羟基酸

Chapter two 4-Hydroxybenzoic acid is connected with PEG6000 through defoliant DCC at rooom temperature, then the product is refluxed with chloroacetic acid in acetone to afford PEG-bound phenyloxyacetic acid, which is reacted with thionyl chloride, ammonium thiocyanate and arylamines in turn to give PEG-bound disubstituded thioureas. After the cleavage with sodium methoxide in methanol, the eleven disubstituted thioureas are obtained.

第二章 利用PEG6000作载体，通过脱水剂DCC在室温下将对羟基苯甲酸以酯键连接在PEG6000上，再与氯乙酸在较温和的条件下生成PEG6000支载的芳氧乙酸，然后，依次与亚硫酰氯、硫氰酸铵、芳胺反应，生成PEG6000支载的硫脲，最后用甲醇钠的甲醇溶液切割PEG，得到了十一种1，3-二取代硫脲。

Herein, we report the enantioselective total syntheses of slagenins A-C and their antipodes. Starting from readily available ethyl -4-chloro-3-hydroxy-butanonate, elongation of the carbon chain with diazomethane, followed by oxidation of the given α-diazoketone using distilled DMD, afforded a key intermediate α-ketoaldehyde .

本文从方便易得的-4-氯-3-羟基-丁酸乙酯出发，经重氮甲烷延伸碳连、DMD氧化相应的α-重氮酮，制得α-酮醛；该化合物与尿素在氢氟酸作用下，以协同方式非对映选择性的直接构建了cis-四氢呋喃并[2，3-d]咪唑啉-2-酮双环结构，进而合成了天然产物slagenins A、B、和C的对映体。

The resultant was hydrogenised to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA.

本文首先对4-ASA的氨基和羟基进行了选择性保护，通过氢化还原法选择性脱除氨基的保护基，然后将氢化产物制成重氮盐，通过与水杨酸、苯酚和水杨酰甘氨酸发生反应生成4-ASA的偶氮衍生物，最后在碱性条件下水解得到最终产物。

Physical properties of the system related to the process of synthesizing ethyl 3-hydroxybutyrate were determined.

主要介绍了3-羟基丁酸乙酯合成过程中的相关物系的物性测定。

Results and Discussion Flavin 2 was synthesized from 3,4-diaminobenzoic acid (3) and alloxane monohydrate (4) in good yield according to standard procedures (Scheme 1).9 The first step afforded flavin 5 in quantitative yield, in 1:1 ratio of the 7- and 8-hydroxycarbonyl regioisomers, and was subsequently methylated by methyl iodide to form flavin 6 in 86% yield, in a 3:2 ratio of the 7- and 8-regioisomers.

结果与讨论黄素二是合成3，4 -二氨基安息香的酸（ 3 ）和氧嘧啶水合物（ 4 ）在良好的收益率根据标准程序（计划1） 0.9的第一步，给予黄素五，在定量产量，在1：1的比例， 7 -8 -羟基羰基 regioisomers ，并随后甲基甲基碘形成黄素6月在86 ％的产量，在一个3：2的比例， 7 -和8 regioisomers 。

The beheviour of four low-molecule weight organic acid lactic acid,hydroxy-acetic acid,mercapto-acetic acid,glyconic acid as iron-containing silicate-aegirines depressants on the hematite direct flotation is investigated in this paper.The results of flota

本文研究了四种小分子有机酸抑制剂乳酸、羟基乙酸、巯基乙酸、葡糖酸在赤铁矿正浮选中对含铁硅酸盐脉石霓石的抑制行为，纯矿物、人工混合矿与实际矿石浮选实验均证明了它们具有良好的选择性抑制作用，可以成功地实现赤铁矿与霓石的浮选分离。

Hydroxycitric acid is the princiole acid of fruit rinds of Garcinia .

羟基柠檬酸是藤黄果皮中的主要酸。

Second, among the seven yeast strains investigated, Rhodotorula gracilis AS 2.499 exhibited the highest activity and stereo-selectivity to tert-butyl-6-chloro-5-hydroxy-3-oxohexanoate.

其次，从实验室保藏的七株酵母菌株中筛选出对-6-氯-5-羟基-3-羰基己酸叔丁酯具有较高还原能力的菌株——Rhodotorula gracilis AS 2.499。

In the scheme,the key reactions were Grignard reaction, dihydroxylation,S_N2 substitution of hydroxyl and epoxide under acidic conditions and etc.

合成过程中的关键反应为Grignard反应，双羟化反应，质子酸催化的羟基与环氧的S_N2亲核取代成环反应。

DMBQ, resorcin, ferulic acid, and hydroxybenzoic acid were effective chemical signal substances in the inducement of haustorium, but the haustorium formation rate was only 3.3%.

适当浓度的2，6-二甲氧基对苯醌、间苯二酚、阿魏酸和对羟基苯甲酸均可诱导肉苁蓉种子萌发形成吸器，吸器形成率最高为3.3%。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。