醋酸乙烯酯在硅橡胶上的辐射接枝研究

研究了不同溶剂中的醋酸乙烯酯在硅橡胶上的辐射接技状况及接枝后硅橡胶表面结构情况．结果表明：（１）在硅橡胶－乙酸乙酯－醋酸乙烯酯体系中，接枝有自加速效应；（２）适量加入对苯二酚，接枝诱导期延长，接枝速率下降，凝胶效应消失，辐射接技经验关联式为ＲＰ＝０．２７×［Ｄ］（－０．５６０）×［Ｉ］（０．４９０）×［Ｃ］（０．９２０），接核反应为扩散控制反应；（３）不同的溶剂对硅橡胶接枝有不同的影响，如甲醇发生敏化作用，提高接枝速率，而苯发生惰化作用，降低接枝速率；（４）在合适的甲醇和苯配比时，接枝反应几乎恒速进行，用扫描电镜（ＳＥＭ）观察断面，接枝区比较均一，出现微相分离．     

一类新的毛细管气相色谱固定液—侧链液晶冠醚聚硅氧烷的研究

合成了一种新的毛细管气相色谱用固定液——侧链含冠醚液晶的聚硅氧烷,这种固定液易于涂渍在弹性石英毛细管柱上,柱效高,热稳定性好,极性中等,它具有高分子液晶和高分子冠醚固定液的双重保留性能,适于分离多种异构体。     

A mesoporous non-precious metal boride system: synthesis of mesoporous cobalt boride by strictly controlled chemical reduction

Generating high surface area mesoporous transition metal boride is interesting because the incorporation of boron atoms generates lattice distortions that lead to the formation of amorphous metal boride with unique properties in catalysis. Here we report the first synthesis of mesoporous cobalt boron amorphous alloy colloidal particles using a soft template-directed assembly approach. Dual reducing agents are used to precisely control the chemical reduction process of mesoporous cobalt boron nanospheres. The Earth-abundance of cobalt boride combined with the high surface area and mesoporous nanoarchitecture enables solar-energy efficient photothermal conversion of CO₂ into CO compared to non-porous cobalt boron alloys and commercial cobalt catalysts.

Generating high surface area mesoporous transition metal boride is challenging but interesting because incorporation of boron atoms can generate lattice distortion to form amorphous metal boride which has unique properties in catalysis.     

The Aldol Reaction of Allenolates with Aldehydes in the Presence of Magnesium Diiodide (MgI2) as Catalyst

Stereoselective synthesis of (Z)‐α‐(hydroxyalkyl)‐β‐iodoacrylates (=(2Z)‐2‐(hydroxyalkyl)‐3‐iodoprop‐2‐enoates) was achieved in a one‐pot coupling reaction from methyl prop‐2‐ynoate, Me₃SiI, and an alkanal under mild conditions with MgI₂ as catalyst (→ 1 – 9 ; see Table and Scheme 1). Baylis‐Hillman β‐iodo adducts were generated in excellent yields with high (Z)‐selectivity. The conversion of methyl prop‐2‐ynoate to an active methyl 3‐iodo‐1‐[(trimethylsilyl)oxy]allenolate intermediate in situ followed by carbonyl addition is proposed as the reaction sequence (Schemes 1 and 2).     

蛋氨酸合成酶催化反应研究Ⅴ：5-氨基-6-（3-羟基-4-溴丁基）尿嘧啶的合成研究

报导了5-氨基-6-（3-丁烯基）尿嘧啶、5-氨基-6-（3-羟基-4-溴丁基）尿嘧 啶的合成方法。以γ-取代的β-酮脂和O-甲基异尿硫酸盐为超始物，经6-取代尿嘧 啶（3）、6-取代-5-偶氮尿嘧啶（4）和未见文献报道的中间体6，首次合成了5-氨 基-6-（3-丁烯基）尿嘧啶（5）及5-氨基-6-（3-羟基-4-溴丁基）尿嘧啶（7）。     

Tasumatrols P – T,Five New Taxoids from Taxus sumatrana

The phytochemical investigation of the more polar fractions from the leaves and twigs of Taxus sumatrana (Taxaceae) afforded five new taxane diterpene esters, tasumatrols P–T ( 1 – 5 ) possessing an 11(15→1),11(10→9)‐diabeotaxane skeleton. Compounds 1, 4 , and 5 contain an α‐hydroxy group at C(14), while 3 has no OH group at either C(13) or C(14). Compound 2 is a natural 4,5‐acetonide derivative, while 4 has an unusual spiro‐connected 2‐hydroxy‐2‐phenyl‐1,3‐dioxolane ring. Ten known taxoids, were also isolated in the course of the chromatographic fractionation. Five additional new O‐acetyl derivatives 3a, 4a, 4b, 5a , and 5b were prepared from the taxanes 3 – 5 . The structures of all new compounds were established on the basis of their spectroscopic analyses. Compound 1 showed mild cytotoxic activity against human Hela and Daoy tumor cells.     

含松香骨架的新型手性季铵盐相转移催化剂的合成及其在不对称环氧化反应中的应用

以天然松香为原料合成了4个新型手性季铵盐类相转移催化剂, 并用于催化不对称查尔酮环氧化反应, 发现这类手性相转移催化剂可以有效地催化查尔酮的不对称环氧化, 环氧化产物ee最高达20%.     

Mathematical Correction for Polyatomic Isobaric Spectral Interferences in Determination of Lanthanides by Inductively Coupled Plasma Mass Spectrometry

The determination of lanthanides by Inductively Coupled Plasma Mass Spectrometry (ICP‐MS) is complicated by several spectral overlaps from M⁺, MO⁺ or MOH⁺ ions formed in the ICP. Especially, it is essential to avoid the spectral interferences from lighter lanthanide and Ba polyatomic ions on middle or heavier lanthanides. To tackle this problem, we have developed a mathematical correction method, which reduces all the spectral overlaps from oxide species of Pr, Nd, Ce and Sm over Gd, Tb, Dy and Ho, and Gd, Tb over Yb and Lu. It can also successfully correct the oxide and hydroxide interference of Ba over Eu. The effectiveness of the proposed the mathematical correction scheme is demonstrated for the USGS Standard Rock samples AGV‐1 and G‐2. The results show that the experimental data obtained by applying the mathematical correction scheme for lanthanides is in good agreement with the reported values, using pneumatic and ultrasonic nebulisation methods, for their ICP‐MS analysis.     

Two new compounds derived from bufalin

The biotransformation of bufalin by cell suspension cultures of Platycodon grandiflorus was investigated and two new biotransformed products were obtained,which was 3-epi-telocinobufagin and 3-epi-bufalin-3-O-β-D-glucoside.     

New azabenzoquinones by ring‐expansion reactions

Ozonolysis of the pyrrolidinediones 4 afforded the pyrrolidinetriones 5 , which in the presence of Lewis acids were converted into maleimide 6 . Analogously, ozonolysis of the pyrrolidinones 7 gave the pyrrolidinediones 8 , which were converted into the pyridinetriones 11a, b via Lewis acid catalyzed isomerization to yield the trihydroxypyridones 10 and ensuing air oxidation. In solution two tautomeric forms of the pyridinetriones 11 may exist both of which represent hydroxy‐azabenzoquinones. In two steps compounds 11 were transformed into the azaquinone derivatives 19 . Representatives of another type of azaquinones are compounds 28a, b. These were generated in two steps from the pyridones 25 . The azaquinone 28a reacted easily with acidic compounds yielding the adducts 26, 27 and 29 or with 2‐butenal forming the cycloadduct 30 .