2-(取代乙炔基)苯甲醛衍生物在有机合成中的应用

作为一类具有特殊结构的重要有机合成中间体，2-(取代乙炔基)苯甲醛衍生物的化学结构是由苯环、取代乙炔基和醛基三部分活性基团构成的共轭体系. 因其具有较高的反应活性，而被广泛的用于构建各种具有新颖结构的苯并碳环或苯并杂环类化合物，如苯并碳环化合物、苯并氮杂环化合物、苯并氧杂环化合物、多元苯并杂环化合物等. 本文综述了2-(取代乙炔基)苯甲醛衍生物在有机合成领域的应用，并对其发展前景进行了展望，为今后2-(取代乙炔基)苯甲醛衍生物在有机合成中的应用提供参考.     

Radikalreaktionen an N-Heterocyclen. V. EPR-Untersuchungen von Nitroxid-Radikalen substituierter 3-Anilino-1,5-diphenyl-pyrazole

Radical Reactions of N-Heterocyclic Compounds. V. ESR-Investigation of Nitroxide Radicals of Substituted 3-Anilino-1,5-diphenyl-pyrazoles The correlation of the e.s.r. splitting constants with the Hammett values for nitroxides from substituted 3-anilino-1,5-diphenylpyrazoles 1a – e and substituted 1,5-diphenyl-3-p-toluidino-pyrazoles 1f – i provides evidence for extensive interannular conjugation between the N¹-benzene ring and the pyrazole ring of these nitroxides. The conjugation between the arylamino group and the pyrazole ring is extensive only in the nitroxides derived from 1f – i . The captodative substituted p-toluidino-nitroxides 2g, h have a better spin distribution than the nitroxide 2i with two electron-donating substituents.     

Synthesis of 3,6-diaryl-1,4,5-thiadiazepines from substituted 2-thiocyano acetophenone and investigation of reaction mechanism

In this work, we have studied the reaction of substituted 2-thiocyanoacetophenone and hydrazine hydrate as a novel and simple pathway for the preparation of the substituted 1,4,5-thiodiazepine ring system. The mechanism of this reaction revealed that in the initial step condensation of hydrazine with carbonyl groups of substituted 2-thiocyanoacetophenons 2a–2f gives the corresponding substituted aromatic dithiocyano azide intermediates which in turn undergo cyclization to1,4,5-thiadiazepines in the presence of hydrazine. This cyclization is a novel method for the preparation of sulfide bond from the reaction of hydrazine and a dithiocyano intermediate. An account of the reaction mechanism is given.     

Non-toxic organic zinc corrosion inhibitors in hydrochloric acid

The efficiency of some substituted N-arylpyrroles as zinc corrosion inhibitors in hydrochloric acid was examined by electrochemical (d.c. and a.c.) and gravimetric methods. The influence of the structure and composition of a molecule on the inhibition characteristics was observed by investigation of the action of the functional group located on the pyrrole ring (-CHO) and at the ortho position of the benzene ring (-H, -Cl, -CH₃). The results have shown that all the organic compounds investigated possess good inhibiting properties. In contrast to most commercial acid corrosion inhibitors, which are highly toxic and very hazardous products, substituted N-arylpyrroles are nontoxic compounds with good environmental characteristics.     

Novel azo dyes derived from phthalimide. Part 2: Dyeing properties and colour fastness on polyester fibres†

The coloration and fastness properties of 18 carbocyclic monoazo disperse dyes bearing a phthalimide ring fused to the aromatic ring of their diazo components have been investigated. In each case, the phthalimidyl nitrogen atom was substituted with either a butyl, sec‐butyl or isopropyl group, while the adjoined phenyl ring bore a substitution pattern typical of commercial colorants. Dye uptake and build‐up onto both conventional and microfibre polyester through exhaustion dyeing were examined: while the expected tendency of greater exhaustion on microfibre was noted, there were few clear trends with respect to dye structure. The nature of the N‐alkyl group made no consistent difference to dye uptake. Attempts to explain the observed percentage exhaustion values by mapping them to calculated partition coefficient or solubility parameter values were unsuccessful. Wash fastness tended to be best for blue dicyano‐substituted derivatives, which may be as a result in part of these substituents promoting hydrolysis of the adjacent phthalimide ring to give more soluble phthalate species. In contrast, the dicyano dyes had relatively poor photostability compared with their unsubstituted analogues.     

The Tautomerism between Ketene Aminals and Amidines

A tautomerie equilibrium between ketene aminals and amidines is disclosed as an electron-donating group is substituted at the para-position of the phenyl ring in 4 .     

Biomimetic Formation of 2‐Tropolones by Dioxygenase‐Catalysed Ring Expansion of Substituted 2,4‐Cyclohexadienones

Substituted 2‐tropolone natural products are found in plants and fungi. Their biosynthesis is thought to occur by ring expansion from a cyclohexadienone precursor, but this reaction has not previously been demonstrated experimentally. Treatment of 6‐hydroxy‐6‐hydroxymethylcyclohexa‐2,4‐dienone with the non‐haem iron(II)‐dependent extradiol catechol dioxygenase MhpB from Escherichia coli results in the formation of the 2‐tropolone ring‐expansion product through a pinacol‐type rearrangement. Three further substituted cyclohexa‐2,4‐dienone analogues were prepared, and treatment of each analogue was found to give the substituted 2‐tropolone ring‐expansion product. This ring expansion could also be effected nonenzymatically by treatment with 1,4,7‐triazacyclononane and FeCl₂. This is a novel transformation for non‐haem iron‐dependent enzymes, and this is the first experimental demonstration of the proposed ring‐expansion reaction in tropolone biosynthesis.     

Identification of a key prenyltransferase involved in biosynthesis of the most abundant fungal meroterpenoids derived from 3,5-dimethylorsellinic acid

Destroying aromaticity: A novel prenyltransferase (Trt2) involved in fungal meroterpenoid biosynthesis was shown to catalyze an unusual aromatic addition reaction onto a fully substituted aromatic ring. The prenylated product serves as a key intermediate in the biosynthesis of the most abundant series of meroterpenoids in fungi.     

Up to 96% Enantioselectivities in the Hydrogenation of Fluorine Substituted (E)‐2,3‐Diphenylpropenoic Acids over Cinchonidine‐Modified Palladium Catalyst

The enantioselective hydrogenation of methoxy‐ and fluorine‐substituted (E)‐2,3‐diphenylpropenoic acid derivatives was studied over cinchonidine‐modified, supported palladium catalysts in the absence and presence of benzylamine as additive. The fluorine substituent in the appropriate position was even more efficient than the methoxy group in increasing the optical purity of the saturated product. High enantioselectivities, up to 96%, were obtained in the hydrogenation of some disubstituted derivatives, unprecedented in the hydrogenation of prochiral unsaturated carboxylic acids over modified heterogeneous catalyst. The best optical purities were reached in the hydrogenation of derivates bearing a para‐substituent on the β phenyl and an ortho‐substituent on the α phenyl ring, respectively. The influence of the substituent on the β phenyl ring was attributed to the increase in the efficiency of the modifier‐substrate interaction by electronic effects or to a decrease in the adsorption strength of the substituted acid over modified surface sites. The beneficial effect of the ortho‐substituent on the α phenyl ring was assumed to be due to the additional interaction of this substituent with the modifier on the surface, its steric hindrance contributing only in a small part to the observed effect. These suggestions were supported by results obtained in the hydrogenations of some methyl‐substituted derivatives.     

香豆素类染料的荧光光谱性能及应用性能研究

研究了9只香豆素类荧光染料(Ⅰ-Ⅶ)的光谱性能和应用性能。香豆素类荧光染料在5’-位有取代基可使最大可见吸收波长和荧光发射波长产生红移;当共轭双键长度增加,可使染料颜色变深(V:544,VI:552)。这9只染料用于涤纶染色有很好的应用性能,差别不大;嗯唑环结构(Ⅰ、Ⅱ、Ⅲ)和喹唑酮结构(Ⅵ)的染料耐光牢度明显好于噻唑环结构(Ⅴ)和咪唑环结构(Ⅶ)的染料。     

Photochemische Reaktionen von Arylglycidethern

Photochemical Reactions of Arylglycidyl Ethers The absorption, fluorescence and phosphorescence spectra, respectively, of arylglycidyl ether 1 correspond to those of other alkyl aryl ethers. Also the photolysis product distribution (λ = 254 nm) is in agreement with a normal ether photolysis. Furthermore, photoinduced epoxy ring opening takes place giving homopolyaddition oligomers and in methanolic solution also CH₃OH addition products. These reactions can be explained using the model of bichromophoric molecules with the ArO-chromophore as donor and the epoxy ring as acceptor. The calculations based on this model are in agreement with the experimental data. In the aromatic nucleus halogene substituted 1 were dehalogenated with high quantum yield (0.25 in the case of bromo substituted compound 1g ). The quantum yields of the ArO-C-bond scission are about 0.08 independently of the aromatic ring substituents. As indicated by sensitization and quenching experiments, respectively, with aromatic hydrocarbons the photo reactions proceed via S₁ state. It was found that phenol quenches the photodegradation of 1 very efficiently. Excited methyl phenyl glycerol ether 5a reacts with phenyl glycidylether 1a in its ground state producing oligomers.     

Synthesis and characterisation of fluorine-containing poly α-esters. II. Thermal and hydroxyl-initiated polymerisation of pentafluorophenyl-substituted anhydrosulphites and anhydrocarboxylates of α-hydroxycarboxylic acids

The use of anhydrosulphite and anhydrocarboxylate derivatives of α-pentafluorophenyl-α-hydroxypropanoic acid as precursors in the formation of fluorine-containing poly α-esters is described. Kinetic studies have enabled the nature of the competing mechanisms to be determined and compared with those occurring in the hydrocarbon analogues. The pentafluorophenyl group markedly enhances the susceptibility of both ring systems to hydroxyl-initiated polymerisation and in the case of the anhydrocarboxylate this is the only viable polymerisation mechanism under the conditions described here. Although polymerisation of the anhydrosulphites is possible, purification of both the phenyl, and especially the pentafluorophenyl substituted monomer, is more difficult than in the case of either alkyl substituted anhydrosulphites or phenyl and pentafluorophenyl substituted anhydrocarboxylates. For this reason anhydrocarboxylate polymerisation represents the preferred route to pentafluorophenyl substituted poly α-esters. The characterisation of the polymers produced is discussed.     

尼龙材料在圆筒形减震器上的应用

简要介绍圆筒形减震器外圈材料由金属改用增强尼龙的过程所产生的问题和解决的办法，并得出橡胶模设计时和尼龙圈相配的模具孔径的设计经验公式：D＝d＋2H×5％－δ（5％为该类产品的收口量）。     

DC electrical conductivity of some oligoazomethines

Six aromatic oligoazomethines were synthesized containing seven benzene rings each. The terminal rings were substituted with different groups, namely, H, Cl, NO₂, OH, OCH₃ and CH₃. The synthesis was carried out by condensing the para‐substituted benzaldehydes with benzidine to give the three‐ring compound, which was then condensed with terephthaldehyde to give the respective seven‐benzene‐ring oligomers. The oligomers were characterized by elemental analysis, electronic spectra, Fourier‐transform infrared and thermal analysis. The oligomers were used to investigate the effects of their molecular structure on their electronic spectra, as well as their thermal, electronic and electrical properties. The different conformers were reported and compared. The DC electrical conductivity variation of oligoazomethines was studied in the temperature range 300–500 K after annealing for 24 h at 100 °C and after doping with 5% I₂. An attempt was made to relate the DC electrical conductivity, electronic properties and thermal properties to the chain length, substituted groups and coplanarity. The fairly low conductivity obtained was attributed to the non‐linearity of the rings in the chain. The different groups (neutral, electron withdrawing or electron donating) attached at the ends of the oligomer showed no influence upon the conductivity of the different oligomers. The action of doping gave almost the same enhancement as that noticed in the case of a long‐chain polymer. The DC electrical conductivity was interpreted using the band energy model. The seven‐benzene‐ring oligomer gave the same DC electrical conductivity as the long‐chain polymer. Copyright © 2004 Society of Chemical Industry     

Cyclic acetals: Synthesis and polymerization

Mixtures of 5‐membered and 6‐membered 2‐vinyl (2‐propenyl or 2‐isopropyl)‐4‐hydroxymethylene or 5‐hydroxy‐substituted cyclic acetals were synthesized by the reaction of aldehydes with glycerol. Reesterification of the hydroxyl group in position 4 or 5 was achieved using methyl methacrylate. The compounds were subjected to radical copolymerization using different initiating systems. Both radical copolymerization and ring cleavage were observed to be dependent on the reaction conditions. The ring cleavage was confirmed on model compounds of 2‐substituted 5‐membered and 6‐membered cyclic acetals without any polymerizable substituent. The rate of the ring opening was measured and compared to the rate of copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2875–2880, 2001     

Polyhydroxy fatty acids and their derivatives from plant oils

A novel process for the industrial production of hydroxylated fatty acids involves epoxidation of plant oils and their derivatives, followed by catalytic epoxy ring opening in the presence of water or other hydrogen donors, such as alcohols, diols, and amines. Depending on the starting material, epoxidation followed by opening of the oxirane ring leads to fatty acids that contain vicinal diol groups or to other substituted hydroxylated fatty acid derivatives. As an example for the preparation of a substituted hydroxylated fatty acid derivative, the reaction of epoxidized rapeseed oil with monobutylamine as hydrogen donor is described. Apart from the intended formation of hydroxyl groups with vicinal aminoalkyl groups, partial aminolysis of the ester compound was also observed. Another example describes the reaction of epoxidized rapeseed oil with different molar proportions of 1,4-butanediol as hydrogen donor. Depending on the molar proportion of the hydrogen donor, interesterification, or intermolecular ether formation were observed as side reactions. The properties of various technical hydroxylated fatty acids and their derivatives, prepared according to this novel process, are given, and potential applications of these products are suggested.     

The enantiomers of 7aH-cyclopenta[b]pyran-7-ones and their thermal racemization

The separation of the enantiomers of 7aH-cyclo-penta[b]pyran-7-ones 1 was performed by enantioselective liquid chromatography with the sorbent/solvent systems triacetylcellulose/methanol, tribenzoylcellulose/methanol, and (+)-poly(trityl methacrylate)/silica gel/n-heptane/isopropanol. Barriers to ring opening were determined for two 7a-methyl and two 7a-phenyl substituted 2,4,5-triaryl derivatives by thermal racemization of the enantiomers. Substituted cyclopentadienones 2 are discussed as intermediates in the thermal electrocyclic ring opening/ring closure reactions.     

1,2,4—三唑[3,4,—b]苯并噻唑的合成

首次以ＰＯＣ１３为环合剂环化苯并噻唑腙,合成了３位取代的１,２,４三唑「３,４－ｂ」苯并噻唑,并提出了合理的反庆历程。     

苯并异噻唑氧化物衍生物的合成及生物活性研究

根据生物电子等排原理,设计合成了6种含取代嘧啶环的目标化合物,其中5种为新化合物,它们的结构经IR、∧1HNMR、MS和元素分析测试而确证,初步的生物活性测试结果表明,含4,6-二甲基嘧啶环的化合物对植物生长有较强抑制性,而含6-甲基嘧啶环或4,5,6-三甲基嘧啶环的化合物对油菜根长具有促进作用。     

新型含嘧啶环的甲氧基丙烯酸酯类化合物的设计、合成及杀菌活性

以取代的苯乙/丙酮类化合物为原料,经酯化、环化和缩合3步制得新型含嘧啶环的甲氧基丙烯酸酯类化合物3a～3k.其化学结构经红外、核磁及元素分析确认.生物活性测定结果表明:部分化合物可有效抑制水稻稻瘟病、番茄晚疫病,对小麦白粉病具有较好的防治效果;嘧啶6位为对甲基(R1)取代的苯基时杀菌活性最好,嘧啶2位(R3)为甲基的化合物杀菌活性优于氢取代的化合物.