Synthesis of 2,5-bis-(Ethynyl) furan Derivatives from 2,5-Furandicarboxaldehyde

A synthesis of the title compounds has been accomplished by conversion of 2,5-furandicarboxaldehyde to the dilithium salt of 2,5-bis-(ethynyl) furan followed by reaction with electrophiles.     

Palladium (II) and platinum (II) complexes with 2,5-dimethylbenzoxazole and 2,5-diphenyloxazole

Some 2,5-diphenyloxazole (PPO) and 2,5-dimethylbenzoxazole (Me₂BO) complexes of palladium (II) and platinum (II) have been prepared and their molar conductivities, i.r. and electronic spectra are reported and discussed. The PPO generally acts as monodentate N-bonded, while the Me₂BO behaves as monodentate O-bonded. The complexes are generally trans-square planar.     

2,5-Diphenyloxazole chromium(III) complexes

Summary Complexes of chromium(III) with 2,5-diphenyloxazole (PPO) of general formula Cr(PPO)_nX₃·m H₂O, where X=Cl^–, Br^–, I^– or NO ₃ ^su– ; n=1–3 and m=0–6, have been prepared and studied by spectroscopic and magnetic methods and by molar conductivity measurements. All the complexes seem to be hexacoordinated, generally with monodentate N-bonded ligand.     

Ether Fission of 2,5-bis(Dialkylamino)hydroquinone Dimethylethers and O-Alkylation of 2,5-bis(Dialkylamino)hydroquinones

In connection with work underway in these laboratories on the total synthesis of Pentacyciic. triterpenes; guitable methods were sought for the introduction of angular methyl groups into preiormed polynuclear systems. A method of some generality was recognized in the work ofNagata³ on the organoaluminum catalyzed conjugate addition of cyanide to α,β-unsaturated ketones and subsequent conversion of the resulting cyano group to the desired angular methyl substttuent. The total synthesis of dl-alnusenone reported^4a earlier from these laboratories has this synthon as its central feature. Another approach that appeared attractive entailed the 1,6-addition ⁵ of cyanide to the dienone 1, available from intermediates already in hand.^4b     

Synthesis and some properties of poly-(2,5-trimethylene benzimidazole) and poly-(2,5-trimethylene benzimidazole hydrochloride)

A polymer, poly(2,5-trimethylene benzimidazole), the first of a new family of nonsymmetrical polymers, was synthesized via an eight-step synthetic route. The polymer, obtained by melt polymerization, is amorphous and in its neutral form behaves as a moderate insulator. It forms 1 : 1 HCl adducts. When cast from formic acid solution, it forms 1 : 1 formic acid adducts. The acid adducts are semiconductors with resistivities in the 10⁶–10⁸ ohm-cm range. Space-charge effects are generated in the adducts as carrier mobility rises.     

The two diastereomers of [3] (2,5) (7,7,8,8-tetracyanoquinodimethano) - [3] (2,5-dimethoxyparacyclophane)

As the first set of stereomeric donor-acceptor cyclophanes with TCNQ as an acceptor, $\text{1}$ and $\text{2}$ were synthesized; their charge-transfer absorptions differ strongly as a consequence of the different donor-acceptor orientation.     

Synthesis of 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione from mucobromic acid

Palladium-catalyzed cross-coupling between 2,5-dimethyl-3-thienylboronic and mucobromic acids under phase transfer catalysis (PTC) conditions gave the expected 3,4-bis(2,5-dimethyl-3-thienyl)-5-hydroxyfuran-2-one in 32% yield. The by-product was 2,2’,5,5’-tetramethyl-3,3’-bithiophene. The oxidation of the obtained hemiacylal with potassium permanganate under PTC conditions afforded 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione in high yield.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2238–2240, October, 2004.     

2,5-Bis-(butyltelluro) thiophene as a convenient precursor for the synthesis of 2,5-bis-(acetylenic) thiophenes

Both symmetrically and unsymmetrically substituted 2,5-bis-(acetylenic) thiophene derivatives were obtained in good yields under mild conditions through palladium-catalyzed cross coupling reaction of 2,5-bis-(butyltelluro) thiophene 2 and terminal alkynes. The methodology represents a general and efficient protocol for carrying out the synthesis of thiophene derivatives with potential biological activities.     

聚(2,5-苯并噁唑)的流变性能

用自制的3-氨基-4-羟基苯甲酸盐酸盐(ABBAH)在多聚磷酸(PPA)中合成聚(2,5-苯并噁唑)(ABPBO),利用衰减全反射红外光谱(ATR-IR)表征了其化学结构.分别用平板流变仪和毛细管流变仪对合成的ABPBO-PPA溶液进行动态和稳态流变测试.结果表明:ABPBO-PPA溶液的储能模量(G ')和损耗模量(G')均随频率升高而增大,且储能模量比损耗模量上升得更快;ABPBO-PPA溶液随温度升高趋于牛顿流体,随浓度升高非牛顿性更显著,ABPBO-PPA溶液表现出强烈的假塑性,并且不同温度下溶液的剪切黏度差值随剪切应力增大而减小.     

Regiodefined substituted poly(2,5-thienylene)s

The polymerization of 3,3″-dialkylterthiophenes overcomes the lack of regiospecificity associated (to some extent) with all the polymerization methods in use, thus allowing the preparation of perfectly regioregular polymers endowed with enhanced electrical and optical properties. Moreover, the larger spacing of the alkyl chains achieved with the insertion of an unsubstituted thiophene unit confers to such regioregular polymers an extraordinary doping stability. Two regiochemically defined alkoxy-substituted terthiophenes were also polymerized and the effects of the effects of the presence and position of the alkoxy group on the polymerization reaction and on the polymer properties are discussed. © 1993 John Wiley & Sons, Inc.     

Cyclophanes—VII : Conformations of [2.2](2,5)furanoparacyclophane,[2.2](2,5)furano(1,4)naphthalenophane and [2.2](2,5)furano(9,10)anthracenophane. perpendicularity of aromatic moieties

Variable temperature NMR spectroscopy was used to study the conformational behavior of [2.2](2,5)furanoparacyclophane (1), [2.2](2,5)furano(1,4)naphthalenophane (2) and [2.2](2,5)furano(9,10)anthracenophane (3). While the method was useful in studying 1, it was not adequate for 2 and 3. Variable temperature UV absorption and fluorescence emission studies provided information on the conformations of 2 and 3. The UV absorption and emission spectra of 1 were blue-shifted relative to their ambient temperature spectra. Those of 2 were not shifted at all and those for 3 were red-shifted. The data is consistent with an anti-orientation of the aromatic rings in 2 both at ambient and low temperture. The aromatic rings in 3 are perpendicular to one another at low temperature and probably at room temperature as well. Exiplex bands were absent in the room temperature emission spectra of 1, 2 and 3 as well as the low temperature spectra of 2 and 3. An exciplex band was observed in the low temperature emission spectrum of 1.     

2,5-Dimethyl-4-(p-alkylbenzyl)pyridines

1,2,5-Trimethyl-4[p-methyl(ethyl, isopropyl) benzyl]-4-piperidole were obtained and converted to the similarly substituted pyridine bases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1642–1645, December, 1970.