共查询到20条相似文献,搜索用时 15 毫秒
1.
3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a=4.8659(10), b=7.4233(15), c=11.602(2), α=96.904(2), β=92.422(3), γ=107.454(2)°, V=395.51(14)3 , Z=2, Dc=1.689g/cm3 , F(000)=208, μ(MoKα)=0.149 mm-1 , the final R=0.0473 and wR=0.1306 for 2853 observed reflections (I>2σ (I)). A three-dimensional framework was assembled through intermolecular hydrogen bonding between water and 3-carboxy-2-pyrazine-carbohydroxamic acid molecules. 相似文献
2.
以取代吡啶为原料,在羟胺-O-磺酸的作用下,得到取代的N-氨基吡啶的硫酸盐,再通过1,3-偶极环加成反应,与丙炔酸乙酯生成吡唑[1,5-a]并吡啶-3-羧酸乙酯衍生物,然后在质量分数30%的NaOH水溶液作用下水解成酸。 该方法将取代的N-氨基吡啶的硫酸盐直接投入到下步反应,省去传统方法中将硫酸盐转化为碘盐的步骤,解决了碘盐不易析出的问题,并将取代的N-氨基吡啶硫酸盐和丙炔酸乙酯分别用水和二甲基甲酰胺溶解后再混合,增加了原料和K2CO3在体系中的溶解性,提高了产率。 本文成功合成了6种化合物(4a~4f),产率为88%~93%,该方法条件温和,后处理简单,成本低,是适合大规模生产的新工艺。 相似文献
3.
Guang Dong LEI Li Xin LI Zhi Yun LU Ming Gui XIE 《中国化学快报》2005,16(8):1039-1042
An improved method for the large-scale preparation of 4,6-dihydroxyisophthalic acid and 2,3-dihydroxyterephthalic acid has been developed.Compared to the previous procedures,this new process-requires much lower CO2 pressure of 0.3 Mpa and shorter reaction time.thus providing a convenient access for large-scale synthesis.The yield is high (93% and 65%,respectively), and the oxidation of phenol is nearly inhibited,neither decolorization nor further chromatographic purification is required. 相似文献
4.
5.
6.
Michael Gerken Stefan Schneider Thorsten Schroer Ralf Haiges Karl O. Christe 《无机化学与普通化学杂志》2002,628(5):909-910
Cesium azide can conveniently be prepared from anhydrous CsF and (CH3)3SiN3 in SO2 solvent in high purity and yield. In this reaction, the initially generated SO2F— anion is converted in SO2 solvent to solvated azide, (SO2)nN3—, which is labile and releases SO2 under dynamic vacuum yielding pure CsN3. 相似文献
7.
8.
A new and efficient route to 5-fluorothiophene-2-carboxylic acid 1 was secured in two steps and 62% yield overall. 相似文献
9.
Shchelkunov S. A. Yashnova N. I. Li M. L. Shchelkunov A. V. 《Russian Journal of General Chemistry》2002,72(8):1319-1319
Russian Journal of General Chemistry - 相似文献
10.
11.
Modification of the method of Stork and Landesman (J. Am. Chem. Soc. 1956, 78, 5129) permitted the synthesis of the title acid (1) in 58% yield from a cyclopentanone enamine. Acid 1 is a useful intermediate for the preparation of 4-substituted cycloheptenes in good yields. 相似文献
12.
A convenient and large-scale preparation of retinoic acid 1 from β-ionone in five steps with 38% overall yield is described.The key steps are the epoxidization of 2 with a new methylated agent and the condensation 4 with tetraethyl methylenediphophonate in one-pot procedure to prepare 6. 相似文献
13.
14.
苯并呋喃骨架广泛存在于天然产物与合成药物中,许多苯并呋喃类衍生物具有重要的生理、药理和毒理学活性,其合成方法备受人们的关注。本文通过"一锅法"合成苯并呋喃-3-甲酸乙酯,在Et_3N存在下以甲苯作溶剂、邻碘苯酚与丙炔酸乙酯的投料摩尔比1∶1. 5,室温反应20min后加入K_2CO_3和Pd(OAc)2/PPh3,85℃反应3. 5h,产率达到78%。本方法避免了反应过程中使用毒性较大的重氮类化合物,反应步骤少,时间短,操作简便,产率较高,并且可以较方便地对目标分子进行结构改变和修饰,对类似化合物的合成具有指导作用。 相似文献
15.
以2-萘甲酸为原料,经硝化,酯化,重氮化,选择性催化氢化,BOC酸酐保护等六步反应,完成了N-BOC-8氨甲基-2-萘甲酸(1a)的合成,为化合物1的合成提供了新的合成途径。 相似文献
16.
Camphorquinone 3-oxime is prepared in 77% yield in one step from camphor. The synthesis avoids the use of toxic selenium reagents, and provides the syn compound as the major stereoisomer. 相似文献
17.
18.
19.
A practical synthesis of 3S-pyrrolidinol and derivatives from L-glutamic acid is described. 相似文献