 1e, containing a five‐membered chelate ring, gave low enantioselectivities (less than 10 % ee), but those with the diphosphane 2e, forming a six‐membered chelate ring or with two monodentate phosphanes, afforded products with moderate enantioselectivity under standard conditions (ee up to 74 %). The results show that the performance of precursors containing monodentate phosphanes was superior to those containing bidentate ligands in both activity and selectivity.

Design, synthesis and anti-Parkinsonian evaluation of 3-alkyl/aryl-8-(furan-2-yl)thiazolo[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine-2(3H)-thiones against neuroleptic-induced catalepsy and oxidative stress in mice

A series of 3-alkyl/aryl-8-(furan-2-yl)thiazolo[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine-2(3H)-thiones (3a–3f) were synthesised in good yield and evaluated for their anti-Parkinsonian and neuroprotective potential. The structures of the synthesised compounds were confirmed on the basis of their spectral data and elemental analysis. All of the compounds were found to be active in haloperidol-induced catalepsy and oxidative stress in mice. The most active compound carried a propyl group at the 3-position of the thiazolotriazolopyrimidine nucleus while substitution with a phenyl ring produced the least active compound among the series. A computational study was carried out for the prediction of pharmacokinetic properties and none of the compounds violated Lipinski’s rule of five, making them potentially promising agents for the treatment of Parkinson’s disease.

Optically active and flame-retardant poly(amide-imide)s based on phosphine oxide moiety and N,N′-(pyromellitoyl)bis-l-amino acid in the main chain: Synthesis and characterization

Six new optically active and flame-retardant poly(amide-imide)s PAIs 5a–5f containing phosphine oxide moiety as a flame-retardant unit in the main chain were synthesized from direct polycondensation reaction of six chiral N,N′-(pyromellitoyl)-bis-L-amino acid 3a–3f with bis(3-aminophenyl)phenyl phosphine oxide 4 in a medium consisting of N-methyl-2-pyrrolidone (NMP), triphenyl phosphite (TPP), calcium chloride (CaCl2) and pyridine. The polymerization reactions produced a series of optically active poly(amide-imide)s with good yield and good inherent viscosity of 0.34–0.70 dLg−1. The resulted polymers were fully characterized by means of FTIR and 1H-NMR spectroscopy, gel permeation chromatography (GPC), elemental analyses, inherent viscosity and solubility tests. Thermal properties and flame-retardant behavior of the PAIs 5a–5f were investigated using thermal gravimetric analysis (TGA and DTG) and limiting oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yield in TGA and good LOI values indicated that the resulting polymers were capable of exhibiting good flame retardant properties. N,N′-(pyromellitoyl)-bis-L-amino acids 3a–3f were prepared in quantitative yields by the condensation reaction of pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylicacid-1,2,4,5-dianhydride) 1 with L-alanine 2a, L-valine 2b, L-leucine 2c, L-isoleucine 2d, L-phenyl alanine 2e and L-2-aminobutyric acid 2f in acetic acid solution.

An Efficient Synthesis of Novel Hexahydropyrido[2,3‐d]pyrimidine Derivatives from (Arylmethylidene)pyruvic Acids (=(3E)‐4‐Aryl‐2‐oxobut‐3‐enoic Acids) in Aqueous Media

Abstractmagnified imageA series of new hexahydropyrido[2,3‐d]pyrimidine derivatives 3 were synthesized by the cyclocondensation reaction of (arylmethylidene)pyruvic acids (=(3E)‐4‐aryl‐2‐oxobut‐3‐enoic acids) 1 and 6‐aminouracils (=6‐aminopyrimidine‐2,4(1H,3H)‐diones) 2 in H2O under reflux conditions (Scheme 1, Table). This novel protocol has the advantages of facility, of easy workup, of high yields, and of an environmentally benign procedure. The structures of compounds 3a–3f were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS). A plausible mechanism for the reaction is proposed (Scheme 2).

Metabolic Stress Induces the Lysosomal Degradation of Neuropilin-1 but Not Neuropilin-2

The neuropilins-1 and -2 (NRP1 and NRP2) function as receptors for both the semaphorins and vascular endothelial growth factor. In addition to their contribution to the development of the nervous system, NRP1 and NRP2 have been implicated in angiogenesis and tumor progression. Given their importance to cancer and endothelial biology and their potential as therapeutic targets, an important issue that has not been addressed is the impact of metabolic stress conditions characteristic of the tumor microenvironment on their expression and function. Here, we demonstrate that hypoxia and nutrient deprivation stimulate the rapid loss of NRP1 expression in both endothelial and carcinoma cells. NRP2 expression, in contrast, is maintained under these conditions. The lysosomal inhibitors chloroquine and bafilomycin A1 prevented the loss of NRP1 expression, but proteasomal inhibitors had no effect. The hypothesis that NRP1 is degraded by autophagy is supported by the findings that its expression is lost rapidly in response to metabolic stress, prevented with 3-methyladenine and induced by rapamycin. Targeted depletion of NRP2 using small hairpin RNA revealed that NRP2 can function in the absence of NRP1 to mediate endothelial tube formation in hypoxia. Studies aimed at assessing NRP function and targeted therapy in cancer and angiogenesis should consider the impact of metabolic stress.

Synthesis and bioassay of improved mosquito repellents predicted from chemical structure

Mosquito repellency data on acylpiperidines derived from the U.S. Department of Agriculture archives were modeled by using molecular descriptors calculated by CODESSA PRO software. An artificial neural network model was developed for the correlation of these archival results and used to predict the repellent activity of novel compounds of similar structures. A series of 34 promising N-acylpiperidine mosquito repellent candidates (4a-4q') were synthesized by reactions of acylbenzotriazoles 2a-2p with piperidines 3a-3f. Compounds (4a-4q') were screened as topically applied mosquito repellents by measuring the duration of repellency after application to cloth patches worn on the arms of human volunteers. Some compounds that were evaluated repelled mosquitoes as much as three times longer than N,N-diethyl-m-toluamide (DEET), the most widely used repellent throughout the world. The newly measured durations of repellency were used to obtain a superior correlation equation relating mosquito repellency to molecular structure.

Thermally stable and organosoluble binaphthylene‐based poly(urea‐ether‐imide)s: one‐pot preparation and characterization

AbstractA new family of wholly aromatic poly(urea‐ether‐imide)s (4a–4f) possessing binaphthylene‐twisted rings was prepared by diphenyl azidophosphate (DPAP)‐activated one‐pot polyaddition reaction of a preformed imide heterocyclic ring‐containing dicarboxylic acid, 2,2′‐bis(4‐trimellitimidophenoxy)‐ 1,1′‐binaphthyl (1) with various kinds of aromatic diamines (3a–3f). At first, with due attention to structural similarity and to compare the characterization data, a model compound 2 was synthesized by the reaction of diimide‐dicarboxylic acid 1 with two mole equivalents of aniline. In this direct method, the polymers were prepared by polyaddition reactions of the in situ‐formed diisocyanate with the aromatic diamines. Molecular weights of the poly(urea‐ether‐imide)s obtained were evaluated viscometrically, and the inherent viscosities (ηinh) measured were in the range 0.10– 0.25 dl/g. All of the polymers were characterized by FT‐IR spectroscopic method and elemental analysis. All of the resulting polymers exhibited an excellent solubility in common polar solvents such as N‐methyl‐2‐pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N‐dimethylformamide (DMF), and N,N‐dimethylacetamide (DMAc). Crystallinity of the resulted polymers was evaluated by wide‐angle X‐ray diffraction (WXRD) method, and they exhibited nearly a non‐crystalline nature as evidenced by their diffractograms. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry (DSC) thermograms were in the range of 274–302°C. The temperatures at 10% weight loss (Td10%) from their thermogravimetric analysis (TGA/DTG) curves were found to be in the range of 389–414°C in nitrogen atmosphere. Copyright © 2008 John Wiley & Sons, Ltd.