Formaldehyde → 2-[[4-[(2,4-Diaminopyrido[2,3-d]pyrimidin-6-yl)methyl-methylamino]benzoyl]amino]pentanedioic acid

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Reaction Steps

Reductive alkylation of diethyl p-aminobenzoyl-L-glutamate) (VI; R=H; R1 =C2H5) with III (Y=CHO) and hydrogen in 70% acetic acid containing Raney nickel gave a 32% yield of 5-deazaaminopterin diethyl ester. Saponification of the ester groups in a mixture of dimethyl sulfoxide-water at ambient temperature gave an 87% yield of 5-deazaaminopterin (II, R=H). Methylation of the latter compound was accomplished by treatment of II (R=H) with formaldehyde and sodium cyanoborohydride in aqueous solution at pH 6.4 to give an 85% yield of 5-deazamethotrexate, (II, R=CH3). The structure of II (R=CH3) was established as described hereinafter in Example 8C by oxidation with alkaline potassium permanganate to give the previously prepared 2-amino-4(3H)oxopyrido[2,3-d]pyrimidine-6-carboxylic acid (VIII), which indicated that methylation had occurred either on the 4- or 10-amino group. Methylation of the 4-amino group was eliminated from consideration by alkaline hydrolysis of the 4-amino group to give 5-deaza-10-methylfolic acid (I, R=CH3).

Provenance & Evidence