偶氮次甲基亚胺作为合成子在有机合成中的应用研究进展

偶氮次甲基亚胺是构筑吡唑酮稠环骨架非常重要的合成子,在有机合成中得到了广泛的应用.由于其具有合成简单、价格低廉等优点,近年来,对于偶氮次甲基亚胺参与的反应引起了广大化学家的关注.本文对近几年来偶氮次甲基亚胺作为合成子在有机合成中的应用按照反应类型进行了总结,详细阐述了其在[3+2]、[3+3]、[3+4]和Mannich反应中的应用,以期为开发新反应及结构新型的含有吡唑酮骨架的合成子提供理论依据.     

有机合成中的合成子与合成等效剂

合成子和合成等效剂是有机合成的发展过程中提出的新概念。深刻了解这一概念及其有关知识对于提高有机合成设计水平和发展有机合成设计技巧,尤其在运用计算机进行有机合成路线的择优中,都具有一定的意义。本文将分别就合成子、合成等效剂以及合成子的类型转换作一介绍。     

DMSO作为氧化剂在有机合成中的应用

简要综述了二甲亚砜作为氧化剂的合成应用在最近十几年来的研究进展。     

酰基膦酸酯的合成及其在有机合成中的应用研究进展

酰基膦酸酯是一类活泼的有机合成中间体。本文归纳介绍了此类化合物的合成方法以及其近年来在有机合成中的应用。     

DMSO—HCL法合成3—甲基—4—甲硫基苯酚

3-甲基-4-甲硫基苯酚,是倍硫磷、克线磷等农药的关键中间体。有关它的制备方法报道较多。文献[1]曾作过总结,归纳起来主要是采用间甲酚进行甲硫基化反应而制得。目前常用的甲硫基化剂有二甲基二硫醚(DMDS),二甲     

二甲亚砜作为甲基化试剂在有机合成中的应用

在药物分子中引入甲基可改变其药代动力学特性与药理特性,这种“神奇的甲基效应”使得甲基化成为有机合成与药物化学领域十分重要的一类反应.近年来,过渡金属催化的偶联反应以及光或电促进的有机反应成为甲基化反应的新策略,并相继开发了系列廉价易得、低毒高效、适用性广的甲基化试剂.其中,二甲亚砜(DMSO)作为一种来源广泛、性能优良的溶剂与多功能反应试剂,受到研究者们越来越多的关注.基于此,聚焦交叉偶联反应与自由基反应,系统阐述DMSO/DMSO-d6作为甲基化/三氘甲基化试剂在有机合成中的应用,并探讨相关的反应机理、发展趋势以及合成过程所面临的挑战.     

同多十钒氧簇与DMSO自组装超分子化合物的合成及其晶体结构

合成了含有十钒酸阴离子的超分子化合物(NH4)4(DMSO)4H2V10O28,并通过X射线衍射分析、IR光谱、51VNMR及元素分析对其结构进行了表征.单晶X射线衍射分析表明化合物属于单斜晶系,P21/n空间群,a=1.0719(2)nm,b=0.9658(2)nm,c=2.0171(2)nm,β=98.42°,V=2.0657(5)nm3,Z=2,F(000)=1336,R1=0.0429,wR2=0.1146.化合物的晶体结构单元由一个二质子化的十钒酸根多阴离子、4个铵根阳离子和4个DMSO分子组成,并且彼此之间通过静电力和氢键形成稳定的三维结构.     

Lewis酸性Mg(II)在有机合成中的应用

综述了Lewis酸性的Mg(II)及其配合物在有机官能团转化和碳—碳键形成反应中的应用 .较强的Lewis酸性、较强的亲氧性和较高的配位数对Mg2 + 独特的催化反应活性起着关键的作用 .     

Lewis酸性Mg(Ⅱ)在有机合成中的应用

综述了Lewis酸性的Mg(Ⅱ)及其配合物在有机官能团转化和碳-碳键形成反应中的应用.较强的Lewis酸性、较强的亲氧性和较高的配位数对Mg2+独特的催化反应活性起着关键的作用.     

N-甲基吡咯烷酮作为一碳合成子在曼尼希反应中的应用

以苯乙酮衍生物为原料,N-甲基吡咯烷酮替代甲醛类似物,考察了其作为一碳合成子在曼尼希反应中的应用。在最优条件下,以46%~93%的收率成功合成了系列曼尼希碱衍生物。该反应底物范围宽泛,官能团兼容性好,并且初步研究了该反应的机理。     

Acid-promoted metal-free synthesis of 3-ketoquinolines from amines,enaminones and DMSO

A metal-free p-toluenesulfonic acid (TsOH·H₂O) mediated synthesis of 3-ketoquinolines from anilines, enaminones and DMSO has been developed. In this transformation, DMSO was activated by TsOH·H₂O and provided the one-carbon unit of the 3-ketoquinolines. A plausible mechanism involving an electrophilic sulfenium ion intermediate was proposed.     

Ketones as a new synthon for quinoxaline synthesis

o-Phenylenediamines react with an array of ketones in PEG-400 at 60 °C under an atmosphere of air in the presence of KOH to afford the corresponding quinoxalines in good yields.     

A new synthon for the synthesis of aminoinositol derivatives

The regio- and stereoselective synthesis of a new synthon, trans-3,8-dioxatricyclo[3.2.1.0^2,4]octane-6,7-diamine, from 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate is reported. Transformation of the acid functionalities to acyl azides followed by Curtius rearrangement gave the corresponding trans-diisocyanate, which was reacted with HCl to produce a trans-diamino compound that is a potentially important synthon for the versatile synthesis of aminocyclitols.     

A direct synthesis of 1,7-dioxaspiro[4.5]decanes from the new 3-methylidenepentane-1,5-dianion synthon

4-Phenylsulfanyl-2-(2-phenylsulfanylethyl)but-1-ene (2) has proved to be an appropriate and new 3-methylidenepentane-1,5-dianion synthon. The reaction of 2 with an excess of lithium powder and a catalytic amount of DTBB (2.5%) in the presence of a carbonyl compound in THF at 0 °C, leads, after hydrolysis, to the expected methylidenic diols 3. These diols undergo double intramolecular iodoetherification promoted by a silver salt, to furnish the corresponding 1,7-dioxaspiro[4.5]decanes (4) in very high yields. The oxidation of compounds 4 to the corresponding lactones is also studied.     

PTSA-catalyzed one-pot synthesis of quinoxalines using DMSO as the oxidant

An efficient p-toluene sulfonic acid–catalyzed, one-pot, two-step oxidative system for cyclization of o-diaminobenzene with 1,2-diaryl-2-hydroxyethanone to quinoxalines was described. A nontoxic, readily available oxidant, dimethylsulfoxide (DMSO), was applied in this process. A broad range of substrates was applied to this method, and target compounds were obtained with good yields.     

Malononitrile as a carbonyl synthon: a one-pot preparation of heteroaryl amide via a SNAr-oxidation-displacement strategy

Malononitrile could be utilized as a synthon for the carbonyl moiety via a one-pot process that was initiated via base-mediated S_NAr substitution of a heteroaryl halide. Subsequent peracetic acid oxidation of the resultant anion delivered an electrophilic acyl nitrile in situ that readily reacted with added nucleophiles to afford heteroaryl carboxylic acid derivatives. The reaction of the sodium salt of malononitrile with a series of heteroaryl chlorides followed by the subsequent addition of an amine and peracetic acid provided the corresponding heteroaryl amides.     

铀在有机合成中的应用研究进展

铀储量丰富,是人类未来可持续发展的重要资源.随着人们对铀独特电子结构及其性质的深入认识,铀的资源化及其潜在应用也获得科学家的广泛关注.本文总结了近年来铀在有机合成中的最新研究成果,并对未来发展趋势进行了展望.该综述主要内容包括四价铀和六价铀催化的有机转化研究.     

A new 3-methylidenepentane-1,5-dianion synthon: synthesis of perhydropyrano[2,3-b]pyrans and 1,7-dioxaspiro[4.5]decanes

4-Phenylsulfanyl-2-(2-phenylsulfanylethyl)but-1-ene (2) has proved to be an appropriate and new 3-methylidenepentane-1,5-dianion synthon. The reaction of 2 with an excess of lithium powder and a catalytic amount of DTBB (2.5%) in the presence of a carbonyl compound in THF at 0 °C, leads, after hydrolysis, to the expected methylidenic diols 3. These diols when subjected to successive hydroboration-oxidation and final oxidation, undergo spontaneous cyclisation to furnish a series of cis-perhydropyrano[2,3-b]pyrans (4) in a highly diastereoselective manner (>99% de). Additionally, diols 3 also undergo double intramolecular iodoetherification promoted by a silver salt, to furnish the corresponding 1,7-dioxaspiro[4.5]decanes (6) in very high yields.     

Development of a convenient route for the preparation of the N-Cbz-protected guaninyl synthon required for Boc-mediated PNA synthesis

An efficient, high yielding, chemo- and regioselective, five-step synthetic route to N²-Cbz-guanin-9-yl acetic acid has been developed, which avoids the use of triphosgene. After formation of the N²-Boc protected purine from 2-amino-6-chloropurine, two successive base-controlled alkylations allowed an N⁹-tert-butyl acetate function followed by an N²-Cbz moiety to be installed. The selectivities of these reactions were confirmed through an X-ray crystallographic study of the 6-(2-nitrophenoxy) analogue. Final hydrolytic dechlorination and removal of the Boc and tert-butyl ester protecting groups were accomplished concomitantly under acidic conditions to afford the guanin-9-yl PNA monomer synthon in an overall yield of 53%.