Synthesis of Photoactive Polyureas Derived from 4-(4-Dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione and Diisocyanates

Summary 4-(4-Dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) was prepared from 4-dimethylaminobenzoic acid in five steps. The reaction of monomer DAPTD with n-isopropylisocyanate was performed at room temperature in N,N-dimethylacetamide (DMAc) solution and the resulting bis-urea derivative was obtained in high yield and was finally used as a model compound for polymerization reaction. The step-growth polymerization reactions of monomer with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and toluene-2,4-diisocyanate (TDI) were performed in DMAc solution in the presence of pyridine, triethylamine or dibutyltin dilurate as catalysts. Some physical properties and structural characterization of these novel polyureas are reported. Fluorimetric studies of the model compound as well as polymers were performed.     

Synthesis and characterization of new polyureas based on 4‐(4′‐aminophenyl)urazole and various diisocyanates

4‐(4′‐Aminophenyl)urazole (AmPU) was prepared from 4‐nitrobenzoic acid in six steps. The reaction of monomer AmPU with n‐isopropylisocyanate was performed in N,N‐dimethylacetamide solutions at different ratios, and the resulting disubstituted and trisubstituted urea derivatives were obtained in high yields and were finally used as models for polymerization reactions. The step‐growth polymerization reactions of AmPU with hexamethylene diisocyanate, isophorone diisocyanate, and toluene‐2,4‐diisocyanate were performed in N‐methylpyrrolidone solutions in the presence of pyridine as a catalyst. The resulting novel polyureas had inherent viscosities of 0.11–0.18 dL/g in dimethylformamide at 25°C. These polyureas were characterized with IR, ¹H‐NMR, elemental analysis, and thermogravimetric analysis. Some physical properties and structural characterization of these novel polyureas are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2692–2700, 2003     

Microwave‐assisted rapid polycondensation reaction of 4‐(4′‐acetamidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione was reacted with 1 mol of acetyl chloride in dry N,N‐dimethylacetamide (DMAc) at ?15°C and 4‐(4′‐acetamidophenyl)‐1,2,4‐triazolidine‐3,5‐dione [4‐(4′‐acetanilido)‐1,2,4‐triazolidine‐3,5‐dione] (APTD) was obtained in high yield. The reaction of the APTD monomer with excess n‐isopropylisocyanate was performed at room temperature in DMAc solution. The resulting bis‐urea derivative was obtained in high yield and was finally used as a model for the polymerization reaction. The step‐growth polymerization reactions of monomer APTD with hexamethylene diisocyanate, isophorone diisocyanate, and tolylene‐2,4‐diisocyanate were performed under microwave irradiation and solution polymerization in the presence of pyridine, triethylamine, or dibutyltin dilaurate as a catalyst. Polycondensation proceeded rapidly, compared with conventional solution polycondensation; it was almost completed within 8 min. The resulting novel polyureas had an inherent viscosity in the range of 0.07–0.17 dL/g in dimethylformamide or sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and thermogravimetric analysis. The physical properties and structural characterization of these novel polyureas are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2103–2113, 2004     

Solid-State Polymerization of 4-(4-Dimethylaminophenyl)-urazole with Diisocyanates

In the present study, the solid-state thermal polymerization of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) with diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and toluylene-2,4-diisocyanate as a new method for synthesis of polyureas are described. The influence of reaction parameters, such as presence of catalyst in the starting material and ratio of DAPTD to diisocyanate were investigated. Polycondensation was successfully preceded without any solvent, which is used in conventional method. The resulting polyureas were obtained in high yields with inherent viscosities ranging from 0.14 to 0.25 dL/g. This method was also compared with two other polycondensation methods for the polymerization reactions which were reported before: conventional solution method and a method using tetrabutylammonium bromide as a molten ionic liquid media.     

Polymerization of 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( 1 ) was reacted with 1,8‐naphthalic anhydride ( 2 ) in a mixture of acetic acid and pyridine (3 : 2) under refluxing temperature and gave 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( NIPTD ) ( 3 ) in high yield and purity. The compound NIPTD was reacted with excess n‐propylisocyanate in N,N‐dimethylacetamide solution and gave 1‐(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐triazolidine‐3,5‐dione ( 4 ) and 1,2‐bis(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐ triazolidine‐3,5‐dione ( 5 ) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate ( HMDI ), isophorone diisocyanate ( IPDI ), and tolylene‐2,4‐diisocyanate ( TDI ) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic‐aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06–0.20 dL g^?1 in conc. H₂SO₄ or DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2861–2869, 2003     

Synthesis and characterization of new polyureas derived from 4‐(4′‐Methoxyphenyl)urazole

4‐(4′‐Methoxyphenyl)urazole (MPU) was prepared from 4‐methoxybenzoic acid in five steps. The reaction of monomer MPU with n‐isopropylisocyanate was performed at room temperature in N,N‐dimethylformamide solution, and the resulting bis‐urea derivative was obtained in high yield and was finally used as a model for polymerization reaction. The step‐growth polymerization reactions of monomer MPU with hexamethylene diioscyanate, isophorone diioscyanate, and toluene‐2,4‐diioscyanate were performed in N,N‐dimethylacetamide solution in the presence of pyridine as a catalyst. The resulting novel polyureas have an inherent viscosity (η_inh) in a range of 0.07–0.21 dL/g in DMF and sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and TGA. Some physical properties and structural characterization of these novel polyureas are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1141–1146, 2002     

Synthesis of novel azo‐containing polyureas derived from 4‐[4′‐(2‐hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione ( HNAPTD ) ( 1 ) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both N? H of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, ¹H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate ( HMDI ) and isophorone diisocyanate ( IPDI ) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate ( TDI ) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL^?1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001     

Synthesis of new polyureas derived from 4‐cyclohexylurazole

4‐Cyclohexylurazole (1) R = cyclohexyl (CHU) was prepared from cyclohexyl isocyanate in two steps. Polycondensation reactions of compound CHU with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and toluene‐2,4‐diisocyanate (TDI) were performed in DMAc/chloroform and DMAC in the presence of pyridine as a catalyst. The resulting novel polyureas have an inherent viscosity in the range of 0.044–0.206 g/dL in DMF at 25°C. These polyureas were characterized by IR, ¹H–NMR, elemental analysis, and TGA. The resulting polymers are soluble in most organic solvents. Some physical properties and structural characterization of these novel polyureas are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1335–1341, 2001     

Synthesis,characterization, and properties of novel aromatic polyamides containing phthalazinone moiety

A unsymmetrical and kink non-coplanar heterocyclic dicarboxylic acid monomer, 4-[4-(4-carboxy phenoxy)-naphthyl]-2-(4-carboxyphenyl)phthalazin-1-one (3) was successfully synthesized with high purity and high yields. A series of novel polyamides containing phthalazinone were prepared from the newly synthesized dicarboxylic acid with various aromatic diamines by means of the phosphorylation polycondensation reaction. Molecular weights of the obtained polyamides were evaluated viscometrically, and the inherent viscosities (η_inh) measured were in the range 0.54–0.69 dL/g. These polyamides were amorphous and readily soluble in many organic solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimetheylformamide, dimethyl sulfoxide, pyridine, and m-cresol etc., and they could easily be solution-cast into transparent, flexible films with good mechanical properties, with tensile strength ranging from 63.9 to 81.6 MPa and elongation at break from 7.2 to 11.4%. These polymers still kept good thermal stability with high-glass transition temperatures in the range of 283–338 °C, and the decomposition temperature in nitrogen for a 10% weight-loss temperatures in excess of 490 °C, and char yield at 800 °C in nitrogen ranged from 56 to 63%. Furthermore, the polyamides films were essentially colorless; their cut-off wavelengths were between 365 and 379 nm.     

Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment

In this study, a new class of highly soluble poly(amide-ester-imide)s (PAEI)s contains poly(ethyleneglycol) (PEG) as hydrophilic and soft segment were prepared. Poly(ethylene glycol)-bis-(N-trimellitylimido-4-phenyl carboxylic acid) (3) as a novel diacid monomer was synthesized via two step. The reaction of poly(ethylene glycol) (PEG 6000) with trimellitic anhydride chloride yield poly(ethylene glycol)-bis-trimellitic anhydride (1). The reaction of dianhydride 1 with p-aminobenzoic acid (2) produces novel diacid monomer 3. The direct polycondensation technique of the diacid 1 with several aromatic diamines was carried out in pyridine/N-methyl-2-pyrrolidone/triphenylphosphite/CaCl₂ as condensing agent. The resulting novel PAEIs with inherent viscosities ranging between 0.21 and 0.42 dl g⁻¹, were obtained in good yield. This group of polymers exhibit excellent solubility in a variety of organic solvents and water. All of these polymers were characterized with FT-IR spectroscopy. Thermal properties, ¹H-NMR and XRD study of these PAEIs were also reported. The results demonstrate that this polymers show crystalline structure as well as high thermal stability. In addition the effect of PEG length on solubility and thermal properties of the polymers were also studied.     

A novel and green method for polycondensation reaction of 4-substituted phenylurazoles with different diisocyanates under solvent-free conditions

In this investigation, a new method for step-growth polymerization reactions of 4-phenylurazole ( PHU ) and 4-(4-methoxyphenyl)urazole ( MPU ) with various diisocyanates were developed under solvent-free conditions. The reaction of these monomers with hexamethylene diisocyanate ( HMDI ), isophorone diisocyanate ( IPDI ), and tolulyene-2,4-diisocyanate ( TDI ) were performed in the presence or absence of dibutyltin dilaurate ( DBTDL ) as a catalyst. The results of polymerization revealed that DBTDL did not have considerable effect on the polymerization process. The resulting polyureas showed good yields and moderate inherent viscosities ranging of 0.17–0.30 dL/g in N,N-dimethylformamide (DMF) at 25°C. They are soluble in most polar organic solvents. All of the above polymers were characterized by ¹H-NMR, FTIR spectroscopy, and thermogravimetric analysis (TGA). This method was compared with the polymerization reaction in N,N-dimethylacetamide as a solvent via solution polymerization. Under solvent-free conditions, higher yields and inherent viscosities were obtained. In addition, in this method we do not need to use any solvents and the polymerization reaction can be classified as a green and environmentally friendly method. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Organosoluble, Low-Colored Fluorinated Polyimides Based on 1,1-Bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane

A novel trifluoromethyl-substituted bis(ether amine) monomer, 1,1-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane, was synthesized that led to a series of novel fluorinated polyimides via chemical imidization route when reacted with various commercially available aromatic tetracarboxylic dianhydrides. These polyimides were highly soluble in a variety of organic solvents such as N-methyl-2-pyrrolidone and N,N -dimethylacetamide, and most of them could afford transparent, low-colored, and tough films. These polyimides exhibited glass-transition temperatures (T _gs) of 227–269 °C and showed no significant decomposition below 500 °C under either nitrogen or air atmosphere. These polyimides had low dielectric constants of 2.87–3.17 at 10 kHz, low water uptake of 0.13%–0.58%, and an ultraviolet-visible absorption cutoff wavelength at 364–410 nm. For a comparative study, a series of analogous polyimides based on 1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane were also prepared and characterized.     

Design,synthesis, antibacterial and antifungal activity of novel spiro-isoxazolyl bis-[5,5′]thiazolidin-4-ones and spiro-isoxazolyl thiazolidin-4-one-[5,5′]-1,2-4 oxdiazolines

The synthesis of novel isoxazolyl 1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h) and isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h) analogs is described. Reaction of N-1-\{3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl}-2-chloroacetamide (2) with aryl isothiocyanates yielded 3,3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl-2-(arylimino)-1,3-thiazolan-4-ones (3). Cyclocondensation of 3 with mercaptoacetic acid furnished novel isoxazolyl-1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h). Cycloaddition of 3 with benzonitrile oxides afforded novel isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h). Compounds 4a–h and 5a–h showed significant biological activity against all the standard strains.     

Novel Optically Active Poly(amide-imide)s Derived from N-Trimellitylimido-L-Isoleucine and Different Diisocyanates

Summary  A new class of optically active poly(amide-imide)s was synthesized via direct solution polycondensation of different aliphatic and aromatic diisocyanates with a chiral diacid monomer. The polymerization of N-trimellitylimido-L-isoleucine (TMIIL)(1) as an aromatic-aliphatic diacid monomer with 4,4’-methylenebis(phenyl isocyanate) (MDI)(2) was carried out by graduate heating as well as refluxing method in the presence of pyridine (Py), dibutyltin dilaurate (DBTDL), triethylamine (TEA) as a catalyst and without catalyst, respectively. In these solution polycondensations we used amino acids as chiral inducing agents. The optimized polymerization conditions of MDI were used for the polymerization of isophorone diisocyanate (IPDI)(3), tolylene-2,4-diisocyanate (TDI)(4), and hexamethylene diisocyanate (HDI)(5). The resulting polymers have inherent viscosities in a range of 0.17–0.48 dL/g. These polymers are optically active, thermally stable and soluble in amide type solvents.     

Synthesis and characterization of new optically active and photolable poly (amide-imide)s from N,N ′-(3,3′,4,4′-benzophenonetetracarboxylic)-3,3′,4,4′-diimido-di-L-methionine and different diamines

Summary N,N^′-(3,3^′,4,4^′-benzophenonetetracarboxylic)-3,3^′,4,4^′-diimido-di-L-methionine (3) was prepared from the reaction of 3,3^′,4,4^′-benzophenonetetracarboxylic-3,3^′,4,4^′-dianhydride (1) with L-methionine (2) in a solution of (glacial acetic acid/pyridine) at refluxing temperature. The phosphorylation polycondensation of the diimide-diacid monomer (3) with 1,3-phenylenediamine (4a), 1,4-phenylenediamine (4b), 2,6-diaminopyridine (4c), 3,5-diaminopyridine (4d), 4,4^′-diaminobiphenyl (4e) and 4,4^′-diaminodiphenylsulfone (4f) was carried out in N-methyl-2-pyrolidone (NMP). The resulting poly (amide-imide)s showed admirable moderate inherent viscosities (0.23–0.48 dl g^-1), good thermal stability and improved optical activity. All of the above compounds were fully characterized by IR spectroscopy, elemental analysis and specific rotation. Some structural characterization and physical properties of these new poly (amide-imide)s are presented.     

Synthesis of novel 2,3-condensed thieno[2,3- d ]pyrimidin-4-ones via Appel's salt chemistry

The chemistry of imino-1,2,3-dithiazoles possessing a thiophene ring with various alkyl and aromatic diamines was investigated in the expectation of obtaining novel 2,3-condensed thieno[2,3-d]pyrimidinone derivatives. Obtained via Appel's salt's (1) chemistry, methyl N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-2-thiophenecarboxylate (2) is confirmed as a very interesting starting material for access to a variety of novel thiophene bioisosters of bioactive pentacyclic tetraaza-pentaphene-5, 8-diones.     

Synthesis and characterization of novel pyridine‐based polyureas with enhanced solubility and high thermal stability

The main aim of this study was the preparation of modified polyureas with improved thermal stability and solubility. Accordingly, a series of aromatic/aliphatic pyridine‐based polyureas was synthesized from the reaction of a novel diamine (DA) with different diisocyanates, including 4,4′‐diphenylmethane diisocyanate, toluene diisocyanate, 1,5‐naphthalene diisocyanate, and isophorone diisocyanate, by a solution polymerization route. The DA monomer was prepared via a two‐step reaction. The nucleophilic substitution reaction of oxydianiline with 6‐chloronicotinoylchloride led to the preparation of a diamide dichloro compound, and the subsequent reaction of this compound with 4‐aminophenol resulted in the preparation of the DA. After polymerization, the structural characterization and physical properties of the polymers were examined. The resulting polymers were soluble in common polar aprotic solvents, and they showed improved thermal stabilities in comparison with common polyureas. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of functionlization of N,N-dibenzyldithiocarbamate: synthesis,spectral and structural studies on bis(N-benzyl-N-(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) and bis(N-benzyl-N-(4-cholrobenzyl)dithiocarbamato-S,S′)cadmium(II) and their use for the preparation of MS (M = Zn,Cd)

Bis(N-benzyl-N-(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) (1) and bis(N-benzyl-N-(4-chlorobenzyl)dithiocarbamato-S,S′)cadmium(II) (2) have been prepared and characterized by elemental analysis, IR and NMR (¹H and ¹³C) spectroscopy and single-crystal X-ray analysis. Complexes 1 and 2 exist as monomer and dimer, respectively. Crystal structures of 1 and 2 confirm the presence of four coordinated zinc in a distorted tetrahedral arrangement and five coordinated cadmium in a distorted square pyramid arrangement, respectively. Both the complexes are further stabilized by various interactions such as C–H···S, C–H···N, C–H···O and C–H···π (chelate). C–H···O interaction leads to the formation of dimer in complex 1. In complex 2, C–H···π (chelate) interaction runs in opposite directions which results in the polymeric chain. ZnS and CdS have been prepared from 1 and 2, respectively, and characterized by powder X-ray diffraction, SEM, UV–Vis and fluorescence spectroscopy. The X-ray diffraction pattern confirms the wurtzite phase of as-prepared ZnS and CdS.     

Synthesis and characterization of a novel kind of thermotropic liquid crystalline poly(urea-ester)s based on bis(4′-hydroxyphenyl)-tolyene-2,4-diurea

A new diphenol monomer bis(4′-hydroxy-phenyl)-tolyene-2,4-diurea was synthesized by reaction of 2,4-toylene diisocyanate with p-aminophenol in N,N-dimethylformamide (DMF). The product was characterized by elemental analysis (EA), differential scanning calorimetry (DSC), and ¹H-NMR. And a novel kind of liquid crystalline poly(urea-ester)s were obtained by using this monomer. By using a polarizing microscope with hot stage (POM), wide-angle X-ray diffraction (WAXD) and small-angle X-ray diffraction (SAXD) the polymers were proven to be nematic liquid crystal. The result of DSC showed that the effect of the monomer composition on the melting point of poly(urea-ester)s was significant. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 577–583, 2001     

Cyclodehydration reactions of methyl 9,10-; 10,12-; and 9,12-dioxostearates with 1,2-diaminoethane under ultrasonic irradiation

Reaction of methyl 9,10-dioxostearate (1) and 9,12-dioxostearate (2) with 1,2-diaminoethane under concomitant ultrasonic irradiation (10–15 min, 60°C) in water furnished the corresponding 2,3-dihydropyrazine (4, 79%) and 1,2,3,4-tetrahydro-1,4-diazocine (5, 70%) derivatives, respectively. Reaction of methyl 10,12-dioxostearate (3) with 1,2-diaminoethane was successful only when glacial acetic acid was used instead of water under ultrasonic irradiation (4×10 min, 70°C) to give a 2,3-dihydro-1H-1,4-diazepine (6, 95%) derivative. The structures of these novel six-membered (4), seven-membered (6), and eight-membered (5) N-heterocyclic fatty ester derivatives were confirmed by a combination of infrared, nuclear magnetic resonance spectroscopic and mass spectral analyses.