An efficient and mild protocol for the visible light-induced radical cascade difluoromethylation/cyclization of imidazoles with unactivated alkenes using easily accessible and bench-stable difluoromethyltriphenylphosphonium bromide as the precursor of the -CF2H group has been developed to afford CF2H-substituted polycyclic imidazoles in moderate to good yields. This strategy, along with the construction of Csp3-CF2H/C-C bonds, is distinguished by mild conditions, no requirement of additives, simple operation, and wide substrate scope. In addition, the mechanistic experiments have indicated that the difluoromethyl radical pathway is essential for the methodology.

师范专业认证工作和基础教育的改革都对高等师范院校师范生的人才培养质量提出了新的要求,课程对人才培养起到支撑的作用.化学教学论课程是化学师范专业必修课,"三环六步"教学模式体现了"以学生为中心"的教学理念,通过"课前导学、课中讲学、课后练学"三个教学环节进行实施,将"三环六步"教学模式应用在化学教学论课程中,提高了师范生学习的自主性和体验性,夯实了基础理论知识,提升了化学教学技能.

在师范认证的推动下,高等师范院校开设的"化学教学论"课程成为化学教育专业人才培养方案中的一门核心课程,"以学生为中心、以产出为导向、以持续改进为机制"的OBE教育理念与师范认证理念相互契合.在"化学教学论"课程教学中融合相应的思政元素是时代的要求,以过程评价来提升师范生的教师职业素养和思政素养,以结果评价考察师范生对理论知识的掌握与应用情况,这不仅能督促师范生主动学习,还能为国家培养现代教育理念的准教师.

Tandem reactions between β-iodoazides and propargyl alcohols under mild conditions are presented, providing a general and convenient method for the synthesis of 6,7-dihydro-4H-[1,2,3]triazolo[5,1-c][1,4]oxazines. The advantages of this method are its simple operation, high efficiency and high product yields (80–95%).

An efficient, one-pot synthesis of 3-substituted-4 H -[1,2,3]triazolo[5,1- c ][1,4]oxazin-6(7 H )-ones is developed via sequential esterification, substitution, and 1,3-dipolar cycloaddition processes of various propargyl alcohols, chloroacetyl chloride, and sodium azide. This method provides a variety of novel 1,2,3-triazole-fused oxazinones and has several advantages including simple operation, high efficiency, and good-to-excellent product yields (80%–95%) without the need to isolate the ester and azide intermediates. Keywords 3-substituted-4 , -[1,2,3]triazolo[5,1- , ][1,4] , oxazin-6(7 , )-ones , chloroacetyl chloride , one-pot procedure , propargyl alcohols , sodium azide

1 问题提出 浓硫酸与铜反应在高中化学实验教学中占有重要的一席之地,它是验证浓硫酸具有强氧化性的一个经典实验.此实验在人教版新旧教材中有着不同的呈现. 1.1人教版旧教材 人教版旧教材中有关浓硫酸与铜反应的实验装置图如图1所示,该实验设计主要是将下端卷成螺丝状的铜丝插入到胶塞侧面,通过上下拉动铜丝来控制反应的发生与终止;用品红溶液来检验SO2的生成,以及将反应后的溶液倒入另一支装有水的试管中来用于另一产物CuSO4的检验.

An efficient, one-pot synthesis of 3-substituted-4H-[1,2,3]triazolo[5,1-c][1,4]oxazin-6(7H)-ones is developed via sequential esterification, substitution, and 1,3-dipolar cycloaddition processes of various propargyl alcohols, chloroacetyl chloride, and sodium azide. This method provides a variety of novel 1,2,3-triazole-fused oxazinones and has several advantages including simple operation, high efficiency, and good-to-excellent product yields (80%–95%) without the need to isolate the ester and azide intermediates.

New diamine, 4-(4-diphenylphosphino)phenyl-2,6-bis(4-aminophenyl)pyridine, was prepared, and the related polyamides (PAs) bearing 2,6-diphenylpyridyl units and pendant diphenylphosphinophenyl groups were synthesized by direct polycondensation of this diamine and various aromatic diacids in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The resulting PAs with inherent viscosities of 0.78–1.06 dL g −1 are readily soluble in polar aprotic solvents such as NMP, N, N-dimethylacetamide, and dimethylsulfoxide as well as less polar solvents such as m-cresol and pyridine. All the PAs are amorphous and could be solution-cast into transparent, flexible, and tough films, which have tensile strengths of 68.2–88.8 MPa, tensile moduli of 1.9–2.4 GPa, and elongations at break of 5.4–10.3%. These polymer films also exhibit high optical transparence with the UV cutoff wavelength in the 361–412 nm range. These PAs display glass transition temperatures of 316–332°C, 10% mass loss temperatures of 524–553°C, and more than 48% residues at 800°C in nitrogen, respectively. Their high char yields and good limited oxygen index values ranging from 39 to 44 indicate the prepared PAs show good thermal stability and flame-retardant property.

4-(4-Diphenylphosphino)phenyl-2,6-bis(4-hydroxyphenyl)pyridine, as a new bisphenol monomer, was prepared from 4-(diphenylphosphino)benzaldehyde and 4-hydroxyacetophenone and used in the preparation of several aromatic poly(ether ketone)s (PEKs) containing 2,6-diphenylpyridyl units and diphenylphosphinophenyl pendant groups via a nucleophilic aromatic substitution polycondensation with difluorinated aromatic ketones. The polycondensation proceeded quantitatively in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the polymers with high molecular weights. The resulting PEKs are amorphous and exhibit high glass transition temperatures of 209–255°C and 5% weight loss temperatures of 536–554°C with char yields of 57–62% at 800°C in nitrogen. Their high char yields and good limited oxygen index values ranging from 39 to 43 indicated these polymers exhibited good thermal stability and flame-retardant property. All new PEKs were soluble in common organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and chloroform and could form tough, flexible, and strong films with tensile strengths of 74.6–86.8 MPa, tensile moduli of 2.9–3.6 GPa, and elongations at break of 5–9%.

A facile, one-pot synthesis strategy for the tertiary arylamines bearing N,N-bis(1,2,3-triazol-4-yl)methyl structure has been developed by sequential diprop-2-ynylation of primary amines with propargyl bromide in the presence of calcium hydride in DMF and [3 + 2] "click" cycloaddition with organic azides promoted by cupric acetate in the mixed DMF-H2O media. This protocol provides some features, such as high efficiency and regioselectivity, easy operation, and moderate to good product yield (56-84%) with a wide substrate scope under mild conditions. [GRAPHICS] .

教学有法,教无定法.一节新课的教学能否达到成功,引课的运用是关键.俗语曾云“良好的开始是成功的一半”,引课设计越加科学合理、新颖独特,就更能在第一时间吸引学生的注意,自然而有效地渗透教学内容,引导学生轻松地进入学习情境.通过对中学化学专家型教师、新手型教师关于《氧气的性质》课堂实录引课类型的对比研究分析,明确课堂引入的原则、功能与类型,以及如何在课堂教学中合理应用各类课堂引入.

A new aromatic diamine, 4-(4-trifluoromethyl)phenyl-2,6-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]pyridine, was synthesized by a modified Chichibabin reaction of 4-(4-nitro-2-trifluoromethylphenoxy)acetophenone with 4-triflouromethylbenzaldehyde, followed by catalytic reduction. A series of fluorinated pyridine-containing aromatic poly(ether imide)s (PEIs) were prepared from the diamine monomer with various aromatic dianhydrides via conventional two-step thermal imidization method. The resulting PEIs had inherent viscosities values of 0.68-0.90 dL/g, and could be cast and thermally converted into transparent, flexible, and tough polymer films. These PEIs were predominantly amorphous, had good solubility in common solvents such as NMP, DMAc and m-cresol at room temperature, and displayed excellent thermal stability with the glass transition temperatures of 258-315 degrees C, the temperatures at 5% weight loss of 550-585 degrees C, and the residue of higher than 55% at 750 degrees C in nitrogen. Moreover, the PEIs films showed outstanding mechanical properties with tensile strengths of 74.8-103.5 MPa, tensile moduli of 1.08-1.45 GPa, and elongations at break of 10.6-24.4%. These PEIs also exhibited low dielectric constants of 2.81-2.98 (1 MHz) and water uptake 0.39-0.68%, as well as high optical transparency with the UV cutoff wavelength in the 350-378 nm range and the wavelength of 80% transparency in the range of 412-510 nm. [GRAPHICS] . A series of fluorinated pyridine-containing poly( ether imide) s derived from a new diamine 4-( 4-trifluoromethyl) phenyl-2,6-bis[ 4-( 4-amino-2-trifluoromethylphenoxy) phenyl] pyridine with various dianhydrides were investigated. The resulting polymers exhibited improved solubility, high optical transparency and low dielectric constants, combined with good thermal and mechanical properties.

随着学科核心素养的提出,传统教学模式已经无法满足学生日益增长的学习需要;另一方面,基于互联网+教育下的MOOC、微课和翻转课堂等新教学模式又使得教师无法及时地关注到学生的学习情况.在此背景下,催生了一种新型教学模式——SPOC混合式教学模式.本文基于SPOC混合式教学模式,将化学学科核心素养融入中学化学教学中,以"蒸馏和萃取"为例开展教学设计.

A simple and efficient one-pot multicomponent approach for the synthesis of tertiary arylamines bearing N,N-bis(isoxazol-5-yl)methyl groups is developed through reactions including sequential diprop-3-ynylation of primary amines with propargyl bromide in the presence of calcium hydride in N,N-dimethylformamide, and 1,3-dipolar cycloaddition with nitrile oxides generated in situ from hydroximyl chlorides in DMF-Et3N. This protocol provides advantages such as high regioselectivity, easy operation, and moderate-to-good product yields with a wide substrate scope under mild conditions.

9,9-Bis(4-aminophenyl)xanthene (BAPX) was prepared simply and effectively via one-pot, two-step procedure using xanthenone and aniline as main substrates. The monomer BAPX was reacted with six aromatic dianhydrides in N, N-dimethylacetamide (DMAc) to yield the corresponding polyimides (PIs) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The resulting PIs exhibited good thermal stability with glass transition temperatures of 308–348°C, initial decomposition temperatures of 470–510°C, 10% weight loss temperatures of 540–565°C, and char yields of 55–59% at 800°C in nitrogen, respectively. All polymers were amorphous and readily soluble in organic solvents such as N-methyl-2-pyrrolidone and DMAc. The PI films had tensile strengths of 71–92 MPa, tensile moduli of 1.91–2.35 GPa, and elongations at break of 5–13%. Meanwhile, these polymer films also had high optical transparency with a cutoff wavelength in the range of 367–415 nm, lower dielectric constants (3.02–3.34 at 10 MHz), and low water uptake of 0.30–0.52%.

Novel binuclear platinum complex (FPT)(2)Pt-2(diPic) and mononuclear platinum complex (FPT)Pt(Pic) were designed and synthesized, where FPT is N-(4-(6-(9,9-diethyl-9H-fluoren-2-yl)pyridin-3-yl)phenyl)-N-phenylbenzenamine, diPic is 3-(6-(2-carboxypyridin-3-yloxy)hexyloxy)picolinic acid, and Pic is picolinic acid. The photophysical, electrochemical and thermal properties, as well as electroluminescent (EL) properties for both platinum(II) complexes were studied. Compared to (FPT)Pt(Pic), (FPT)(2)Pt-2(diPic) exhibited stronger phosphorescent emission in PL spectra and higher Phi(PL), owing to the enhanced spin-orbit interaction of platinum centers. Moreover, the monochromatic devices based on (FPT)(2)Pt-2(diPic) showed better EL properties than (FPT) Pt(Pic). Based on that, the single-emissive-layer WPLEDs using (FPT)(2)Pt-2(diPic) as orange emitter and FIrpic as blue emitter were also obtained. The WPLEDs show best performances with a maximal LE of 1.3 cd/A, and a CIE coordinates of (0.35, 0.37) which is very close to the pure white emission. Work is still underway to improve the device efficiency and color purity of these iridium and platinum complexes co-doped WPLEDs.

A simple and efficient, one-pot approach for the synthesis of ether-linked diisoxazole derivatives has been developed through sequential reactions, which includes O-propargylation of 2-bromohomoallylic alcohols with propargyl bromide in the presence of sodium hydride in THF, and 1,3-dipolar cycloaddition by the addition of hydroximinoyl chlorides and triethylamine. This protocol provides some advantages such as high regioselectivity, easy operation and good product yields with a wide scope of substrates under mild conditions.

考察了一系列手性吡咯烷叔胺硫脲催化剂对4-氯代乙酰乙酸乙酯与亚胺的不对称Mannich/Cyclization串联反应的催化性能,合成了一系列具有潜在生物活性的手性特窗酸类衍生物,产率62％～92％,对映选择性68％～96％,产物结构经1 H NMR,13 C NMR,IR和HR-MS确证.并对反应条件进行了优化,对反应机理进行了推测.

4-(4-Trifluoromethylphenyl)-2,6-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]pyridine (9FPBAPP), as a new aromatic diamine, was prepared by a modified Chichibabin reaction of 4-(4-nitro-2-trifluoromethylphenoxy)acetophenone with 4-triflouromethylbenzaldehyde, followed by a catalytic reduction. A series of fluorinated poly(ether imide)s containing pyridine and/or phenylphosphine oxide moieties were prepared from bis(3-aminophenyl)phenylphosphine oxide (BAPPO), 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), and 9FPBAPP via a conventional two-step thermal imidization procedure with various mole ratios of BAPPO and 9FPBAPP. All the polymers were amorphous and soluble in common organic solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone and had Tg’s of 277–285°C, 5% weight loss temperature of 521–550°C in nitrogen. Furthermore, high char yields and good limited oxygen index values indicated that these polymers exhibited good thermal stability and flame-retardant property. Tough and flexible polymer films also had good mechanical properties with tensile strengths of 75–99 MPa, tensile moduli of 1.1–1.6 GPa, and elongations at break of 12%–24% and low dielectric constants of 2.81–3.53 (1 MHz), as well as high optical transparency with the ultraviolet cutoff wavelength in the range of 350–384 nm.

教学技能是师范生在成为教师前必须熟练掌握的职业技能,微格教学实训是提升师范生教学技能非常有效的训练途径.通过"学""观""写""练""录""评""改""查"8步的实践训练,师范生的教学技能可以在较短时间内得到大幅度的提升.