Reaction of alpha-aminoacetophenone oximes (2) with ethyl 6-amino-4-chloro-5-nitropyridine-2-carbamate (1) gave ethyl 6-amino-5-nitro-4-[(2-oxo-2-phenylethyl)amino]pyridine-2-carbamate oximes (3), which were hydrolyzed under acidic conditions to give the corresponding ketones (4). Related pyridines substituted with a keto side chain were prepared from 1 and 1,3-diaminopropanone oximes and by oxidation of the side-chain hydroxy group of ethyl 6-amino-4- [[3-(N-methyl-N-phenylamino)-2-hydroxypropyl]amino]-5-nitropyridine-7- carbamates (6). Catalytic hydrogenation of the nitro group of 4 over Raney nickel in a large volume of ethanol gave the 1-deaza-7,8-dihydropteridines (7). Several of the oximes 3 were successfully hydrogenated to give 7 directly. The resulting 1-deaza-7,8-dihydropteridines showed potent cytotoxicity against cultured L1210 cells and significant anticancer activity against lymphocytic leukemia P-388 in mice. These biological activities are attributed to the accumulation of cells at mitosis.
An activated carbamate, 2-nitrophenyl (2-fluoroethyl)nitrosocarbamate (3), was used to advantage in the synthesis of the water-soluble (2-fluoroethyl)nitrosoureas 6a--d from 2-aminoethanol, (1 alpha, 2 beta, 3 alpha)-2-amino-1,3-cyclohexanediol, cis-2-hydroxycyclohexanol, and 2-amino-2-deoxy-D-glucose. In a variation of this method, 2,4,5-trichlorophenyl (2-fluoroethyl)carbamate (4) was used to prepare the urea from which the essentially water-insoluble N-(2,6-dioxo-3-piperidinyl)-N-(2-fluoroethyl)-N-nitrosourea (6e) was derived. The anticancer activity of these nitrosoureas was determined against the murine tumors B16 melanoma and Lewis lung carcinoma and found to be significant and comparable to their chloroethyl counterparts. On the basis of results from both systems, the dihydroxycyclohexyl derivative 6b may be the most effective.
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