2000年全国高中学生化学竞赛(决赛)理论试题答案及评分标准

1—1 X——SiCl4（5分）1—2 Y——SiOSiCl2（3分）1—3 Z——Si（NHSiCl2）SiCl4（2分）     

STRUCTURAL STUDIES OF AN ARABINOGALACTAN——A WATER SOLUBLE POLYSACCHARIDE FROM THE POLLEN OF PAPAVER SOMNIFERUM

A polysaccharide,PS(1),has been isolated from the pollen of papaver somniferum.PS(1)is ahighly branched arabinogalactan,which,mainly contains α—L—arabinofuranosyl(1→)and(3,6→1)—β—D—galactopyranosyl residues.We also studied the circular dichroism and immunoactivity of PS(1).     

一种新的选择性氧化苏-（1S，2S）-2-（N，N-二甲胺基）-1-（对硝基苯基）-1，3-丙二醇的N-甲基为N-甲酰基的方法

报告多官能团化合物苏—(1S，2S)—2—(N，N-二甲胺基)—1—(对硝基苯基)—1，3—丙二醇与聚合物支载条件下的溴试剂发生的—种新的选择性N-甲基氧化为N-甲酰基的反应．在Na2HPO4存在下，苏—(1S，2S)—2—(N，N-二甲胺基)—1—(对硝基苯基)—1，3．丙二醇于水—CCL4体系中被717阴离子交换树脂支载的溴在60℃氧化24h给出51％收率的苏—(1S，2S)—2—(N-甲基—N—甲酰胺基)—1—(对硝基苯基)-1，3-丙二醇.这种选择性N—甲基氧化为N-甲酰基的反应在2—氨基—1，3—丙二醇衍生物化学中是第—次观察到．     

利用溶解度参数选择有机溶剂提取土壤中多种有机氯农药

采用基团贡献法计算了提取溶剂（正己烷、二氯甲烷、正己烷—甲醇（体积比4：1)、正己烷—丙酮（体积比1：1)、正己烷—二氯甲烷(体积比1：1))和有机氯农药（o,p′—DDT,o．p′—DDE,o,p′—DDD,α—endosubn,endrin,HCB)的色散溶解度参数(δd)、极性溶解度参数(δp)和氢键溶解度参数(δh),运用溶解度参数的理论筛选有机溶剂提取江西红壤中多种有机氯农药：研究表明正己烷—甲醇（体积比4：1)和正己烷—丙酮（体积比1：1)是提取江西红壤中o,p′—DDT,o,p′—DDE,o,p′—DDD多种有机氯农药的最佳提取溶剂（回收率大于82％),对α—endosulfan,endrin,HCB的提取也能满足检测需要（回收率大于75％)。超声波提取的结果验证了溶解度参数预测的合理性。     

A NEW SYNTHETIC ROUTE TO α-DAMASOONE

A new synthetic route to α—damascone (4) starting from citral is described-The synthesis features allylatioa of α—cyclocitral (1) with allylic bromide in the presence of tin powder to give the crucial intermediate 1—(2',6',6'—trimethylcyclo— hexen —2'—yl)—3—buten —1—ol(2a) and (2b) in a combined yield of 70%.     

调味品中氯丙醇的GC/ECD和GC/MS/MS衍生化检测方法研究及应用

报道了调味品中氯丙醇的衍生化气相色谱(GC／ECD)和衍生化气相色谱双串联质谱法(GC／MS／MS)测定。GC／ECD测定酱油中3—氯—1，2—丙二醇(3—MCPD)的检出限达到0．01mg／kg，回收率为91％～104％，变异系数为2．27％～7．96％；GC／MS／MS同时测定酱油中1，3—二氯—2—丙醇、2，3—二氯—1—丙醇和3—氯—1，2—丙二醇，1，3—二氯—2—丙醇、2，3—二氯—1—丙醇的检出限为0．02mg／kg，3—氯—1，2—丙二醇的检出限为0．01mg／kg，回收率在92％～106％，变异系数为3．51％～13．33％。     

牛蒡矮化类病毒(BSV)的研究——BSV-RNAs的变性行为和在植株中的分别存在

本文用双向聚丙烯酰胺凝胶电泳技术,研究了BSV—RNAs的变性行为,进一步证实了它们具有环状分子结构。1980—1983年对BSV—RNAs在不同植株中分布的电泳分析证明,BSV—RNA—1和BSV—RNA—2分别存在于不同的植株中。从含BSV—RNA—1的病叶诱导的愈伤组织的生长比健叶的缓慢。BSV—RNA—1可在愈伤组织中连续复制8个月以上,表明它具有类病毒复制的特征。     

STUDY ON 1,2,3-DIAZAPHOSFHOLE V THE REACTION OF 1,2,3-DIAZAPHOSPHOLE WITH 2-BUTYNE-1,4-DIOL

2-Acetyl-5-methyl-2H-1,2,3—diaraphosphole 1 reacted with 2—butyne—1, 4—diol to form a tricoordinated phosphorus compound 7, which then rearranged to a novel 2, 3-disubstituted-1, 3-diene.Similar rearrangement has been observed when diphenylchloropbosphine reacted with 2-butyne—1,4-diol     

以毫克当量倒数为当量浓度的标准溶液

本文介绍采用毫克当量倒数为当量浓度的标准溶液,可大大简化分析结果的计算。如容量分析的计算式为:X=V×N×K/G (1)X=V×N×K/D×W (2)式中 X—计算结果;N——标准溶液当量浓度;V——消耗标准溶液的体积(毫升);K——被测物质毫克当量数(或换算成计算结果的系数);G——样品重量(克),D——样品比重;W——样品体积(毫升)。如使上式中N×K=1,N×K/W=1,或,N×K/W×D=1(D变化可忽略不计),则式(1)可简化为X=V/G;式(2)可简化为为X=V/G 或X=V。     

YLID化学

ylid(或ylide。内鎓盐)是指结构为Y—CR~1R~3的一类化合物的总称。目前已知的有磷ylid R_3P—CR~1R~2、砷ylid R_3As—CR~1R~2、锑ylid R_3Sb—CR~2R~2、碗ylidR_2S—CR~1R~2、R_2SOCR~1R~2、氮ylid R_3N—CR~1R~2和硼ylidR_3B—CR~1R~2等。     

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%.     

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.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.