Process for the production of (S)-vinyl and allenyl gaba
申请人:Merrell Dow Pharmaceuticals Inc.
公开号:US05208345A1
公开(公告)日:1993-05-04
The present invention is directed to a new class of pyrrolidinone derivatives that are useful as chemical intermediates in the synthesis of S-allenyl and S-vinyl GABA, both of which are antiepileptic agents.
Serendipitous Discovery of α-Hydroxyalkyl Esters as β-Lactamase Substrates
作者:Ryan B. Pelto、R. F. Pratt
DOI:10.1021/bi101071r
日期:2010.12.14
O-(1-Carboxy-1-alkyloxycarbonyl) hydroxamates were found to spontaneously decarboxylate in aqueous neutral buffer to form O-(2-hydroxyalkylcarbonyl) hydroxamates, While the former molecules do not react rapidly with serine beta-lactamases, the latter are quite good substrates of representative class A and C, but not D, enzymes, and particularly of a class C enzyme. The enzymes catalyze hydrolysis of these compounds to a mixture of the alpha-hydroxy acid and hydroxamate. Analogous compounds containing aryloxy leaving groups rather that hydroxamates are also substrates. Structure-activity experiments showed that the alpha-hydroxyl group was required for any substantial substrate activity. Although both D- and L-alpha-hydroxy acid derivatives were substrates, the former were preferred. The response of the class C activity to pH and to alternative nucleophiles (methanol and D-phenylalanine) suggested that the same active site functional groups participated in catalysis as for classical substrates. Molecular modeling was employed to explore how the alpha-hydroxy group might interact with the class C beta-lactamase active site. Incorporation of the alpha-hydroxyalkyl moiety into novel inhibitors will be of considerable interest.
Transition State Analogy of Phosphonic Acid Peptide Inhibitors of Pepsin
作者:Paul A. Bartlett、Mark A. Giangiordano
DOI:10.1021/jo952074c
日期:1996.1.1
A series of 11 phosphonate peptide analogs, RO(2)C-Xaa-Yaa-Phe-(PO2--O)-Phe O-(3-(4-pyridyl)propyl ester), were synthesized and evaluated as inhibitors of the aspartic peptidase pepsin. For the inhibitors with Gly or Ala at the P-2 position, the K-i values correlate with the K-m/k(cat) values of the corresponding substrates, demonstrating that these analogs mimic the transition state in the way the P-2-P-4 residues bind. Deviations from the correlation for the other inhibitor/substrate pairs imply a different binding orientation as a result of N-substitution at P-2 (Pro), contamination with the more potent diastereomer (D-Ala), or a change in rate-limiting step for turnover (lie).