Synthesis and antifolate evaluation of the 10-propargyl derivatives of 5-deazafolic acid, 5-deazaaminopterin, and 5-methyl-5-deazaaminopterin.
5-Deaza-10-propargylfolic acid (4), an analogue of the thymidylate synthase (TS) inhibitor 10-propargyl-5,8-dideazafolic acid (PDDF, 1), was prepared via alkylation of diethyl N-[4-(propargylamino)benzoyl]-L-glutamate (7) by 2-amino-6-(bromomethyl)-4(3H)-pyrido[2,3-d]pyrimidinone (15). Bromomethyl intermediate 15 was prepared from the corresponding hydroxymethyl precursor 14 by treatment with 48% HBr. Hydroxymethyl compound 14 was obtained by deamination of reported 2,4-diaminopyrido[2,3-d]pyrimidine-6-methanol (12a) in refluxing 1 N NaOH. Both 12a and its 5-methyl-substituted analogue 12b were converted to versatile 6-bromomethyl intermediates 13a and 13b from which important antifolates may be readily derived. Alkylation of 7 by 13a,b led to 10-propargyl-5-deazaaminopterin (5) and 5-methyl-10-propargyl-5-deazaaminopterin (6). As an inhibitor of TS from H35F/F cells, 4 gave an IC50 value showing it to be approximately 6-fold less inhibitory than PDDF (90 nM for 4 vs 14 nM for PDDF). In in vitro studies, IC50 (microM) values obtained for 4 vs L1210 and S180 of 1.50 and 2.35, respectively, were similar to those obtained for PDDF (2.61 and 1.97). Against HL60 cells, 4 was about 7-fold more cytotoxic than PDDF (IC50 values 0.72 and 5.29 microM). Inclusion of thymidine did not establish TS as the site of cytotoxic action for either 4 or PDDF in the cell lines used. In in vivo tests against L1210 in mice, 4 failed to show therapeutic effect. The 2,4-diamino compounds 5 and 6 were as potent inhibitors of DHFR from L1210 cells as MTX and 7- and 35-fold, respectively, more inhibitory than MTX toward L1210 cell growth. In mediated influx into L1210 cells, 5 and 6 were transported 2.7- and 8.5-fold, respectively, more readily than MTX. Against the EO771 mammary adenocarcinoma in mice, 6 produced greater antitumor effect than MTX. A dose of 36 mg/kg per day for 5 days caused no toxic deaths while the average tumor volume among 10 mice was reduced to 8-9% of that of the control, and 20% of the test animals were rendered tumor free.
Piper
J R
JR
Kettering-Meyer Laboratory, Southern Research Institute, Birmingham, Alabama 35255.
Malik
N D
ND
Rhee
M S
MS
Galivan
J
J
Sirotnak
F M
FM
D000630:Aminopterin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D005492:Folic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D005493:Folic Acid Antagonists / Q000138:chemical synthesis* / Q000494:pharmacology; D006801:Humans; D007939:Leukemia L1210 / Q000188:drug therapy; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy; D051379:Mice; D011799:Quinazolines / Q000494:pharmacology; D013940:Thymidylate Synthase / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured / Q000187:drug effects
D005493:Folic Acid Antagonists; D011799:Quinazolines; C072406:10-propargyl-5-deazafolic acid; C072405:10-propargyl-5-deazaaminopterin analog of folic acid; C072407:10-propargyl-5-methyl-5-deazaaminopterin analog of folic acid; C031662:CB 3717; D005492:Folic Acid; D013940:Thymidylate Synthase; D000630:Aminopterin