3 Synthesis of Analogues of Folic Acid, Aminopterin and Methotrexate as Antitumour Agents

Abstract

Publisher Summary This chapter discusses the syntheses of folic acid, aminopterin, and methotrexate analogs in which an intact L-glutamic acid side-chain is present while simultaneously varying the pteridine ring moiety, the C-9, N- 10 bridge and/or the benzoyl group. Several analogs of folic acid are known in which the only remaining structural feature of the folic acid molecule is the p-aminobenzoylglutamic acid moiety. Biological results are discussed in those cases where the analog has significant activity in tumor systems relative to methotrexate (MTX) or aminopterin (AP). Of the many classes of deazaFA derivatives investigated, none has received more attention or resulted in more promising candidate drugs than 5,8-dideaza (quinazoline) analogs. Methylation of folic acid (FA) with a 4-molar excess of methyl iodide gave a low yield of the tetramethyl derivative. A Dimroth rearrangement brought about by base at room temperature then gave hydrolysis of the methyl esters having taken place under the conditions of the rearrangement.