含2-三氟甲基苯并咪唑杂环化合物的合成

以2-三氟甲基苯并咪唑-1-乙酰肼为原料,在不同条件下合成了一系列新的1,3,4-(丰刀女)二唑啉及均三唑并噻二唑衍生物,所得化合物的结构经元素分析,IR,¹HNMR和MS确证,并对其波谱性质进行了讨论.     

从容易制备的三氟甲基噁唑酮直接合成三氟甲基吡咯及其有关化合物

作者考察了三氟甲基(口恶)唑酮与缺电子烯烃在不同条件下的反应,发现了三氟甲基(口恶)唑酮与α-氯代丙烯腈的串联Micheal加成一类Mannich反应-脱羧消除反应.提供了分别通过1,3-偶极环加成反应和串联的环合反应从三氟甲基(口恶)唑酮直接合成三氟甲基吡咯及其有关三氟甲基杂环化合物的方法.     

一种含三氟甲基和呫吨结构聚酰胺的合成与性能

在浓硫酸和3-巯基丙酸催化下,3′-三氟甲基苯基-2,2,2-三氟苯乙酮(1)和甲苯于40～50℃下缩合反应8 h,制得中间体-1,1-二(4-甲基苯基)-1-(3′-三氟甲基苯基)-2,2,2-三氟甲基乙烷(2),继而在光照和N-溴代丁二酰亚胺促进下,将中间体氧化得到二羧酸-1,1-二(4-羧基苯基)-1-(3′-三氟甲基苯基)-2,2,2-三氟甲基乙烷(3),二步反应总收率为77.4%.采用Yamazaki体系,3和9,9-二[(4-氨基苯氧基)苯基]呫吨进行溶液亲核缩聚反应,制得了一种高分子量的(数均分子量为43000,分子量分布为1.8)新型含三氟甲基和呫吨结构的聚酰胺.该聚酰胺为非晶态结构并具有良好的透光率(λcutoff=330 nm),其玻璃化转变温度(Tg)为242℃,在氮气气氛中5%的热失重温度(Td5)为465℃,800℃时的残炭率为50%.聚合物易溶于N,N-二甲基乙酰胺(DMAc)、N-甲基吡咯烷酮(NMP)、间甲酚、吡啶(Py)和四氢呋喃(THF)等有机溶剂中,并可浇注得到韧性好和透明的薄膜,其拉伸强度为85 MPa,拉伸模量为2.0 GPa,断裂伸长率为10%.同时,该聚合物的体积电阻、表面电阻和介电常数分别为2.85×1015Ωcm,4.23×1014Ω和3.55(100 Hz),呈现了良好的电绝缘性能.     

用Heck反应合成1-羟基-4-(3-吡啶基)丁-2-酮

在Heck反应条件下,以Ph3P为催化剂配体,由3-卤代吡啶和3-丁烯-1,2-二醇进行偶合可以得到1-羟基-4-(3-吡啶基)丁-2-酮,具有原料易得、合成方法简单的优点.     

一种含三氟甲基和咕吨结构聚酰胺的合成与性能

在浓硫酸和3-巯基丙酸催化下,3'-三氟甲基苯基-2,2,2-三氟苯乙酮(1)和甲苯于40～50℃下缩合反应8 h,制得中间体-1,1-二(4-甲基苯基)-1-(3'-三氟甲基苯基)-2,2,2-三氟甲基乙烷(2),继而在光照和N-溴代丁二酰亚胺促进下,将中间体氧化得到二羧酸-1,1-二(4-羧基苯基)-1-(3'-三...     

含2-三氟甲基苯并咪唑的1,3,4-噻二唑的合成

2-三氟甲基苯并咪唑-1-乙酰肼在无水乙醇中与芳基异硫氰酸酯反应得到相应的酰氨基硫脲(Ⅲa~Ⅲd)。再于室温条件下,与浓硫酸反应4h,制得2-(2-三氟甲基苯并咪唑-1--亚甲基)-5-芳氨基-1,3,4-噻二唑(Ⅳa~Ⅳd)。目标化合物经元素分析、IR和1HNMR进行了结构确证。     

氟烷基三甲基硅化合物的合成和反应研究

羰基化合物的氟烷基化反应是把含氟基团引入有机分子中去的一个重要手段。文献报道的主要是通过氟烷基金属试剂来进行此反应。但氟烷基金属试剂不太稳定,容易分解。这就给它们的应用带来了许多不便。我们发现,氟烷基三甲基硅化合物(1)作为氟烷基阴离子前体,在比较温和的条件下,便可使醛发生氟烷基化反应。首先,参照文献方法,通过氟烷基格氏试剂与三甲基氯硅烷反应,方便地制得了两个新的氟烷基三甲基硅化合物 R_F-SiMe_3(1)。     

1-(三氟甲基)-1,2-苯碘酰-3(1H)-酮在芳杂环上三氟甲基化的应用研究

以1-(三氟甲基)-1,2-苯碘酰-3(1H)-酮为三氟甲基源,并以2-氨基-5-溴吡啶为三氟甲基化底物,采用响应面分析法对合成工艺进行了分析优化,确定了最佳反应条件为:反应时间4 h,催化剂用量0.16 eq,反应温度50℃.经过3次验证实验,其平均收率为87％.最后继续合成了多个三氟甲基杂环芳香胺,且化合物结构经1...     

含三氟甲基均三唑衍生物的合成及结构表征

以3－三氟甲基－4－氨基－5－巯基－1,2,4－三唑为原料,在不同反应条件下与取代苯甲酸或芳醛缩合,得到15个含三氟甲基均三唑衍生物,利用元素分析,IR,^1H NMR和MS确定了这些化合物的组成与结构。     

5-三氟甲基胡椒醛的合成研究

以香草醛为起始原料,经碘代、脱甲基、亚甲基醚化、三氟甲基化反应以较高收率合成了5-三氟甲基胡椒醛,产物结构经过了1H NMR,13C NMR,19F NMR和HRMS的确证.重点研究了三氟甲基化反应,考察了不同三氟甲基化试剂、溶剂、催化剂用量、反应温度以及反应时间对三氟甲基化反应收率的影响,确定了最佳反应条件.随后,该方法成功运用于3,4位不同取代的5-碘苯甲醛的三氟甲基化反应,制得了三种5-三氟甲基胡椒醛的衍生物.     

无溶剂条件下Yb(OTf)3催化的亚甲基化合物和醛的Knoevenagel反应

在Yb(OTf)₃催化下, 不用任何溶剂, 将活泼亚甲基化合物和各类醛进行Knoevenagel反应, 得到相应的取代烯烃衍生物. 此法操作简便, 对环境友好, 具有很高的反应产率, 且副产物少; 此外, 催化剂能够在进行反复回收利用之后仍然保持很高的催化活性.     

Sc(OTf)3-catalyzed intramolecular aza-Prins cyclization for the synthesis of heterobicycles

The coupling of (E)- and (Z)-hex-3-ene-1,6-ditosylamide with various aldehydes in the presence of 10 mol % Sc(OTf)₃ gave the corresponding trans- and cis-fused 1,5-ditosyl-octahydro-1H-pyrrolo[3,2-c]pyridines, respectively, in good yields via intramolecular aza-Prins cyclization, whereas the coupling of (E)- and (Z)-N-(6-hydroxyhex-3-enyl)-4-methylbenzenesulfonamide afforded the corresponding trans- and cis-fused octahydro-1-tosylpyrano[4,3-b]pyrroles derivatives, respectively, via intramolecular Prins-cyclization.     

三氟甲磺酸镱催化吲哚与硝基烯Friedel-Crafts反应的研究

用三氟甲磺酸镱和配体共同催化吲哚与β-硝基烯的Friedel-Crafts反应,从而发展了一条简捷新颖地合成天然产物中广泛存在的3-取代吲哚衍生物的方法.该催化剂有反应条件温和、操作简单和价格较低等优点.     

Asymmetric Friedel-Crafts alkylation of activated benzenes with methyl (E)-2-oxo-4-aryl-3-butenoates catalyzed by [Pybox/Sc(OTf)3]

The asymmetric Friedel-Crafts reaction between methyl (E)-2-oxo-4-aryl-3-butenoates (1a-c) and activated benzenes (2a-d) has been efficiently catalyzed by the Sc^III triflate complex of (4′S,5′S)-2,6-bis[4′-(triisopropylsilyl) oxymethyl-5′-phenyl-1′,3′-oxazolin-2′-yl]pyridine (pybox 3). The 4,4-diaryl-2-oxo-butyric acid methyl esters (4) are usually formed in good yields and the enantioselectivity is up to 99% ee. The sense of the stereoinduction can be rationalized with the same octahedral complex (10) between 1, pybox 3 and Sc triflate already proposed for other reactions involving pyruvates, and catalyzed by the same complex.     

Functionalization of Csp-H bond—Sc(OTf)3-catalyzed domino 1,5-hydride shift/cyclization/Friedel-Crafts acylation reaction of benzylidene Meldrum’s acids

Under Sc(OTf)₃ catalysis, benzylidene Meldrum’s acids bearing a tethered p-methoxyphenethyl group were observed to undergo a [1,5]-hydride shift/cyclization at room temperature, representing a mild Csp³-H bond functionalization. The resulting spiro Meldrum’s acid intermediates then underwent intramolecular Friedel-Crafts acylation, completing the one-pot, domino reaction. The reported protocol generates the 6-6-5-6 tetracyclic core of tetrahydrobenzo[b]fluoren-11-ones.     

IBX/Sc(OTf)3-promoted one-pot oxidative conjugate addition of allyltrimethylsilane to Baylis-Hillman adducts

Baylis-Hillman adducts undergo smooth one-pot oxidative Michael addition with allyltrimethylsilane in the presence of 2-iodoxybenzoic acid (IBX)/Sc(OTf)₃ under mild conditions to afford homoallyl β-ketoesters in good yields with high 1,4-selectivity.     

An approach to the Paal-Knorr pyrroles synthesis catalyzed by Sc(OTf)3 under solvent-free conditions

A facile synthesis of N-substituted pyrroles by the Paal-Knorr condensation has been accomplished using a simple procedure. Among different metal triflates screened, 1 mol % Sc(OTf)₃ efficiently promoted the reaction to give excellent yield (89-98%) under mild reaction conditions. Additionally, Sc(OTf)₃ could be recovered easily after the reactions and reused without evident loss in activity.     

Sc(OTf)3-catalyzed diastereoselective Friedel-Crafts reactions of arenes and hetarenes with 3-phenylglycidates

Five different para-substituted 3-phenylglycidates (3-phenyloxirane-2-carboxylates) were prepared and subjected to reactions with arenes and hetarenes under Lewis acid catalysis. Sc(OTf)(3) was found to effectively (5 mol%) promote a Friedel-Crafts reaction in nitromethane as the solvent. The reaction was shown to proceed stereoconvergently, which makes the intermediacy of a benzylic cation likely. The diastereoselectivities varied depending on the choice of the nucleophile and 3-arylglycidate. Best results were obtained with tert-butyl 3-anisylglycidate, which delivered the respective products with high syn-preference in diastereomeric ratios (d.r.) between 82 : 18 and >95 : 5. The observed selectivity can be explained by a model, according to which the intermediate benzylic cations adopt a preferred conformation, which allows for diastereoface-differentiation by the adjacent stereogenic center.     

Sc(OTf)3-catalyzed, solvent-free domino synthesis of functionalized pyrazoles under controlled microwave irradiation

An efficient, rapid, and green synthesis of functionalized pyrazoles has been accomplished under solvent-free conditions by the reaction of phenyl hydrazine, aldehydes and ethyl acetoacetate. This approach exploits the synthetic potential of microwave irradiation and scandium triflate combination and offers many advantages such as excellent product yields, shorter reaction time, easy isolation of products, and environmentally benign reaction conditions.     

Sc(OTf)3-Catalyzed [3+2]-cycloaddition of aziridines with nitriles under solvent-free conditions

[3+2]-Cycloaddition of aziridines with various nitriles in the absence of organic solvent catalyzed by Sc(OTf)₃ afforded the corresponding imidazolines in good to excellent yields under extremely mild reaction conditions.