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一类新型的双β-氨基醇的合成及催化硼烷对芳酮的不对称还原反应 总被引:7,自引:0,他引:7
以L-半胱氨酸盐酸盐出发,经与二卤代烷偶联,成酯和格氏反应制得三种双手性β-氨基醇,1,2-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]乙烷(4a),1,3-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]丙烷(4b),1,4-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]丁烷(4c)。将此类双手性β-氨基醇与硼烷在THF溶液中反应,in situ制备双手性恶唑硼烷催化硼烷对芳酮的不对称还原,产物苯乙醇的光学收率达72.8%、α-溴代苯乙醇的光学收率达91.4%。 相似文献
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冠醚化二苯甲酮的合成及其光物理行为 总被引:1,自引:0,他引:1
本文报道采用在多聚磷酸中酰化的方法,合成了冠醚化二苯甲酮1~8。它们与叔胺类共用可能被用作光引发剂。为此,用紫外光谱详细研究了这些化合物及其络合后的光物理行为。还提及化合物3和4作为紫外吸收剂的可能性。 相似文献
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为了合理利用甾体皂甙元资源, 系统地考察了16R-溴代孕甾-3S,20S-二醇二乙酸酯在不同反应条件下与碱的反应. 给出了选择性地分别转化16R-溴代孕甾-3S,20S-二醇二乙酸酯成为孕甾-16-烯-3S,20S-二醇二乙酸酯、16R-溴代孕 甾-3S,20S-二醇、孕甾-3S,16S,20S-三醇、孕甾-14,16-二烯-3S-醇乙酸酯和雄甾-16-烯-3S-醇等化合物的可控性反应结果. 这些条件可控性反应结果不仅为甾体药物和生物活性天然甾体化合物合成提供了新的合成中间体, 也为它们新合成策略和途径的设计提供了机遇. 相似文献
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R-四氢噻唑-2-硫酮-4-羧酸反应得到有光学活性的二聚体酰胺双四氢噻唑-2-硫酮并二氧代氢化吡嗪,用半经验量子化学PM3方法研究了反应物、中间产物和二聚体的电子结构. 相似文献
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采用简单的化学偏聚法合成出Ag3PO4纳米颗粒、磷酸钴(Co3(PO4)2,CoP)纳米片以及它们两者的纳米复合结构(CoP/Ag3PO4),同时还比较了它们的可见光催化活性.采用场发射扫描电镜(FESEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱以及光致发光谱等手段对其形貌、结构、光学以及可见光催化性能等进行表征.结果表明,CoP/Ag3PO4复合纳米结构的可见光降解甲基橙(MO)的速率和循环稳定性均明显优于其它两种物质.这表明CoP应该起着共催化剂的作用,它能够抑制光生电子与空穴之间的复合,并且提供大量高活性的光生空穴.此外,我们还发现CoP/Ag3PO4降解另一种阳离子型染料——罗丹明B(RhB)的能力则远不如纯Ag3PO4,这可能是与光催化剂的表面性质发生改变有关,造成更低的RhB吸附能力.本文提供了一种廉价制备高效可见光催化剂的新方法. 相似文献
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采用简单的化学偏聚法合成出Ag3PO4纳米颗粒、磷酸钴(Co3(PO4)2,CoP)纳米片以及它们两者的纳米复合结构(CoP/Ag3PO4),同时还比较了它们的可见光催化活性.采用场发射扫描电镜(FESEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱以及光致发光谱等手段对其形貌、结构、光学以及可见光催化性能等进行表征.结果表明,CoP/Ag3PO4复合纳米结构的可见光降解甲基橙(MO)的速率和循环稳定性均明显优于其它两种物质.这表明CoP应该起着共催化剂的作用,它能够抑制光生电子与空穴之间的复合,并且提供大量高活性的光生空穴.此外,我们还发现CoP/Ag3PO4降解另一种阳离子型染料——罗丹明B(RhB)的能力则远不如纯Ag3PO4,这可能是与光催化剂的表面性质发生改变有关,造成更低的RhB吸附能力.本文提供了一种廉价制备高效可见光催化剂的新方法. 相似文献
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Two new type dicoumarins (dicoumaro-p-menthanes), named dibothrioclinins I (1) and II (2) were isolated from the roots and rhizomes of Gerbera piloselloides (L.) CASS., collected in Yunnan Province, China. Their structures were elucidated on the basis of MS, 1D ((1)H-NMR, (13)C-NMR, DEPT and NOE) and 2D ((1)H-(1)H COSY, HMQC, HMBC) NMR spectral analyses. The relative structures of the two compounds were established by NOE difference spectroscopy and further confirmed by single-crystal X-ray diffraction studies. 相似文献
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Forsythiasuspensa(ThUnb.)VahlhasbeenusedintradihonalChinesemedicineforanhiallammatoryandamibacterialpmposes.AnUInberofcompoundssuchasforsythiaside,phillygeninrengyoletc.haVebeenidentifiedl-#fromthefactsofmisplat.AsPartofourstudyontheachveprinciplesoftradihonalChinesemedicine,wereinvestigatCdthechemicalconstitllentsofRsuspensa.heartycompoundshavebeenisolatCdfromthisspecies.ThispaperdescribesthestrUcturalelucidahonofthreenewcompoundsfsuspenolicacid(1),forSythensideA(2),andforsythensideB(3)… 相似文献
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Katritzky AR Akhmedov NG Wang M Rostek CJ Steel PJ 《Magnetic resonance in chemistry : MRC》2004,42(12):999-1011
Regioselective addition of allylthiol at the C-3 position adjacent to the nitrogen carrying the phenyl group of the 1,4-phenylenediamine moiety of compounds 1-4 was rigorously confirmed by 1D NOE difference in combination with gHMBC experiments. The structures of 1,4-phenylenediamines 1-4, allylsulfanyl-N1-alkyl-N4-phenyl-1,4-phenylenediamines 5-8 and cyclization products 9-14 were completely analyzed in both CDCl3 and DMSO-d6 solutions. The 1H and 13C NMR spectra of 10 and 11, which contain two chiral centers, exhibit duplication for several signals, indicating the existence of two diastereomeric forms. The full structures of 5 and 9 were unambiguously confirmed by x-ray crystallography. The 1H and 13C NMR spectra of all compounds were assigned using one- and two-dimensional NMR techniques (APT, DEPT, 1D NOE difference, COSY, NOESY, HETCOR, gHMQC and gHMBC). 相似文献
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M. J. Musmar Gary E. Martin Robert T. Gampe Vincent M. Lynch Stanley H. Simonsen Milton L. Lee Marvin L. Tedjamulia Raymond N. Castle 《Journal of heterocyclic chemistry》1985,22(2):545-553
1-Methylphenanthro[3,4-b]thiophene was prepared by the photocyclization of 1-(4′-methyl-2′-thienyl)-2-(2″-naphthyl)ethene. The 1H and 13C-nmr spectra were assigned using two-dimensional 1H/13C heteronuclear chemical shift correlation and relayed coherence transfer (RELAY) experiments. From nuclear Overhauser difference spectra, the H11-C1 methyl-H intramolecular distance was determined to be 2.10 Å. The molecule crystallized from chloroform in the monoclinic system, space group P21/c. A total of 3536 unique reflections were measured and the structure was solved by direct methods and refined to a final R = 0.049. The molecule is helical with both chiral forms observed in the crystal. The H11-C1 methyl-H distance in the crystal was 2.12(3)Å in excellent agreement with the distance measured in solution by NOE techniques. 相似文献
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N. E. Alexandrou G. E. Mertzanos J. Stephanidou-Stephanatou C. A. Tsoleridis 《Journal of heterocyclic chemistry》1996,33(3):697-702
1-Phenyl-cyclopenteno[1,2-d]-1,2,3-rriazolo-5-spiro-4′-[perhydropyrazolino-3′,5′-dione] (5) afforded in situ, by oxidation with lead tetraacetate, the corresponding cyclopentenotriazolo-spiropyrazolodione 6 , which was trapped with dienes giving the hetero-Diels-Alder adducts 10–12 in good yields. The Diels-Alder reactions were examined on the basis of AM1 MO calculations. Total assignment of the 1H- and 13C-nmr chemical shifts as well as the relative configuration of these adducts was accomplished with the help of 2D (1H-1H COSY, 1H -1 H NOESY, 1H-13C XHCORR, 1H-13C COLOC) and NOE difference spectroscopy. The structures of compounds 11a and 11b were also examined by molecular modeling. 相似文献
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(1)H and (13)C NMR data for N-substituted morpholines 1-20 were measured using 1D (DEPT, 1D NOE difference) and 2D NMR spectroscopic methods including (1)H-(1)H COSY, long-range (1)H-(1)H COSY, NOESY, gHMBC and gHMQC experiments. At room temperature the (1)H NMR spectra of protonated compounds 2 and 9 show the chair conformation for the morpholine ring. Spin-spin coupling constants were deduced from the resolution-enhanced proton spectra. 相似文献
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Katritzky AR Akhmedov NG Wang M Rostek CJ Steel PJ 《Magnetic resonance in chemistry : MRC》2004,42(7):648-658
The 1H and 13C NMR spectra of compounds 1-11 and 16-22 in CDCl3 and DMSO-d6 solutions allowed structural assignment to regioisomers 1/5 and 2/6 and their regioselective cyclization products 16-18 utilizing one- and two-dimensional NMR techniques (APT, DEPT, NOE difference, COSY, NOESY, HETCOR and gHMQC, gHMBC). Temperature-dependent 1H NMR spectra of 8-anilino-5-(4-methyl-2-pentyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one (18) indicated a free energy of activation (deltaG++) of ca 17 kcal mol(-1) for interconversion between rotamers. The 1H and 13C NMR spectra of 20 and 22 containing two chiral centers exhibit duplication of several signals, indicating the existence of two diastereomeric forms. The structure of 4 was unambiguously confirmed by x-ray crystallography. 相似文献
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Electrophilic substitution of the nido-dicarbaborate anion 7,8-nido-C2B9H12- with sulfenyl chlorides
Frank R Grell T Hiller M Hey-Hawkins E 《Dalton transactions (Cambridge, England : 2003)》2012,41(20):6155-6161
Sulfenyl chlorides RSCl (R = p-C(6)H(4)OMe, Ph, p-C(6)H(4)NO(2), CN or 2-C(5)H(4)N) react with 7,8-nido-C(2)B(9)H(12)(-) with asymmetric substitution on the pentagonal C(2)B(3) face to give 9-RS-7,8-nido-C(2)B(9)H(11)(-) (R = p-C(6)H(4)OMe (3), Ph (4), p-C(6)H(4)NO(2) (5), CN (6)) and the zwitterion 9-(S-2-C(5)H(4)NH)-7,8-nido-C(2)B(9)H(11) (7), respectively, in high yield, while tBuSCl did not react and S(2)Cl(2) led to decomposition. Further reaction of 5-7 with iodine gave the corresponding iodo derivatives NMe(4) [9-I-11-RS-7,8-nido-C(2)B(9)H(10)] (R = p-C(6)H(4)NO(2) (8), CN (9)) and the zwitterion 9-I-11-(S-2-C(5)H(4)NH)-7,8-nido-C(2)B(9)H(11) (10), respectively. Compounds 3-10 were fully characterised by (1)H, (11)B, (11)B{(1)H}, (13)C{(1)H} spectroscopy, IR spectroscopy, mass spectrometry and elemental analysis, 3-7 also by (11)B-(11)B{(1)H} COSY NMR spectroscopy and 8-10 by X-ray structure determination. 相似文献