Mesolite: An Efficient Heterogeneous Catalyst for One-Pot Synthesis of 2-Amino-4H-chromenes

An efficient and environmentally benign method for one-pot three-component synthesis of 2-Amino-4H-chromenes has been developed by cyclocondensation of benzaldehyde, malononitrile and resorcinol using newly modified mesolite-type natural zeolite as green catalyst. The catalyst was structurally modified by sulfuric acid treatment and characterized by X-ray diffraction, FT-IR, NH₃-TPD, SEM-EDS and BET. This method offers several advantages over the reported methods such as simple and inexpensive modification of catalyst, mild reaction conditions, excellent yield and reusability of catalyst.     

7-氟-6-胺基-2H-1,4-苯并恶嗪-3(4H)-酮的合成

由1，5-二氟-2，4-二硝基苯为原料经醚化、还原合成7-氟-6-胺基-2H-1，4-苯并恶嗪-3(4H)-酮，产率为66.3％(以1，5-二氟-2，4-二硝基苯计)，产物经IR,^1HNMR证实了结构。该化合物是合成除草剂丙炔氟草胺(Flumioxaxin)的关键中间体。     

2,5-二甲基-4-羟基-3(2H)-呋喃酮的合成研究

天然产物2,5-二甲基-4-羟基-3(2H)-呋喃酮在香料工业中占有重要地位。今采用作者提出的化学反应路径选择因子对呋喃酮的合成方法进行计算比较,确定了以丙酮醛为原料,通过偶联反应合成中间体苏式3,4-二羟基-2,5-己二酮,再由成环反应制备产物呋喃酮的合成路线。考察了各个因素对偶联反应、成环反应的影响,得出较为合适的条件。并针对文献中呋喃酮分离条件苛刻、难工业化的缺点,摸索得到了较简便的呋喃酮的分离提纯方法,有利于实现呋喃酮的工业化生产。     

催化加氢合成6-氨基-7-氟-2H-1,4-苯并口恶嗪-3(4H)-酮

6-氨基-7-氟-2H-1,4-苯并口恶嗪-3(4H)-酮(Ⅱ)是合成除草剂丙炔氟草胺的关键中间体,该文采用雷尼镍催化加氢还原7-氟-6-硝基-2H-1,4-苯并口恶嗪-3(4H)-酮(Ⅰ)高收率的制得了目标化合物Ⅱ,确定了最佳合成工艺条件:反应温度80℃,反应时间5 h,催化剂用量为原料质量的5%,氢气压力6 MPa,产品的收率95.2%,质量分数98.5%,溶剂和催化剂循环使用5次,对收率和产品质量分数无影响。产品结构经元素分析、红外光谱、核磁共振确证。     

7-氨基-6-氰基-5-(3-硝基苯基)吡喃并嘧啶-2,4-二酮的合成

报道了常温、超声辐射、水中、无催化剂条件下，以3-硝基苯甲醛、丙二腈和巴比妥酸为原料合成标题化合物的方法。考察了超声技术、反应时间及反应温度对反应的影响。最佳反应条件为：室温、超声辐射2h，收率为86．2％。     

2,5-二甲基-4-羟基-3(2H)-呋喃酮的合成研究

以丙酮醛为原料 ,用锌粉作偶联剂 ,加入适量的氯化锂和碘化四丁基铵 ,n(CH3COCHO)∶n(Zn)∶n(HOAc) =1 0∶1 0∶1 5 ,在 2 5℃反应 1 5～ 2 0h ,可得产率为 6 1 5 %的 2 ,5 二羟基 3,4 己二酮 ;用磷酸氢二钠作缩合剂 ,用超声波加热回流 12h ,可得产率为 6 8 2 %的标题化合物 ;二步的总产率为 41 9%。     

4—羟基—2，5—二甲基—3（2H）呋喃酮的合成研究

本文研究了以 3 ,4 -二羟基 -2 ,5 -己二酮为原料制备 4 -羟基 -2 ,5 -二甲基 -3 (2H)呋喃酮的实验方法 ,讨论了主要因素对得率的影响 ,得到了制备的较佳条件 :pH值为 6.5 ,3 ,4 -二羟基 -2 ,5 -己二酮浓度为 1 0 % ,反应温度为1 0 0℃ ,反应时间为 1 6小时 ,哌啶浓度为 7.5 % ,此条件下 ,4 -羟基 -2 ,5 -二甲基 -3 (2H)呋喃酮得率为 5 5 %。     

Amino Functionalized Nano Fe3O4@SiO2 as a Magnetically Green Catalyst for the One-Pot Synthesis of Spirooxindoles Under Mild Conditions

(3-Aminopropyl)-triethoxysilane attached to Fe₃O₄@SiO₂ nanoparticles has been characterized by powder X-ray diffraction, vibrating sample magnetometer, scanning electronic microscope, transmission electron microscope, energy dispersive X-ray, thermal gravimetric analysis, and Fourier transform infrared spectroscopy. The prepared nanoparticles employed as a heterogeneous catalyst in the synthesis of spirooxindoles derivatives in one-pot four-component reactions of isatin, methyl cyanoacetate or malononitrile, hydrazine hydrate, and ethyl acetoacetate. Amino-functionalized magnetic nanoparticles showed high catalytic activity in mild reaction conditions and excellent yields of products in short reaction times. Also, this nanocatalyst can be easily recovered by a magnet and reused for subsequent reactions for at least 5 times without noticeable loss in catalytic activity.     

4-氯-1-甲基-3-硝基-2(1H)-喹啉酮的合成

以N-甲基苯胺为起始原料,经过环合反应制得4-羟基-1-甲基-2(1H)-喹啉酮,再经硝化和氯代反应合成了目标化合物,该方法所用原料廉价易得,产物处理简单,适合工业化生产,总收率可达51.9%。     

4-(5-硝基-6-羟基-7-甲基苯并噁唑-2-基)苯甲酸甲酯的合成

针对聚对苯撑苯并二噁唑(PBO)纤维的抗压性能差和成型困难等问题,提出并合成出一种新单体的前体化合物4-(5-硝基-6-羟基-7-甲基苯并噁唑-2-基)苯甲酸甲酯(MMNB),总收率56.42%、纯度97.5%;可用于制备AB型单体和甲基改性PBO纤维,以改善PBO纤维的加工性能及热交联后提高轴向抗压能力。结果表明:对苯二甲酸单甲酯(MTA)先经酰氯化,然后在二氯甲烷溶剂中、三乙胺作缚酸剂与2-甲基-4-氨基-6硝基间苯二酚盐酸盐(MANR·HCl)缩合一锅法制备中间体4-[N-(2,4-二羟基-3-甲基-5-硝基苯基)氨甲酰基]苯甲酸甲酯(MNHB),收率为73.65%;MNHB在二乙二醇二甲醚溶剂中多聚磷酸作用下环合脱水合成MMNB,收率为76.61%;并经IR、MS和 ¹H NMR确认。     

7-溴-6-氯-4(3H)-喹诺酮的合成

球虫病是一种对家禽肠道有损害的寄生虫病。常山酮是一种较好的抗球虫药物,但是长期以来由于价格昂贵,限制了其在临床上的广泛应用。7-溴-6-氯-4(3H)-喹诺酮是合成抗球虫药物常山酮的重要中间体。以间氯甲苯作为起始原料,经溴化、氧化、氨化、环化共4步反应,合成了标题化合物,总收率50.61%。并用MS和1HNMR进行了结构表征。     

反相液相色谱法测定7-羟基-3,4-二氢-2(1H)-喹啉酮的含量

建立了反相液相色谱测定7-羟基-3,4-二氢-2(1H)-喹啉酮含量的方法。采用shim-pack C18柱(5μm,4.6mmi.d.×250mm),流动相为v(甲醇)∶v[缓冲溶液(含事先配制好的0.075mol/L的磷酸二氢铵,磷酸调至pH=3)]=50∶50,流速为0.8mL/min,检测波长为250nm。外标法定量,7-羟基-3,4-二氢-2(1H)-喹啉酮1～100μg/mL浓度范围内呈良好的线性关系,线性回归系数r为0.9997,平均回收率为99.26%,RSD=1.17%(n=9)。     

Fe3O4@SiO2-SnCl4: An Efficient Catalyst for the Synthesis of Xanthene Derivatives under Ultrasonic Irradiation

Grafting of SnCl₄ on the Fe₃O₄@SiO₂ nanoparticles afforded Fe₃O₄@SiO₂-SnCl₄ as a novel inorganic heterogenous catalyst, which was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), Field Emission Scanning Electron Microscopy (FE-SEM), and transmission electron microscopy (TEM). In this research, we report a convenient and efficient direct protocol for the preparation of xanthene derivatives via condensation of β-naphthol, dimedone, or mixture of β-naphthol and dimedone with various aromatic aldehydes in the presence of the catalytic amount of Fe₃O₄@SiO₂-SnCl₄ under ultrasonic irradiation. This procedure has a lot of advantages such as: very easy reaction conditions, absence of any tedious workup, or purification, and much milder method. The corresponding products have been obtained in excellent yields, high purity, and short reaction times.     

1-甲基-3-(7-氟-4-炔丙基-1,4-苯并噁嗪-3-酮-6-基)-1,3-喹唑啉-2,4-二酮的合成及其除草活性

标题化合物(SYP-298)是沈阳化工研究院的试验除草剂,由邻硝基苯甲酸经5步反应制得。其结构经核磁共振谱和质谱分析确证。SYP-298在温室条件下38 g a.i./hm2可防多种阔叶杂草,在600 g a.i./hm2对玉米和水稻安全。     

1-硝基-2-(2,6-二氨基-4(3H)-氧代嘧啶-5-基)-4-(4-乙氧甲酰苯基)丁烷的合成

1-硝基-2-(2,6-二氨基-4(3H)-氧代嘧啶-5-基)-4-(4-乙氧甲酰苯基)丁烷是合成培美曲塞二钠的关键中间体。研究了以4-碘苯甲酸,2,6-二氨基-4-羟基嘧啶为原料,经酯化,加成,缩合,消除,加成,得目标产物。本法收率高,适合工业化生产。     

6-氨基-7-氟-2H-1,4-苯并(噁)嗪-3(4H)-酮的高效液相色谱法测定

叙述了采用反向高效液相色谱法,以甲醇为溶剂,甲醇与水(体积比65∶35)为流动相,ODS为填料和紫外检测器分离测定6-氨基-7-氟-2H-1,4-苯并嗪-3(4H)-酮。该方法的标准偏差为0.29,变异系数为0.32%,回收率为99.85%,线性关系系数为0.9997。     

Melamine-(H2SO4)3/melamine-(HNO3)3 instead of H2SO4/HNO3: a safe system for the fast oxidation of thiols and sulfides under solvent-free conditions

Melamine reacted with neat sulfuric acid and fuming nitric acid readily to form two new organic solid acids, namely melamine-(H₂SO₄)₃ and melamine-(HNO₃)₃. Mixture of them acts as a unique powerful system instead of a hazardous H₂SO₄/HNO₃ system for the direct oxidation of thiols. Also, this system can oxidize the sulfides in the presence of a catalytic amount of KBr and few drops of water. This procedure offers advantages such as very low reaction time, simple work-up, excellent yield and matching with some green chemistry protocols.     

HClO4催化合成3,4-二氢嘧啶-2-酮

HClO4催化下,芳香醛、β-酮酸酯、脲或硫脲(物质的量比1∶1∶1.5)在冰醋酸中环化缩合,合成3,4-二氢嘧啶-2-酮衍生物,反应时间3.5 h,产率75%~98%。     

1-[7-氟-4-炔丙基-1，4-苯并噁嗪-3-酮-6-基]-3-正丙基-2-硫代咪唑啉三酮的合成及其除草活性

标题化合物(SYP-300)是沈阳化工研究院的试验除草剂。由丙基异硫氰酸酯与6-氨基-7-氟-4-炔丙基-1，4-苯并噁嗪-3-酮经两步反应制得。其结构经核磁共振谱、红外光谱和元素分析确证。SYP-300在温室条件下100ga．i．／hm^2可防除多种阔叶杂草，在200ga．i．／hm^2对小麦和水稻安全。     

抗球虫药常山酮中间体7-溴-6-氯-4(3H)-喹唑啉酮的合成

7-溴-6-氯-4(3H)-喹唑啉酮是合成抗球虫药物常山酮的重要中间体。作者以硝基苯为起始原料,经溴化、还原、缩合、环化等7步反应,合成了题示物,总收率60%。在n(硝基苯)∶n(硫酸)∶n(溴酸钠)=1∶10∶1,硫酸质量分数为64%,反应温度为25℃,反应时间为1.5 h时,产率为95%。作者通过改变起始原料,降低了合成成本,使反应条件温和,为常山酮及其衍生物的合成提供了新的思路。