N''-叔丁基-N''-取代苯甲酰基-N-(苯并二氢吡喃-5-甲酰基)肼的设计合成及晶体结构

以间羟基苯甲酸为起始原料通过7步反应合成了15个新颖的的N'-叔丁基-N'-取代苯甲酰基-N-(苯并二氢吡喃-5-甲酰基)肼类化合物.中间体3-炔丙氧基苯甲酸甲酯在N,N-二乙基苯胺中发生克莱森重排后得到主要产物苯并吡喃-5-甲酸甲酯和副产物苯并吡喃-7-甲酸甲酯.通过氢谱、元素分析或高分辨质谱确定了这些化合物的结构,化合物1a的X射线单晶衍射分析发现苯并二氢吡喃的吡喃环与苯环不共平面,其中的C(1)和C(2)分别位于相应苯环平面的两侧.     

N′-叔丁基-N′-取代苯甲酰基-N-(苯并二氢吡喃-5-甲酰基)肼的 设计合成及晶体结构

以间羟基苯甲酸为起始原料通过7步反应合成了15个新颖的N′-叔丁基-N′-取代苯甲酰基-N-(苯并二氢吡喃-5-甲酰基)肼类化合物. 中间体3-炔丙氧基苯甲酸甲酯在N,N-二乙基苯胺中发生克莱森重排后得到主要产物苯并吡喃-5-甲酸甲酯和副产物苯并吡喃-7-甲酸甲酯. 通过氢谱、元素分析或高分辨质谱确定了这些化合物的结构, 化合物1a的X射线单晶衍射分析发现苯并二氢吡喃的吡喃环与苯环不共平面, 其中的C(1)和C(2)分别位于相应苯环平面的两侧.     

干姜中的二芳基庚烷类化合物及其在四逆汤煎煮过程中的立体选择性反应

采用高效液相色谱多级质谱联用鉴定了干姜水煎剂的18个二芳基庚烷类化合物。发现此类化合物的电喷雾质谱碰撞诱导裂解反应的特征主要表现在吡喃环的次级逆Diels Alder反应裂解或C1和C5OH发生次级麦氏重排裂解,这两种裂解反应对归属芳环的取代非常重要。比较了复方四逆汤配伍对二芳基庚烷类化合物的影响,从色谱保留行为、质谱数据等推测化合物2-(3,4-二羟基-5-甲氧基苯基)-6-(3,4-二羟基苯乙基)-2氢-吡喃-4-醇(Ⅲ-1)的一组差向异构体,2-(3,4-二羟基-5-甲氧基苯基)-6-(4-羟基苯乙基)-2氢-吡喃-4-醇(Ⅲ-2)的一组差向异构体以及2-(3,4-二羟基-5-甲氧基苯基)-6-(4-二羟基-3-甲氧基苯乙基)-2氢-吡喃-4-醇(Ⅲ-3)的2组差向异构体在复方煎煮过程中发生显著的立体选择性反应,由外消旋体变成单一旋光异构体。吡喃环4-位的乙酰化可能是减少这种反应的关键因素。     

9,10-二氢苯并[h]香豆素类化合物的双羟化反应研究及酯化产物的合成

报道了在9,10-二氢苯并[h]香豆素类化合物1a,1b的不对称双羟化反应中,除了得到正常的cis-7,8-双羟化产物2a,2b外,还以中等收率(52%和45%)得到了过度氧化产物7-羰基-8-羟基化合物3a,3b,并讨论了氧化剂用量及反应温度对产物分布的影响.双羟化产物2a,2b的ee值通过其樟脑酯化产物4a,4b的1HNMR图谱所示的非对映异构体比例进行了初步推测.过度氧化产物3b及其樟脑酯化产物5b的结构经X射线单晶衍射分析确证     

KF-蒙脱土催化下2-氨基-3-氰基-4-芳基-7,7-二甲基-5-氧代-4H-5,6,7,8-四氢苯并[b]吡喃的合成

以KF-蒙脱土为催化剂, 取代肉桂腈与5,5-二甲基-1,3-环己二酮在95%乙醇中回流反应得2-氨基-3-氰基-4-芳基-7,7-二甲基-5-氧代-4H-5,6,7,8-四氢苯并[b]吡喃, 此方法快速、方便、高效, 同时考察了溶剂、催化剂对反应的影响.     

两种苯并二氢吡喃-4-酮衍生物的合成

分别以间甲氧基苯酚与间苯二酚为原料,经过3步合成了(E)-7-甲氧基-3(4-甲氧基苯哑甲基)与(E)-7-羟基-3-(3',4',5'-三甲氧基苯哑甲基)取代的苯并二氢吡喃-4-酮.合成路线简单,易于操作,两者的最终收率分别为20.1%和15.3%.     

轴手性联二萘酚酰胺催化剂的合成及应用

以2,2′-二羟-1,1′-联二萘-3,3′-二羧酸为原料,合成了3个具有轴手性的联二萘酚酰胺类衍生物(1a~1c),将其作为催化剂应用到四氢吡喃酮与醛的不对称直接Aldol反应中,考察其催化活性。研究结果表明: 15 mmol% 1c为催化剂,CH₂Cl₂为溶剂,于0 ℃反应28 h,四氢吡喃酮与醛能有效进行不对称直接Aldol反应,获得较好的收率（最高91%）和较高的对映选择性(最高95% ee)。     

微波辐射下2-[4-二-(4-氟苯)甲基]哌嗪乙酰腙化合物的合成

微波辐射条件下, 以丙酮作溶剂, 1-[二-(4-氟苯)甲基]哌嗪与氯乙酸乙酯反应得到2-[二-(4-氟苯)甲基]哌嗪乙酸乙酯(1), 1与水合肼在微波辐射条件下反应得到2-[二-(4-氟苯)甲基]哌嗪乙酰肼(2), 进一步在微波辐射条件下由2-[二- (4-氟苯)甲基]哌嗪乙酰肼(2)与取代芳香醛反应制得目标化合物3a～3f. 合成的6个目标化合物通过熔点测定和质谱、红外光谱、核磁共振氢谱分析、元素分析对其结构进行确证.     

5-溴-2-羟基苯甲醇的不对称羟基保护

采用分步法对5-溴-2-羟基苯甲醇中的不对称羟基进行了选择性保护.以2,3-二氢吡喃和氯甲醚为保护基,经两步反应得5-溴-2-甲醚氧基苯甲-2-(四氢吡喃)醚,其结构经1H NMR, IR和MS表征.     

8-5’新木脂素类化合物的合成方法研究

对羟基桂皮酸甲酯和阿魏酸甲酯分别在氧化银催化下发生自由基仿生氧化偶联反应, 合成得苯并二氢呋喃环结构化合物1, 1经甲基化反应得2. 1a和1和2分别在无水碳酸钾、10%氢氧化钠水溶液等不同的碱性条件下进行反应, 获得了11个苯并二氢呋喃环开环产物, 即8-5’新木脂素类化合物3a～9b, 实现了由苯并二氢呋喃新木脂素向8-5’新木脂素的转变, 也为合成芪类化合物提供了一种新方法. C-8位上的吸电子基团如酯基的影响使苯并二氢呋喃环易在碱性条件下开环形成8-5’新木脂素类化合物．所合成化合物的结构由MS, IR, 1H NMR和13C NMR进行了表征.     

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.     

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.     

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.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.