246545-31-3Relevant articles and documents
5-Deazafolate analogues with a rotationally restricted glutamate or ornithine side chain: Synthesis and binding interaction with folylpolyglutamate synthetase
Rosowsky, Andre,Forsch, Ronald A.,Null, Allison,Moran, Richard G.
, p. 3510 - 3519 (2007/10/03)
Rotationally restricted analogues of 5-deazapteroyl-L-glutamate and (6R,6S)-5-deaza-5,6,7,8-tetrahydropteroyl-L-glutamate with a one-carbon bridge between the amide nitrogen and the 6'-position of the p-aminobenzoyl moiety were synthesized and tested as substrates for folylpolyglutamate synthetase (FPGS), a key enzyme in folate metabolism and an important determinant of the therapeutic potency and selectivity of classical antifolates. The corresponding bridged analogues of 5-deazapteroyl-L- ornithine and (6R,6S)-5-deaza-5,6,7,8-tetrahydropteroyl-L-ornithine were also synthesized as potential inhibitors. Condensation of diethyl L-glutamate with methyl 2-bromomethyl-4-nitrobenzoate followed by catalytic reduction of the nitro group, reductive coupling with 2-acetamido-6-formylpyrido[2,3- d]pyrimidin-4(3H)-one in the presence of dimethylaminoborane, and acidolysis with HBr/AcOH yielded 2-L-[5-[N-(2-acetamido-4(3H)-oxopyrido[2,3-d]pyrimidin- 6-yl)methylamino]-2,3-dihydro-1-oxo-2(1H)-isoindolyl]glutaric acid (1). When acidolysis was preceded by catalytic hydrogenation, the final product was the corresponding (6R,6S)-tetrahydro derivative 2. A similar sequence starting from methyl N(δ)benzyloxycarbonyl-L-ornithine led to 2-L-[5-[N-(2-amino- 4(3H)-oxopyrido[2,3-d]pyrimidin-6-yl)methylamino]-2,3-dihydro-1-oxo-2(1H)- isoindolyl]-5-aminopentanoic acid (3) and the (6R,6S)tetrahydro derivative 4. Compounds 3 and 4 were powerful inhibitors of recombinant human FPGS, whereas 1 and 2 were exceptionally efficient FPGS substrates, with the reduced compound 2 giving a Km (0.018 μM) lower than that of any other substrate identified to date. (6R,6S)-5-Deazatetrahydrofolate, in which the side chain is free to rotate, was rapidly converted to long-chain polyglutamates. In contrast, the reaction of 1 and 2 was limited to the addition of a single molecule of glutamic a cid. Hence rotational restriction of the side chain did not interfere with the initial FPGS-catalyzed reaction and indeed seemed to facilitate it, but the ensuing γ-glutamyl adduct was no longer an efficient substrate for the enzyme.
