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[reaction: see text] Metalation of oxazoles at the 4 and 5 position was achieved after regioselective C-2 silyl protection. Removal of the protecting group was then accomplished under mild conditions allowing for a straightforward preparation of C-5 monosubstituted and C-4,5 disubstituted oxazoles. The first practical C-2 protecting group of oxazoles has been demonstrated. 相似文献
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Andrew G McDonald Sinéad Boyce Gerard P Moss Henry BF Dixon Keith F Tipton 《BMC biochemistry》2007,8(1):14
Background
We describe the database ExplorEnz, which is the primary repository for EC numbers and enzyme data that are being curated on behalf of the IUBMB. The enzyme nomenclature is incorporated into many other resources, including the ExPASy-ENZYME, BRENDA and KEGG bioinformatics databases. 相似文献3.
Zhong YL Gauthier DR Shi YJ McLaughlin M Chung JY Dagneau P Marcune B Krska SW Ball RG Reamer RA Yasuda N 《The Journal of organic chemistry》2012,77(7):3297-3310
An efficient, new, and scalable semisynthesis of glucan synthase inhibitors 1 and 2 from the fermentation product enfumafungin 3 is described. The highlights of the synthesis include a high-yielding ether bond-forming reaction between a bulky sulfamidate 17 and alcohol 4 and a remarkably chemoselective, improved palladium(II)-mediated Corey-Yu allylic oxidation at the highly congested C-12 position of the enfumafungin core. Multi-hundred gram quantities of the target drug candidates 1 and 2 were prepared, in 12 linear steps with 25% isolated yield and 13 linear steps with 22% isolated yield, respectively. 相似文献
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Palucki M Um JM Yasuda N Conlon DA Tsay FR Hartner FW Hsiao Y Marcune B Karady S Hughes DL Dormer PG Reider PJ 《The Journal of organic chemistry》2002,67(16):5508-5516
An efficient and practical asymmetric synthesis of (+)-trans-3-hydroxymethyl-4-(3-fluorophenyl)cyclopentanone (1) is described. An asymmetric Mo-catalyzed alkylation reaction was used to establish the first stereocenter and a Cu-catalyzed intramolecular diastereoselective cyclopropanation reaction was used to set the second stereocenter. The last step involved a one-pot ring-opening/deprotection/hydrolysis/decarboxylation sequence that furnished the desired product in good yield. 相似文献
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M Julia BF Flaminio Alexandre S Borges Daryl V Nydam David W Horohov Rolf Hecker Mary Beth Matychak 《Journal of immune based therapies and vaccines》2007,5(1):1-17
Background
Cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN) has been used successfully to induce immune responses against viral and intracellular organisms in mammals. The main objective of this study was to test the effect of CpG-ODN on antigen presenting cells of young foals. 相似文献6.
Karady S Cummins JM Dannenberg JJ del Rio E Dormer PG Marcune BF Reamer RA Sordo TL 《Organic letters》2003,5(8):1175-1178
[reaction: see text] Experiments show that free radical hydrogen shift is significant in the Pschorr cyclization of diphenyl ethers (X = O) and thioethers (X = S) and does not take place with sufoxides (X = SO) and sulfones (X = SO(2)). DFT calculations of the product ratios, activation energies, rate constants for H-transfers, and ring-closings at the UB3PW91/6-31G(d,p) level are in excellent agreement with the experimental results reported here and elsewhere in the literature. 相似文献
7.
Ken-ichi Asakawa Kenneth J. Fitch Chie Kadowaki Satoshi Kii Benjamin F. Marcune Ross A. Miller 《Tetrahedron letters》2005,46(30):5081-5084
2-Lithio benzimidazoles were acylated with esters, lactones, and lactams. The tetrahedral hemiacetal intermediates responsible for the efficient conversion were characterized by low temperature NMR. 相似文献
8.
Marcune BF Karady S Reider PJ Miller RA Biba M DiMichele L Reamer RA 《The Journal of organic chemistry》2003,68(21):8088-8091
The Sharpless asymmetric dihydroxylation reaction of enol ethers derived from their corresponding cyclic ketones, gave alpha-hydroxyketones with high enantioselectivity. The enantiomeric excess was found to be proportional to the length of the unbranched enol ether chain with a maximum ee for the pentyl enol ether. An efficient synthesis of alpha-hydroxy chromanone in >90% ee was demonstrated using this method. 相似文献
9.
Norihiro Ikemoto Ross A. Miller Joseph F. Leone Benjamin Marcune Joseph D. Armstrong III 《Tetrahedron letters》2005,46(11):1867-1871
Two syntheses of the title compound 1 were developed based on different approaches for installing the oxazole ring moiety. Formation and dehydration of ketoamide was initially used and scaled up to afford 1 on several kilogram scale, then oxazolyl anion/iminium coupling reaction was developed for a more convergent approach. 相似文献
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