亚磺化脱卤研究 Ⅴ.RCCl_3型化合物的亚磺化脱卤反应

本文报道RCCl_3型化合物的亚磺化脱卤反应.在温和的条件下,四氯化碳及1,1,1-三氯多氟烷烃RCCl_3(R=Cl,F,CF_3,Cl(CF_2)_n,n=2,4,6,8)与连二亚硫酸钠反应,得到亚磺化脱氯产物RCCl_2SO_2Na,产率最高达85％以上.反应在水-乙腈或水-乙醇溶剂中以及碳酸氢钠或碳酸钠存在下进行.反应的最佳温度为25℃左右,提高反应温度,则脱氯氢化成为主要反应.三氯溴甲烷和三氯碘甲烷的亚磺化反应分别生成脱溴及脱碘产物,三氯甲基亚磺酸钠(CCl_3SO_2Na),产率80％左右.RCCl_3型化合物的亚磺化脱卤反应,提供了合成三氯甲基亚磺酸、磺酸及其衍生物的一种新方法,并首次应用于合成α,α-二氯多氟烷基亚磺酸、磺酸等类化合物.     

亚磺化脱卤研究 X: 全氟及多氟溴代烷的反应研究

本文报道溴代全氟烷和α,ω-二溴代全氟烷在亚磺化脱卤反应体系中与烯烃的反应及其与相应的碘代全氟烷的区别. 合成了全氟仲溴代烷CF3CFBrOCF2CF(CF3)O(CF2)2SO2F(7), 它与烯烃反应可得到1:1的加成物. 7的水解产物CF3CFBrOCF2CF(CF3)O(CF2)2SO3Na(11)与连二亚硫酸钠反应只得到氢化脱溴产物. 多氟溴化物CF3CBr2X(13X=F; 14X=Cl; 15X=Br)经亚磺化脱溴可得到相应的亚磺酸钠盐CF3CBrXSO2Na(16X=F; 17X=Cl; 18X=Br), 其中间体多氟烷自由基可用烯烃捕集, 得到高产率的1:1加成产物.     

亚磺化脱卤研究 X: 全氟及多氟溴代烷的反应研究

本文报道溴代全氟烷和α,ω-二溴代全氟烷在亚磺化脱卤反应体系中与烯烃的反应及其与相应的碘代全氟烷的区别. 合成了全氟仲溴代烷CF3CFBrOCF2CF(CF3)O(CF2)2SO2F(7), 它与烯烃反应可得到1:1的加成物. 7的水解产物CF3CFBrOCF2CF(CF3)O(CF2)2SO3Na(11)与连二亚硫酸钠反应只得到氢化脱溴产物. 多氟溴化物CF3CBr2X(13X=F; 14X=Cl; 15X=Br)经亚磺化脱溴可得到相应的亚磺酸钠盐CF3CBrXSO2Na(16X=F; 17X=Cl; 18X=Br), 其中间体多氟烷自由基可用烯烃捕集, 得到高产率的1:1加成产物.     

RCCl3型化合物的脱卤亚磺化反应研究

本文主要研究RCCl₃型化合物的脱卤亚磺化反应,这是我们发现的一个新反应。在温和的条件下,四氯化碳及1,1,1-三氯多氟烷烃与连二亚硫酸钠反应,生成脱氯亚磺化产物氟氯烷基亚磺酸钠,产率最高可达85%以上。     

亚磺化脱卤研究III.全氟伯碘代烷及a,w-全氟伯碘代烷在连二亚硫酸钠作用下的亚磺化脱碘反应

应用相转移催化和加入共溶剂的技术,全氟碘代烷如Cl(CF2)2I(1a)、Cl(CF2)4I(1b),Cl(CF2)6I(1c),H(CF2)8I(1d),C4F9I(1e),C6F13I(1f),C8F17I(1g)及α,ω-全氟二碘代烷如(ICF2CF2)2O(3a),I(CF2)6I(3b),I(CF2)8I(3c),I(CF2)10I(3d)等均可与连二亚硫酸钠水溶液在温和的条件下发生亚磺化脱碘反应,生成全氟亚磺酸盐Cl(CF2)2SO2Na(2a),Cl(CF2)4SO2Na(2b),Cl(CF2)6SO2Na(2c),H(CF2)8SO2Na(2d),C4F9SO2Na(2e),C6F13SO2Na(2f),C8F17SO2Na(2g)及O(CF2CF2SO2K)255a),KO2S(CF2)6SO2K(5b),KO2S(CF2)8SO2K(5c),KO2S(CF2)10SO2K(5d)全氟α,ω-二亚磺酸钠易潮解,均转化为相应的钾盐。这些亚磺酸盐均可用常规方法氯化成对应的磺酰氯,从而提供了由全氟碘代烷、二碘代烷制备全氟亚磺酸盐、二亚磺酸盐及全氟磺酸,二磺酸及衍生物的一种实用方法。     

关于亚磺化脱卤反应的若干新探索全氟和α,α-二氯多氟烷基亚磺酸盐及磺酰溴的反应研究

本论文由两部分组成。第一部分“关于亚磺化脱卤反应的若干新探索”。作者发现,1,1,1-三氯多氟烷烃在温和条件下与连二亚硫酸钠发生亚磺化脱氯反应,生成α,α-二氯多氟烷基亚磺酸盐。多卤甲烷(CCl_3X,X=Cl,Br,I)在类似条件下发生亚磺化脱卤反应,生成三     

从α-三氟甲基苄溴合成烷基硫酸盐——脱卤亚磺化反应的延伸

脱卤亚磺化反应是引入氟烷基基团的一种常用方法.探索了α-三氟甲基苄溴在脱卤亚磺化条件下的反应,发现产物并不是亚磺酸盐[Ar CH(CF_3)SO_2Na],而是烷基硫酸盐[Ar CH(CF_3)OSO_3Na].即使在烯烃的存在的条件下,α-三氟甲基苄溴在脱卤亚磺化条件下产生了自由基,也不与烯烃发生加成反应,而是直接生成亚磺酸盐,亚磺酸盐被空气氧化成烷基硫酸盐.     

脱卤亚磺化研究——-四氯化碳及1,1,1-三氯多氟烷烃的脱氯亚磺化反应

全氟碘代烷及溴代烷与连二亚硫酸钠反应可生成对应的亚磺酸钠,但全氟氯代烷(R_FCl)在相同条件下不能发生类似的反应.本文报道某些RCCl_3型化合物在相当温和的条件下发生脱氯亚磺化反应,得到α,α-二氯多氟烷基亚磺酸盐(RCCl_2SO_2Na)的研究结果. 在水和乙腈的共溶剂反应体系中,四氯化碳(1a)和氟氯烷1b～1f均可在25℃下与连二亚硫酸钠-碳酸氢钠反应,生成相应的亚磺酸钠盐2a～2f,产率可达80％以上.这些亚磺酸盐与氯气反应均可转化为对应的磺酰氯3a～3f,产率75～90％.     

连二亚硫酸钠的亚磺化脱卤反应研究

本论文分两个部分,第一部分"全氟及多氟烷基卤化物的亚磺化脱卤反应"对连二亚硫酸钠与全氟烷基碘化物的作用进行考察,在碘化物S-碘-3-氧杂-八氟磺酸钠进行亚磺化脱碘反应并得到验证后,将反应用于其他带极性基因的全氟烷基碘化物上,随即采用相转移催化及共溶剂技术将反应推广到一般的全氟碘代烷上,证明连二亚硫酸钠对广谱的全氟烷基碘化物都是一个有效的便利的亚磺化脱碘试剂。在亚磺化脱碘研究的同时,还进行了亚磺化脱澳研究,得到了相应的全氟烷基亚磺酸及1,1-二卤亚磺酸盐。将全氟碘代烷与电化学体系中连续产生的二氧化硫阴离子基反应,得到了预期的全氟烷基亚磺酸盐,从而证实了二氧化硫阴离子墓确实是作为亚磺化反应主体的亲核试剂,电化学亚磺化脱碘反应将异相反应转化为均相反应,是一种很有前途的合成方法。仲全氟卤代烷与连二亚硫酸钠反应只能得到脱卤氢化产物,这和伯全氟碘代烷亚硫化的副产物一起,都说明了在这还原性体系中全氟烷自由墓形成全纸烷基阴离子的可能性。     

亚磺化脱卤研究 VI.带极性取代基的伯碘代全氟烷的亚磺化脱碘

本文研究了取代基对亚磺化脱碘反应的影响,带极性取代基的碘代全氟烷I(CF~2)~nO(CF~2)~2-SO~3Na(1a～1c, n=2,4,6)、I(CF~2)~nOCF~2CO~2Na(2a～2b,n=2,4)、I(CF~2)~2O(CF2)2SO~2K(3)及I(CF~2)~4OCF~2CONH~2(4)于水溶液中在温和条件下可与连二亚硫酸钠进行亚磺化脱碘反应,生成相应取代的全氟烷基亚磺酸盐NaO~2(CF~2)~nSO~3O(CF2)2Na(5a～5c,n=2,4,6)、NaO~2S(CF~2)~2-OCF~2CO~2Na(6a～6b,n=2,4)、NaO~2S(CF~2)~2O(CF~2)~2SO~2K(7)及NaO~2(CF~2)~4OCF~2CONH2(8).这些亚磺酸盐均可按常规方法转化成相应取代的磺酰氯,从而提供了合成带这些取代基的全氟烷基亚磺酸盐及磺酸等衍生物的方便途径。     

Studies on sulfinato-dehalogenation: XII. Sodium dithionite-initiated addition of N,N-diethyliododifluoroacetamide to multiple bonds

N, N-deithyl-iododifluoroacetamide 1 reacted with alkenes, alkynes in aqueous acetonitrile solutions of sodium dithionite and sodium hydrogen carbonate at room temperature to give the corresponding adducts, thus constituting a new method for introducing the CF₂ group into organic molecules. Compound 1 reacted with conjugated olefins 2b, c to afford the iodine-free adducts 7b, c. The adducts 3d—f, from addition of 1 to alkenes 2d—f, could be converted into α,α-difluoro-γ-lactones 5d—f by treatment with silica gel. Compound 1 reacted with ethyl vinyl ether 2i to give aldehyde 8, and perfluoroalkyl or polyfluoroalkyl iodides reacted similarly. A radical mechanism was proposed for the addition reaction. Under the same condition, N,N-diethyl-bromodifluoroacetamide produced only the corresponding sulfinate Et₂NC(O)CF₂SO₂Na.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).