IRREVERSIBLE ENZYME INHIBITORS .155. ACTIVE-SITE-DIRECTED IRREVERSIBLE INHIBITORS OF DIHYDROFOLIC REDUCTASE DERIVED FROM 1-[4-(OMEGA-AMINOALKOXY)-3-CHLOROPHENYL]-4,6-DIAMINO-1,2-DIHYDRO-2,2-DIMETHYL-S-TRIAZINES BEARING A TERMINAL SULFONYL FLUORIDE

A series of 22 candidal e active-site-directed irreversible inhibitors of dihydrofolic reductase derived from 1-[4-(ω-ammoalkoxy)-3-chloiOphenyl]-4,6-diammo-1,2-dihydro-2,2-dimethyl-s-triazines by acylation of the terminal amino group by a fluorosulfonylbenzoyl, fluorosulfonylphenylsulfonyl, or fluorosulfonylphenylcariiamido group were synthesized and evaluated on the enzyme from L1210 mouse leukemia and mouse liver as well as L1210 cell culture; the alkoxy unit was varied between two and four carbons. Of these 22 compounds, 14 were excellent irreversible inhibitors of L1210 dihydrofolic reductase that at 5-10 × 10-8 M gave 84-100% inactivation of the enzyme; the presence of the 3-Cl atom was necessary for good irreversible inhibition. Of these 14 compounds, none showed complete specificity since the liver enzyme could also be inactivated 18-83%. The three best compounds showing <25% inactivation of the liver enzyme were m- or p-fiuorophenylcarbamido derivatives containing two (16) or three (3, 6) CH2, groups. When the efficiency of kill of L1210 cell culture was measured, the best six compounds (11, 13, 16, 21-23) showed ED50's in the range of 0.003-0.15 μM. The best compound of the series was, therefore, 1-[4-(p-fluorosulfonylphenylureidoethoxy)-3-ehlorophenyl]-4,6-diamino-1,2-dihydro-2,2-dimethyl-s-triazine (16) which had ED50 = 0.003 μM and at 0.072 μM showed 86% inactivation of L1210 dihydrofolic reductase in <2 min at 37°, but at 0.16 μM showed only 18% inactivation of the liver enzyme in 60 min. © 1969, American Chemical Society. All rights reserved.