811-49-4Relevant articles and documents
Transition-metal-free stereoselective synthesis of C(1)–C(6) fragment of epothilones and their structural analogues
Shklyaruck, Denis G.,Fedarkevich, Artsiom N.,Kozyrkov, Yurii Yu.
, p. 8015 - 8021 (2016/11/22)
Two efficient and scalable asymmetric syntheses of C(1)–C(6) fragment of epothilones and their structural analogues from commercially available 1,2:5,6-di-O-isopropylidene-D-mannitol have been performed in seven and 12 steps with 35% and 36% overall yields, respectively. Both the approaches include of one-pot, sequential transformations. The key steps are L-histidine-catalyzed aldol reaction, Barton–McCombie deoxygenation, zinc-mediated Vasella fragmentation, and oxidative nitrile synthesis.
Directional properties of fluorenylidene moieties in unsymmetrically substituted N-heterocyclic carbenes. Unexpected CH activation of a methylfluorenyl group with palladium. Use in palladium catalysed Suzuki-Miyaura cross coupling of aryl chlorides
Teci, Matthieu,Brenner, Eric,Matt, Dominique,Gourlaouen, Christophe,Toupet, Loic
, p. 12251 - 12262 (2014/08/05)
Benzimidazolium salts having their two nitrogen atoms substituted by different 9-alkylfluorenyl groups (4a-e and 4g, alkyl1/alkyl 2 = Me/Et, Me/Pr, Me/n-Bu, Me/i-Pr, Me/Bn, Me/CH2SMe have been synthesised in high yields in two or three steps from N,N′-bis(9H- fluoren-9-ylidene)benzene-1,2-diamine (1). The imidazolium salts 4a-e were converted readily into the corresponding PEPPSI-type palladium complexes (PEPPSI = pyridine-enhanced precatalyst preparation stabilisation and initiation), while reaction of the methylthioether-substituted salt 4g with PdCl 2/K2CO3/pyridine afforded the palladacycle 5g resulting from metallation of the methyl group attached to the fluorenylidene moiety. NMR and X-ray diffraction studies revealed that the carbene ligands in 5a-5e behave as clamp-like ligands, the resulting metal confinement arising from a combination of the orientational properties of the fluorenylidene moieties that push the alkyl groups towards the metal centre and attractive anagostic interactions involving CH2(fluorenyl) groups. Complexes 5a-e were assessed in Suzuki-Miyaura cross-coupling reactions. Like their symmetrical analogues they displayed high activity in the coupling of phenyl boronic acid with p-tolylchloride but their performance remained slightly inferior to that of the related, symmetrical Et/Et complex 5h.
SUBSTITUTED DIHYDROPHENANTHRIDINESUL FONAMIDES
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Page 73, (2010/02/07)
This invention provides a compound of formulae (I) or (II) having the structure or a pharmaceutically acceptable salt thereof which are useful for the treatment of the inflammatory component of diseases and are particularly useful in treating atherosclerosis, myocardial infarction, congestive heart failure, inflammatory bowel disease, arthritis, type II diabetes, and autoimmune diseases such as multiple sclerosis and rheumatiod arthritis.
Vitamin D analogues
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Page column 20, (2010/02/05)
The invention relates to novel bicyclic compounds having the general formula (I): as well as to a method for preparing them and to their use in pharmaceutical compositions intended for use in human or veterinary medicine (in dermatology, in carcinology and in the field of autoimmune diseases and that of organ or tissue transplants in particular), or alternatively in cosmetic compositions.
Method for producing alkyl-bridged ligand systems and transition metal compounds
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, (2008/06/13)
The invention relates to a method for producing highly substituted alkyl-bridged ligand systems on the basis of indene derivatives and transition metal compounds. Said alkyl-bridged ligand systems can be obtained in high yields using this method.
Ethyllithium in dibutyl ether
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, (2008/06/13)
This patent describes a solution of ethyllithium in dibutyl ether, a non-pyrophoric solution of ethyllithium in dibutyl ether in a concentration of 7 to 8%, a non-pyrophoric solution of ethyllithium in dibutyl ether and in a hydrocarbon in a concentration of 2 to 8%, process for preparing the solutions and the use of the solutions.
Enantioselective synthesis of 1,2-diamines via nucleophilic 1,2-addition to dibenzylamino-acetaldehyde-SAMP-hydrazone
Enders, Dieter,Chelain, Evelyne,Raabe, Gerhard
, p. 299 - 306 (2007/10/03)
Nucleophilic 1,2-addition of RM/CeCl3 in THF or allyl Grignard reagent in toluene to dibenzylamino-acetaldehyde-SAMP-hydrazone 2 after reductive N-N bond cleavage leads to differently protected 1,2-diamines 4 in good yields and of high enantiomeric purity (ee = 92-99percent).The absolute configuration was determined by X-ray structure analysis on the 1,2-adduct 3e. - Keywords: SAMP-hydrazone; nucleophilic 1,2-addition; asymmetric synthesis; vicinal diamine; organocerium reagent
Acylketene acetals in organic synthesis
Eid Jr.,Konopelski
, p. 975 - 992 (2007/10/02)
The preparation and reactivity of achiral and enantiomerically pure acylketene acetals are described. The key reactions of these substrates involve facile conjugate hydroboration and organolithium addition. Enantiomerically pure acylketene acetals were employed to generate a homochiral β-keto ketal through a highly diastereoselective lithium enolate quench. This β-ketal, which was also prepared through a desymmetrization ketalization reaction on a meso dione, was employed in the synthesis of the insect pheromone sitophilure.
REMARKABLE STEREOCONTROL IN THE ADDITION OF AN ANION TO AN α-ALKOXYALDEHYDE BY ENCOURAGING OR DISCOURAGING INTERNAL COMPLEXATION. APPLICATION TO BRIEF SYNTHESES OF THE MUS MUSCULUS (HOUSE MOUSE) PHEROMONE AND EXO-BREVICOMIN.
Bhupathy, M.,Cohen, Theodore
, p. 2619 - 2622 (2007/10/02)
Stereoselective addition of ethylmetallic reagents to acrolein dimer 1 and the conversion of the threo alcohol 4t to exo-brevicomin and the Mus musculus pheromone are reported.
