共查询到20条相似文献,搜索用时 140 毫秒
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为了寻找抗菌先导化合物,以蛇床子素为原料,对其7位进行结构改造,经脱甲基化、醚化,设计合成了15个目标化合物,经1H NMR、13C NMR和MS对化合物进行结构确证。抗菌活性测试结果表明:该类衍生物对革兰氏阴性菌大肠杆菌(E.coli)有较好的抑制活性,其中,尤以化合物Ⅱb[8-异戊烯基-7-环丙甲氧基香豆素]的活性最为显著,对E.coli的最小抑菌浓度(MIC)为32 mg·L-1,远优于蛇床子素的活性,接近对照药苯唑西林(MIC=16 mg·L-1)的活性。该类衍生物的潜在抗菌活性,值得进一步结构优化和深入研究。 相似文献
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根据生物电子等排原理,以2,3,4-三氟苯甲酸为原料,经硝化、还原、氧化和亲核取代反应制得中间体2-(2,3,4-三氟-5-硝基苯)-1,3-二氧戊环(4); 4分别经7步反应合成了12个新型的苯并噁唑酮或苯并咪唑酮螺嘧啶三酮类化合物(12a~12f, 19a~19f),其结构经1H NMR, 13C NMR和ESI-MS表征。采用CLSI标准研究了12和19对甲氧西林耐药金黄色葡萄球菌(A)、甲氧西林耐药表皮葡萄球菌(B)、青霉素耐药肺炎链球菌(C)和化脓性链球菌(D)的体外抗菌活性。结果表明:12的抗菌活性优于19,其中12a的抗菌活性最好,对A~D的MIC值分别为8~16 μg·mL-1。 相似文献
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以微管菌素为先导化合物, 设计合成了一系列类似物; 所有化合物的结构均经1H NMR, 13C NMR及HRMS确证, 均为新化合物. 采用噻唑蓝(MTT)法对其抗肿瘤活性进行了初步筛选, 结果表明, 化合物Ⅱb具有一定的抗肿瘤活性. 相似文献
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以大黄素为先导化合物,根据活性基团拼接原理,将具有良好抗菌活性的香豆素噻唑和大黄素通过酰胺键连接到同一分子上,设计并合成了6个含有香豆素噻唑的大黄素酰胺类衍生物(8a~8f),并对其抗菌活性进行了评价。结果表明:化合物8b、8c和8f对哈氏弧菌活性存在不同程度的抑制作用,抑菌圈分别为13.37±0.07 mm、 13.60±0.12 mm和13.54±0.09 mm, MIC均为0.25 mg/mL。所有化合物的结构经IR、1H NMR以及HR-MS(ESI)确证。 相似文献
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Marie-Lise Bourguet-Kondracki Marie-Th r se Martin Mich le Guyot 《Tetrahedron letters》1992,33(52):8079-8080
Smenoqualone, a novel quinonic terpenoid with a rearranged drimane skeleton was isolated from a marine sponge Smenospongia sp. The stereostructure was determined by detailed analyses of 1H and 13C NMR spectra, 1H-1H COSY, 1H-13C correlations via HMQC, HMBC and NOE difference NMR experiments. 相似文献
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从海绵RhaphisiaPallida中分离到2个白色晶体,经综合运用波谱方法测定出它们的结构,是2个十分罕见的具有二酰亚胺基和脲基的十元杂环新化合物. 相似文献
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Donald C. Bradley Halina Chudzynska Michael B. Hursthouse Majid Motevalli Ruowen Wu 《Polyhedron》1993,12(24):2955-2960
From reactions involving M{N(SiMe3)2}3 (M = La, Pr and Eu) and triflurotertiary butano[(CF3)Me2COH; tftb.H], the compounds [La(tftb)3(thf)1.5] (1), [Pr(tftb)3 (2) and [Eu(tftb)3] (3) have been isolated. From variable temperature 1H and 19F NMR studies it is suggested that 1 is a mixture of [La3(tftb)9(thf)2] (1a) and [La2(tftb)6(thf)4] (1b). X-ray crystallography has shown that 2 is the trimer [Pr3(tftb)9] and variable temperature 1H and 19F NMR suggests that 3 is also a trimer, [Eu3(tftb)9]. 相似文献
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二苯基烷基膦-硼烷的合成杨文谦,黄天宝,刘玲飞,何良年,张景龄(华中师范大学有机合成研究所,武汉,430070)关键词二苯基烷基膦-硼烷,三苯基膦-硼烷,合成,烷基化膦-硼烷化合物(R3P→BH3),特别是连接不同取代基的膦-硼烷(R1R2R3P→B... 相似文献
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Alberto Plaza Sonia Piacente Angela Perrone Arafa Hamed Cosimo Pizza Giuseppe Bifulco 《Tetrahedron》2004,60(52):12201-12209
Stemmosides C and D, two novel pregnane glycosides characterized by an unusual C-17 side chain were isolated from the pericarps of Solenostemma argel. In addition, stemmoside D displays an uncommon 14β proton configuration, apparently being the first pregnane isolated from plants known to have a 15 keto, cis CD ring junction. Their structures have been established by ESIMS and NMR experiments. The relative configuration of the molecules was determined using a strategy based on the simulation of 1H, 13C, and J coupling NMR parameters. DFT calculations of 1H and 13C chemical shifts, and of the 1H homonuclear spin–spin coupling constants were performed with the mPW1PW91 functional using the 6-31G(d,p) basis set on the fully optimized geometries of all the possible stereoisomers. 相似文献
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The copolymer composition of N-vinyl-2-pyrrolidone/butyl acrylate (V/B) copolymers was determined from the quantitative 13C{1H} NMR spectra. The monomer reactivity ratios for N-vinyl-2-pyrrolidone (V) and butyl acrylate (B) were found to be rV=0.11±0.07, rB=0.54±0.19, using the Kelen–Tudos and non-linear least-square error-in-variable (EVM) methods. The 13C{1H} and 1H NMR spectra of these copolymers are overlapping and complex. The complete spectral assignment of the carbon and proton NMR spectra were done by employing distortionless enhancement by polarization transfer (DEPT) and two-dimensional (2D) 13C–1H heteronuclear single quantum correlation spectroscopy experiments. The 2D total correlation spectroscopy (TOCSY) (1H–1H homonuclear TOCSY) NMR spectrum was used to ascertain the various geminal and vicinal couplings in the copolymer. 相似文献
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Ren Miranda Jorge Escobar Francisco Delgado Manuel Salm n Armando Cabrera 《Journal of molecular catalysis. A, Chemical》1999,150(1-2):299-305
The cyclooligomerization of piperonyl alcohol (1) afforded trimethylendioxyorthocyclophane (2), a novel product, which was promoted by the catalytic action of a commercial bentonitic earth, Tonsil Actisil FF, as well as by hydrochloric acid in 1, 4-dioxane. The structure of 2 was established by 1H, 13C NMR and HMQC experiments (DMSO-d6 and in the solid state), and by the corresponding mass spectrometric data (EI, CID and HR). 相似文献