松毛虫性信息素前体(4Z,6E)-十一碳二烯醛的合成

从简单原料乙炔出发, 通过炔对丙烯醛的加成得到7-溴代-(4Z,6E)-庚二烯醛, 经乙二醇保护、Pd催化偶联、水解等步骤立体选择性地得到松毛虫性信息素前体(4Z,6E)-十一碳二烯醛.     

ω-苯基-(2S)-N-叔丁氧羰基氨基酸乙酯的制备

格氏试剂和N-叔丁氧羰基焦谷氨酸乙酯反应生成中间体ω-苯基-δ-氧代-(2S)-N-叔丁氧羰基氨基酸乙酯, 分别用对甲基苯磺酰肼和醋酸硼氢化钠结合的一锅法还原或Pd/C催化氢化还原中间体得到ω-苯基-(2S)-N-叔丁氧羰基氨基酸乙酯.     

氯化铯催化芳硒化钠对炔硒醚加成合成(Z)-1,2-二芳硒基烯

氯化铯催化下, 以商业DMF作溶剂, 芳硒化钠与炔硒醚在室温、氮气保护下反应, 立体选择地生成(Z)-1,2-二芳硒基烯.     

(αE,E)-α-(甲氧亚氨基)-2-[1-(芳香醛酮肟氧基)甲基]苯乙酸甲酯的立体选择性合成及生物活性研究

使用邻甲苯基重氮盐与乙醛酸甲酯肟偶联反应高立体选择性合成出 (E)-2-(羟基亚氨基)-2-邻甲基苯乙酸甲酯,经硫酸二甲酯的甲基化反应可得到重要的中间体(E)-2-(甲氧亚氨基)-2-邻甲基苯乙酸甲酯, 再经NBS溴化后与 (E)-芳香醛酮肟进行醚化反应最终得到目标物(αE,E)-α-(甲氧亚氨基)-2-[1-(芳香醛酮肟氧基)甲基]苯乙酸甲酯, 这些化合物多数具有很好的广谱杀菌活性.     

Brown反应特例及机理初探

报道了一例非Brown反应类型. 3-甲氧基-3,5,17(20)-雄甾三烯(1)用乙硼烷或9-BBN处理时, 没有进行Brown反应生成3-甲氧基-3,5-三烯-17β-羟甲基雄甾(2), 而是发生了17(20)碳碳双键的断裂, 得到3-甲氧基-3,5-二烯-17β-羟甲基雄甾(3). 对于该反应的机理, 进行了初步探讨.     

手性3,5-二甲基-2-芳基-2-吗啉醇盐酸盐的合成及其晶体结构

以(S)-2-氨基丙醇为手性源与α-溴-3-氯苯丙酮反应, (R)-2-氨基丙醇为手性源与6-甲氧基-2-(2-溴丙酰基)萘反应, 分别合成了手性纯化合物(2R,3R,5S)-3,5-二甲基-2-(3-氯苯基)-2-吗啉醇盐酸盐(4a)和(2S,3S,5R)-3,5-二甲基-2-(6-甲氧基-2-萘基)-2-吗啉醇盐酸盐(4b), 利用X射线单晶衍射仪测定了两化合物的晶体结构和两化合物的空间结构, 并初步分析两化合物空间结构, 化合物4a晶体属正交晶系, 空间群为P2₁2₁2, 晶胞参数为: a＝0.8718(2) nm, b＝0.7883(2) nm, c＝2.0247(6) nm, Z＝4, V＝1.3915(7) nm³, D_c＝1.328 g/cm³, F(000)＝584, R₁＝0.0399, wR₂＝0.0797, S＝1.042. 化合物4b晶体属正交晶系, 空间群为P2₁2₁2₁, 晶胞参数为: a＝0.71035 (9) nm, b＝0.77703(10) nm, c＝2.9820(4) nm, Z＝4, V＝1.6318(4) nm³, D_c＝1.318 g/cm³, F(000)＝688, R₁＝0.0520, wR₂＝0.1108, S＝0.994.     

10,10-二苄基-9(10H)蒽醇的酸催化选择性环化反应

蒽酮(1)与3,5-二甲氧基苯甲醛(2)在吡啶/哌啶中反应生成10-(3,5-二甲氧基苯甲亚基蒽酮(3); 3经Pd/C催化氢化生成10-(3,5-二甲氧基苄基蒽酮(4); 4与3-甲氧基苄基氯(5)进行相转移催化烷基化反应生成10-(3,5-二甲氧基苄基)-10-(3-甲氧基苄基)蒽酮(6); 6经NaBH₄还原生成10-(3,5-二甲氧基苄基)-10-(3-甲氧基苄基)-9(10H)-蒽醇(7); 7在酸催化下发生选择性1,7-脱水反应, 生成高三蝶烯(homotriptycene) (8). 其反应机理可能是7在酸存在下生成正碳离子中间体, 然后选择性地亲电进攻富电荷的3,5-二甲氧基苯基, 而不进攻3-甲氧基苯基.     

α-亚胺酮的不对称转移氢化合成(R)-沙丁胺醇

用手性(S,S)-Ru-TsDPEN催化剂不对称转移氢化α-亚胺酮化合物5-[(1,1-二甲基乙基)亚胺基]乙酰基-2-羟基苯甲酸甲酯(2)得光学纯β-氨基芳基乙醇类化合物(R)-5-[2-[(1,1-二甲基乙基)氨基]-1-羟乙基]-2-羟基苯甲酸甲酯(3), 再经一步还原反应即得(R)-(－)-沙丁胺醇. 对反应关键一步α-亚胺酮的不对称转移氢化反应条件进行了研究.     

手性β-氨基醇催化α,β-不饱和酮的不对称环氧化反应

将以烯烃为原料通过Sharpless不对称双羟化等多步反应合成的8种手性β-氨基醇, 作为有机小分子催化剂, 用于催化α,β-不饱和酮的不对称环氧化反应．考察了影响对映选择性的催化剂结构、催化剂用量、氧化剂种类、溶剂、反应温度等因素．结果表明, 当催化剂用量为30 mol%、氧化剂为TBHP(叔丁基过氧化氢)、正己烷溶剂、在室温下、以(1S,2R)-(＋)-1,2-二苯基-2-甲氨基乙醇(3)作催化剂时, 所得环氧化物的对映体过量最高为70% ee, 产率最高为84%.     

4(R)-(2,4,6-三甲基苄氧基)-(S)-脯氨酸促进的直接不对称羟醛反应

方便地合成了一种新的不对称羟醛反应的手性催化剂4(R)-(2,4,6-三甲基苄氧基)-(S)-脯氨酸. 以过量的丙酮作溶剂, 使用5 mol%该催化剂, 有效地催化了多种取代苯甲醛与丙酮间的不对称羟醛反应, 产率最高达91.0%, ee最高达84.3%.     

Novel solvent-controlled chemoselective palladium/copper(II) halide catalyzed oligomerization of <Emphasis Type="Italic">tert</Emphasis>-butyl acetylene

Solvent-controlled chemoselective palladium-catalyzed oligomerization of tert-butyl acetylene is reported in this paper. The reaction was carried out smoothly in benzene/n-BuOH binary solvent system. When unpolar aprotic benzene was the preponderating component in the binary system, a cyclotrimerization process occurred to produce 1,3,5-tri-tert-butylbenzene via a mechanism of three acetylene molecules, inserted step by step, forming σ-butadienyl-Pd and σ-hexatrienyl-Pd intermediates. While when the polar, protic and strong coordinating component n-BuOH, which aids Cu(II) to cleave the C-Pd σ-bonds and solvate Pd(II), Cu(II) cations, halo anion, σ-butadienyl-Pd intermediate, etc., was increased to a certain extent in the binary solvent system, the reaction proceeded readily via a n-BuOH-promoted mechanism to give (3Z,5Z)-2,2,7,7-tetramethyl-3,6-dichloro-3,5-octadiene or (3Z,5Z)-2,2,7,7-tetramethyl-3,6-dibromo-3,5-octadiene, respectively. Possible weak hydrogen bonds and n-π weak force between n-BuOH (electron pair donor (EPD)) and tert-butyl acetylene (and σ-butadienyl-Pd intermediate, electron pair acceptor (EPA)) in the latter process were also in favor of the n-BuOH promoted pathway. Meanwhile, the coupling product 2,2,7,7-tetramethyl-3,5-octadiyne was exclusively obtained when the reaction was conducted in singular polar H₂O. Influences of the solvent, catalysts, as well as possible mechanism were discussed in this paper.     

Selective and recyclable palladium porphyrins-catalyzed oligomerization of tert-butyl acetylene in environment-friendly ionic liquids

Efficient and selective palladium porphyrins-catalyzed olimerization of tert-butyl acetylene to form (3Z,5Z)-2,2,7,7-tetramethyl-3,6-dihalo-3,5-octadiene has been developed in environment-friendly ionic liquids. The reaction proceeded readily with effective recycling of the ionic liquids and easy isolation of the products.     

Tunable Synchronicity of Molecular Valence Tautomerism with Macroscopic Solid-Liquid Transition by Molecular Lattice Engineering

The combination of a cobalt-dioxolene core that exhibits valence tautomerism (VT) with pyridine-3,5-dicarboxylic acid functionalized with chains bearing two, four, or six oxyethylene units led to new complexes ConEGEspy (n = 2, 4, and 6). These complexes commonly form violet crystals of the low-spin (ls)-[Co^III(nEGEspy)₂(3,6-DTBSQ)(3,6-DTBCat)] (ls-[Co^III], 3,6-DTBSQ = 3,6-di-tert-butyl semiquinonato, 3,6-DTBCat = 3,6-di-tert-butyl catecholato). Interestingly, violet crystals of Co2EGEspy in the ls-[Co^III] transitioned into a green liquid, accompanied by an almost complete VT shift (94 %) to the high-spin (hs)-[Co^II(nEGEspy)₂(3,6-DTBSQ)₂] (hs-[Co^II]) upon melting. In contrast, violet crystals of Co4EGEspy and Co6EGEspy in the ls-[Co^III] exhibited partial VT (33 %) and only a 9.3 % VT shift after melting, respectively. These data demonstrate the tunability of the synchronicity of the molecular VT and macroscopic solid-liquid transitions by optimizing the tethered chains, thus establishing a new strategy for coupling bistable molecules with the macroscopic world.     

Synthesis and structure of heterocyclic derivatives of pyran-2-ones based on the dimer of 4,6-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)-3-hydroxy-1,2-benzoquinone

Acid-catalyzed reaction of 6,10a-dihydroxy-3,4a,7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo-[b,e][1,4]dioxine-1,2-dione with 2-methylquinoline derivatives led to the formation of a previously unknown system 6-[(Z)-2-(quinolin-2-yl)-1-hydroxyethen-1-yl]pyran-2-one. The molecular structure of 3,5-di(tert-butyl)-6-[(Z)-2-(7,8-dimethyl-4-chloroquinolin-2-yl)-1-hydroxyvinyl]pyran-2-one was established by XRD method; the energy and structural characteristics of its isomers in the gas phase and in a polar solvent were calculated by quantumchemical methods (B3LYP/6-31G**).     

Alkylation of pyrocatechol in <Emphasis Type="Italic">tert</Emphasis>-butyl alcohol-sulfuric acid-benzene

Alkylation of pyrocatechol with tert-butyl alcohol in benzene in the presence of sulfuric acid gave 3,5-di-tert-butylbenzene-1,2-diol in a higher yield than in analogous reaction with tert-butyl alcohol. This result was rationalized by reduction of inhibitory effect of liberated water, formation of heterogeneous system, and occurrence of the alkylation process in nonpolar organic phase. Intermediate products were identified and found to undergo intra- and intermolecular tert-butyl group transfer with formation of more stable 3,5-di-tertbutylbenzene-1,2-diol. The formation of p-di-tert-butylbenzene indicated participation of benzene in crossalkylation processes.     

The reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide

Reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide in aprotic solvents leads to the generation of semiquinone (SQ^.H), alkylperoxy (ROO^.), and alkyloxy radicals. The reaction of SQ^.H and ROO^. produces 2,5-di-tert-butyl-6-hydroxy-1,4-benzoquinone, 3,6-di-tert-butyl-1-oxacyclohepta-3,5-diene-2,7-dione, and 2,5-di-tert-butyl-3,6-dihydroxy-1,4-benzoquinone. The radical generated from solvent attacks SQ^.H at position 4 with C−C bond formation. 4-Benzyl-2,5-di-tert-butyl-6-hydroxycyclohexa-2,5-diene-1-dione produced in this way is transformed into 4-benzyl-3,6-di-tert-butyl-1,2-benzoquinone under the reaction conditions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 943–946, May, 1999.     

Low-temperature oxidation of 3,6-di-tert-butyl-o-benzoquinone and 3,6-di-tert-butylpyrocatechol with tert-butyl hydroperoxide in the presence of aluminum, titanium, and zirconium tert-butylates

Systems consisting of metal (Al, Ti, Zr) tert-butylate and tert-butyl hydroperoxide oxidize 3,6-di-tert-butyl-o-benzoquinone under mild conditions (room temperature, benzene). With (t-BuO)₃Al and (t-BuO)₄Zr, the major reaction products are 5-hydroxy-3,6-di-tert-butyl-2,3-epoxy-p-benzoquinone, and with (t-BuO)₄Ti, 2-hydroxy-3,6-di-tert-butyl-p-benzoquinone. Under the conditions of this reaction, 3,6-di-tert-butylpyrocatechol initially transforms into 3,6-di-tert-butyl-o-benzoquinone. The reactions involve metalcontaining peroxides.     

Structure,synthesis, and voltammetric investigation of 1-(quinolin-2-yl)-2-(pyran-2-yl)ethane-1,2-dione derivatives

By the XRD analysis the structure was established of 1-(7,8-dimethyl-4-chloroquinolin-2-yl)-2-[3,5-di(tert-butyl)-6-oxo-6H-pyran-2-yl]ethane-1,2-dione formed as a result of the oxidation of 3,5-di(tert-butyl)-6-[(Z)-2-(quinolin-2-yl)-1-hydroxyethen-1-yl]pyran-2-ones. By the cyclic voltammetry the oxidation of 1-(quinolin-2-yl)-2-(pyran-2-yl)ethane-1,2-dione derivatives was shown to proceed in two stages.     

1,4-Diazobicyclo[2.2.2]octane-catalyzed coupling of aldehydes and activated double bonds. Part 3. A short ans practical synthesis of mikanecic acid (4-vinyl-1-cyclohexene-1,4-dicarboxylic acid)

The title dicarboxylic acid 1d has been prepared in 24% overall yield via, 1,4-diazabicyclo[2.2.2]octane (DABCO)-catalyzed coupling of ethanal and tert-butyl propenoate ( 3 ) to 4 , S_N2′-reaction to tert-butyl (Z)-2-romomethyl-2-butenoate ( 5a ), dehydrobrominatin to tert-butyl 2-methylidene-3-butenoate ( 2c ), dimerizatoin to di-tert-butyl 4-vinyl-1-cyclohexene-1,4-dicarboxylate ( 1c ) and acidic ester cleavage. Acidic cleavage of easily obtainable 5a affords (Z)-2-bromomethyl-2-butenoic acid ( 5a ) in 68% yield with respect to ethanal.     

Synthesis and cytotoxic activity of derivatives of 6<Emphasis Type="Italic">Z</Emphasis>-acetylmethylenepenicillanic acid <Emphasis Type="Italic">tert</Emphasis>-butyl ester

The sulfoxide of 6Z-[2-(methoxyimino)propylidene]penicillanic acid tert-butyl ester and the sulfones of 6Z-[2-(hydroxyimino-, methoxyimino-, benzyloxyimino-, 2-bromo- and 4-bromobenzyloxyimino)-propylidene]penicillanic acid in the syn and anti forms have been synthesized by the condensation of the sulfoxide and sulfone of 6Z-acetylmethylenepenicillanic acid tert-butyl ester with hydroxylamine, methoxyamine, benzyloxyamine, 2-bromo- and 4-bromobenzyloxyamines. The syn and anti isomers of 3Z-(2-methoxyiminopropylidene)-4R-(benzothiazolyl-2-dithio)-2-oxoazetidinyl-1R-(2-propenyl)acetic acid tert-butyl ester were obtained by opening of the thiazolidine ring in 6Z-[2-(methoxy-imino)propylidene]-1-oxopenicillanic acid tert-butyl ester with 2-mercaptobenzothiazole. The 3Z-(2-methoxyiminopropylidene)-4R-(methylsulfonyl)-2-oxoazetidinyl-1-(2-propylidene)acetic acid tert-butyl ester was synthesized by the interaction of 1,8-diazobicyclo[5.4.0]undec-7-ene and methyl iodide with 6Z-[2-(methoxyimino)propylidene]-1,1-dioxopenicillanic acid tert-butyl ester. A dependence of the cytotoxic effect in relation to cancer and normal cells in vitro on the structure of the substituent in position 6 and the syn and anti isomerism of the oxyimino group was established for the synthesized compounds.