2,3,3',4'-联苯四甲酸二酐的合成

报道了一种从卤代邻二甲苯偶联和液相氧化制备2,3,3',4'-联苯四甲酸二酐(3,4'-BPDA)的简便方法。 以NiF₂-PPh₃(PPh₃:三苯基膦)为催化体系,高效地实现了4-溴邻二甲苯格氏试剂与3-氯代邻二甲苯的交叉偶联反应,合成了2,3,3',4'-四甲基联苯(3,4'-TMDP),后者经液相氧化、高温脱水成酐制备了3,4'-BPDA,两步总产率达到74%。 这条路线与从邻苯二甲酸二甲酯或混合氯代邻苯二甲酸二甲酯制备3,4'-BPDA相比,不涉及酯的水解及异构体的分离等过程,因此分离及环保方面具有非常明显的优势,同时合成路线更简便。     

新型蒎烷基吡唑酰胺类衍生物的合成及其生物活性研究

以诺蒎酮为原料,合成了新型蒎烷基吡唑酰胺类衍生物,并对其生物活性进行了研究.诺蒎酮与芳香醛进行缩合反应,得到中间体3-芳亚甲基诺蒎酮2a~2g,2a~2g与水合肼经环化、脱氢芳构化反应,得到新型蒎烷基吡唑类化合物3a~3g;以N,N-二甲基甲酰胺为溶剂,3a~3g与2-氯乙酰胺在碱催化作用下,合成了7种吡唑酰胺类化合物4a~4g.其结构经~1H NMR,~(13)C NMR,IR,和HRMS表征.通过X射线衍射分析测定了化合物2-(6',6'-二甲基-3'-(4'-甲氧基苯基)-4',5',6',7'-四氢-5',7'-桥亚甲基-吲唑-1'-基)乙酰胺(4d)的晶体结构.探讨了化合物3a~3g和4a~4g的抑菌活性和对蚜虫的杀虫活性.实验结果表明,2-(6',6'-二甲基-3'-(4'-氟苯基)-4',5',6',7'-四氢-5',7'-桥亚甲基-吲唑-1'-基)乙酰胺(4g)既具有较好的抑菌效果,同时对紫薇蚜虫也表现出较好的杀虫活性.     

苯并噻唑偶氮吡唑和苯并噻唑偶氮嘧啶的合成

2-氨基苯并噻唑重氮盐与丙二腈偶联, 生成2-(苯并噻唑腙基)-丙二腈, 然后分别与水合肼, 苯肼和硝酸胍反应, 形成相应的4'-(苯并噻唑-2-偶氮)-3',5'-二氨基吡唑, 4'-(苯并噻唑-2-偶氮)-3',5'-二氨基-2'-苯并吡唑和5'-(苯并噻唑-2-偶氮)-2',4',6'-三氨基嘧啶.     

2,6-二甲基-3,5-二氯-4-吡啶酚糖苷的合成

在相转移催化条件下, 使 a-D-乙酰基化溴代的葡萄糖、半乳糖、葡萄糖醛酸甲酯1a, 1b, 1c分别与2,6-二甲基-3,5-二氯-4-吡啶酚(俗称氯吡醇, 氯羟吡啶)作用, 合成了氯吡醇的糖苷: 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基-β-D-葡萄吡喃糖苷(2a), 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基β-D-半乳吡喃糖苷(2b), 1-O-(2'6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4-三-O-乙酰基-β-D-葡萄吡喃糖醛酸甲酯(2c)。2a, 2b, 2c分别在甲醇中氨解, 相应得到: 1-O-(2', 6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖苷(3a), 1-O(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-半乳吡喃糖苷(3b),1-O-(2', 6'-二甲基-3',5'-二氯-(4'-吡啶基)-β-D-葡萄吡喃糖醛酸酰胺(3c)。2c用CH~3ONa/CH~3OH处理, 得到1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖醛酸甲酯(3d)。     

钯配合物催化的芳基-芳基不对称偶联反应

本文以三种匀性膦作配体制成了零价钯配合物, 并分虽试验了由它们催化苯酚得到的α-溴-β-苄氧基萘和进一步衍生而得的格氏试剂的偶联反应, 制成了β'β'-二苄氧基-α', α'-联萘.     

1,2,3,4-四(6,7,-二甲基苯并 唑)环丁烷光谱特性研究

本文测定并对1,2,3,4-四(6',7'-二甲基苯并 唑)环丁烷(1)及其模型化合物反-1,2-二(6',7'-二甲基苯并 唑-1',3'-基-2')乙烯(2), 1,2-二(6',7'-二甲基苯并唑-1',3'-基-2')乙烷(3), 2-甲基苯并 唑(4)的紫外吸收光谱和荧光发射光谱进行对比。研究了化合物1由于跨环共轭效应所引起的电子光谱的变化, 并从溶剂效应及晶体结构进行了探讨。     

1,2,3,4-四(6,7,-二甲基苯并 唑)环丁烷光谱特性研究

本文测定并对1,2,3,4-四(6',7'-二甲基苯并 唑)环丁烷(1)及其模型化合物反-1,2-二(6',7'-二甲基苯并 唑-1',3'-基-2')乙烯(2), 1,2-二(6',7'-二甲基苯并唑-1',3'-基-2')乙烷(3), 2-甲基苯并 唑(4)的紫外吸收光谱和荧光发射光谱进行对比。研究了化合物1由于跨环共轭效应所引起的电子光谱的变化, 并从溶剂效应及晶体结构进行了探讨。     

(±)-Malaysianone A和(±)-Tanariflavanones B的全合成

以取代苯乙酮和5-醛基-8-甲氧甲氧基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃为原料,经羟醛缩合反应制得两个中间体——7,2',4'-三甲氧甲氧基-6'-羟基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃查尔酮(3a)和7,2',4'-三甲氧甲氧基-5'-异戊烯基-6'-羟基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃查尔酮(3b);3a经环合和脱保护基反应合成了(±)-Malaysianone A(4a),产率12.9%;3b经脱保护基和环合反应合成了(±)-Tanariflavanones B(4b),产率5.2%。4a和4b的结构经1H NMR,13C NMR和HR-ESI-MS确证。     

新型苯并吡喃黄酮的合成及其抗肿瘤活性

2,2-二甲基-8-乙酰基-7-羟基-5-甲氧基色满分别与对甲基苯甲酰氯,间氯苯甲酰氯和间三氟甲基苯甲酰氯经Baker-Venkataraman重排和关环反应合成了3个新型的苯并吡喃黄酮(3a~3c);1-(2″,4″-二甲氧基苯基)-3-(2',2'-二甲基-7'-羟基-5'-甲氧基色满-8')-1,3-二酮(4)分别与烯丙基溴,异戊烯基溴和碘甲烷经取代和关环反应合成了3个新型的3-烃基苯并吡喃黄酮(6a~6c)。3和6的结构经1H NMR,13C NMR和MS表征。采用MTT法和SRB法研究了3和6体外对人白血病细胞(K562)和人肺癌细胞(K549)的抗肿瘤活性。结果表明:2',4'-二甲氧基-2″,2″-二甲基-3″,4″-2H二氢吡喃-3-甲基-5″,6″:5,6-黄酮(6c)显示了较好的抗肿瘤活性。     

三联噻吩-吡唑啉类化合物的合成

以2-溴噻吩为原料,经溴代反应和格氏试剂反应制得2,2':5',5'-三联噻吩(1);1乙酰化后与4-取代苯甲醛发生亲核加成反应得到α,β-不饱和酮(3a～3e);3与80%水合肼发生关环反应,合成了5个α-三联噻吩-毗唑啉类化合物(4a～4e),收率74.3%～89.7%.其结构经H NMR,IR和元素分析表征.3和4均为新化合物.     

Synthesis and computational studies of Mg complexes supported by 2,2':6,2'-terpyridine ligands

The reactions of the substituted 2,2':6,2'-terpyridine ligands, 4'-mesityl-2,2':6',2'-terpyridine (mesitylterpy) (1a), 4,4',4'-tri-tert-butyl-2,2':6',2'-terpyridine (tri-(t)Buterpy) (1b) and 4'-phenyl-2,2':6',2'-terpyridine (phenylterpy) (1c) with Grignard reagents were investigated. When half an equivalent of mesitylterpy or tri-(t)Buterpy were treated with MeMgBr in diethyl ether, the only products were (R-terpy)MgBr(2) (R = mesityl (5a), or tri-(t)Bu (5b)) and Me(2)Mg and a similar reaction was observed in THF. Compounds 5a and 5b were characterized by X-ray crystallography. Changing the Grignard reagent to PhMgBr also generated 5a and 5b along with Ph(2)Mg, while the reaction between MeMgCl or PhMgCl and 1a or 1b generated (R-terpy)MgCl(2) (R = mesityl (6a), or tri-(t)Bu (6b)) and either Me(2)Mg or Ph(2)Mg, respectively. The products from reactions between phenylterpy (1c) and Grignard reagents were highly insoluble and could not be fully characterized but appeared to be the same as those from reactions with 1a and 1b. In contrast to other studies using tridentate nitrogen ligands, which formed either mixed halide alkyl species or dihalide and bis(alkyl) species depending on whether the Grignard reagent was reacted with the ligand in diethyl ether or THF, the formation of mixed halide, alkyl complexes of the type (R-terpy)MgR'X (R' = Me or Ph; X = Cl or Br) or dialkyl species such as (R-terpy)MgR'(2) (R' = Me or Ph) was not observed here, regardless of the reaction conditions. DFT studies were performed to complement the experimental studies. The experimental results could not be accurately reproduced unless π-stacking effects associated with free terpyridine were included in the model. When these effects were included, the calculations were consistent with the experimental results which indicated that the formation of the terpy Mg dihalide species and R'(2)Mg (R' = Me or Ph) is thermodynamically preferred over the formation of mixed alkyl halide Mg species. This is proposed to be due to the increased steric bulk of the terpy ligand in the coordination plane, compared with other tridentate nitrogen donors.     

A non-Diels-Alder approach to the cis-decalin core of branimycin

The synthesis of the highly substituted cis-decalin core of branimycin has been accomplished. A catalytic copper mediated SN2' opening of oxabicycle 7 with Grignard reagent and ring-closing metathesis served as key transformations.     

Double addition of grignard reagents to N-glycosyl nitrones: a new tool for the construction of enantiopure azaheterocycles

[Reaction: see text] C-Phenyl-N-erythrosylnitrone 3 behaves as a C1,C1' bis-electrophile, undergoing a double addition of Grignard reagents in a domino fashion to afford acyclic hydroxylamines 4. The reaction proceeds at 0 degrees C with variable degrees of diastereoselectivity, from moderate to good, mainly depending on the organomagnesium reagent used. The usefulness of compounds 4 has been exemplified with the synthesis of pyrroloazepine 12 through a ring closing metathesis key step.     

Highly regioselective synthesis of gem-difluoroallenes through magnesium organocuprate SN2' substitution

[reaction: see text]. The reaction of gem-difluoropropargyl electrophiles with Grignard reagents is complicated by the inherent difficulty of executing nucleophilic substitutions on a CF2 group, and the facile formation of carbenoid intermediates arising from alpha-elimination of fluoride. In the presence of an excess amount of a copper salt, a Grignard reagent reacts with gem-difluoropropargyl bromide via an S(N)2' mechanism to produce gem-difluoroallene in high yield. If desired, the resulting difluoroallene can undergo a second nucleophilic attack on the CF2 terminus to yield a trisubstituted monofluoroallene through an addition-elimination mechanism.     

Tandem copper-catalyzed enantioselective allylation-metathesis

Grignard reagents undergo enantioselective (up to 86% ee) copper-catalyzed S(N)2' substitution on achiral allylic chlorides. The reaction is wide in scope for both the Grignard reagent and the allylic substrate. The resulting terminal alkene could be submitted to intra- or intermolecular metathesis to afford new chiral synthons. The experimental conditions are compatible with a one-pot overall substitution-metathesis procedure without loss of enantioselectivity. [reaction: see text]     

Asymmetric synthesis of all the known phlegmarine alkaloids

The asymmetric synthesis of all four of the known natural phlegmarines and one synthetic derivative has been accomplished in 19-22 steps from 4-methoxy-3-(triisopropylsilyl)pyridine. Chiral N-acylpyridinium salt chemistry was used twice to set the stereocenters at the C-9 and C-2' positions of the phlegmarine skeleton. Key reactions include the use of a mixed Grignard reagent for the second N-acylpyridinium salt addition, zinc/acetic acid reduction of a complex dihydropyridone, and a von Braun cyanogen bromide N-demethylation of a late intermediate. These syntheses confirmed the absolute stereochemistry of all of the known phlegmarines.     

Nickel-catalyzed cross-coupling reaction of alkynyl bromides with Grignard reagents

We describe a convenient method for the synthesis of 1,2-disubstituted acetylenes via a cross-coupling reaction of （bromoethynyl）benzene with Grignard reagents. The reaction of （bromoethynyl）benzene （1 mmol） with Grignard reagent （1.3 mmol） mediated by NiCl2 （4 mol%） and （p-CH3Ph）3P （8 mol%） in THF could produce 1,2-disubstituted acetylenes in good yields at room temperature.     

A Convenient Preparation of Symmetric and Asymmetric Trifluoromethylphosphines

Abstract

Chloro(diethylamino)trifluoromethylphosphine (1), easily prepared from 2 by the method of W. Volbach and I. Ruppert [l], reacts with Grignard compounds to yield 3; the latter can be converted by HCl into the corresponding chloroderivatives, which upon repeated treatment with Grignard reagent yield symmetric and asymmetric trifluoro-methylphosphines 4.     

Ligand exchange reactions of aryl pyridyl sulfoxides with grignard reagents: Convenient preparation of 3- and 4-pyridyl grignard reagents and examination of the leaving abilities of pyridyl anions

Aryl 3- and 4-pyridyl sulfoxides undergo ligand exchange in reactions with aryl Grignard reagents to generate 3- and 4-pyridyl Grignard reagents, which, upon treatment with aldehydes or ketones, give the corresponding addition products in moderate-to-good yields. The mechanism for the exchange reaction was investigated by treating optically active 3- and 4-pyridyl p-tolyl sulfoxides with a phenyl Grignard reagent. Inversion of the configuration of the sulfur atom was the stereochemical result of the reactions. In the reactions of phenyl 2-pyridyl sulfoxide with Grignard reagents, the leaving ability of the 2-pyridyl group competes with that of the phenyl group. Both the experimental and MO calculated enthalpy values for deprotonation of α-, β-, and γ-protons of pyridine in the gas phase [1] are in accordance with the following order of the leaving abilities of aryl and pyridyl Grignard reagents: 4-PyMgBr > 3-PyMgBr » PhMgBr > p-TolMgBr > 2-PyMgBr.     

3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的合成

报道了以草酸二乙酯为原料,制备具有焦糖香味的香料化合物3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的方法:首先乙基溴化镁与草酸二乙酯通过格氏反应,以约50%产率生成2-氧代丁酸乙酯,然后其在碳酸钾的作用下发生缩合反应,以约94%产率得到3-羟基-4-甲基-5-乙基-5-乙氧羰基-2(5H)-呋喃酮,再通过水解、脱羧反应,得到3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮.路线总收率约36%.