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17 results on '"Kucznierz, R."'

10. Tetrahydro-isoquinoline-Based Factor Xa Inhibitors

Author

Kucznierz, R., Grams, F., Leinert, H., Marzenell, K., Engh, R. A., and Saal, W. von der

Abstract

Derivatives of (2-amidino-1,2,3,4-tetrahydro-isoquinolin-7-yloxy)phenylacetic acid (TIPAC) were developed as inhibitors of factor Xa (fXa). The compounds are prepared using 15 synthetic steps on average. The most potent compounds (14, 17, 22−26) display inhibition constants of Ki = 21−55 nM but do not inhibit thrombin (Ki = 5−>100 μM) and only weakly inhibit trypsin (Ki = 0.08−5 μM). They bear a second basic moiety, e.g., substituted 1-(iminomethyl)piperidines, which is linked to C-4 of the phenyl group of TIPAC via an oxygen atom. The inhibition constants of these compounds are almost independent of the size of the (iminomethyl)piperidine substituent. Due to the fact that fXa displays two cation binding sites, namely, the S1 and S4 sites, in principle two binding modes are conceivable for the novel dibasic fXa inhibitors. Molecular modeling experiments based on the X-ray structures of uninhibited fXa and the DX-9065a/fXa complex were carried out. The results taken together with the inhibition constants clearly favor one binding mode:  the tetrahydro-isoquinoline fills the S1 pocket even better than the naphthalene moiety of DX-9065a, and the (iminomethyl)piperidine residues occupy the S4 site.

Published
1998

17. Syntheses and selective inhibitory activities of terphenyl-bisamidines for serine proteases.

Author

von der Saal W, Engh RA, Eichinger A, Gabriel B, Kucznierz R, and Sauer J

Subjects
Amidines chemical synthesis, Amidines pharmacology, Factor Xa Inhibitors, Humans, Serine Proteinase Inhibitors pharmacology, Serine Proteinase Inhibitors chemical synthesis
Abstract

Biphenyl nitriles 5a-c, terphenyl dinitriles 11a-d, and naphthalene-bis(benzonitrile) 11c were prepared by palladium-catalyzed cross coupling reactions and subsequently converted to biphenyl amidines 8a-c and bis(benzamidines) 4a-e. Among the biphenyl amidines 8 only the meta-derivative 8b inhibits factor Xa and trypsin (Ki = 10 microM). The terphenyl bisamidine 4c does not inhibit factor Xa, trypsin, thrombin, and plasmin, while 4a and 4d are almost equipotent inhibitors of these enzymes (Ki 1-6 microM), and 4b and 4e are selective for trypsin (Ki = 0.2 and 0.3 microM; but Ki > 1 microM for factor Xa, thrombin, and plasmin). X-ray analysis of crystals of 4b complexed with bovine trypsin revealed a unique binding mode: one benzamidino group binds in the S1 site to the side chain carboxylate of Arg189. The central phenyl group is twisted away from the S2/S3 sites and the second amidino group contacts the Asn143 side chain.

Published
1996
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