Abstract: A new thiophene substituted antitumor antifolate, N{[5-(2,4-diamino-6-pteridinyl)ethyl]2-theonyl}-L-glutamic acid having the structural formula 1 is provided, as well as methods for its preparation. The new thiophene substituted antifolate 1 is a very potent inhibitor of the enzyme dihydrofolate reductase, undergoes moderate polyglutamylation and is transported to tumor cells more effectively than methotrexate. Compound 1 is an excellent inhibitor of tumor cells growth in culture, the potency being superior to methotrexate against CCRF-CEM human lukemia cells.

Abstract: Three new non-polyglutamatable glutamic acid derivatives in the antifolate series are provided as well as procedures for their preparation. These compounds are: 4-amino-4-deoxy-10-deazapteroyl-.tau.-methyleneglutamic acid (1); 4-amino-4-deoxy-10-ethyl-10-deazapteroyl-.tau.-methylene-glutamic acid (2); and 4-amino-4-deoxy-10-deazapteroyl-3-hydroxyglutamic acid (3). None of the compound undergo polyglutamylation as determined by their inability to serve as substrates for folylpolyglutamate synthetase (FPGS). Compounds 1 and 2 are transported more effectively to tumor cells and they are more powerful in inhibiting the growth of human leukemia cells in culture as compared to the standard anticancer drug methotrexate. All three compounds (1, 2, and 3) inhibit human dihydrofolate reductase to the same extent as methotrexate.