101. Prodrugs for Amidines: Synthesis and Anti-Pneumocystis carinii Activity of Carbamates of 2,5-Bis(4-amidinophenyl)furan
- Author
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Rahmathullah, S. M., Hall, J. E., Bender, B. C., McCurdy, D. R., Tidwell, R. R., and Boykin, D. W.
- Abstract
Syntheses of several carbamate analogues of 2,5-bis(4-amidinophenyl)furan (
1 ) under mild conditions and their evaluation as prodrugs against Pneumocystis carinii pneumonia (PCP) in an immunosuppressed rat model are described. Thus, nine new bis-carbamates: methoxycarbonyl (2 ), 2,2,2-trichloroethoxycarbonyl (3 ), ethylthiocarbonyl (4 ), benzyloxycarbonyl (5 ), (4-methyl-2-oxo-1,3-dioxol-4-en-5-yl)methoxycarbonyl (6 ), phenoxycarbonyl (7 ), 4-fluorophenoxycarbonyl (8 ), 4-methoxyphenoxycarbonyl (9 ), and (1-acetoxy)ethoxycarbonyl (10 ) and a bis-carbonate ethoxycarbonyloxy (11 ) of the bis-amidine1 have been synthesized and evaluated. The in vivo results show that the 4-fluorophenyl carbamate8 and the 4-methoxyphenyl carbamate9 in this series had the best anti-PCP activity by both intravenous and oral administration at a dosage level of 22 mol and 33 μmol/kg/day, respectively. Compounds3 −7 were also more active than the parent drug (1 ) on oral administration. The acute toxicity usually exhibited by the parent amidine1 at a dosage level of 22 μmol/kg/day on intravenous administration has been significantly reduced by the prodrug modifications, with the exception of compound10 which exhibited some toxicity. This report also describes the synthesis of several aryl−alkyl and aryl−aryl carbonates (12 −14, 16 −23 ) as efficient reagents for the preparation of carbamate derivatives from bis-arylamidines.- Published
- 1999