Polymers from a levopimaric acid–acrylonitrile Diels–Alder adduct: Synthesis and characterization

The Diels–Alder adduct of levopimaric acid with acrylonitrile was efficiently prepared from resin acids. Excellent addition reaction yields (ca. 95%) were obtained. The adduct was converted into polyamides by polycondensation with diamines. When the same adduct was subjected to a dehydrodecarboxylation reaction, a novel ketone dinitrile derivative was obtained. This trifunctional product was also converted into polyamides by polycondensation with diamines. When the ketone dinitrile was hydrolyzed in the presence of alkalies and the reaction product was chlorinated, a ketone diacid chloride was obtained. A polyester was synthesized by the polycondensation of the diacid chloride with a diol. The structures of the Diels–Alder adduct, ketone dinitrile derivative, ketone diacid chloride, and polymers were established by means of elemental analysis, IR and NMR spectroscopy, and molecular weight determinations. Both the polyamides and the polyester were low‐molecular‐weight polymers soluble in polar solvents. The thermal behavior of the monomers and polymers was evaluated by thermogravimetric analysis. The thermal studies showed that the polymers were fairly thermostable substances, except the polyester, which appeared to be a substance with good thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6308–6322, 2005     

Sulfone/ester polymers containing pendent ethynyl groups

Sulfone/ester polymers containing pendent ethynyl groups were prepared by multistep and direct routes. Hydroxy-terminated sulfone oligomers(M _n = 2650 and 8890 g/mol) were reacted with diacid chlorides to yield high-molecular-weight polymers. In the multistep route, a pendent bromo group on the polymer was converted to an ethynyl group. In the direct route, the hydroxy-terminated sulfone oligomers were reacted with a stoichiometric amount of 5-(4-ethynylphenoxy)isophthaloyl chloride to yield high polymers. The pendent ethynyl groups on the sulfone/ester polymers were reacted in the 200 to 300°C range to provide branching and crosslinking. The resultant polymers exhibited higher T_gs and better resistance to chloroform than comparable polymers void of ethynyl groups. Films of the cured polymers displayed good mechanical properties. The synthesis and characterization of the monomer, oligomers, and polymers are discussed.     

A Facile Synthesis of 4-(3β -Methoxy-5α-androstan-17β-YL)-3-pyrrolin-2-one

The title compound was prepared in 4 steps from 3β-methoxy-21-hydroxy-5α-pregnan-20-one (1). The required intermediate (4) was obtained using lithium enolate derived from t-butyl acetate. Interesting enough, p-tosyl chloride in pyridine quantitatively converted compound 1 into the α-chloro ketone derivative (2).     

Synthesis of 4-substituted 1,4-benzodiazepine-3,5-diones

Synthetic routes leading to the preparation of 4-substituted 1,4-benzodiazepine-3,5-diones are described. Thus, 2-carbobenzoxyaminobenzoic acid was converted to its p-nitrobenzyl ester (I) and the decarbobenzoxylated product (II) gave, with ethyl α-bromoacetate, N-(2-carboxy p-nitrobenzylate)phenylglycine ethyl ester (III). The latter was hydrogenolyzed to N-(2-car-boxy)phenylglycine ethyl ester (IV), which was coupled with benzylamine to give N-(2-carboxy-benzylamido)phenylglycine ethyl ester (VIa). Saponification of VIa afforded N-(2-carboxy-benzylamido)phenylglycine (VIIa) which was cyclized with DCCI to produce 4-benzyl-2H-1,4-benzodiazepine-3,5(lH,4H)dione (VIIIa). Alternatively, 2-nitro-N-phenylbenzamide (Xb) was reduced to 2-amino-N-phenylbenzamide (XIb) which was converted to N-(2-carboxanih'do)-phenylglycine ethyl ester (VIb). The latter was converted to 4-phenyl-2H-1,4-benzodiazepine-3,5(1H,4H)dione (VIIIb) in an analogous fashion described for VIIIa.     

The synthesis,configuration, and conformation of cis- and trans-3-amino-3,4-dihydro-1-hydroxy-4-methylcarbostyrils and other configurationally related compounds

The cis- and trans-3-amino-3,4-dihydro-1-hydroxy-4-methylcarbostyrils (Ia and Ib) were synthesized by catalytic hydrogenation of erythro- and threo-α-amino-β-(o-nitrophenyl)butyric acid hydrochlorides, IIIa and IIIb, respectively, under acidic conditions. The free bases of IIIa and IIIb were catalytically hydrogenated under neutral conditions to yield the erythro- and threo-α-amino-β-(o-aminophenyl)butyric acids (VIa and VIb), which were converted by acidification to their corresponding lactams, cis- and trans-3-amino-3,4-dihydro-4-methylcarbostyrils, IIa and IIb. The erythro and threo isomers of α-amino-β-(o-nitrophenyl)-butyric acid were prepared and separated by liquid chromatography via a diastereomeric mixture of (V) of methyl α-acetamido-β-(o-nitrophenyl)butyrates. The configurations and conformational assignments of the cyclic hydroxamic acids Ia and Ib were first established by analysis of the proton nmr spectra. In turn, the configurations of the o-nitroaromatic amino acids IIIa and IIIb were assigned as well as the other structurally related compounds (VIa, VIb, IIa and IIb) derived therefrom.     

New Chiral Polyurethane Polymers Based on Functionalized Cyclotriphosphazenes

Abstract

Novel hybrid polymers using chiral phosphaznes were prepared in the following way: Starting from hexachlorocyclofriphosphazene, N₃,P₃,Cl₆, chelating phenolates were introduced by reaction with the corresponding sodium salt. Thus, reaction with two equivalents of atropisomeric binaphtolate yields chiral lb in high yield. Subsequently, p-methoxyphenolates were reacted with the remaining PCl₂, functionality and the p-MeO groups were converted to hydroxy groups [I] to give bifunctional 2a,b. Finally, polyadditions to diisocyanates lead to new cyclolinear polyurethanes 3a,b which were characterized by thermal analysis [2,3]. The T₁₀, is 320 and 240°C for 3a and 3b respectively. In particular, the chifal polymer 3b [α=lll°] may have interesting properties as catalyst support.     

t-Butyl Chloromethyl Ether

A convenient preparation of t-butyl methylthiomethyl ether (2) and its conversion to t-butyl chloromethyl ether (1) are described. Methylthiomethanol (4), which was previously unknown, was isolated as a by-product from the preparation of (2): it is a stable distillable liquid.     

New aromatic benzazole polymers. I. Benzobisthiazole and benzobisoxazole polymers with main-chain triarylamino units

Thermally stable, nonrigid-rod poly(benzobisthiazoles), (R)TPA-PBZT , where R = H, Me, NMe₂, and OH, and poly(benzobisoxazoles), (R)TPA-PBO , where R = Me, NMe₂ containing electron-rich triarylamine groups with various para-substituents (Rs) on the pendent phenyl ring, were synthesized from either 2,5-diamino-1,4-benzenedithiol dihydrochloride or 2,4-diamino-1,5-benzenediol dihydrochloride and the respective triarylamine-based dinitrile or diacid monomer in polyphosphoric acid. Whereas (R)TPA-PBZT polymers were obtained in moderate molecular weights, analogous (R)TPA-PBO polymers were only prepared in low molecular weights. No lyotropic behaviors, characteristic of the unmodified rigid-rod benzazole polymers, as evidenced by the absence of either stir opalescence or birefringence under crosspolarizers, were observed for these homopolymers at about 10 wt % polymer concentration. Among these polymers, only (Me)TPA-PBZT and (NMe₂)TPA-PBZT formed cast films with good mechanical integrity. In their pristine state, their film conductivity values were in the range of 10⁻¹⁰–10⁻⁹ S/cm at room temperature. Upon exposure to iodine vapor, their conductivities were increased to the maximal values of 5.0 × 10⁻⁵ S/cm ( (Me)TPA-PBZT ) and 4.1 × 10⁻⁴ S/cm ( (NMe₂)TPA-PBZT ). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1909–1924, 1997     

Synthesis and characterization of new highly organosoluble poly(etherimide)s derived from 1,1‐bis{4‐[4‐(3,4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane} dianhydride

A new bulky pendent bis(ether anhydride), 1,1‐bis[4‐(4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane dianhydride, was prepared in three steps, starting from the nitrodisplacement of 1,1‐bis(4‐hydroxyphenyl)‐4‐phenylcyclohexane with 4‐nitrophthalonitrile to form bis(ether dinitrile), followed by alkaline hydrolysis of the bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s were prepared from the bis(ether anhydride) with various diamines by a conventional two‐stage synthesis including polyaddition and subsequent chemical cyclodehydration. The resulting poly(ether imide)s had inherent viscosities of 0.50–0.73 dL g^?1. The gel permeation chromatography measurements revealed that the polymers had number‐average and weight‐average molecular weights of up to 57,000 and 130,000, respectively. All the polymers showed typical amorphous diffraction patterns. All of the poly(ether imide)s showed excellent solubility in comparison with the other polyimides derived from adamantane, norbornane, cyclododecane, and methanohexahydroindane and were readily dissolved in various solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, pyridine, cyclohexanone, tetrahydrofuran, and even chloroform. These polymers had glass‐transition temperatures of 226–255 °C. Most of the polymers could be dissolved in chloroform in as high as a 30 wt % concentration. Thermogravimetric analysis showed that all polymers were stable up to 450 °C, with 10% weight losses recorded from 458 to 497 °C in nitrogen. These transparent, tough, and flexible polymer films could be obtained by solution casting from DMAc solutions. These polymer films had tensile strengths of 79–103 MPa and tensile moduli of 1.5–2.1 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2066–2074, 2002     

α,β,γ,δ-四-{4-[3-(9-(4-(3-(9-(4-(2-(5,5-二酰氧基甲基-1,3-二噁烷基))))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基)))苯基-2,4,8,10-四氧杂螺[5.5] 十一烷基]}苯基卟啉星形化合物的合成

以对苯二甲醛、丙二腈、季戊四醇和吡咯为原料, 合成了含有螺环结构单元的中间体3-[4-(2,2-二氰基)乙烯基]苯基-9-(4-甲酰基)苯基-2,4,8,10-四氧杂螺[5.5]十一烷(3)和α,β,γ,δ-四-(4-甲酰基苯基)卟啉(4). 4与过量的季戊四醇反应, 得到α,β,γ,δ-四-{4-[2-(5,5-二羟甲基-1,3-二噁烷基)]}苯基卟啉(5), 5与3的反应产物经10% NaOH 处理后, 再与过量的季戊四醇反应, 得到α,β,γ,δ-四-{4-[3-(9-(4-(3-(9-(4-(2-(5,5-二羟甲基-1,3-二噁烷基))))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基)))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基]}苯基卟啉(6), 6与乙酐、丙酐、苯甲酰氯反应, 得到α,β,γ,δ-四-{4-[3-(9-(4-(3- (9-(4-(2-(5,5-二乙酰氧基甲基-1,3-二噁烷基))))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基)))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基]}苯基卟啉(7), α,β,γ,δ-四-{4-[3-(9-(4-(3-(9-(4-(2-(5,5-二丙酰氧基甲基-1,3-二噁烷基))))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基)))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基]}苯基卟啉(8)和α,β,γ,δ-四-{4-[3-(9-(4-(3-(9-(4-(2-(5,5-二苯甲酰氧基甲基-1,3-二噁烷基))))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基)))苯基-2,4,8,10-四氧杂螺[5.5]十一烷基]}苯基卟啉(9)等三种卟啉星形化合物. 中间体1～6和星形化合物7～9均进行了IR, ¹H NMR, MS和元素分析等结构表征. 对影响反应的诸因素进行了讨论.      

Reactions with samarium diiodide in polymer synthesis

Reactions induced by Sml₂, such as reduction, coupling and cyclization are occurring in high yield upon mild conditions. It is due to the high redox potential of divalent samarium. Now reactions with Sml₂ are used in the polymer synthesis as well. By the coupling reaction of various diacid chlorides poly-α-diketones having molecular weight up to 20000 have been obtained at room temperature in quantitative yield. Isomeric difluorobenzils prepared by the one-step reaction of Sml₂ and relevant fluorobenzoyl chlorides have been used in the nucleophylic substitution reaction with bisphenols. Film-forming high molecular weight copolyetherketone-α-diketones have been synthesized when such difluorobenzils have been used as the comonomers in the polycondensation of 4,4'-difluorobenzophenone and bisphenols. All these polymers bearing α-diketogroups have been transformed into linear and network polyquinoxalines by their reaction with aromatic (bis)o-diamines. Aromatic polypinacols have been synthesized by the reaction of dialdehydes and Sml₂ in THF under mild conditions. The availability of the reactive α-hydroxy groups made it possible to carry out polymer chain reactions. It was stated that the imide cycle is reduced by Sml₂ at room temperature. The treatment of polyimides by Sml₂ leads to the change of polymer properties, mainly heat resistance and solubility. The possibility of formation of Si-Si bonds by reductive coupling of organochlorosilanes with the use of Sml₂ instead of Na has been shown. It was found that the reaction of diorganodichlorosilanes with Sml₂ easily proceeds in THF solution at room temperature to yield α,ω-dichloro-oligosilanes.     

Crystal structure of polyamides containing 1,3-cyclohexane rings

The effect of 1,3-cyclohexane rings in the chain backbone on the crystal structure of polyamides has been studied using polyamides (denoted 1,3-CBMA-n) obtained from 1,3-cyclohexane-bis(methylamine) (1,3-CBMA) and n-carbon dicarboxylic acids. The crystallinity of the 1,3-CBMA-n polymers changes greatly with variation in the value of n. This is attributed to hydrogen-bond changes associated with the relative length of the diacid moiety to the diamine moiety in the monomeric unit of each polymer. In 1,3-CBMA-6, the cis-1,3-cyclohexane rings are readily accommodated in the molecular chains to form crystals in a manner similar to the m-benzene rings in poly(m-xylylene adipamide) (MXD-6). The crystal lattice, however, is more expanded than in MXD-6 since the 1,3-cyclohexane rings is bulkier than the m-benzene ring. The crystal structure of the 1,3-CBMA-n polymers is essentially the same as that of MXD-6.     

Self-regulating polycondensations: Ordered aromatic polyamide-esters

The polycondensation of aminophenols with diacid chlorides was examined to determine if the amide-ester polymers obtained are random or ordered. All of the evidence obtained points to the conclusion that ordered copolymers indeed are prepared and that a “self-regulating” polymerization process is operating by virtue of the considerably greater reactivity of aromatic amino groups relative to phenol groups. The first step of the reaction involves the in situ preparation of a diphenol-amide which undergoes further condensation. The diphenol-amide intermediate may be isolated or reacted in situ. In addition to the ordered polymer from a given aminophenol and a single diacid chloride, ordered copolymers from two different diacid chlorides were prepared in which the diacid moieties appear in an alternating fashion; the structure of such polymers depends on the order of addition of the diacid chlorides. Corresponding polymers also may be prepared from the preformed diphenol-amide monomers. The molecular weights of certain of the polymers were sufficient for the preparation of films which could be hot-stretched severalfold. Interfacial polycondensations gave polymers of higher inherent viscosities than did solution polymerizations when aminophenols or diphenol-amide monomers were condensed with diacid chlorides.     

Polycyclic nitrogen compounds. Part I. Synthesis of new heterotricyclic quinoxalinones with bridgehead nitrogen atoms

New tricyclic quinoxalinone skeletons with a fully-reduced ring ‘C’ -1,2,3,3a-tetrahydropyrrolo[1,2-α]quin-oxalin-4-one (I-II) and 7,8,9,10-tetrahydropyrido[1,2-α]quinoxalin-6-one (III-IV) derivatives were obtained by selective hydrogen transfer reductive cyclisation of N-(2-nitrophenyl)pyrrolidine-2-carboxylic acid esters and N-(2-nitrophenyl)piperidine-2-carboxylic acid esters (VIa,b and VIIIa,b), respectively.     

Komplexe mit sterisch anspruchsvollen liganden XIII. Komplexierung des 1,3-Di-t-butylcyclopentadienyl-Liganden am Eisen,Cobalt und Titan

The reaction of di-t-butylcyclopentadienyllithium Li[η⁵-C₅H₃(CMe₃)₂-1,3], prepared by addition of methyllithium to 2-t-butyl-6,6-dimethylfulvene, with FeCl₂, CoCl₂, and TiCl₃ has been studied. A barrier to ring rotation of ΔG³ 12.6 kcal mol^-1 has been estimated by variable-temperature ¹H NMR spectroscopy for 1,1′,3,3′-tetra-t-butylcobaltocenium ion.     

Self-regulating polycondensations. IV. Ordered oxadiazole-imide copolymers

Ordered oxadiazole-imide copolymers are prepared from simple aminobenzhydrazide monomers by a step-wise reaction which begins with the condensation of a diacid chloride to produce in situ a diamine containing hydrazide linkages. The in situ diamine is then reacted with a dianhydride to yield an ordered hydrazide-amic-acid copolymer; this precursor is converted by heating to the ordered heterocycle copolymer. Polymers prepared via this manner are identical in properties to those obtained by the reaction of a dianhydride with a diamine containing hydrazide linkages preformed by a straight forward synthesis from a dinitro precursor. Fibers spun from the soluble precursor polymers were converted via cyclodehydration to thermally stable fibers. Another polyoxadiazole-imide was produced in similar fashion; e.g., an aminobenzhydrazide was reacted with the acid chloride of trimellitic anhydride to yield an in situ AB monomer which was polymerized to yield a precursor polyhydrazide-amic-acid, which in turn was converted by cyclodehydration to an AB type polyoxadiazole-imide. Additional examples are cited of the formation of polymers from the in situ intermediates produced by the “self-regulating” reaction of aminobenzhydrazides with acid chlorides followed by polycondensation with difunctional monomers.     

Donor-Acceptor Complexes in Copolymerization. XLIV. Copolymerization of Styrene and α-Methylstyrene with Acrylic and α-Substituted Acrylic Esters in the Presence of Aluminum Compounds

Abstract

The copolymerization of styrene (S) with methyl acrylate (MA) and with methyl methacrylate (MMA) in the presence of AlEt₃ yields equimolar, alternating copolymers while no polymer is formed in α-methylstyrene (MS)-MA and MS-MMA systems. In the presence of AlEt_1.5Cl_l,5 (EASC), S-MA and S-MMA yield alternating copolymers, S-methyl a-chloroacrylate (MCA), MS-MA and MS-MMA yield a mixture of alternating and cationic polymers, and MS-MCA yields cationic polymer only. In the presence of A1C1₃, S-MA and MS-MA yield a mixture of alternating and cationic polymers and S-MMA and MS-MMA yield cationic polymer only. The cotacticity distributions of the alternating S-MA and S-MMA copolymers prepared in the presence of AlEt₃, EASC, and A1C1, are the same; the coisotactic, co-heterotactic, and cosyndiotactic fractions being approximately in the ratio 1:2:1. The cosyndiotactic fractions of the alter-nating copolymers prepared in the presence of EASC are in the order MS-MMA > MS-MA > S-MCA > S-MMA=S-MA.     

Synthesis,spectroscopic investigation and molecular structure of pentacarbonyl-5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo[3.3.01,5]octanechromium(0)

The compound pentacarbonyl-5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo-[3.3.0^1,5]octanechromium(0) was prepared in good yield by the reaction of 5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo[3.3.0^1,5]octane with Cr(CO)₆ in THF under UV-irradiation. The crystal and molecular structure was determined from three-dimensional X-ray data. The crystals are monoclinic, space group P2₁/c. The unit cell, with dimensions a 14.963(9), b 10.026(5), c 13.565(5)Å, β 114.68°(5), contains 4 molecules. The structure was solved by the Patterson-method. The full-matrix refinement with the 2734 independent reflexions gave a final R value of 0.034. The eight-membered ring adopts an asymmetric boat-boat conformation with a tin-nitrogen bond lenght of 2.40 Å; the tin-chromium bond length is 2.62 Å.     

A New and Efficient Synthesis of α-Amino Cycloalkyl-Phosphonic Acids via Electrophilic Azidation of Cycloalkylphosphonates

α-Amino cyclobutyl-, cyclopentyl-and cyclohexylphosphonic acids (13) were efficiently prepared from the related unsubstituted cycloalkylphosphonates (5), in three steps including electrophilic azidation of the corresponding lithiated carbanions, catalytic hydrogenation of the intermediate α-azido cycloalkyl-phosphonates (10) and acidic hydrolysis of the resulting α-amino cycloalkyl-phosphonates (12).     

Synthesis and characterization of tetra-armed-thiosemicarbazone and its salen/salophen capped transition metal complexes: Investigation of their thermal and magnetic properties

In this work, we aimed to synthesize and characterize a novel tetra-directional ligand, (2E,2′E)-2,2′-((((2-(1,3-bis(4-((E)-(2-carbamothioylhydrazono)methyl)phenoxy)propan-2-ylidene)propane-1,3-diyl)bis(oxy))bis(4,1-phenylene))bis(methanylylidene))bis(hydrazinecarbothioamide) (5), including thiosemicarbazone group and its novel tetra-directional-tetra-nuclear Schiff base complexes. For this purpose, we used 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) as starting material. 4,4′-((2-(1,3-Bis(4-formylphenoxy)propan-2-ylidene)propane-1,3-diyl) bis(oxy))dibenzaldehyde (3) was synthesized by the reaction of an equivalent 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) and 4 equivalents of 4-hydroxybenzaldehyde. Then, compound 5 was synthesized in high yield (86%) by a condensation reaction of compound 3 with thiosemicarbazide (4). Finally, four novel tetra-nuclear Cr(III) or Fe(III) complexes of compound 5 were synthesized. The synthesized compounds were characterized using elemental analyses, ¹H NMR, Fourier transform–infrared spectrometry, liquid chromatography–mass spectrometry (ESI⁺), and thermal analyses. The metal ratios of the prepared complexes were determined using an atomic absorption spectrophotometer. We also investigated their effects on the magnetic behaviors of [salen, salophen, Cr(III)/Fe(III)] capped complexes. The complexes were found to be low-spin distorted octahedral Fe(III) and distorted octahedral Cr(III), all bridged by thiosemicarbazone.