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文章名     作者     期刊名     摘要     卷     期         如果没有找到您所需要的文献，请点击 ——此处申请     共23条记录   Preparation of the beta(2)-Homoselenocysteine Derivatives Fmoc-(S)-beta(2)hSec(PMB)-OH and Boc-(S)-beta(2)hSec(PMB)-OH for Solution and Solid-Phase Peptide Synthesis [作者：Patora-Komisarska, K; Podwysocka, DJ; Seebach, D,期刊：Helvetica Chimica Acta, 页码：1-17 , 文章类型： Article，,卷期：2011年94-1] Fmoc-beta(2)hSer(Bu-t)-OH was converted to Fmoc-beta(2)hSec(PMB)-OH in five steps. To avoid elimination of HSeR, the selenyl group was introduced in the second last step (Fmoc-beta(2)hSer(Ts)-OAll -> Fmoc-beta(2)hSec(PMB... A New Synthesis of Fused Oxa- and Thiacrown Ethers-Thiophene/Furan Oligomers [作者：Garzino, F; Meou, A; Brun, P,期刊：Helvetica Chimica Acta, 页码：18-27 , 文章类型： Article，,卷期：2011年94-1] We have developed a two-step sequence for preparing a series of macrocyclic oxa- and thiacrown ethers affixed to a thiophene/furan oligomer. The sequence involves the intramolecular Mn-III-promoted cyclization of linear ... Reactions with 4-Hydroxy-2-methylbutananilides: Unexpected Formation of a Cyclopropanecarboxamide [作者：Mekhael, MKG; Linden, A; Heimgartner, H,期刊：Helvetica Chimica Acta, 页码：28-37 , 文章类型： Article，,卷期：2011年94-1] The successive treatment of the N,N-disubstituted 4-hydroxy-2-methylbutanamide 2a with lithium diisopropylamide (LDA) and diphenyl phosphorochloridate (DPPCl) led to the 1-methylcyclopropanecarboxamide 10 in good yield. ... Flavone 8-C-Glycosides from Haberlea rhodopensis FRIV. (Gesneriaceae) [作者：Ebrahimi, SN; Gafner, F; Dell'Acqua, G; Schweikert, K; Hamburger, M,期刊：Helvetica Chimica Acta, 页码：38-45 , 文章类型： Article，,卷期：2011年94-1] Phytochemical profiling of a MeOH extract from Haberlea rhodopensis by a combination of liquid/liquid extraction, and preparative and semi-preparative HPLC afforded three new flavone C-glycosides, hispidulin-8-C-(2''-O-s... Synthesis of Diheteroarylamine Ligands by Palladium-Catalyzed Mono- and Diamination of Dichloroheteroarenes with Heteroarenamines [作者：Samson, D; Daltrozzo, E,期刊：Helvetica Chimica Acta, 页码：46-60 , 文章类型： Article，,卷期：2011年94-1] The syntheses of bidentate (see 6 and 12), bis-bidentate (7, 10, and 13) up to oligo-bidentate (see 11 and 14) diheteroarylamine-based N,N-ligands are reported (Tables 2, 4, and 5). In the course of investigations on het... New Phenylphenalene Derivatives from Water Hyacinth (Eichhornia crassipes) [作者：Wang, MZ; Cai, XH; Luo, XD,期刊：Helvetica Chimica Acta, 页码：61-66 , 文章类型： Article，,卷期：2011年94-1] Water hyacinth (Eichhornia crassipes) is a cause of great concern in terms of environmental and agricultural impacts in many parts of the world. Phytochemical investigation of water hyacinth led to the isolation of six n... Two-Step Synthesis of 1,3-Disubstituted 3,4-Dihydro-4-thioxoquinazolin-2(1H)-ones from 1-Bromo-2-fluorobenzenes [作者：Kobayashi, K; Komatsu, T; Yokoi, Y; Konishi, H,期刊：Helvetica Chimica Acta, 页码：67-72 , 文章类型： Article，,卷期：2011年94-1] An efficient synthesis of 3-alkyl-3,4-dihydro-4-thioxobenzoquinazolin-2(1H)-ones 3 has been accomplished in two steps and in satisfactory yields from 1-bromo-2-fluorobenzenes 1. Thus, the reaction of 1-fluoro-2-lithioben... Phytochemical Investigation of Artemisia pallens [作者：Ruikar, AD; Jadhav, RB; Phalgune, UD; Rojatkar, SR; Puranik, VG; Deshpande, NR,期刊：Helvetica Chimica Acta, 页码：73-77 , 文章类型： Article，,卷期：2011年94-1] Two new eudesmanolides, pallensin (1) and 4-epipallensin (2), along with a known eudesmanolide, santonin, and a known flavone, 4-epivalgarin, have been isolated from the aerial part of A. pallens. Their structures were e... Reaction of 3-Hydroxyquinoline-2,4-diones with Isocyanates and Thermally Induced Transformation of the Reaction Products [作者：Mrkvicka, V; Lycka, A; Vicha, R; Klasek, A,期刊：Helvetica Chimica Acta, 页码：78-91 , 文章类型： Article，,卷期：2011年94-1] 3-Hydroxyquinoline-2,4-diones 1 react with isocyanates to give novel 1,2,3,4-tetrahydro-2,4-dioxoquinolin-3-yl (alkyl/aryl) carbamates 2 and/or 1,9b-dihydro-9b-hydroxyoxazolo[5,4-c]quinoline-2,4(3aH,5H)-diones 3. Both of... Ypsilactosides A and B, Two New C-22-Steroidal Lactone Glycosides from Ypsilandra thibetica [作者：Lu, Y; Xie, BB; Chen, CX; Ni, W; Hua, Y; Liu, HY,期刊：Helvetica Chimica Acta, 页码：92-97 , 文章类型： Article，,卷期：2011年94-1] Two new C-22-steroidal lactone glycosides, ypsilactosides A (1) and B (2), were isolated from the EtOH extract of the whole plant of Ypsilandra thibetica. Their structures were established as (3 beta,5 alpha,16 beta,20S)... First Synthesis of a C-Homosteroid from Pregn-4-ene-3,11,20-trione [作者：Zhang, ZL; Wang, LZ; Bian, XQ; Sun, QA; Xu, HX; Wang, CD,期刊：Helvetica Chimica Acta, 页码：98-104 , 文章类型： Article，,卷期：2011年94-1] (3 alpha,5 alpha)-3-Hydroxy-C-homopregnane-11,20-dione (3) was prepared in eleven steps from the commercially available pregn-4-ene-3,11,20-trione (4) via the 11-oxo-13-formyl-12,13-secopregnane intermediate 11 (Scheme 2... Three New Eudesmanolactones (=Eudesmanolides) from Camchaya loloana [作者：Li, CS; Yu, HW; Chen, XZ; Wu, XQ; Li, GY; Zhang, GL,期刊：Helvetica Chimica Acta, 页码：105-110 , 文章类型： Article，,卷期：2011年94-1] Three new eudesmanolactones (=eudesmanolides), loloanolide A (1), loloanolide B (2), and 1-O-acetylloloanolide B (3), together with five known compounds, were isolated from the CHCl3 extract of the aerial parts of Camcha... One-Pot Syntheses of 2-(2-Sulfanyl-4H-3,1-benzothiazin-4-yl) acetic Acid Derivatives via Reactions of 3-(2-Isothiocyanatophenyl)prop-2-enoic Acid Derivatives with Thiols or Sodium Sulfide [作者：Fukamachi, S; Konishi, H; Kobayashi, K,期刊：Helvetica Chimica Acta, 页码：111-118 , 文章类型： Article，,卷期：2011年94-1] Two efficient methods for the preparation of 2-(2-sulfanyl-4H-3,1-benzothiazin-4-yl) acetic acid derivatives 3 under mild conditions have been developed. The first method is based on the reaction of 3( 2-isothiocyanatoph... Bismuth(III) Chloride-Catalyzed Highly Efficient Transesterification of beta-Keto Esters [作者：Sabitha, G; Srinivas, R; Gopal, P; Bhikshapathi, M; Yadav, JS,期刊：Helvetica Chimica Acta, 页码：119-121 , 文章类型： Article，,卷期：2011年94-1] Bismuth(III) chloride was found to be an efficient catalyst for the transesterification of a variety of beta-keto esters with a wide range of alcohols to afford transesterified products in good to high yields in short re... Two New C-20-Diterpenoid Alkaloids from Aconitum carmichaelii [作者：Shen, Y; Zuo, AX; Jiang, ZY; Zhang, XM; Wang, HL; Chen, JJ,期刊：Helvetica Chimica Acta, 页码：122-126 , 文章类型： Article，,卷期：2011年94-1] Two new C-20-diterpenoid alkaloids, named aconicarchamines A and B (1 and 2, resp.), were isolated from Aconitum carmichaelii. By UV, IR, MS, and 1D- and 2D-NMR analyses, their structures were elucidated as 14,17-dihydro... Stereocontrolled Synthesis of Unnatural Tetrapeptides Containing L-Valine Units [作者：Balducci, D; Porzi, G,期刊：Helvetica Chimica Acta, 页码：127-135 , 文章类型： Article，,卷期：2011年94-1] The stereoselective synthesis of the new nonproteinogenic branched tetrapeptides 9a-9d and 15a,b, containing two L-valine units and unnatural alpha-amino acids, was accomplished starting from the chiral synthon 1a, a mon...