132343-91-0Relevant academic research and scientific papers
Synthesis and potent antifolate activity and cytotoxicity of B-ring deaza analogues of the nonpolyglutamatable dihydrofolate reductase inhibitor N(α)-(4-amino-4-deoxypteroyl)-N(δ)-hemiphthaloyl-L-ornithine (PT523)
Rosowsky, Andre,Wright, Joel E.,Vaidya, Chitra M.,Bader, Henry,Forsch, Ronald A.,Mota, Clara E.,Pardo, Jorge,Chen, Cindy S.,Chen, Ying-Nan
, p. 5310 - 5319 (1998)
Six new B-ring analogues of the nonpolyglutamatable antifolate N(α)- (4-amino-4-deoxypteroyl)-N(δ)-hemiphthaloyl-L-ornithine (PT523, 3) were synthesized with a view to determining the effect of modifications at the 5- and/or 8-position on dihydrofolate reductase (DHFR) binding and tumor cell growth inhibition. The 5- and 8-deaza analogues were prepared from methyl 2- L-amino-5-phthalimidopentanoate and 4-amino-4-deoxy-N10-formyl-5-deaza- and 8-deazapteroic acid, respectively. The 5,8-dideaza analogues were prepared from methyl 2-L-[(4-aminobenzoyl)-amino]-5-phthalimidopentanoate and 2,4- diaminoquinazoline-6-carbonitriles. The K(i) for inhibition of human DHFR by the 5-deaza and 5-methyl-5-deaza analogues was about the same as that of 3 (0.35 pM), 11-fold lower than that of aminopterin (AMT, 1), and 15-fold lower than that of methotrexate (MTX, 2). However the K(i) of the 8-deaza analogue was 27-fold lower than that of 1, and that of the 5,8-dideaza, 5-methyl-5,8- dideaza, and 5-cloro-5,8-dideaza analogues was approximately 50-fold lower. This trend was consistent with the published literature on the corresponding DHFR inhibitors with a glutamate side chain. In colony formation assays against the human head and neck squamous carcinoma cell line SCC25 after 72 h of treatment, the 5- and 8-deaza analogues were approximately as potent as 3, whereas the 5,8-dideaza analogue was 3 times more potent. 5-Methyl and 5- chloro substitution was also favorable, with the 5-methyl-5-deaza analogue being 2.5-fold more potent than the 5-deaza analogue. However the effect of 5-methyl substitution was less pronounced in the 5,8-dideaza analogues than in the 5-deaza analogues. The 5-chloro-5,8-dideaza analogue of 3 was the most active member of the series, with an IC50 = 0.33 nM versus 1.8 nM for 3 and 15 nM for MTX. The 5-methyl-5-deaza analogue of 3 was also tested at the National Cancer Institute against a panel of 50 human tumor cell lines in culture and was consistently more potent than 3, with IC50 values in the low-nanomolar to subnanomolar range against most of the tumors. Leukemia and colorectal carcinoma cell lines were generally most sensitive, though good activity was also observed against CNS tumors and carcinomas of the breast and prostate. The results of this study demonstrate that B-ring analogues of 3 inhibit DHFR activity and tumor cell colony formation as well as, or better than, the parent compound. In view of the fact that 3 and its B-ring analogues cannot form polyglutamates, their high cytotoxicity relative to the corresponding B-ring analogues of AMT is noteworthy.
Synthesis and in Vitro Biological Activity of New Deaza Analogues of Folic Acid, Aminopterin, and Methotrexate with an L-Ornithine Side Chain
Rosowsky, Andre,Forsch, Ronald A.,Bader, Henry,Freisheim, James H.
, p. 1447 - 1454 (2007/10/02)
The 5-deaza and 5,8-dideaza analogues of Nα-pteroyl-L-ornithine (Pter-Orn), the 5-deaza, 8-deaza, and 5,8-dideaza analogues of Nα-(4-amino-4-deoxypteroyl)-L-ornithine (APA-Orn), and the Nδ-carboxymethyl derivative of Nα-(4-amino-4-deoxy-N10-methylpteroyl)-L-ornithine (m-APA-Orn) were synthesized and tested as inhibitors of dihydrofolate reductase (DHFR) and as inhibitors of tumor cell growth in culture.Reductive amination of 2-acetamido-6-formylpyridopyrimidin-4(3H)-one with methyl Nα-(4-aminobenzoyl)-Nδ-(benzyloxycarbonyl)-L-ornithinatefollowed by removal of the blocking groups afforded the 5-deaza analogue of Pter-Orn, whereas N-alkylation of methyl Nα-(4-aminobenzoyl)-Nδ-(benzyloxycarbonyl)-L-ornithinate with 2-amino-6-(bromomethyl)quinazolin-4(3H)-one and deprotection gave the corresponding 5,8-dideaza analogue.Reductive coupling of 2,4-diaminopyridopyrimidine-6-carbonitrile and 4-aminobenzoic acid followed by reaction with 96-97percent formic acid yielded 4-amino-4-deoxy-5-deaza-N10-formylpteroic acid, which on condensation with methyl Nδ-(benzyloxycarbonyl)-L-ornithinate and deprotection gave the 5-deaza analogue of APA-Orn.A similar sequence starting from 2,4-diaminoquinazoline-6-carbonitrile led to the corresponding 5,8-dideaza compound, whereas treatment of 2,4-diaminopyridopyrimidine-6-methanol with phosphorus tribromide followed by condensation with methyl Nα-(4-aminobenzoyl)-Nδ-(benzyloxycarbonyl)-L-ornithinate and deprotection afforded the 8-deaza analogue.For the preparation of the Nδ-carboxymethyl derivative of mAPA-Orn, Nα-(benzyloxycarbonyl)-L-ornithine was subjected to Nδ-monoalkylation with glyoxylic acid and sodium cyanoborohydride, followed by Nδ-acylation with ethyl trifluoroacetate, Nα-deprotection by hydrogenolysis, condensation with 4-amino-4-deoxy-N10-methylpteroic acid, and Nδ-deprotection by gentle treatment with ammonia.The 2,4-diamino derivatives all inhibited the growth of tumor cells in culture, with IC50 values of 0.2-2 μM, and inhibited purified DHFR with IC50 values of 0.02-0.08 μM.Deletion of ring nitrogens and Nδ-carboxymethylation both increased potency in the cell growth assay; however, the ornithine derivatives were less potent than aminopterin or methotrexate.
