- PYRROLOBENZODIAZEPINE PRODRUGS AND ANTIBODY CONJUGATES THEREOF
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The invention relates generally to pyrrolobenzodiazepine monomer and dimer prodrugs having a glutathione-activated disulfide prodrug moiety, a DT-diaphorase-activated quinone prodrug moiety or a reactive oxygen species-activated aryl boronic acid or aryl boronic ester prodrug moiety. The invention further relates to pyrrolobenzodiazepine prodrug dimer-antibody conjugates.
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Page/Page column 177; 178
(2018/03/06)
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- 1H NMR studies on the reductively triggered release of heterocyclic and steroid drugs from 4,7-dioxoindole-3-methyl prodrugs
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Hypoxia is a feature of several disease states, including cancer and rheumatoid arthritis. Prodrug systems which, after bioreduction, selectively release active drugs in these tissues may be important in therapy. An improved preparation of 1,2-dimethyl-3-hydroxymethyl-5-methoxyindole-4,7-dione was developed. Mitsunobu coupling with (5-substituted) isoquinolin-1-ones (potent inhibitors of poly(ADP-ribose)polymerase) gave 1-(1,2-dimethyl-4,7-dioxo-5-methoxyindol-3-ylmethoxy)isoquinolines and N-(1,2-dimethyl-4,7-dioxo-5-methoxyindol-3-ylmethyl)isoquinolin-1-ones. Similar coupling with the anticancer drug pentamethylmelamine gave its potential prodrug 1,2-dimethyl-3-(N-(4,6-bis(dimethylamino)-1,3,5-triazin-2-yl)-N- methylaminomethyl)-5-methoxyindole-4,7-dione. Treatment of sodium prednisolone hemisuccinate with 3-chloromethyl-1,2-dimethyl-5-methoxyindole-4,7-dione gave an analogous candidate prodrug of the anti-inflammatory drug prednisolone. In a chemical model system for bioreduction, SnCl2 in CDCl3/CD3OD triggered rapid stoichiometric release of isoquinolin-1-ones from the O-linked prodrugs but not from the N-linked analogues. Use of this system allowed the release process to be monitored in situ by 1H NMR spectroscopy. Diethyl hydrazine-1,2-dicarboxylate was found to reduce SnIV to SnII, making the overall reductive release catalytic in tin. The reduced (hydroquinone) prodrug may have a short lifetime under these reductive conditions, meaning that only good leaving groups are expelled. Thus 1-(1,2-dimethyl-4,7-dioxo-5-methoxyindol-3-ylmethoxy)isoquinolines and analogues may be useful as reductively triggered prodrugs.
- Ferrer, Sandra,Naughton, Declan P.,Threadgill, Michael D.
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p. 3445 - 3454
(2007/10/03)
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- Indium metal as a reducing agent in organic synthesis
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The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
- Pitts,Harrison,Moody
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p. 955 - 977
(2007/10/03)
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- Indolequinone antitumor agents: Reductive activation and elimination from (5-methoxy-1-methyl-4,7-dioxoindol-3-yl)methyl derivatives and hypoxia- selective cytotoxicity in vitro
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A series of indolequinones bearing a variety of leaving groups at the (indol-3-yl)methyl position was synthesized by functionalization of the corresponding 3-(hydroxymethyl)indolequinone, and the resulting compounds were evaluated in vitro as bioreductively activated cytotoxins. The elimination of a range of functional groups-carboxylate, phenol, and thiol- was demonstrated upon reductive activation under both chemical and quantitative radiolytic conditions. Only those compounds which eliminated such groups under both sets of conditions exhibited significant hypoxia selectivity, with anoxic:oxic toxicity ratios in the range 10-200. With the exception of the 3-hydroxymethyl derivative, radiolytic generation of semiquinone radicals and HPLC analysis indicated that efficient elimination of the leaving group occurred following one-electron reduction of the parent compound. The active species in leaving group elimination was predominantly the hydroquinone rather than the semiquinone radical. The resulting iminium derivative acted as an alkylating agent and was efficiently trapped by added thiol following chemical reduction and by either water or 2-propanol following radiolytic reduction. A chain reaction in the radical-initiated reduction of these indolequinones (not seen in a simpler benzoquinone) in the presence of a hydrogen donor (2-propanol) was observed. Compounds that were unsubstituted at C-2 were found to be up to 300 times more potent as cytotoxins than their 2-alkyl-substituted analogues in V79-379A cells, but with lower hypoxic cytotoxicity ratios.
- Naylor, Matthew A.,Swann, Elizabeth,Everett, Steven A.,Jaffar, Mohammed,Nolan, John,Robertson, Naomi,Lockyer, Stacey D.,Patel, Kantilal B.,Dennis, Madeleine F.,Stratford, Michael R. L.,Wardman, Peter,Adams, Gerald E.,Moody, Christopher J.,Stratford, Ian J.
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p. 2720 - 2731
(2007/10/03)
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