Cross-coupling of E,E-1,4-diiodobuta-1,3-diene with nucleophiles catalyzed by Pd or Ni complexes: a new route to functionalized dienes

E,E-1,4-Diiodobuta-1,3-diene can enter into cross-coupling reactions with carbon- or other element-centered nucleophiles in the presence of Pd or Ni complexes as catalysts. Convenient procedures were developed for the stereoselective synthesis of E,E-1,4-dialkenylbuta-1,3-dienes, dienyl-1,4-bisphosphonates, E,E-1,4-bis(diphenylphosphino)buta-1,3-diene, E,E-1,4-diphenylbuta-1,3-diene, and E,E-1,4-bis(thiophenyl)buta-1,3-diene.     

Synthesis of aromatic polyesters and polyamides by alternating copolymerizations of 1,4-dicarbonyl-1,4-dihydronaphthalene with bezoquinones and benzoquinone diimines

1,4-Dicarbonyl-1,4-dihydronaphthalene ( 1 ) was synthesized by the dehydrochlorination reaction of 1,4-dihydronaphthalene-1,4-dicarbonyl chloride with triethylamine and obtained as its very dilute solution, but it easily polymerized in the concentration as high as 0.1 mol/L to give its polymer. 1 generated in situ by the dehydrochlorination reaction of 1,4-dihydronaphthalene-1,4-dicarbonyl chloride in a deoxygenated toluene polymerized alternatingly with benzoquinones such as 2-dodecylthio-p-benzoquinone, 2,5-di(tert-butyl)-p-benzoquinone, p-benzoquinone, and 2,3-dichloro-5,6-dicyano-p-benzoquinone, and with benzoquinone diimines such as N,N′-diethoxycarbonyl-p-benzoquinone diimine, N,N′-dibenzoyl-p-benzoquinone diimine, and N,N′-diphenyl-p-benzoquinone diimine to give aromatic polyesters and polyamides, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1929–1936, 1998     

Evaluation of a novel metal–organic framework as an adsorbent for the extraction of multiclass pesticides from coconut palm (Cocos nucifera L.): An analytical approach using matrix solid‐phase dispersion and liquid chromatography

We report the synthesis, characterization, and application of [Zn(1,4‐benzenedicarboxylate)(H₂O)₂]_n , Zn(1,4‐benzenedicarboxylate)_0.99(NH₂‐1,4‐benzenedicarboxylate)_0.01(H₂O)₂]_n , [Zn(1,4‐benzenedicarboxylate)_0.95(NH₂‐1,4‐benzenedicarboxylate)_0.05(H₂O)₂]_n , and [Zn(1,4‐benzenedicarboxylate)_0.9(NH₂‐1,4‐benzenedicarboxylate)_0.1(H₂O)₂]_n as sorbents for the extraction of multiclass pesticides from coconut palm. Liquid chromatography with ultraviolet diode array detection was used as the analysis technique, and the experiments were performed at one fortification level (0.1 μg/g). The recoveries were 47–67, 51–70, 58–72, and 64–76% for [Zn(1,4‐benzenedicarboxylate)(H₂O)₂]_n , Zn(1,4‐benzenedicarboxylate)_0.99(NH₂‐1,4‐benzenedicarboxylate)_0.01(H₂O)₂]_n , [Zn(1,4‐benzenedicarboxylate)_0.95(NH₂‐1,4‐benzenedicarboxylate)_0.05(H₂O)₂]_n , and [Zn(1,4‐benzenelate)_0.95(NH₂‐1,4‐benzenedicarboxylate)_0.05(H₂O)₂]_n , and [Zn(1,4‐benzenedicarboxylate)_0.9(NH₂‐1,4‐benzenedicarboxylate)_0.1(H₂O)₂]_n , respectively, with relative standard deviation ranging from 1 to 7% (n = 3). Detection and quantification limits were 0.01–0.05 and 0.05–0.2 μg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.01–10.0 μg/g) with r ² > 0.9991. A direct comparison of [Zn(1,4‐benzenedicarboxylate)_0.9(NH₂‐1,4‐benzenedicarboxylate)_0.1(H₂O)₂]_n with the commercially available neutral alumina showed that [Zn(1,4‐benzenedicarboxylate)_0.9(NH₂‐1,4‐benzenedicarboxylate)_0.1(H₂O)₂]_n was a similar extracting phase for the pesticides investigated.     

A new methodology of annelation of five- and seven-membered heterocycles to quinoxalines

Pyrazolo[3,4-b]-, isoxazolo[4,5-b]-, benzo[2,3]-1,4-diazepino-, and benzo[2,3]-1,4-oxazepinoquinoxalines were prepared by reactions of 2-quinoxalinecarboxaldehyde with 1,2-N,N-, 1,2-N,O and 1,4-N,N- and 1,4-N,O-dinucleophiles.     

N-trimethylsilylpyrroles as dienes in the synthesis of 1,4-dihydronaphthalen-1,4-imines and isoindoles

A convenient, general synthetic method for 1,4-dihydronaphthaIen-1,4-imines via the Diels-Alder addition of benzyne to N-trimethylsilylpyrrole is described. The N-trimethylsilyl protecting group protected the product from secondary benzyne reactions and was easily removed. The use of a 1,3-dipolar reagent to convert 1,4-dihydronaphthalen-1,4-imines to isoindoles via a retro-Diels-Alder sequence is illustrated.     

Syntheses for 2-amino and 2-mercapto-2H-1,4-benzoxazin-3(4H)-one and 2H-1,4-benzothiazin-3(4H)-one as aza and thio analogues of the natural product blepharigenin

2-Amino-2H-1,4-benzoxazin-3(4H)-one 3 , 2-amino-2H-1,4-benzothiazin-3(4H)-one 4 , 2-mercapto-2H-1,4-benzoxazin-3(4H)-one 7 , and 2-mercapto-2H-1,4-benzothiazin-3(4H)-one 8 representing aza and thio analogues of the natural product's aglucone Blepharigenin (2-hydroxy-2H-1,4-benzoxazin-3(4H)-one) from Gramineae and Acantnaceae species have been synthesized for the first time from their 2-bromo precursors 1 and 2 . Attempts to similarly prepare the 4-hydroxy derivatives of 7 and 8 , which would represent new thio analogues of the naturally occurring cyclic hydroxamic acid, 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one, have failed.     

Quinazolincs and 1,4-benzodiazepines. LXXXVI. The synthesis of imidazothienodiazepines and imidazopyrazolodiazepines

The thieno[3,2-e][1,4]diazepin-2-one ( 1a ), the thieno[2,3-e] [ 1,4] diazepin-2-one ( 1b ), the pyrazolo[3,4-e][1,4]diazepin-2-one ( 1c ) and a chloro analog of 1b , compound 1d , were each converted to derivatives of the novel tricyclic ring systems 4H-imidazo[1,5-a]thieno[2,3-f] [1,4]-diazepine, 4Himidazo[1,5a]thieno[2,3f][1,4]diazepine and 4H-imidazo[ 1,5-a]pyrazolo[4,3-f]-[1,4]diazepine. Depending on the substituents desired on the imidazo ring, two different synthetic pathways were employed.     

Influence of stereochemistry on the thermal properties of partially cycloaliphatic polyamides

The effects of the partial substitution of 1,4‐disubstituted cyclohexane monomers for linear aliphatic monomers in polyamides are discussed. More specifically, the relation between the stereochemistry of the cycloaliphatic residues and the thermal properties [melting temperature (T_m) and crystallization temperature (T_cr)] was investigated. For this purpose, two different types of copolyamides were synthesized: in polyamides 12.6, the adipic acid residues were partially replaced by cis/trans‐1,4‐cyclohexanedicarboxylic acid (1,4‐CHDA), whereas in polyamides 4.14, the 1,4‐diaminobutane residues were partially substituted with cis/trans‐1,4‐diaminocyclohexane (1,4‐DACH). For both systems, increasing the degree of substitution of cycloaliphatic residues for linear aliphatic residues resulted in a rise of both T_m and T_cr. This points to the isomorphous crystallization of the linear and cycloaliphatic residues. In contrast to the use of 1,4‐DACH as a comonomer, 1,4‐CHDA residues showed isomerization upon thermal treatment of the polyamides. This isomerization of the cyclohexane residues influenced the thermal properties of the copolyamides. The use of a nonisomerizing cis–trans mixture of 1,4‐DACH exhibited the large influence of the stereochemistry of the cycloaliphatic residues on the T_m of the copolyamides. For both the 1,4‐CHDA‐ and 1,4‐DACH‐based copolyamides, differential scanning calorimetry analysis revealed that recrystallization occurs during melting. This exothermal effect becomes less pronounced with an increasing content of rigid cycloaliphatic residues. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1962–1971, 2002     

Determination of the configuration of substituted 1,4:3,6-dianhydrohexitols by 13C NMR spectroscopy

The configurations of 1,4:3,6-dianhydro-2,5-di-O-mesyl-D -mannitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-D -glucitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-L -iditol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D -mannitol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D -glucitol, 1,4:3,6-dianhydro-2-deoxy-2-iodo-5-O-mesyl-L -iditol, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-D -glucitol and 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-L -iditol were determined by ¹³C NMR spectroscopy, by invoking the field-effect.     

Quantitative estimation of trans-1,4 and cis-1,4 isomers in polychloroprene by high-resolution NMR

In the ¹H-NMR spectrum of polychloroprene dissolved in C₆D₆, the ?CH proton signal was separated into two triplet peaks. These triplet signals were assigned to the ?CH proton in the trans-1,4 and cis-1,4 isomers by measurement of ¹H-NMR spectra of 3-chloro-1-butene and a mixture of trans- and cis-2-chloro-2-butene as model compounds for the 1,2, trans-1,4 and cis-1,4 isomers. In ¹H-NMR spectra (220 Mcps) of polychloroprene dissolved in C₆D₆, two triplet signals were separated completely from which the relative concentrations of trans-1,4 and cis-1,4 isomers could be obtained quantitatively.     

Synthesis of nucleoside analogs of 1,4-oxathiane, 1,4-dithiane,and 1,4-dioxane

The two regioisomers 6-chloro-9-(1, 4-oxathian-3-yl)-9H-purine ( 5 ) and 6-chloro-9-(1,4-oxathian-2-yl)-9H-purine ( 6 ) were obtained when 3-acetoxy-1,4-oxathiane ( 3 ) was subjected to the acid-catalyzed fusion procedure; compound 3 was prepared by a Pummerer reaction with 1,4-oxathiane 4-oxide ( 2 ). The nucleoside analog 6 could he converted into the adenine derivative 7 and 9-(1,4-oxathian-2-yl)-9H-purine-6(1H)thione ( 8 ). The following nucleoside analogs have also been synthesized: 6-chloro-9-(1,4-dithian-2-yl)-9H-purine ( 13 ), 9-(1,4-dithian-2-yl)adenine ( 14 ), 9-(1,4-dithian-2-yl)-9H-purine-6(1H)thione ( 15 ), and 6-chloro-9-(1,4-dioxan-2-yl)-9H-purine ( 18 ).     

Synthesis of some heterocyclic skeletons via organoiron complexes. Crystal and molecular structure of (5a,6,7,8,9,9a-η6-1,4-benzoxathiino[3,2-b]pyridine)(η5-cyclopentadienyl)iron hexafluorophosphate

Synthesis of the heterocyclic skeletons of some biologically active compounds from (η⁶-o-dichlorobenzene)(η⁵-cyclopentadienyrl)iron hexafluorophosphate in a two step procedure is described. Cyclopentadienyliron hexafluorophosphate complexes of 1,4-benzodioxino[2,3-b]pyridine, 1,4-benzoxathiino[3,2-b]pyridine, 10H-pyrido[3,2-b]benzoxazine, benzo[b]naphtho[2,3-e][1,4]dioxin, 4-methylbenzo[b]benzopyran-2-one[7,6-e][1,4]dioxin and benzo[b]anthracen-9,10-diono[1,2-e][1,4]dioxin were isolated and characterized. Upon pyrolytic sublimation of these complexes the free heterocycles were obtained and characterized. (η⁶-1,4-Benzoxathiino[3,2-b]pyridine)(η⁵-cyclopentadienyl)iron hexafluorophosphate crystalizes in the orthothombic system, space group Pbca; the dihedral angle between the planes of outer rings was found to be 176.8 (1).     

Poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate): Influence of stereochemistry of 1,4‐cyclohexylene units on the thermal properties

A series of poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate) (PCCD) samples, characterized by different cis/trans ratio of the 1,4‐cyclohexanedicarbonyl unit, have been synthesized and analyzed by thermogravimetry (TGA), calorimetry (DSC), and X‐ray diffraction (WAXD). The thermal stability results are good and are not affected by the stereochemistry of the 1,4‐cyclohexylene units. On the other hand, the thermal transitions are notably influenced by the cis/trans content. With the increment of the trans content the polymer changes from completely amorphous to semicrystalline material. T_g, T_m, and crystallinity increase. These results suggest that the trans configuration induces a better chain packing and higher symmetry, improving the crystallizability of the samples. The effect of the molecular structure on the thermal properties is analyzed by using a statistical approach. From the effective correlations found between stereochemistry of the C₆ rings and transition temperatures it is possible to extrapolate that the configuration of 1,4‐cyclohexylene ring deriving from 1,4‐cyclohexanedicarboxylic acid or dimethyl 1,4‐cyclohexanedicarboxylate results to be the main element responsible for the thermal properties. This is due to the high rigidity of the 1,4‐cyclohexanedicarbonyl unit with respect to 1,4‐cyclohexanedimethyleneoxy unit, deriving from the diol. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 619–630, 2008     

Thermally stable silarylene-1,3,4-oxadiazole polymers

The effects of incorporating a p-phenylene- (or m-phenylene)-1,3,4-oxadiazole fragment into the backbone of poly[1,4-phenylene(diphenylsilyl)-1,4-phenylene-2,5-(1,3,4-oxadiazole)], which was developed by the authors, was investigated. Bis[(p-carbohydrazidophenyl)]diphenylsilane was copolymerized with dipentachlorophenyl terephthalate or isophthalate to produce the prepolymers poly[N-(p-diphenylsilylbenzoyl)-N′N″-(terephthaloyl)-N″′-(p-benzoyl)dihydrazide] and poly[N-(p-diphenylsilylbenzoyl)-N′,-N″-(isophthaloyl)-N″′-p-(benzoyl) dihydrazide], respectively. The polyhydrazides were converted by thermal dehydration into poly[1,4-phenylene(diphenylsilyl)-1,4-phenylene-(1,3,4-oxadiazole-2,5-diyl)-1,4-phenylene-2,5-(1,3,4-oxadiazole)] and poly[1,4-phenyl-ene(diphenylsilyl)-1,4-phenylene-(1,3,4-oxadiazole-2,5-diyl)-1,3,4-(oxadiazole)]. The new polymers were soluble in organic solvents. Films cast from these solutions exhibited good adhesion to glass and metal surfaces. Thermal analysis showed that the heat stability of all these polymers was about the same and that they were resistant to decomposition when heated in air to about 400°C. The results also indicated that these polymers were somewhat less heat-resistant than samples of poly-[1,4-phenylene(diphenylsilyl)-1,4-phenylene-2,5-]1,3,4-(oxadiazole) synthesized from bis(p-carbohydrazidophenyl)diphenylsilane and bis-(p-carbopentachlorophenoxy-phenyl)diphenylsilane.     

Reaction sites of <Emphasis Type="Italic">N,N′</Emphasis>-substituted <Emphasis Type="Italic">p</Emphasis>-phenylenediamine antioxidants

The geometries of N,N′-diphenylbenzene-1,4-diamine (DPPD), N-phenyl-N′-(1-phenylethyl)benzene-1,4-diamine (SPPD), N-(4-methylpentan-2-yl)-N′-phenylbenzene-1,4-diamine (6PPD), N-propan-2-yl-N′-phenylbenzene-1,4-diamine (IPPD), N-(2-methoxybenzyl)-N′-phenylbenzene-1,4-diamine (MBPPD), and N-phenyl-N′-(2-phenylpropan-2-yl)benzene-1,4-diamine (CPPD) as well as of their dehydrogenation products were optimized by the semiempirical AM1 method. The results support the idea of stable N_B=C_X structures formation during the consecutive dehydrogenation of SPPD, 6PPD, IPPD, and MBPPD antioxidants. The biradicals formed during the second step of dehydrogenation of substituted phenylenediamines might be important for their antioxidant effectiveness. Dedicated to Professor Vladimír Kvasnička, DrSc., in honour of his 65th birthday     

1,4-Dihydro-1λ5,4λ5-[1,4]diphosphinine und ein 1,4-Dihydro-1λ3,4λ3-[1,4]diphosphinin

1,4-Dihydro-1λ⁵,4λ⁵-[1,4]diphosphinines and a 1,4-Dihydro-1λ³,4λ³-[1,4]diphosphinine Reaction of thio- or dithiocarbonic acids with ethinyl amino phosphanes leads to 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine-1,4-disulfides. By this route compounds 4, 7 , and 8 have been prepared. Desulfurization of 4 with tri-n-butylphosphane results in 1,2,4,5-tetraphenyl-1,4-dihydro-1λ³,4λ³-[1,4]-diphosphinine 5 , which can be oxidized with tert-butyl-peroxide to the corresponding dioxide, 6 . From the reaction mixture of phenyl-phenylethinyl diethylamino phosphane and thioacetamide compound 4 and the unsymmetrical 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine 9 were isolated. Properties, nmr, ir and mass spectra of all new products are reported. A mechanism for the formation of 9 is suggested. The results of the X-ray structure determination of 8 and 9 are described.     

A study of the synthesis and some reactions of 3-phenyl-1,4-benzothiazines

Condensation of o-aminothiophenol with 2-bromoacetophenone yields 3-phenyI-1,4-benzo-thiazine hydrobromide, which upon treatment with alkali gave a mixture of 3-phenyl-2H-1,4-benzothiazine (VIIa) and 3-phenyl-4H-1,4-benzothiazine (VIIb). Catalytic hydrogenation led to rearrangement of the benzothiazine (VIIa) to 2-phenyl-2-methyl-2,3-dihydrobenzothiazole (X), while reduction with lithium aluminium hydride resulted in 3-phenyl-2,3-dihydro-4H-1,4-benzothiazine (XVI). The latter was transferred to 3-phenyl-4-aminoalkyl-2,3-dihydro-4H-1,4-benzothiazines (XVII and XVIII).     

Synthesis of difunctional 1,4-dimethyl-1,4-disilacyclohexanes

Transformations of HVinSiCl₂, HVinSi(Me)Cl, HVinSi(Me)Ph, and HVinSi(Me)NEt₂ in the presence of Pt catalyst were studied. In dilute solutions, the reaction gave a mixture of structural and stereoisomers of five- and six-membered disilacyclanes, resulting from intramolecular cyclization of the initially formed linear dimer. In the case of methyl(phenyl)disilacyclane, the structural isomers were separated andtrans-1,4-dimethyl-1,4-diphenyl-1,4-disilacyclohexane was isolated. The reaction of this product with HCl in the presence of AlCl₃ followed by hydrolysis resulted in the synthesis oftrans-1,4-dichloro- andtrans-1,4-dihydroxy-1,4-dimethyl-1,4-disilacyclohexanes. The structures of the structural and stereoisomers synthesized were confirmed by¹H,¹³C, and²⁹Si NMR and IR spectroscopies and mass spectrometry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1734–1738, September, 1999.     

Chlorination of N-acyl Derivatives of p-Aminophenols (Naphthols) and p-Phenylenediamines

The chlorination of N-acyl derivatives of p-aminophenols can provide either N-acyl-2,3,6-trichloro-4-aminophenols or N-acyl-2,3,5,6-tetrachloro-1,4-benzoquinone imines depending on solvent nature, process temperature, and molar ratio initial compound-chlorine. The chlorination of N-acyl-4-amino-1-naphthols affords only N-acyl-2,3-dichloro-1,4-naphthoquinone imines. N,N'-Diacyl-1,4-phenylenediamines give rise on chlorination to a mixture of 2,5-dichloro-, 2,6-dichloro-, and 2,3-dichloro-N,N'-diacyl-1,4-phenylenediamines.     

Chemical interactions between 2-mercaptobenzazoles and π-acceptors

Summary 2-Mercaptobenzazoles (1a–c) interact with several -acceptors such as tetracyanoethylene (TCNE) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL) dicyanomethyleneindane-1,3-dione (CNIND), 2,3-dicyano-1,4-naphthoquinone (DCNQ), 9-dicyanomethylene-2,4,7-trinitrofluorene (DTF), and 2,3-dichloro-1,4-naphthoquinone (DCHNQ)via the formation of charge-transfer (CT) complexes to yield various heterocyclic compounds.

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Chemische Wechselwirkungen zwischen 2-Mercaptobenzazolen und -Akzeptoren

Zusammenfassung Die 2-Mercaptobenzazole1a–c reagieren mit verschiedenen -Akzeptoren wie Tetracyanoethylen (TCNE), 2,3-Dichlor-5,6-dicyano-1,4-benzochinon (DDQ), 2,3,5,6-Tetrachlor-1,4-benzochinon (CHL), Dicyanomethylenindan-1,3-dion (CNIND), 2,3-Dicyano-1,4-naphthochinon (DCNQ), 9-Dicyanomethylen-2,4,7-trinitrofluoren (DTF) und 2,3-Dichlor-1,4-naphthochinon (DCHNQ) unter Ausbildung von charge transfer — Komplexen (CT) zu heterocyclischen Verbindungen.