- Four congenetic zinc(II) MOFs from delicate solvent-regulated strategy: Structural diversities and fluorescent properties
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Four new congenetic zinc(II) MOFs, namely [Zn5(bdcpp)3(DMF)(H2O)4]n·x(solvent) (1), [Zn2(bdcpp)(Hbdcpp)]n·y(solvent) (2), [Zn2(bdcpp)(DMF)(H2O)2]
- Wen, Gui-Lin,Liu, Bo,Liu, Dao-Fu,Wang, Feng-Wu,Li, Li,Zhu, Liang,Song, Dong-Mei,Huang, Chao-Xiu,Wang, Yao-Yu
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- Synthesis, crystal structure, and resolution of [10](1,6)pyrenophane: An inherently chiral [n]cyclophane
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A synthetic approach to a set of three inherently chiral [n]cyclophanes, [n](1,6)pyrenophanes (29a-c, n = 8-10) was investigated. Progress toward 29a was thwarted by the failure of the key dithiacyclophane-forming reaction. For the next higher homologue, the synthesis was completed, but the desired [9](1,6)pyrenophane (29b) could only be partially separated from an isomeric pyrenophane, [9](1,8)pyrenophane (28b), and an unidentified byproduct. Work aimed at the synthesis of the next higher homologue resulted in the isolation of a 7:4 mixture of [10](1,8)pyrenophane (28c) and [10](1,6)pyrenophane (29c), which could not be separated by column chromatography or crystallization. However, single-crystal X-ray structures of 28c and 29c were obtained after manual separation of two crystals with different morphologies from the same batch of crystals obtained from the 7:4 mixture of 28c and 29c. The pyrene system of 29c was found to have a gentle end-to-end bend as well as a significant longitudinal twist. Short intermolecular C(sp3)- H???π contacts (2.64 to 2.76 A) between H-atoms on the bridge and the centroids of three of the four six-membered rings of the pyrene system of a neighboring pyrenophane of like chirality give rise to the formation of single enantiomer columns. From a DNMR study of the mixture of 28c and 29c, the bridge in [10](1,8)pyrenophane (28c) was found to undergo a conformational flip from one side of the pyrene system to the other with ΔG = 14.9 ± 0.2 kcal/mol. A two-stage preparative HPLC protocol was subsequently developed for the separation of 28c and 29c (Chiralpak AD-H column) and then the enantiomers of 29c (Chiralcel OJ-H column). This enabled the measurement of their optical rotations and CD spectra.
- Yang, Yixi,Mannion, Michael R.,Dawe, Louise N.,Kraml, Christina M.,Pascal, Robert A.,Bodwell, Graham J.
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experimental part
p. 57 - 67
(2012/03/10)
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- A novel class of inhibitors for human steroid 5α-reductase: Phenoxybenzoic acid derivatives. I
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In a search for novel nonsteroidal inhibitors of human prostatic 5α- reductase, we found anew series of phenoxybenzoic acid derivatives to be potent human prostatic 5α-reductase inhibitors. Among them, 4-(biphenyl-4- yloxy)benzoic acid derivatives (2n, YM
- Igarashi, Susumu,Kimura, Takenori,Naito, Ryo,Hara, Hiromu,Fujii, Masahiro,Koutoku, Hiroshi,Oritani, Hiroyuki,Mase, Toshiyasu
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p. 1073 - 1080
(2007/10/03)
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