- A large-scale synthesis of the bioreductive drug 1,4-bis{[2-(dimethylamino)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione bis-N-oxide (AQ4N)
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A large-scale synthesis of the bis-bioreductive drug 1,4-bis{[2-(dimethylamino)ethyl]amino}-5,8-dihydroxy-anthracene-9,10-dione bis-N-oxide (AQ4N) has been developed. This six-step synthesis provides AQ4N in 20% overall yield from readily available tetrachlorophthalic anhydride. The key step was a KF-NaF-mediated conversion of 3,6-dichlorophthalic anhydride to 3,6-difluorophthalic anhydride, which could be achieved in 77% yield on a 100 g scale. A trace impurity in AQ4N was determined (by LC-MS and independent synthesis) to be the mono-N-oxide 1-amino-4-[2-(dimethylamino)ethyl]amino-5,8-dihydroxyanthracene-9,10-dione N-oxide. This is formed spontaneously from AQ4N under a number of conditions, including during HPLC on reversed-phase columns. The Royal Society of Chemistry 1999.
- Lee, Ho H.,Denny, William A.
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p. 2755 - 2758
(2007/10/03)
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- Process for the preparation of salts of substituted or unsubstituted phthalic acids
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The present invention relates to a process for the preparation of salts of substituted or unsubstituted phthalic acids, by reacting a compound of the formula STR1 in which R1, R2, R3 and R4 are identical or different and are H, F, Cl, Br, CF3, OH, an alkoxy or alkyl radical in each case having 1 to 4 carbon atoms, or a radical --NR7 R8, in which R7 and R8 are identical or different and are H, an alkyl radical having 1 to 4 carbon atoms, or a phenyl radical, R5 and R6 are identical or different and are H, a --CO-- alkyl group having 1 to 6 carbon atoms in the alkyl radical, or a benzoyl group, or R5 and R6 together form a radical of the formula STR2 in which R9, R10, R11 and R12 are identical or different and are H, F, Cl, Br, CF3, OH, an alkoxy or alkyl radical in each case having 1 to 4 carbon atoms, or a radical --NR7 R8, in which R7 and R8 are identical or different and are H, an alkyl radical having 1 to 4 carbon atoms, or a phenyl radical, with water, a water-soluble base, and an oxidizing agent at a temperature of -10° to 150° C. in the presence or absence of a water-insoluble solvent inert under the reaction conditions.
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