排序方式: 共有57条查询结果,搜索用时 891 毫秒
51.
52.
van Eis MJ Wijsman GW de Wolf WH Bickelhaupt F Rogers DW Kooijman H Spek AL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(9):1537-1546
The course of the hydrogenation of [5]- and [6]metacyclophane (1b and 1c) and their thermochemistry is described. Both compounds are hydrogenated rapidly (within 10 s) to furnish the bridgehead olefins 13b and 12c. The accompanying hydrogenation enthalpies are -220 and -141 kJmol(-1), respectively. Strain energies (SE) and olefinic strains (OS) of a number of bridgehead olefins have been evaluated by DFT calculations; it was concluded that 13b belongs to the class of hyperstable olefins which correlates nicely with its reluctance to undergo hydrogenation. By combining experimental hydrogenation enthalpies and DFT calculations, SE of 187 and 121 kJmol(-1) were derived for 1b and 1c. 相似文献
53.
New synthetic routes towards the natural product psammaplin A were developed with the particular view to preparing diverse analogues for biological assessment. These routes utilize cheap and commercially available starting materials, and allowed access to psammaplin A analogues not accessible via currently reported methods. Preliminary biological studies revealed these compounds to be the most potent non peptidic inhibitors of the enzyme histone deacetylase 1 (HDAC1, class I) discovered so far. Interestingly, psammaplin A and our synthetic analogues show class I selectivity in vitro, an important feature for the design and synthesis of future isoform selective inhibitors. 相似文献
54.
Cherblanc F Lo YP De Gussem E Alcazar-Fuoli L Bignell E He Y Chapman-Rothe N Bultinck P Herrebout WA Brown R Rzepa HS Fuchter MJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(42):11868-11875
Isolation and semisynthetic modification of the fungal metabolite chaetocin gave access to a desulfurized analogue of this natural product. Detailed chiroptical studies, comparing experimentally obtained optical rotation values, electronic circular dichroism spectra, and vibrational circular dichroism spectra to computationally simulated ones, reveal the desulfurization of chaetocin to unambiguously proceed with retention of configuration. Consideration of the plausible mechanisms for this process highlighted inconsistencies in the stereochemical assignment of related molecules in the literature. This in turn allowed the stereochemical reassignment of the natural product analogue dethiodehydrogliotoxin. 相似文献
55.
Lee JK Fuchter MJ Williamson RM Leeke GA Bush EJ McConvey IF Saubern S Ryan JH Holmes AB 《Chemical communications (Cambridge, England)》2008,(39):4780-4782
A high yielding, batch mode synthesis of diaryl ethers and sulfides by an S(N)Ar fluoride-mediated process in scCO(2) has been developed; the use of a polymer-supported imidazolium fluoride reagent in batch mode led to the development of a fixed-bed continuous flow process, with high conversions. 相似文献
56.
Fuchter MJ Schaefer J Judge DK Wardzinski B Weimar M Krossing I 《Dalton transactions (Cambridge, England : 2003)》2012,41(27):8238-8241
We have unambiguously demonstrated the binding of the silver(I) ion in the central cavity of [7]-helicene, given that the counterion is weakly coordinating. In such a binding mode, the helicene is functioning as a chiral molecular tweezer. 相似文献
57.
Goslinski T Zhong C Fuchter MJ Stern CL White AJ Barrett AG Hoffman BM 《Inorganic chemistry》2006,45(9):3686-3694
Reductive deselenation of selenodiazole-fused porphyrazines, followed by acylation of the resultant labile porphyrazinediamines, was used to prepare macrocycles bearing two Collins ligands, two oxamido residues, or two quinoline-2-carboxamido units. Peripheral coordination of copper(II) to the di-(quinoline-2-carboxamido)-porphyrazine gave a metal-linked face-to-face porphyrazine dimer array. Sequential derivatization of the two amino groups in the porphyrazinediamines was used to prepare mixed peripheral ligand systems including a dimetallic picolinamido-Schiff base porphyrazine. Such systems exhibit strong metal-metal spin coupling and are anticipated to be of value in the synthesis of novel electronic and magnetic materials. 相似文献