甲基

Starting from piperonal, the initial total synthesis of CET involved BischlerNapieralski reaction, 3, 2-sigmatropic rearrangement, unusual Nazarov-type electrocyclization, and autoxidative dehydrogenation of desmethylcephalotaxine to desmethylcephalotaxinone etc.

第一条路线我们以胡椒醛为起始原料，经Bischler-Napieralski反应，[3，2]-σ重排，6-6环系到7-5环系的还原重排，Nazarov氧化环化；碱性条件下脱甲基三尖杉碱到脱甲基三尖杉酮碱的氧化脱氢等20步反应，完成了三尖杉碱的全合成。

Under the protection of purified water-free, oxygen-free argon, using Schlenk technique, the rare rarth organometallic complexes containing piperonal dimethyl acetal and dicyclopentadienyl and involving silylene-bridged fluorenyl have been synthesized.

合成了含胡椒醛二甲基缩醛基和二茂基稀土金属有机配合物。采用Schlenk技术，在干燥纯氩气保护下进行。将溴代胡椒醛二甲基缩醛基锂盐与二茂基一氯稀土（Ln：Yb，Dy，Pr，La，Sm）反应，形成5个新的文献未曾报道的稀土金属有机配合物。

The method has the advantages of high analysis speed and high sensitivity, can detect micro-target DNA methylation, and can carry out the joint detection of the polygene methylation.

具有分析速度快、灵敏度高，能检测微量靶DNA甲基化，可同时进行多基因甲基化的联合检测。

A commercial and practical synthesis rout with-2-(3-acetoxy-l-me-thyl-l~propenyl)-5,5-dimethyl-l,3-dioxane as starting material by couple,oxidation, Ramberg-Backlund and deprotection is chosen and studied in this paper.

本文选择了以2-(3-氯-1-甲基-1-丙烯)-5，5-二甲基-1，3-二噁烷为原料，经偶连、氧化、Ramberg-Bcklund反应及脱保护基四步反应的合成路线，对该中间体进行合成研究。

The chemical structure of Ligustrazine is tetramethyl pyrazine, its four methyl can show different efficiency, when they are replaced by different functional units.

川芎嗪化学结构为四甲基吡嗪，其四个甲基被不同的功能基因替代后可产生不同效应，研究发现川芎嗪对心血管系统的作用有多种不同的作用途径和作用机制。

The comparison results suggested that Bacillus subtilis could produce tetramethyl pyrazine by use of both the two mediums. Among the two mediums, it was found that the strain in wheat mediun had a higher pyrazine tetramethyl content (1.86 mg/kg wheat).

结果表明，该菌利用2种培养基均能代谢生成酱香型白酒中含量较高的4-甲基吡啶，其中以小麦为培养基所产4-甲基吡啶含量达1.86 mg/kg小麦。

The comparison results suggested that Bacillus subtilis could produce tetramethyl pyrazine by use of both the two mediums. Among the two mediums, it was found that the strain in wheat mediun had a higher pyrazine tetramethyl content (1.86 mg /kg wheat).

结果表明，该菌利用2种培养基均能代谢生成酱香型白酒中含量较高的4-甲基吡嗪，其中以小麦为培养基所产4-甲基吡嗪含量达1.86 mg /kg小麦。

Nine new compounds were characterized, and they were: opuntioside Ⅰ(11), 4-ethoxyl-6-hydroxymethyl-α-pyrone (14),--ester (22), 1-butoxyl--malate (24), ethyl α-L-rhamnopyranoside (26), opuntioside Ⅱ(34), kaempferol 7-O-β-D-glucopyranosyl (1→4)-β-D-glucopyranoside (46), methyl α-D-glucopyranoside-6-(methyl 4-malate)-ester (47), and opuntioside Ⅲ(48). Opuntioside Ⅰ,Ⅱ,Ⅲ and 4-ethoxyl-6-hydroxymethyl-α-pyrone belong to the skelecton of α-pyrone.

新化合物分别是：仙人掌苷Ⅰ（11），4-乙氧基-6-羟甲基-α-吡喃酮（14），琥珀酸乙酯--酯（22），L--苹果酸-1-丁酯（24），乙基α-L-吡喃鼠李糖苷（26），仙人掌苷Ⅱ（34），山奈酚7-O-β-D-吡喃葡萄糖基（1→4）-β-D-吡喃葡萄糖苷（46），α-D-吡喃葡萄糖甲苷-6-（苹果酸-4-甲酯）-酯（47），仙人掌苷Ⅲ（48），其中仙人掌苷Ⅰ、Ⅱ、Ⅲ及4-乙氧基-6-羟甲基-α-吡喃酮均为α-吡喃酮骨架类型的新化合物。

Results Eleven compounds were isolated and identified as:quercetin(1),kaempferol(2),quercitrin(3),protocatechuic acid(4),gallic acid(5),protocatechuic acid ethyl ester(6),ethyl gallate(7),vanillic acid(8),1,5,7-trihydroxyl-3methylan...

结果得到11个化合物，分别鉴定为：槲皮素(1)、山柰酚(2)、槲皮苷(3)、原儿茶酸(4)、没食子酸(5)、原儿茶酸乙酯(6)、没食子酸乙酯(7)、香草酸(8)、1，5，7-三羟基-3-甲基蒽醌(9)、琥珀酸(10)、5-羟甲基糠醛(11)。结论化合物6、7、9、11为首次从该属植物中分离得到。

When the radical center is located at the bridge methyl group, ring expansion is the favored rearrangement pathway unless a radical-stabilizing substituent is placed in the cyclobutyl ring adjacent to the bridge methyl group.

当自由基中心位于双环的桥甲基时，扩环过程占主导地位，但是与桥甲基相邻的环丁基上存在能够稳定自由基的取代基时，重排以开环为主。

My first article for Screen Power Magazine, which is to this day is the official magazine of Jackie Chan, was a DVD review of the Hong Kong actioner Gen-X Cops, starring Nicholas Tse and Daniel Wu.

我的第一篇文章为屏幕力量杂志，在对这天是Jackie Chan 正式杂志，是香港actioner Gen X 警察的DVD 回顾，担任主角Nicholas Tse 和丹尼尔吴。

His lips grazed hirs, Now what are you going to do?

他的唇使吃草了 hirs，现在你将要做什麼？