3-硝基-2-氨基苯甲酸的合成

以邻苯二甲酸酐为起始原料,经硝化、脱水、酰胺化、霍夫曼重排4步反应合成了3-硝基-2-氨基苯甲酸,总收率19%,其结构经1H NMR, IR和元素分析表征.探讨了酰胺化和霍夫曼重排反应条件对产率的影响.结果表明, n(脲素) ∶ n(3-硝基邻苯二甲酸酐)=2.0 ∶ 1.0,于50 ℃～60 ℃反应5 h～6 h,酰胺化反应收率85%～91%.n(NaClO) ∶ n(3-硝基-2-甲酰胺基苯甲酸)=1.2 ∶ 1.0,于60 ℃反应3 h,重排反应收率94%.     

2-(4′-氨基苯甲酰基)苯甲酸的合成方法改进

以邻苯二甲酸酐,乙酰苯胺为原料,二氯乙烷为溶剂,无水三氯化铝为催化剂,通过Friedel-Crafts酰基化反应制得2-(4′-乙酰氨基苯甲酰基)苯甲酸(1),1在酸性条件下回流,除去乙酰基得到2-(4′-氨基苯甲酰基)苯甲酸(2)。通过1H NMR,IR,MS和元素分析对1和2的结构进行了表征。最佳的Friedel-Crafts反应条件为:邻苯二甲酸酐20 mmol,n(邻苯二甲酸酐)∶n(乙酰苯胺)=1∶1,n(邻苯二甲酸酐)∶n(AlCl3)=1∶3,于45℃反应2 h,收率70.4%。     

2-氨基-4-甲氧基氯代苯甲酸的合成研究

以2-氨基-4-甲氧基苯甲酸甲酯为原料,通过氯代反应,再分别通过酯水解反应得到化合物2-氨基-5-氯-4-甲氧基苯甲酸和2-氨基-3-氯-4-甲氧基苯甲酸。其中间体及产物结构经~1H NMR、~(13)C NMR和ESI-MS确证,并考察了最佳氯代反应条件。结果表明:物料配比为n(2-氨基-4-甲氧基苯甲酸甲酯)∶n(NCS)=1∶1. 2,反应溶剂为N,N-二甲基甲酰胺,反应时间为16 h,两种氯代产物2-氨基-5-氯-4-甲氧基苯甲酸甲酯和2-氨基-3-氯-4-甲氧基苯甲酸甲酯收率分别为47%和39%。     

NaHSO4·H2O催化合成苯甲酸甲酯

以NaHSO4*H2O催化苯甲酸与甲醇的酯化反应,合成了苯甲酸甲酯.研究结果表明,NaHSO4*H2O具有较高的催化活性.考察了苯甲酸/甲醇摩尔比、催化剂用量及反应时间对酯产率的影响.在优化反应条件[n(苯甲酸)∶n(甲醇)∶n(NaHSO4*H2O)=1∶2∶0.29,回流8h]下,苯甲酸甲酯产率达85.3%.     

黑索今的新型合成路线

以乙腈/三聚甲醛为原料合成1,3,5-三乙酰基-均-三嗪（TRAT）,再硝解制备黑索今(RDX)。 聚合反应中,当n(CH3CN)∶n(C3H6O3)=2∶1,n(H2SO4)∶n(C3H6O3)=1∶7.5,反应温度75 ℃,反应3 h时,TRAT的产率为95.2%。 硝解反应中,当n(N2O5)∶n(TRAT)=7∶1,n(HNO3)∶n(N2O5)=6∶1,反应温度45 ℃,反应1 h时,RDX的产率为87.2%。 RDX的全程产率为83.0%。 该工艺简单、易于控制,废酸污染小,有望应用于工业化生产。     

相转移催化法合成肉桂酸

用K2CO3作催化剂、PEG 400作相转移催化剂,对肉桂酸的合成工艺进行了研究.最佳条件为n(苯甲醛)∶n(乙酸酐)∶n(碳酸钾)=1∶3.25∶1,10mLPEG 400/0.1mol苯甲醛,反应时间1h,反应温度140～150℃,收率可达77.4%.     

4-(5-硝基-6-羟基-2-苯并(噁)唑基)苯甲酸甲酯的合成

研究了以关键中间体4-氨基-6-硝基间苯二酚盐酸盐(ANR·HCl)和对苯二甲酸单甲酯(MTA)为原料,分别经酰氯化、缩合、环合分步或原位合成AB型新单体前体-4-(5-硝基-6-羟基-2-苯并唑基)苯甲酸甲酯(MNB)的技术. 反应优化条件为:在甲基异丁基酮溶剂中,n(ANR·HCl)∶ n(MTA)=1.00∶ 1.03,115 ℃缩合反应2.5 h,m(ANR·HCl)∶ m(PPA)=1.00∶ 3.25的多聚磷酸(PPA),120 ℃环合8.5 h,MNB收率75.68%(以ANR·HCl计),HPLC测定ω(MNB)=96.32%. 产物结构经1H NMR和IR测试技术得以确证.     

NHPI, CoSPc和TBAB催化的乙苯液-液非均相绿色氧化反应研究

以水为催化剂溶剂与原料乙苯组成液-液非均相体系,以NHPI结合CoSPc组成催化体系,在TBAB为相转移催化剂的作用下,对乙苯的氧化反应条件进行了研究.研究发现乙苯在该催化体系中的最佳氧化条件依次是:水油体积比为3∶1;n(TBAB)∶n(乙苯)=1∶40;n(NHPI)∶n(乙苯)=1∶10,n(NHPI)∶n(CoSPc)=24∶1,反应温度110℃,氧气压力0.75 MPa,搅拌速率350 rpm,反应时间0.5 h.在最佳反应条件下乙苯转化率为60.6%,苯乙酮的选择性为95.2%,1-苯乙醇的选择性为4.5%,产物总选择性达到了99.7%.在此基础上延长反应时间并不能提高乙苯的转化率,苯乙酮的选择性也会下降,研究发现NHPI的分解是乙苯转化率不随反应时间的延长而提高的原因,而苯乙酮的过度氧化为苯甲酸是产物选择性下降的原因.     

固体超强酸ZrO_2/S2O_8~(2-)催化合成肉桂酸甲酯

研究了在固体超强酸ZrO2/S2O2-8催化下,肉桂酸与甲醇作用合成肉桂酸甲酯的工艺.考查了催化剂的用量、酸醇摩尔比、反应时间及催化剂的性能对反应的影响.最佳反应条件为∶n(肉桂酸)∶n(甲醇)=1∶10,m(肉桂酸)∶m(催化剂)=3∶1,反应温度90～95℃,反应时间5h,酯化率为95.7%.     

Na_(12)[WZn_3(H_2O)_2(ZnW_9O_(34))_2]催化剂的制备及其催化活性

采用重结果法制备了催化剂Na12[WZn3(H2O)2(ZnW9O34)2](CatZn)。以1,2-丙二醇(1)催化选择性氧化制备羟基丙酮(2)为探针反应考察了CatZn的催化性能。在最佳反应条件[1 50 mmol,n(CatZn)∶n(1)=0.06,n(H2O)∶n(1)=1.4,n(H2SO4)∶n(1)=0.15,于70℃反应1.5 h]下,收率43.85%,选择性68.87%。     

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%.     

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.     

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.     

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.     

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.     

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.