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.     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.