139060-46-1Relevant academic research and scientific papers
Racemization-free chemoenzymatic peptide synthesis enabled by the ruthenium-catalyzed synthesis of peptide enol esters via alkyne-addition and subsequent conversion using alcalase-cross-linked enzyme aggregates
Schroeder, Hilmar,Strohmeier, Gernot A.,Leypold, Mario,Nuijens, Timo,Quaedflieg, Peter J. L. M.,Breinbauer, Rolf
supporting information, p. 1799 - 1807 (2013/07/19)
The C-terminal activation of peptides as prerequisite for the formation or ligation of peptide fragments is often associated with the problem of epimerization. We report that ruthenium-catalyzed alkyne addition with (+)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane as ligand allows the racemization-free synthesis of peptide enol esters tolerating a wide range of functional groups. The transformation can be performed in a variety of different solvents addressing the solubility issues imposed by peptides with varying amino acid side chain patterns. We show that peptide enol esters with an amide motif in the enol moiety are excellent acyl donors for the peptide condensation with other peptide fragments in organic solvents using serine endopeptidase subtilisin A as catalyst. The reported combination of transition metal catalysis with enzymatic peptide ligations adds an important tool for the racemization-free synthesis and ligation of peptides which is compatible even with unprotected amino acid side chains. Copyright
Synthetic and solution calorimetric investigations of chelating phosphine ligands in Ru(allyl)2(PP) complexes (PP = diphosphine)
Smith D.C.,Cadoret,Jafarpour,Stevens,Nolan
, p. 626 - 631 (2007/10/03)
Reaction enthalpies of (COD)Ru(allyl)2 (COD = η4-1,5-cyclooctadiene; allyl = 2-methylpropenyl) with a series of bidentate phosphines (dppm, dppf, dppe, dppb, dppp, depe, dmpe) have been measured by anaerobic solution calorimetry. The relative stability of the resulting complexes is strongly influenced by the electronic donor properties of the bidentate phosphine ligand. Reactions involving ligands that are better σ donors result in higher enthalpy values and, therefore, more thermodynamically stable complexes. Additionally, the synthesis and characterization of two new ruthenium allyl complexes Ru(allyl)2(dppf) (3) and Ru(allyl)2(depe) (8) and the X-ray crystal structure of 3 are reported.
The co-crystallization of Ru((R)-binap)(η3-Me-allyl)2 and binap dioxide, and synthesis of Ru(Ph2P(CH2)4PPh2)(η 3-Me-allyl)2
MacFarlane, Kenneth S.,Rettig, Steven J.,Liu, Zhaoquing,James, Brian R.
, p. 213 - 219 (2007/10/03)
The molecular structure of the 2-methylallyl species Ru((R)-binap)(η3-Me-allyl)2 (3) was established by X-ray crystallography of a crystal of 3a, the asymmetric unit of which is composed of half of a molecule of 3 and half of a (R)-(+)-2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl(binap dioxide) molecule, co-crystallized with two disordered deuterobenzenes; crystals of 3a are tetragonal, space group I422, with Z=8, a=21.344(1) A and c=36.453(2) A. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R=0.034 and Rw=0.032 for 3431 reflections with I≥3σ(I). The 1,4-bis(diphenylphosphino)butane (dppb) analogue (2) of 3 was also prepared and characterized by 1H and 31P{1H}-NMR spectroscopy and elemental analysis, and the reactivities of 2 and 3 toward halogen acids are discussed.
