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951.
Manganese‐Catalyzed Dehydrogenative [4+2] Annulation of N?H Imines and Alkynes by C?H/N?H Activation
Ruoyu He Zhi‐Tang Huang Qi‐Yu Zheng Congyang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(19):5050-5053
Described herein is a manganese‐catalyzed dehydrogenative [4+2] annulation of N H imines and alkynes, a reaction providing highly atom‐economical access to diverse isoquinolines. This transformation represents the first example of manganese‐catalyzed C H activation of imines; the stoichiometric variant of the cyclomanganation was reported in 1971. The redox neutral reaction produces H2 as the major byproduct and eliminates the need for any oxidants, external ligands, or additives, thus standing out from known isoquinoline synthesis by transition‐metal‐catalyzed C H activation. Mechanistic studies revealed the five‐membered manganacycle and manganese hydride species as key reaction intermediates in the catalytic cycle. 相似文献
952.
Jia‐Xuan Yan Hu Li Xiang‐Wei Liu Jiang‐Ling Shi Xin Wang Zhang‐Jie Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(19):5045-5049
3,4‐Dihydroquinolinones were synthesized by the palladium‐catalyzed, oxidative‐addition‐initiated activation and arylation of inert C(sp3) H bonds. Pd(OAc)2 and P(o‐tol)3 were used as the catalyst and ligand, respectively, to improve the efficiency of the reaction. A further advantage of this reaction is that it could be performed in air. A relatively rare seven‐membered palladacycle was proposed as a key intermediate of the catalytic cycle. 相似文献
953.
Xue‐Jun Wu Xiao Huang Xiaoying Qi Hai Li Bing Li Hua Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(34):9075-9079
Two‐dimensional (2D) copper‐based ternary and quaternary semiconductors are promising building blocks for the construction of efficient solution‐processed photovoltaic devices at low cost. However, the facile synthesis of such 2D nanoplates with well‐defined shape and uniform size remains a challenge. Reported herein is a universal template‐mediated method for preparing copper‐based ternary and quaternary chalcogenide nanoplates, that is, CuInS2, CuInxGa1−xS2, and Cu2ZnSnS4, by using a pre‐synthesized CuS nanoplate as the starting template. The various synthesized nanoplates are monophasic with uniform thickness and lateral size. As a proof of concept, the Cu2ZnSnS4 nanoplates were immobilized on a Mo/glass substrate and used as semiconductor photoelectrode, thus showing stable photoelectrochemical response. The method is general and provides future opportunities for fabrication of cost‐effective photovoltaic devices based on 2D semiconductors. 相似文献
954.
Zixin Huang Josie E. Auckett Peter E. R. Blanchard Brendan J. Kennedy Wojciech Miiller Qingdi Zhou Maxim Avdeev Mark R. Johnson Mohamed Zbiri Gaston Garbarino William G. Marshall Qinfen Gu Chris D. Ling 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(13):3482-3485
Pressure‐induced charge transfer from Bi to Ir/Ru is observed in the hexagonal perovskites Ba3+nBiM2+nO9+3n (n=0,1; M=Ir,Ru). These compounds show first‐order, circa 1 % volume contractions at room temperature above 5 GPa, which are due to the large reduction in the effective ionic radius of Bi when the 6s shell is emptied on oxidation, compared to the relatively negligible effect of reduction on the radii of Ir or Ru. They are the first such transitions involving 4d and 5d compounds, and they double the total number of cases known. Ab initio calculations suggest that magnetic interactions through very short (ca. 2.6 Å) M M bonds contribute to the finely balanced nature of their electronic states. 相似文献
955.
Wu Jinming Zhu Xiting Chen Qi Ge Cunwang Dai Bin Jia Xueping Shen Aibao Chen Tingting 《Journal of solution chemistry》2014,43(8):1421-1435
Journal of Solution Chemistry - The binding interaction of 4β-(benzoyl-thioureido)-4-deoxypodophyllotoxin (HY-1) with human serum albumin (HSA) was investigated by fluorescence,... 相似文献
956.
Recombination fractions between forensic STRs can be extrapolated from the International HapMap Project, but the concordance between recombination fractions predicated from genetic maps and derived from observation of STR transmissions in families is still ambiguous for autosomal STRs because of limited family studies. Therefore, the main goal of this study is to compare recombination fractions estimated by pedigree analysis with those derived from HapMap phase SNP data. Genotypes of nine autosomal STR pairs (TPOX‐D2S1772, D5S818‐CSF1PO, D7S3048‐D7S820, D8S1132‐D8S1179, TH01‐D11S2368, vWA‐D12S391, D13S325‐D13S317, D18S51‐D18S1364, and D21S11‐PentaD) from 207 two‐generation families with two to five children (the number of families with five, four, three, and two children was 2, 3, 20, and 182, respectively) were used to analyze the recombination. The linkage analysis showed that significant linkage was observed at six STR pairs (D5S818‐CSF1PO, D8S1132‐D8S1179, TH01‐D11S2368, vWA‐D12S391, D13S325‐D13S317, and D18S51‐D18S1364) with genetic distances <36.22 cM in HapMap. Their recombination fractions calculated from family data were very close to those derived from HapMap. However, three STR pairs of TPOX‐D2S1772, D7S3048‐D7S820, and D21S11‐PentaD showed no significant linkage with genetic distances from 43.38 to 91.49 cM. Our results indicate that recombination fractions extrapolated from HapMap can provide a substitute if empirical data are unavailable for the linkage STR pair with a genetic distance spanned <36.22 cM. 相似文献
957.
A general and efficient P(V)–N activation method for the preparation of symmetrical and asymmetrical dinucleoside polyphosphates (NpnN′s, n=2–4) and P2,P3-CX2-dinucleoside tetraphosphates (X=H, F, and Cl) has been established. Twenty-two dinucleoside polyphosphates and their phosphonate analogs were synthesized from nucleoside 5′-phosphoropiperidates with 4,5-dicyanoimidazole as the activator in good to high yields. 相似文献
958.
Yuanpeng Liang Bin Xiang Chao Liu Xiangdong Zhou Dan Wang Shan Song Genghua Bai Qi An Quehong Huang Shujun Chen Xuefeng Wei 《Tetrahedron》2014
Novel fluorine-containing ultraviolet absorbers (FBPs) with low surface energy were successfully synthesized based on 2,4-dihydroxy benzophenone (BP-1), and their structures were characterized by 1H NMR, 13C NMR, FTIR, and HRMS. UV absorption of FBPs was studied in 10−4 M dichloromethane (CH2Cl2), which demonstrated the superior UV absorption capability of FBPs (ca. ?=1.7×104 to 2.2×104 at λmax) over the matrix (?=1.7×104 at λmax). Quantum chemistry calculation was performed to investigate the stable structure and UV electronic absorption bands of FBPs. The surface chemistry information of high-chlorinated polyethylene (HCPE) coating films embedded with ultraviolet absorbers (UVAs) was given by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The results show that the surface enrichment capability of FBPs is remarkably better than traditional UVAs (including BP-1, BP-3, BP-12) because of the low surface energy properties of FBPs. 相似文献
959.
Qun Dang Zhibo Zhang Bingyu Tang Yang Song Ling Wu Tongqian Chen Stephane Bogen Vinay Girijavallabhan David B. Olsen Peter T. Meinke 《Tetrahedron letters》2014
To discover novel nucleosides as potential antiviral agents, 2′-spirolactam and 2′-spiropyrrolidine-containing nucleoside analogs were envisioned. Efficient synthetic routes were developed with an epoxide opening as the key step to establish the quaternary center at the 2′ position, leading to the design and synthesis of uridine analogs 8 and 21, prodrugs 13–16, and cytidine analog 11. 相似文献
960.
A silver(I)-catalyzed reaction of 2-alkynylaryl aldimine with trimethyl(trifluoromethyl)silane is reported. This reaction proceeds efficiently under extremely mild conditions to generate 1-(trifluoromethyl)-1,2-dihydroisoquinolines in good yields. A three-component reaction of 2-alkynylbenzaldehyde, amine, with trimethyl(trifluoromethyl)silane is presented as well. 相似文献