942919-64-4Relevant academic research and scientific papers
Tandem Palladium and Isothiourea Relay Catalysis: Enantioselective Synthesis of α-Amino Acid Derivatives via Allylic Amination and [2,3]-Sigmatropic Rearrangement
Spoehrle, Stéphanie S. M.,West, Thomas H.,Taylor, James E.,Slawin, Alexandra M. Z.,Smith, Andrew D.
supporting information, p. 11895 - 11902 (2017/09/07)
A tandem relay catalytic protocol using both Pd and isothiourea catalysis has been developed for the enantioselective synthesis of α-amino acid derivatives containing two stereogenic centers from readily accessible N,N-disubstituted glycine aryl esters and allylic phosphates. The optimized process uses a bench-stable succinimide-based Pd precatalyst (FurCat) to promote Pd-catalyzed allylic ammonium salt generation from the allylic phosphate and the glycine aryl ester. Subsequent in situ enantioselective [2,3]-sigmatropic rearrangement catalyzed by the isothiourea benzotetramisole forms syn-α-amino acid derivatives with high diastereo- and enantioselectivity. This methodology is most effective using 4-nitrophenylglycine esters and tolerates a variety of substituted cinnamic and styrenyl allylic ethyl phosphates. The use of challenging unsymmetrical N-allyl-N-methylglycine esters is also tolerated under the catalytic relay conditions without compromising stereoselectivity.
TUBULYSIN D ANALOGUES
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Page/Page column 41, (2009/03/07)
The present invention provides novel tubulysin analogues, methods of making and methods of using such analogues and conjugates thereof. The essential features for the potent cytotoxicity of tubulysin D have been established for the first time by the synthesis and evaluation of a series of analogues. By identifying functionality that surprisingly is not necessary for activity, highly potent cell-growth inhibitors have been developed that are smaller and considerably more stable than tubulysin D.
Synthesis and biological evaluation of pretubulysin and derivatives
Ullrich, Angelika,Herrmann, Jennifer,Mueller, Rolf,Kazmaier, Uli
experimental part, p. 6367 - 6378 (2011/03/21)
Pretubulysin, a biosynthetic precursor of the tubulysins, shows potent biological activity in the subnanomolar range towards various tumor cell lines. Its activity is only slightly less than those of the structurally more complex tubulysins. With a straig
Design, synthesis, and biological properties of highly potent tubulysin D analogues
Patterson, Andrew W.,Peltier, Hillary M.,Sasse, Florenz,Ellman, Jonathan A.
, p. 9534 - 9541 (2008/12/22)
Ten analogues of tubulysin D were synthesized and assayed against established mammalian cell lines, including cancer cells measuring inhibition of cell growth by an MTT assay. These experiments establish for the first time the essential features for the potent cytotoxicity of tubulysin D. The activities of analogues 2 to 5 demonstrate that numerous modifications may be introduced at the C-terminus of the natural product with only modest loss in activity, while the activities of analogues 6 to 8 suggest that a basic amine must be present at the N-terminus to maintain activity. Most surprisingly, analogue 10 establishes that replacement of the chemically labile O-acyl N,O-acetal with the stable N-methyl group results in almost no loss in activity. In aggregate, these structure-activity relationships enable the design of analogues such as 11 that are smaller and considerably more stable than tubulysin D but that maintain most of its potent cell-growth inhibitory activity.
