1. [Optimization of alkaline hydrolysis based on the side chain of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolic acid]
M M Yuan, M Wang, J Y Liu, Z L Zhang Beijing Da Xue Xue Bao Yi Xue Ban. 2017 Aug 18;49(4):714-718.
Objective:To optimize and establish the best hydrolysis method of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate through the optimization of simple compound of diethyl N-(4-aminobenzoyl)-L-glutamate. Methods:To increase the low yield of hydrolysis reaction of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate due to the by-products and difficult purification, we studied the effect of NaOH and KOH, two kinds of alkalis, three concentrations between 0.175-1 mol/L and five types of reaction time involved in 20, 30, 60, 120 and 180 min on the common side chain diethyl N-(4-aminobenzoyl)-L-glutamate. A high performance liquid chromatography was established for measuring the target product and the by-products in reaction liquid in different reaction conditions. Finally, on the basis of the best hydrolysis method of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate, we completed the optimization of the hydrolysis reaction conditions of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate. Results:We developed the best reaction condition for the hydrolysis of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate, which could be carried out easily and efficiently. The results indicated that treated with the optimized condition of 0.3 mol/L KOH in 60 min at the room temperature, diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydrofolate was converted into its diacid derivative in 95.6 % yield, which turned to be a better reaction condition compared with the previous reaction condition. The structures of those compounds were identified to be correct by 1H nuclear magnetic resonance(1H NMR), 13C nuclear magnetic resonance(13C NMR) and electrospray ionization time of flight mass spectrometry (ESI-MS). The purity of the diacid derivative of the compound was determined to be 96% by high performance liquid chromatography(HPLC).The new hydrolysis reaction condition could not only avoid the formation of single ester hydrolysis product and amide bond hydrolysis product, but also improve the yield of the hydrolysis reaction.Conclusion:We have developed an efficient reaction for the hydrolysis of diethyl ester 4-amino-N5-formyl-N8, N10-dideazatetrahydro. Since the final step of the synthesis of classical folic acid antagonists is always the catalyzed hydrolysis of the side chain glutamate, the reaction also has great significance for anti-folic acid anti-tumor inhibitors synthesis.
2. Detection of apoptosis by PET/CT with the diethyl ester of [¹⁸F]ML-10 and fluorescence imaging with a dansyl analogue
Manikandan Kadirvel, Michael Fairclough, Christopher Cawthorne, Emily J Rowling, Muhammad Babur, Adam McMahon, Paul Birkket, Alison Smigova, Sally Freeman, Kaye J Williams, Gavin Brown Bioorg Med Chem. 2014 Jan 1;22(1):341-9.doi: 10.1016/j.bmc.2013.11.019.Epub 2013 Nov 20.
The diethyl ester of [(18)F]ML-10 is a small molecule apoptotic PET probe for cancer studies. Here we report a novel multi-step synthesis of the diethyl ester of ML-10 in excellent yields via fluorination using Xtal-Fluor-E. In addition, a one-pot radiosynthesis of the diethyl ester of [(18)F]ML-10 from nucleophilic [(18)F]fluoride was completed in 23% radiochemical yield (decay corrected). The radiochemical purity of the product was ≥99%. The diethyl ester of [(18)F]ML-10 was used in vivo to detect apoptosis in the testes of mice. In parallel studies, the dansyl-ML-10 diethyl ester was prepared and used to detect apoptotic cells in an in vitro cell based assay.
3. Synthesis of Functionalized Diethyl(pyrrolidin-2-yl)phosphonate and Diethyl(5-oxopyrrolidin-2-yl)phosphonate
Iwona E Głowacka, Anna Hartwich, Iwona Rozpara, Dorota G Piotrowska Molecules. 2021 May 25;26(11):3160.doi: 10.3390/molecules26113160.
Short and efficient syntheses of functionalized (pyrrolidin-2-yl)phosphonate and (5-oxopyrrolidin-2-yl)phosphonate have been developed. The synthetic strategy involved the diastereospecific 1,3-dipolar cycloaddition of N-benzyl-C-(diethoxyphosphoryl)nitrone to cis-1,4-dihydroxybut-2-ene and dimethyl maleate, respectively. O,O-Diethyl 3-carbamoyl-4-hydroxy(5-oxopyrrolidin-2-yl)phosphonate was obtained from O,O-diethyl 2-benzyl-4,5-dimethoxycarbonyl(isoxazolidin-3-yl)phosphonate by hydrogenation and subsequent treatment with ammonia, whereas transformation of O,O-diethyl 2-benzyl-4,5-dihydroxymethyl(isoxazolidin-3-yl)phosphonate into O,O-diethyl 3-aminomethyl-4-hydroxy(pyrrolidin-2-yl)phosphonate was accomplished by mesylation followed by hydrogenolysis to undergo intramolecular cyclization and the introduction of amino group via ammonolysis. Stereochemistry of the isoxazolidine cycloadducts, as well as the final functionalized (pyrrolidin-2-yl)- and (5-oxopyrrolidin-2-yl)phosphonates were established based on conformational analyses using vicinal H-H, H-P, and C-P couplings and supported by the observed diagnostic NOESY correlation signals.
