相转移催化无溶剂合成N-(ω-溴烷基)邻苯二甲酰亚胺

本文以N-(3-溴丙基)邻苯二甲酰亚胺合成为模板反应,研究了相转移催化无溶剂合成N-(ω-溴烷基)邻苯二甲酰亚胺的影响因素,实验证实相转移催化剂及其用量、催化剂K2CO3的用量等对反应的影响明显,得到N-(3-溴丙基)邻苯二甲酰亚胺的优化合成条件为:反应物配比为PA∶C3Br2∶K2CO3∶TBAB=1∶2∶4∶0.2,反应温度80℃,反应时间1h,N-(3-溴丙基)邻苯二甲酰亚胺产率为92%。在相同反应条件下,N-(ω-溴烷基)邻苯二甲酰亚胺的产率随α,ω-二溴烷烃的烷基链长度增加而降低。     

微波辐射法合成4-氨基邻苯二甲酰亚胺

以4-硝基邻苯二甲酰亚胺为原料,通过微波辐射合成了4-氨基邻苯二甲酰亚胺。结果表明:选择铁粉作为催化剂,乙酸乙酯为萃取剂,在4-硝基邻苯二甲酰亚胺/氯化铵/铁粉的摩尔比为1.0∶1.0∶3.5,微波辐射时间100 s,微波辐射功率480 W的条件下,4-氨基邻苯二甲酰亚胺的收率最高,达到93.4%。     

羧基功能化苯并三氮唑类离子液体的合成及在萃取-氧化脱硫中的应用

合成了新型离子液体(ILs)1-烷基-3-羧甲基苯并三氮唑双三氟甲磺酰亚胺盐,并对其进行了表征.将其与双氧水组成催化氧化体系,考察了脱除模型油品中硫化物的效果.结果表明,以离子液体1-5基-3-羧甲基苯并三氮唑双三氟甲磺酰亚胺盐[C2O2BBTA][NTf2]为萃取/催化剂,设定n(H2O2)∶n(S)=2.5∶1,m(模型油)∶m(离子液体)=5∶1,在75℃下反应1 h后,模型油中二苯并噻吩(DBT)、苯并噻吩(BT)和4,6-二甲基二苯并噻吩(4,6-DMDBT)的脱硫率分别为98.3%,98.3%和96.6%.所合成离子液体重复使用10次,脱硫率无明显变化.该方法操作简单、反应条件温和,可以实现深度脱硫.     

响应面法优化邻苯二甲酰亚胺微波合成工艺

采用响应面法优化邻苯二甲酰亚胺的微波合成工艺条件。以邻苯二甲酸酐和尿素为原料,N,N-二甲基甲酰胺(DMF)为反应溶剂,通过Box-Behnken中心组合实验,考察微波辐射温度、原料摩尔配比和反应溶剂量(相对于原料邻苯二甲酸酐的摩尔比例)三个因素对邻苯二甲酰亚胺收率的影响,得出其最佳微波合成条件参数组合并建立多元回归数学模型。结果表明:微波合成最佳反应条件为n(邻苯二甲酸酐)/n(尿素)/n(DMF)=1∶1.25∶1,微波144℃下搅拌回流反应1min得到的产物收率最高(96.28%)。     

咪唑类离子液体在邻苯二甲酰亚胺的N-烷基化反应中的相转移催化作用

研究了1-正丁基-3-甲基咪唑{[BMIM][R],R-[Br],[PF6],[HSO4],[H2PO4]}类离子液体(ILa)在邻苯二甲酰亚胺(1)的N-烷基化反应中的相转移催化作用.考察了ILs的结构及用量、反应温度和反应时间、卤代烃(2)的结构及用量、溶剂等对N-烷基化反应的影响.最佳反应条件为:120mmol,n(1):n(2):n(ILs):n(K2CO3)=1.0:1.5:0.1:1.5,在1,4-二氧六环中于80℃反应3 h,收率86.7%.     

对硝基邻苯二乙醚合成技术研究

以邻苯二酚与溴乙烷为原料、聚乙二醇为相转移催化剂合成邻苯二乙醚,再经过冰醋酸和硝酸硝化得到对硝基邻苯二乙醚。研究了反应温度、反应时间、原料摩尔比和催化剂用量等对反应收率的影响,获得了合成邻苯二乙醚的优化工艺条件:n(C6H4(OH)2)∶n(NaO H)∶n(C2H5Br)=1∶2.6∶2.4,反应温度80℃,反应时间4h,催化剂用量2g,该反应条件下邻苯二乙醚平均收率88%。混酸硝化条件下合成对硝基邻苯二乙醚的较佳工艺条件为n(C10H14O2)∶n(HNO3)=1∶1.2,乙酸25mL,反应时间30min,反应温度20℃,该反应条件下对硝基邻苯二乙醚平均收率为99%。     

新型1,4,5,8-萘酰亚胺类衍生物的合成

以1,4,5,8-萘四甲酸二酐(1)和2-乙基己胺(2)为原料,设计并合成了3种新型的1,4,5,8-萘酰亚胺类衍生物,其结构经1H NMR,IR和MS表征。中间体N-(2-乙基己基)-萘-1,8-二甲酸单酐-4,5-单甲酰亚胺的最佳反应条件为:19.7 mmol,n(1)∶n(2)=1.1∶1.0,以醋酸锌为催化剂,在DMF(20 mL)中于140℃反应15h,收率25%。     

4-氨基-1-丁醇的合成研究

使用四丁基溴化铵为相转移催化剂,以4-氯-1-丁醇作为起始原料,与邻苯二甲酰亚胺钾盐反应制备N-(4-羟基丁基)邻苯二甲酰亚胺(中间产物),中间产物在氢氧化钠的作用下水解得到4-氨基-1-丁醇。通过高分辨质谱、核磁共振谱等对中间产物和产品进行了测定和结构表征。考察了反应溶剂、4-氯-1-丁醇与邻苯二甲酰亚胺钾盐摩尔比、反应温度、反应时间、四丁基溴化铵与邻苯二甲酰亚胺钾盐摩尔比对中间产物收率的影响,优化反应条件之后4-氨基-1-丁醇最佳的总收率为77. 2%。此工艺路线具有合成方法简便、反应条件温和、产品收率高等优点,可以进行工业放大。     

氟苯尼考琥珀酸单酯的合成工艺优化

以氟苯尼考和琥珀酸酐为原料,4-二甲氨基吡啶(DMAP)催化合成了氟苯尼考琥珀酸单酯。通过正交试验确定最佳反应条件为:氟苯尼考14 mmol,n(氟苯尼考)∶n(琥珀酸酐)=1.0∶1.5,w(DMAP)=4%,于60℃反应4 h,产率88.1%。在最佳反应条件下做放大实验,氟苯尼考3 kg,产率88.9%     

相转移催化不对称合成(Ⅰ)——相转移催化反应合成光学活性α-氨基酸

在固液两相条件下用手性季铵盐为相转移催化剂,邻苯二甲酰亚胺钾与α-溴代羧酸酯反应,合成了十二个具有光学活性的α-(邻苯二甲酰亚胺基)羧酸酯,经肼解和水解,得到相应的光学活性α-氨基酸,光学纯度百分率为3.6—17.8％。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

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.