Reactions of epoxides derived from internal perfluoroolefins with o-phenylenediamine and 2-aminophenol

The reactions of epoxy derivatives of internal perfluoroolefins with o-phenylenediamine and 2-aminophenol in dioxane gave 23–67% of the corresponding 2,3-bis(perfluoroalkyl)quinoxalines and 2,3-bis(perfluoroalkyl)-2H-1,4-benzoxazin-2-ols, respectively. When N,N-dimethylacetamide was used as a solvent, the main reaction pathway was anionic isomerization of epoxides into ketones which were then converted into 2-perfluoroalkylbenzimidazoles (in the reactions with o-phenylenediamine) or 2-hydroxy-N-perfluoroalkanoylanilines (in the reactions with 2-aminophenol). The reaction of 3,4-epoxydodecafluorohexane with 2-aminophenol in N,N-dimethylacetamide was accompanied by unusual cyclization to afford 2-pentafluoropropanoyl-2-pentafluoroethyl-1,3-benzoxazolidine.     

A route to fluorocontaining N,S-heterocycles via octafluoro-2,3-epoxybutane

The reaction of octafluoro-2,3-epoxybutane 1 with 2-aminothiophenol gave three kinds of novel fluorocontaining N,S-heterocyclic compounds depending on the solvent nature: 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol 2, 2-trifluoromethyl-2-[1-(2-aminophenylthio)-2,2,2-trifluoroethyl]-1,3-benzothiazolidine 6 and 5a,11a-bis(trifluoromethyl)-5a,6,11a,12-tetrahydro-5,11-dithia-6,12-diazanaphthacene 5. Use of the toluene, dioxane, tetrahydrofuran, acetonitrile and dimethoxyethane gave the unexpected dihydrobenzothiazine 2 (RS,SR > RR,SS) in good to moderate yields. In dimethylsulfoxide and N,N-dimethylacetamide, unusual cyclization occurred resulting in benzothiazolidine 6 (RS,SR/RR,SS ∼ 1:1) in moderate yields. Formation of minor 1,1,1,3,4,4,4-heptafluoro-3-(2-aminophenylthio)-2,2-dihydroxybutane 4 which was converted into bis(benzothiazine) 5 was observed in all solvents tested with the exception of toluene and dioxane. The molecular structure of the RS,SR-diastereomer of dihydrobenzothiazine 2, bis(benzothiazine) 5 and the RS,SR-diastereomer of benzothiazolidine 6 has been established by X-ray crystallography.     

Reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol

The reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol in N,N-dimethylacetamide gave 3-(2-aminophenylsulfanyl)-1,1,1,3,4,4,4-heptafluorobutane-2,2-diol. In the reaction of the same compounds in dioxane, 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol was formed as a result of primary attack by the amino group in 2-aminobenzenethiol on the epoxy ring. The same product was obtained by treatment with 2-aminobenzenethiol of 2,3-bis(trifluoromethyl)-2H-1,4-benzoxazin-2-ol which was synthesized from 2,3-epoxyoctafluorobutane and 2-aminophenol.     

The interaction of fluorinated 2-arylhydrazono-1,3-dicarbonyl compounds with o-phenylenediamine

2-Arylhydrazono-3-fluoroaklyl-3-oxo esters react with o-phenylenediamine under neutral conditions to form mainly o-aminoanilides, from which can be obtained 1,5-benzodiazepin-2-ones. Ethyl-2-(benzimidazol-2-yl)-2-(4-methylphenyl)hydrazonoethanoate was isolated also from the reaction of di(tri)fluoromethyl-containing 2-arylhydrazono-3-oxo esters. The reactions of o-phenylenediamine with 1,2,3-triketone 2-arylhydrazones containing alkyl substituents result in the formation of 1-(benzimidazol-2-yl)-1,2-dioxoalkane arylhydrazones, whereas phenylsubstituted analogues afford 2-phenylbenzimidazole. Nickel(II) chelates of N,N′-phenylene-bis(2-arylazo-1,3-aminovinylketones) were obtained from 1,2,3-triketone 2-arylhydrazones and o-phenylenediamine using a template method.     

The first example of a preparative 1,4-perfluoroalkylation using (perfluoroalkyl)trimethylsilanes

Reactions of 2-perfluoroalkylchromones with (perfluoroalkyl)trimethylsilanes proceed as a 1,4-nucleophilic perfluoroalkylation to give 2,2-bis(perfluoroalkyl)chroman-4-ones in high yields after acid hydrolysis. Oxidation of 2,2-bis(trifluoromethyl)-6-methylchroman-4-one with K₂S₂O₈ leads to fluorinated analogs of natural lactarochromal and the corresponding acid.     

Mercury(II) iodide coordination polymers generated from polyimine ligands

A series of new HgI₂ organic polymeric complexes, [Hg₂(L1)I₄]_n (1), [Hg(L2)I₂]_n (2), [Hg(L3)I₂]_n (3), [Hg₂(L4)I₄]_n (4), [Hg(L5)I₂]_n (5), [Hg(L6)I₃](HL6) (6) {L1 = 1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene, L2 = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, L3 = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, L4 = 2,5-bis(2-pyridyl)-3,4-diaza-2,4-hexadiene, L5 = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene and L6 = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene} was prepared from reactions of mercury(II) iodide with six organic nitrogen donor-based ligands under thermal gradient conditions using the branched tube method. All these compounds were structurally characterized by single-crystal X-ray diffraction. The HgI₂ coordination polymers obtained with the ligands L2, L3 and L5 show one-dimensional zig-zag motifs and in these compounds the HgI₂ units are connected to each other by the ligands L2, L3 and L5 through the pyridyl nitrogen atoms. The L1 and L4 ligands in the compounds 1 and 4 act as both a chelating and bridging group. In the compound 6 the ligand L6 acts as a monodentate ligand, resulting form a discrete compound. The thermal stabilities of compounds 1–6 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA).     

Synthesis and characterisation of dialkyltin 2,3-bis(diphenylphosphino)maleic acid adducts

The novel dialkyltin 2,3-bis(diphenylphosphino)maleic acid adducts (R₂Sn)(O,O′-dpmaa) [1a, R = Me; 1b, R = Bu; dpmaa = bis(diphenylphosphino)maleic acid] were synthesised from dpmaa and R₂SnCl₂ or Bu₂SnO. They were fully characterised by elemental analysis, IR- and multinuclear NMR-spectroscopies as well as X-ray crystallography [in the case of 1a as its Ph₂P(O)(CH₂)₂P(O)Ph₂ adduct]. Both were found to be cyclic trimers in the solid state that dissolve in the case of 1b into an equilibrium mixture of oligomers.     

Synthesis and reactions of 2-hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester

2-Hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester (1) was synthesized by the reaction of pentafluoroacetophenone with dimethyl oxalate in the presence of sodium methylate. Subsequently, reactions of compound 1 with aniline, o-phenylenediamine, and o-aminophenol were investigated. In addition, the thermal cyclization of ester 1 was studied and led to the formation of 5,6,8-trifluoro-7-methoxy-4-oxo-4H-chromene-2-carboxylic acid methyl ester (6) due to nucleophilic substitution of the 3-fluoro group. Hydrolysis of compound 1 and subsequent cyclization by treatment with SOCl₂ gave 5-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-furan-2,3-dione (3). Thermal decarbonylation of compound 3 under mild conditions resulted in the formation of 3-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-propene-1,3-dione (4) which dimerized to pyranone 5.     

Synthesis of fluorine containing glycolurils and oxazolines from oxides of internal perfluoroolefins

The reaction of oxides of internal perfluoroolefins 1-3 with urea gave two kinds of novel fluorine containing N-heterocyclic compounds depending on the solvent nature: 1,5-bis(perfluoroalkyl)tetraazabicyclo[3.3.0]octane-3,7-diones 4a-c and 2-amino-5-fluoro-4,5-bis(perfluoroalkyl)-4,5-dihydrooxazol-4-ols 7a-d. Use of polar dimethylsulfoxide, N,N-dimethylacetamide and acetonitrile afforded glycolurils 4a-c in moderate yields. In dioxane, unexpected cyclization occurred resulting in oxazolines 7a-d in high yields. A similar reaction of oxiranes 2, 3 with urea in aqueous dioxane gave mixtures of 4,5-dihydroxy-4,5-bis(perfluoroalkyl)imidazolidine-2-ones 9b, c, glycolurils 4b, c and oxazolines 7b-d. The molecular structure of trans-isomers of oxazoline 7b and imidazolidine 9b has been established by X-ray crystallography.     

Synthesis and properties of Ortho-linked aromatic polyamides based on 4,4′-(2,3-naphthalenedioxy) dibenzoic acid

A novel aromatic dicarboxylic acid monomer, 4,4′-(2,3-naphthalenedioxy)-dibenzoic acid ( 3 ), was prepared by the fluorodisplacement reaction of p-fluorobenzonitrile with 2,3-dihydroxynaphthalene in N,N-dimethylformamide (DMF) in the presence of potassium carbonate followed by alkaline hydrolysis of the intermediate dinitrile. A series of novel aromatic polyamides containing ortho-linked aromatic units in the main chain were synthesized by the direct polycondensation of diacid 3 and a variety of aromatic diamines using triphenyl phosphite and pyridine as condensing agents in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides had inherent viscosities higher than 0.74 and up to 2.10 dL/g. All of these polyamides were soluble in polar solvents, such as NMP, DMF, N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide. Transparent, flexible, and tough films could be cast from their DMAc or NMP solutions. The solvent-cast films had high tensile strengths and moduli. Extensions to break were relatively low, except for the polymers derived from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and 3,4′-oxydianiline, which had elongations of 82 and 62%, respectively. Except for the polyamide based on p-phenylenediamine, all the other polyamides were amorphous in nature. All the polymers are thermally stable to temperatures in excess of 450°C in either air or nitrogen atmosphere. The polymers exhibited glass transition temperatures ranging from 183 to 260°C and decomposition temperatures (10% weight loss) ranging from 462–523°C in air and 468–530°C in nitrogen. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3385–3391, 1997     

Stereoselective Synthesis and Diels-Alder Reactions of (Z)- and (E)-1,2-bis(Phenylthio)-1,3-Butadiene

Bromination of 3-phenylthio-2-sulfolene (2) with N-bromosuccinimide gave 2-bromo-3-phenylthio-2-sulfolene (3) which was converted mainly to 2,3-bis(phenylthio)-2-sulfolene (4) by treatment with sodium phenylthiolate. Thermal desulfonylation of 4 at different temperatures in the presence of a base (DBU) yielded stereoselectively the (Z)- and (E)-1,2-bis(phenylthio)-1,3-butadiene (6). These two geometric isomers could be thermally interconverted. The Diels-Alder reactions of 6 were also investigated. Only the (Z)-diene 6a could undergo the Diels-Alder reaction; the (E)-diene 6b was in situ converted to the Z isomer before undergoing (he Diels-Alder reaction. The reaction of 6a with N-phenylmaleimide gave the cycloaddition product 7 with complete endo selectivity, but under daylight or during chromatography it readily underwent a thioallylic rearrangement to yield 8 with inversion of configuration. The cycloaddition of 6a with methyl acrylate proceeded regiospecifically, but generating a mixture of endo and exo isomers. The endo/exo ratio could be increased by using ZnCl₂ as the catalyst.     

New poly(amide-imide)s syntheses. VIII. Preparation and properties of poly (amide-imide)s derived from 2,3-bis(4-aminophenoxy)naphthalene,trimellitic anhydride,and various aromatic diamines

The new polymer-forming diimide-diacid, 2,3-bis(4-trimellitimidophenoxy) naphthalene (I), was readily obtained by the condensation reaction of 2,3-bis (4-aminophenoxy) naphthalene with trimellitic anhydride. A series of novel aromatic poly (amide-imide)s were prepared by the direct polycondensation of diimide-diacid I with various aromatic diamines using triphenyl phosphite in N-methyl-2-pyrrolidone (NMP)/pyridine solution containing dissolved calcium chloride. The resultant polymers have inherent viscosities in the range of 0.65–1.02 dL/g at 30°C in N, N-dimethylacetamide. These polymers were readily soluble in various organic solvents and could be cast into transparent, tough, and flexible films. Their casting films showed tensile strength at break up to 86 MPa, elongation to break of 5–9%, and initial moduli up to 2.35 GPa. The wide-angle X-ray diffraction revealed that those polymers containing p-phenylene or p-oxyphenylene group are partially crystalline, and the other polymers are evidenced as amorphous patterns. These polymers show a glass transition in the range of 213–290°C in their differential scanning calorimetry (DSC) traces. The thermal stability of the polymers was evaluated by thermogravimetry analysis, which showed the 10% weight-loss temperatures in the range of 508–565°C in nitrogen and 480–529°C in air atmosphere. © 1994 John Wiley & Sons, Inc.     

Michael reaction of indoles with 3-(2′-nitrovinyl)indole under solvent-free conditions and in solution. An efficient synthesis of 2,2-bis(indolyl)nitroethanes and studies on their reduction

Michael reaction of 3-(2′-nitrovinyl)indole with eight 3-unsubstituted indoles on TLC-grade silica gel furnished unsymmetrical bis(indolyl)nitroethanes in 7-12 min under microwave irradiation and in 8-14 h at rt. In contrast, the p-TsOH-catalysed reaction of the nitrovinylindole with the 3-unsubstituted and two 3-substituted indoles in solution under reflux furnished both unsymmetrical and symmetrical bis(indolyl)nitroethanes, the latter resulting from novel tandem Michael addition-elimination-Michael addition reactions. The synthesis of a 2′,3″-bis(indolyl)nitroethane, the precursor core structure of two bioactive marine metabolites, and the reduction of 2,2-bis(3′-indolyl)nitroethane to the corresponding ethylamine, isolated as its N-acetyl derivative, have been achieved. Significantly, attempted hydrolysis of three nitronates, derived from the corresponding bis(indolyl)nitroethanes, with buffered aqueous TiCl₃ has led to the first isolation of oximes (syn/anti-mixture) as the only products.     

Organosoluble optically transparent poly(amide-imide)s based on 2,2-bis [<Emphasis Type="Italic">N</Emphasis>-(3-carboxyphenyl)phthalimidyl]- hexafluoropropane and 2,2-bis [<Emphasis Type="Italic">N</Emphasis>-(4-carboxyphenyl)phthalimidyl]- hexafluoropropane and various aromatic diamines

 Two diimide-dicarboxylic acids, 2,2-bis[N-(4-carboxyphenyl)phthalimidyl]hexafluoropropane (p-I) and 2,2,-bis[N-(3-carboxyphenyl)phthalimidyl]hexafluoropropane (m-I), were prepared by azeotropic condensation of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride and p-aminobenzoic acid or m-aminobenzoic acid at a 1:2 molar ratio in N,N-dimethylacetamide/toluene. Two series of organosoluble and colorless poly(amide–imide)s were synthesized from diimide–diacid p-I or m-I with ten kinds of aromatic diamines by direct polycondensation using triphenyl phosphite and pyridine as condensing agents. The thin films cast from N,N-dimethylacetamide were measured by UV–vis spectroscopy and Macbeth color-eye colorimetery, the cutoff wavelengths of almost all the films were below 400 nm (361–389 nm) and the values of the parameter b* were between 15.31 and 34.72; these polymers are much lighter in color than other analogous polymers. Almost all the polymer were soluble in N-methyl-2-pyrrolodone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide, and some polymers could dissolve in less polar solvents, such as dioxane and tetrahydrofuran, etc. The cast films exhibited yield strengths of 95–131 MPa, tensile strengths ranging from 92 to 130 MPa, elongations at break from 9 to 27%, and initial moduli from 2.1 to 3.3 GPa. The poly(amide–imide)s had glass-transition temperatures between 259 and 328°C and 10%-weight-loss temperatures above 510 °C in nitrogen and air, indicating excellent thermal stability. Received: 25 April 2001 Accepted: 27 June 2001     

Temperature dependent selective synthesis of linear 2-bromo and 2-alkoxyfuro[2,3-b]quinolines: reaction of 3-(2,2-dibromovinyl-)quinolin-2(1H)-ones with alcoholic KOH

Base promoted and temperature dependent reactions of 3-(2,2-dibromovinyl)quinolin-2(1H)-ones have been described. At 50 °C, the cyclization reactions afforded 2-bromofuro[2,3-b]quinolines in good yields. However, at elevated temperature (80 °C) the domino reaction proceeded affording 2-alkoxyfuro[2,3-b]quinolines via cyclization and nucleophilic substitution reactions.     

Reactions of polyfluorinated thietanes: Selective synthesis of 4-R-2,2-bis(trifluoromethyl)thietane-1-S-oxides and 2-substituted 5-fluoro-4-(trifluoromethyl)-2,3-dihydrothiophenes

Oxidation of 4-substituted 2,2-bis(trifluoromethyl)thietanes by m-chloroperoxybenzoic acid results in selective formation of the corresponding S-oxides in 65-86% yield. Oxidation of 4-C₂H₅S-2,2-bis(trifluoromethyl)thietane under mild conditions led to selective formation of 4-C₂H₅SO₂-2,2-bis(trifluoromethyl)thietane, which under more rigorous conditions was selectively converted into trans-4-C₂H₅SO₂-2,2-bis(trifluoromethyl)thietane-1-S-oxide. Reaction of 4-substituted 2,2-bis(trifluoromethyl)thietanes with activated aluminum powder results in a highly selective ring expansion process, producing the corresponding 5-fluoro-4-(trifluoromethyl)-2,3-dihydro-2-alkoxythiophenes in 58-93% yield. These compounds were also prepared in 61-85% yield using a “one-pot” procedure, starting from sulfur, hexafluoropropene and the corresponding vinyl ether without isolation of any intermediates. Both 2-i-C₃H₇O- and 2-t-C₄H₉O- 5-fluoro-4-(trifluoromethyl)-2,3-dihydrothiophenes were converted into 2-fluoro-3-trifluormethylthiophene by reaction with P₂O₅.     

Formation of 2,3-diaminophenazines and their self-assembly into nanobelts in aqueous medium

One-dimensional (1D) nanobelts of several hundred micrometers in length, several hundred nanometers in width and several hundred nanometers in height are obtained by direct mixing of ortho-phenylenediamine (oPD) and FeCl₃ aqueous solution at room temperature. The nanobelts were characterized by elemental analysis, liquid chromatography/mass spectrometry (LC/MS), NMR (¹H and ¹³C), FT-IR, UV-vis, thermogravimetric (TG) and conductivity measurement. The nanobelts are identified as 2,3-diaminophenazine assemblies. The formation of the nanobelts involves two stages: (1) oxidation of oPD by FeCl₃, yielding individual 2,3-diaminophenazine molecules; and (2) self-assembly of the 2,3-diaminophenazine, forming the 1D nanobelts. The nanobelts exhibit fairly high thermal stability and show conductivity at the level of semiconductors.     

5-(N-2-羟乙基)羟乙酰氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺的合成

5-氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(2)在N,N-二甲基乙酰胺中可直接与乙酰氧基乙酰氯反应, 产物再经碱性水解得5-羟乙酰氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(3), 后者再与氯乙醇反应生成5-(N-2-羟乙基)羟乙酰胺基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(1), 经乙二醇甲醚/正丁醇重结晶, 纯度高于99% (HPLC), 反应总收率由39.3% (文献值)提高到55.1%.     

A new class of aromatic polybenzoxazoles containing ortho-phenylenedioxy groups

A series of poly(o-hydroxy amide)s having both ether and ortho-catenated phenylene unit in the main chain were synthesized via the low-temperature solution polycondensation of 4,4^′-(1,2-phenylenedioxy)dibenzoyl chloride and 4,4^′-(4-tert-butyl-1,2-phenylenedioxy)dibenzoyl chloride with three bis(o-aminophenol)s including 4,4^′-diamino-3,3^′-dihydroxybiphenyl, 3,3^′-diamino-4,4^′-dihydroxybiphenyl, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. The poly(o-hydroxy amide)s exhibited inherent viscosities in the range of 0.23-0.96 dl/g. Most of the poly(o-hydroxy amide)s were soluble in polar organic solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP) and could afford flexible and tough films by solution casting. Subsequent thermal cyclodehydration of the poly(o-hydroxy amide)s afforded polybenzoxazoles. However, the polybenzoxazoles were organic-insoluble except for those with the hexafluoroisopropylidene group. The polybenzoxazoles exhibited glass-transition temperatures (T_g) in the range of 200-232 °C by DSC and softening temperatures (T_s) of 250-256 °C by thermomechanical analysis. Thermogravimetric analyses indicated that most polybenzoxazoles were stable up to 500 °C in air or nitrogen. The 10% weight loss temperatures were recorded in the ranges of 546-606 °C in air and 574-631 °C in nitrogen.     

Interaction of 5-Aryl-2,3-dihydrofuran-2,3-diones with Functionally Substituted Hydrazides and Diaminoglyoxal Diphenylhydrazone

The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with cyanoacetylhydrazide, o-(hydrazinocarbonyl)phenylthiourea, and the diphenylhydrazone of diaminoglyoxal leads to the synthesis of the corresponding N-cyanoacetylhydrazides of aroylpyruvic acids, 2-(N-aroylpyruvoylhydrazinocarbonyl)-phenylthioureas, and 5,6-bis(phenylhydrazono)-3-aroylmethylenepiperazin-2-ones. The results of the primary investigation of the biological activity of N-cyanoacetylhydrazides of aroylpyruvic acids are given.