- The azaquinone-methide elimination: Comparison study of 1,6- and 1,4-eliminations under physiological conditions
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The azaquinone-methide elimination is a powerful and efficient reaction useful for disassembly of spacers in prodrug systems. We and others have used the spacer-technique to develop dendritic and polymeric self-immolative molecular systems that can disass
- Erez, Rotem,Shabat, Doron
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supporting information; experimental part
p. 2669 - 2672
(2009/02/02)
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- Novel anthracycline-spacer-β-glucuronide, -β-glucoside, and -β-galactoside prodrugs for application in selective chemotherapy
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A series of anthracycline prodrugs containing an immolative spacer was synthesized for application in selective chemotherapy. The prodrugs having the general structure anthracycline-spacer-β-glycoside were designed to be activated by β-glucuronidase or β-galactosidase. Prodrugs with -chloro, -bromo or -n-hexyl substituents on the spacer were synthesized as well as prodrugs containing a -β-glucuronyl, -β-glucosyl or -β-galactosyl carbamate specifier. The key step in the synthesis of all prodrugs is the highly β-diastereoselective addition reaction of the anomeric hydroxyl of a glycosyl donor to a spacer isocyanate resulting in the respective β-glycosyl carbamate pro-moieties. The resulting protected pro-moieties were coupled to an anthracycline. Prodrugs were evaluated with respect to activation rate by the appropriate enzyme and additionally, their IC50 values were determined. Optimal prodrugs in this study were at least 100- to 200-fold less toxic than their corresponding drug in vitro and were activated to the parent drug in a half-life time of approximately 2h. Copyright (C) 1999 Elsevier Science Ltd.
- Leenders, Ruben G. G.,Damen, Eric W. P.,Bijsterveld, Edward J. A.,Scheeren, Hans W.,Houba, Pieter H. J.,Van Der Meulen-Muileman, Ida H.,Boven, Epie,Haisma, Hidde J.
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p. 1597 - 1610
(2007/10/03)
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- 2-Nitrophenylcarbamoyl-(S)-prolyl-(S)-3-(2-naphthyl)alanyl-N-benzyl-N- methylamide (SDZ NKT 343), a potent human NK1 tachykinin receptor antagonist with good oral analgesic activity in chronic pain models
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A lead compound which had sub-micromolar affinity for the rabbit NK1 receptor but negligible affinity for rat NK1 receptors, 3a, was discovered by directed screening. 2-Substitution in the ring of the benzylthiourea substituent in the initial lead was found to be important, and halogens (Cl, Br) in this position were found to improve affinity for the human receptor. The activity of a series of 2-halo-substituted benzylthioureas was then optimized by modification of the proline diphenylmethyl amide, guided by a simple conceptual model based on structural overlay between these early antagonists and NK1 selective peptides. In this way, aromatic amino acid amides were identified which had improved affinity with respect to the starting diphenylmethyl (DPM) amides. The first sub-nanomolar ligand for the human NK1 receptor which arose from this series, 4af, combined a 2- chlorobenzylthiourea unit with a 2-naphthylalanine amide. Contemporaneously it was discovered that the benzylthiourea unit could be simplified to a phenylthiourea providing that an appropriate 2-substituent was also incorporated. Combination of these two series gave 2-NO2 phenylthiourea analogues which led directly to the analogous urea, 5f (2- nitrophenylcarbamoyl-(S)-prolyl-(S)-3-(2-naphthyl)alanyl-N-benzy-N- methylamide, SDZ NKT 343), a highly potent ligand for the human NK1 receptor (K(i) = 0.16 nM). In addition to its high in vitro potency, 5f proved to be a potent orally active analgesic in guinea pig models of chronic inflammatory and neuropathic pain. The nature of the 2-aryl substituent was found to be critical for oral activity in this series. Clinical evaluation of 5f as a novel analgesic agent is currently underway.
- Walpole,Ko,Brown,Beattie,Campbell,Dickenson,Ewan,Hughes,Lemaire,Lerpiniere,Patel,Urban
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p. 3159 - 3173
(2007/10/03)
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