The Study on the Synthesis of Rosuvastatin Intermediate via DDQ/TBN Catalyzed Aerobic Oxidative Aromatization

以DDQ和TBN为催化剂,氧气为氧源,研究了罗素伐他汀母核合成过程中从多取代二氢嘧啶（I）转化为相应的嘧啶中间体（II）的氧化芳构化反应.考察了反应温度,反应溶剂及催化剂用量对氧化芳构化反应的影响.优化实验结果表明,以2%的DDQ及10%TBN为催化剂,氧气为氧源,在甲苯中60℃反应24 h,多取代二氢嘧啶完全转化,获得高选择性的氧化芳构化产物嘧啶中间体（II）.在50 mmol规模的氧化芳构化反应的实验中获得了98.8%的分离收率,反应的后处理方便简洁.     

微波辐射下4,6-二羟基嘧啶与醛的反应研究

以甲胺为催化剂、醋酸为溶剂, 微波促进下芳香醛与两分子4,6-二羟基嘧啶反应得到6-羟基-5-[(4-羟基-6-氧代-1,6-二氢嘧啶-5-基)芳甲基]嘧啶-4(3H)-酮衍生物.     

2,3-二氯-5,6-二氰基-1,4-苯醌促进的3,4-二氢嘧啶硫酮的氧化偶联反应合成1,2-二嘧啶基二硫醚

在室温、空气气氛下,以2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)为氧化剂,快速实现了3,4-二氢嘧啶-2-硫酮的氧化偶联芳构化反应,以较高产率合成了系列1,2-二嘧啶基二硫醚.该法与已知的合成1,2-二嘧啶基二硫醚的方法相比,具有反应温度低、反应时间短及产率高的优点.通过1H NMR,13C NMR,HRMS及X射线单晶衍射对其结构进行了表征,并简要探讨了其结构特性和反应机理.     

2,3-二氯-5,6-二氰基-1,4-苯醌/NaNO2

设计了一种由 2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)和NaNO2组成的复合催化剂,该催化剂在9,10-二氢蒽氧化脱氢生成蒽的反应中表现出很高的催化活性和选择性. 在120 ℃和1.3 MPa O2下反应 8 h, 9,10-二氢蒽转化率达到99%以上,蒽的选择性为99%. 采用红外光谱和核磁共振方法对催化氧化脱氢的反应历程进行了研究. 结果表明, 9,10-二氢蒽氧气氧化脱氢生成蒽的反应是通过DDQ/DDQH2和NO2/NO两个氧化还原对的电子传递来推动的,以DDQ/NaNO2为催化剂可以有效催化9,10-二氢蒽氧化脱氢生成蒽.     

Ni(PPh3)2Cl2催化2-氯嘧啶与芳基硼酸的Suzuki-Miyaura偶联反应

本文在Ni(PPh3)2 Cl2催化下顺利实现了不同取代基2-氯嘧啶与芳基硼酸的Suzuki-Miyaura偶联反应.实验表明,取代基的电子效应和空间位阻效应对2-氯嘧啶的反应活性影响较小.该反应产率良好,官能团耐受性好,为2-芳基嘧啶衍生物的合成提供了一类简单有效的方法.     

一锅法合成N1,N3-二烷基取代-3,4-二氢嘧啶-2(1H)-酮及其抗菌活性研究（英文）

在温和的相转移催化剂存在下,合成得到一系列N1,N3-二烷基取代-3,4-二氢嘧啶-2(1H)-酮,并测定了取代二氢嘧啶酮对灰霉菌、小麦赤霉菌、辣椒疫霉病菌、油菜菌核病菌、水稻纹枯病菌、稻瘟病菌六种霉菌的抗菌活性。多数取代二氢嘧啶酮对后五种霉菌体现出不错的抗菌活性,特别是N原子上被(CH2)nBr取代的二烷基取代二氢嘧啶酮对于油菜菌核病菌、小麦赤霉菌以及辣椒疫霉病菌表现出不错的抗菌活性。数据表明,二氢嘧啶酮中嘧啶环和酯基上的取代基变化有助于改善嘧啶酮的抗菌活性。     

可见光驱使下有机染料与镍配合物催化放氢芳构化反应研究

在可见光催化下,联合廉价易得的有机染料曙红Y与容易制备的镍催化剂在室温条件下,高效绿色地实现了分子内的脱氢芳构化,此过程中只放出氢气无副产物,无需外在氧化剂,条件温和,产率高,对环境友好.此外,在其他条件相同的情况下,将绝氧条件下的放氢反应跟与有氧条件下的需氧氧化反应进行了对照,发现汉斯酯衍生物及1,4-二氢嘧啶衍生物在放氢条件下得到较高产率;而在需氧氧化条件下3,4-二氢噻吩衍生物、2,5-二氢吡咯衍生物芳构化的转化率更高.     

2-氨基-4,5-二取代烃嘧啶类衍生物的新合成方法

研究了2-氨基-4,5-二烃基取代嘧啶类衍生物的一个新的简易合成方法,该方法以简单且廉价的4个芳香醛和3个脂肪醛为原料,经过四步反应得到12个2-氨基-4,5-二烃基取代嘧啶类化合物,总收率在40%～70%,经氢核磁共振(1H NMR)、碳核磁共振(13C NMR)和高效液质联用(LC-MS)对其目标产物进行表征.     

2，3-二氯-5，6-二氰基-1，4-苯醌／NaNO2催化9，10-二氢蒽氧化脱氢

设计了一种由2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ）和NaN02组成的复合催化剂,该催化剂在9,10-二氢葸氧化脱氢生成蒽的反应中表现出很高的催化活性和选择性．在120℃和1．3MPaO2下反应8h,9,10二氢蒽转化率达到99％以上,葸的选择性为99％．采用红外光谱和核磁共振方法对催化氧化脱氢的反应历程进行了研究．结果表明,9,10-二氢蒽氧气氧化脱氢生成蒽的反应是通过DDQ／DDQH2和NO2／NO两个氧化还原对的电子传递来推动的,以DDQ／NaNO2为催化剂可以有效催化9,10-二氢蒽氧化脱氢生成蒽．     

氮杂环并二氢嘧啶及嘧啶衍生物的合成及生物活性评价

利用微波促进,以芳香醛、乙酰乙酸乙酯、2-氨基咪唑或3-氨基-1,2,4-三唑为原料,通过Knoevenagel缩合反应和Atwal改进的Biginelli反应串联,简便、高效地合成了系列新型芳基取代咪唑(三唑)并二氢嘧啶衍生物.对所合成化合物进一步芳构化,得到系列氮杂环并嘧啶类化合物,为此类嘧啶化合物的合成提供一条简便的途径.对所合成的部分化合物进行了体外肿瘤细胞(Hela和A549)的细胞毒性及苹果树腐烂病菌的抑制活性测试.     

TBN as a metal-free reagent initiated sp3 C–H functionalization of glycine esters: Synthesis of quinoline-2-carboxylate esters

As a metal-free reagent, tert-butylnitrite (TBN) initiated aerobic sp³ C–H bond oxidation of glycine esters was achieved, providing a series of quinoline-2-carboxylates in good yields. The mechanistic investigation revealed that in the presence of molecular oxygen, TBN derived radicals were involved in the C–H bond oxidation and the terminal aromatization.     

Mn(OAc)3—an efficient oxidant for regeneration of DDQ: deprotection of p-methoxy benzyl ethers

Mn(OAc)₃ has been successfully developed as a new oxidant for the regeneration of DDQ from HDDQ. This DDQ regeneration technique, making use of 3 equiv. of Mn(OAc)₃–DDQ (10 mol%), was applied to the deprotection of p-methoxy benzyl (PMB) ethers.     

Synthesis of 5,15-diaryltetrabenzoporphyrins

A general method of synthesis of 5,15-diaryltetrabenzoporphyrins (Ar 2TBPs) has been developed, based on 2 + 2 condensation of dipyrromethanes followed by oxidative aromatization. Two pathways to Ar 2TBPs were investigated: the tetrahydroisoindole pathway and the dihydroisoindole pathway. In the tetrahydroisoindole pathway, precursor 5,15-diaryltetracyclohexenoporphyrins (5,15-Ar 2TCHPs) were assembled from cyclohexeno-fused meso-unsubstituted dipyrromethanes and aromatic aldehydes or, alternatively, by way of the classical MacDonald synthesis. In the first case, scrambling was observed. Aromatization by tetracyclone was more effective than aromatization by DDQ but failed in the cases of porphyrins with electron-withdrawing substituents in the meso-aryl rings. The dihydroisoindole pathway was found to be much superior to the tetrahydroisoindole pathway, and it was developed into a general preparative method, consisting of (1) the synthesis of 4,7-dihydroisoindole and its transformation into meso-unsubstituted dipyrromethanes, (2) the synthesis of 5,15-diaryloctahydrotetrabenzoporphyrins (5,15-Ar 2OHTBPs), and (3) their subsequent aromatization by DDQ. Ar 2TBP free bases exhibit optical absorption spectra similar to those of meso-unsubstituted tetrabenzoporphyrins and fluoresce with high quantum yields. Pd complex of Ph 2TBP was found to be highly phosphorescent at room temperature.     

Efficient NO equivalent for activation of molecular oxygen and its applications in transition-metal-free catalytic aerobic alcohol oxidation

tert-Butyl nitrite (TBN) was identified as an efficient NO equivalent for the activation of molecular oxygen. The unique property of TBN enabled TEMPO-catalyzed aerobic alcohol oxidation to be performed in high-volume efficiency. Up to a 16,000 turnover number was achieved in this transition-metal-free aerobic catalytic system. Under the optimal reaction conditions, various alcohols were converted into their corresponding carbonyl compounds with TEMPO/HBr/TBN as catalyst. The newly developed method was suitable for the oxidation of solid substrate alcohols with high melting point and/or low solubility under the help of minimum solvent to form a slurry.     

Metal-free oxidative aromatization of 2-aryloxycyclohex-2-en-1-ones to 2-aryloxyphenols using DDQ/Amberlyst-15

Efficient metal-free oxidative aromatization of 2-aryloxycyclohex-2-en-1-ones was achieved by a combination of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and Amberlyst-15. The conditions for oxidative aromatization are mild and applicable for a variety of substrates, and Amberlyst-15 can be successfully recovered and recycled.     

Scandium triflate catalyzed cycloaddition of imines with 1,1-cyclopropanediesters: efficient and diastereoselective synthesis of multi-substituted pyrrolidines

A tandem ring-opening-cyclization reaction of cyclopropanes with imines in the presence of 5 mol% of scandium triflate was developed for the highly diastereoselective synthesis of multi-substituted pyrrolidines.     

Stereochemistry of Dehydrogenation of 1,4,-Cyclohexadiene with 2,3-Dichloro-5,6-dicyano-p-benzoquinone

cis- and trans-(3,6-D₂)-1,4-cyclohexadienes 1a and 1b have been synthesized from cis-3,4-dichlorocyclobutene (5). Aromatization to benzene with DDQ is cis-stereospecific with an uncertainty of 5%. This result is discussed in relation to concerted or stepwise mechanisms for aromatization of 1,4-dihydroaromatics with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ).     

Application of laccase/DDQ as a new bioinspired catalyst system for the aerobic oxidation of tetrahydroquinazolines and Hantzsch 1,4-dihydropyridines

Laccase/DDQ as a new bioinspired quinone-based cooperative catalytic system was used for the biomimetic aerobic oxidative synthesis of 2-substituted quinazolines and Hantzsch pyridines from the oxidative cyclocondensation of 2-aminobenzylamine and aldehydes and the oxidative aromatization of 1,4-dihydropyridines, respectively. The products were obtained in good to high yields in a phosphate buffer (0.1 M, 12.5 mL, pH 4.5) and acetonitrile (4 vol%) mixture as a solvent. These methods are more eco-friendly, efficient, simple, and practical than other currently available ones because of mild reaction conditions and because they are free from any halide and toxic and expensive transition metals. Therefore, these methods can be applied in pharmaceutical and other sensitive synthetic procedures.     

Metal-Free Highly Efficient Aerobic Oxidation of Sulfides to Sulfoxides Catalyzed by DBDMH/TBN/H2O

A highly efficient metal-free catalytic system, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH)–tert-butylnitrite (TBN)–H₂O, has been developed for an environmentally friendly and economical aerobic acid-free oxidation of sulfides. TBN was identified as an efficient NO equivalent for the activation of molecular oxygen. Under optimal conditions, a variety of sulfides substrates were converted into their corresponding sulfoxides in good yields by molecular oxygen.     

PyHBr3/TBN/H2O as catalytic system for the oxidation of sulfides to sulfoxides with air as the oxidant

Pyridinium bromide perbromide (PyHBr₃) and tert-butyl nitrite (TBN) catalytic system was used for the oxidation of sulfides with air as the oxidant. Under mild conditions (at room temperature), a series of sulfide substrates have been oxidized to their corresponding sulfoxides with high conversion rate. To the best of our knowledge, for the first time, the PyHBr₃/TBN/H₂O is reported as exceptional catalyst system for the oxidation discussed in this Letter.