4789-08-6Relevant academic research and scientific papers
Oxidative synthesis of amides and pyrroles via dehydrogenative alcohol oxidation by ruthenium diphosphine diamine complexes
Schley, Nathan D.,Dobereiner, Graham E.,Crabtree, Robert H.
scheme or table, p. 4174 - 4179 (2011/10/03)
A series of ruthenium complexes can perform the acceptorless dehydrogenation of diols as well as the reaction of amines and alcohols to form ester, lactam, and amide products. The ligand criteria necessary for high catalytic activity are identified to guide future catalyst development for amide formation from amines and alcohols. These complexes can be employed in a dehydrogenative Paal-Knorr pyrrole synthesis to give 2,5-dimethyl-N- alkylpyrroles.
Lightening Agents and/or Dyes that Contain Aldehyde(s)
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, (2010/12/29)
Agents for dyeing and/or lightening keratin fibers, in particular human hair, containing, relative to the weight thereof, 0.001 to 15 wt. % of at least one aldehyde of the formula (I): wherein X represents —CH(R2)—SO2—Y—R1, —CR3R4R5, or wherein Y represents —CH(CHO)— or —CH2— or a chemical bond, and wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 independently represents —H or —CN or —F or —Cl or —Br or —I or —CHO or —NH2 or —NO2 or —CF3 or —CCl3 or —CF2CF3 or —CCl2CCl3 or an optionally substituted (C1-C6) alkyl group or a hydroxyalkyl group or a polyhydroxyalkyl group or an optionally substituted (C1-C6) alkylene group, and wherein the agent contains no oxidation dye precursors of developer and coupler type.
An experimental-theoretical study of the factors that affect the switch between ruthenium-catalyzed dehydrogenative amide formation versus amine alkylation
Nova, Ainara,Balcells, David,Schley, Nathan D.,Dobereiner, Graham E.,Crabtree, Robert H.,Eisenstein, Odile
experimental part, p. 6548 - 6558 (2011/02/17)
A ruthenium(II) diamine complex can catalyze the intramolecular cyclization of amino alcohols H2N(CH2)nOH via two pathways: (i) one yields the cyclic secondary amine by a redox-neutral hydrogen-borrowing route with loss of water; and (ii) the second gives the corresponding cyclic amide by a net oxidation involving loss of H2. The reaction is most efficient in cases where the product has a six-membered ring. The amide and amine pathways are closely related: DFT calculations show that both amine and amide formations start with the oxidation of the amino alcohol, 5-amino-1-pentanol, to the corresponding amino aldehyde, accompanied by reduction of the catalyst. The intramolecular condensation of the amino aldehyde takes place either in the coordination sphere of the metal (path I) or after dissociation from the metal (path II). Path I yields the Ru-bound zwitterionic form of the hemiaminal protonated at nitrogen, which eliminates H2, forming the amide product. In path II, the free hemiaminal dehydrates, giving an imine, which yields the amine product by hydrogenation with the reduced form of the catalyst generated in the initial amino alcohol oxidation. For amide to be formed, the hemiaminal must remain metal-bound in the key intermediate and the elimination of H2 must occur from the same intermediate to provide a vacant site for β-elimination. The elimination of H2 is affected by an intramolecular H-bond in the key intermediate. For amine to be formed, the hemiaminal must be liberated for dehydration to imine and the H2 must be retained on the metal for reduction of the imine intermediate.
DI- OR TRIPEPTIDE RENIN INHIBITORS CONTAINING LACTAM CONFORMATIONAL RESTRICTION IN ACHPA
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, (2008/06/13)
Enzyme di-or tripeptides of the formula: STR1 and analogs thereof which inhibit renin and are useful for treating various forms of renin-associated hypertension, hyperaldosteronism and congestive heart failure; compositions containing these renin-inhibitory peptides, optionally with other antihypertensive agents; and methods of treating hypertension, hyperaldosteronism or congestive heart failure or of establishing renin as a causative factor in these problems which employ these novel peptides.
