* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
2,5-dioxopyrrolidin-1-yl (((9H-fluoren-9-yl)methoxy)carbonyl)-L-valinate[ No CAS ]
[ 159858-21-6 ]
Yield
Reaction Conditions
Operation in experiment
53%
With sodium hydrogencarbonate; In 1,2-dimethoxyethane; water; at 25 - 30℃; for 48.0h;Cooling with ice;
Step 2 Synthesis of (S)-2-((S)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-methylbutanamido)-5-ureidopentanoic acid (90) To a solution of compound 89 (40.14 g, 0.229 mol) and NaHCO3 (19.23 g, 0.229 mol) in water (750 mL) was added the solution of compound 88 (100 g, 0.229 mol) in DME (750 mL) dropwise under ice-bath. During the addition, a white suspension was formed. Additional THF (400 mL) was added to improve the solubility. After addition, the solution was stirred at 25-30 C. for 2 days. To the reaction was added saturated aq. K2CO3 to adjust pH to 8-9, then extracted with EtOAc (500 mL*5). The aqueous layer was adjusted pH to 3-4 with aq. citric acid. A gelatinous material was formed and filtered. The wet cake was dissolved in THF (1.5 L). Methanol was added until the solid was dissolved. The solution was concentrated in vacuum to remove 30% of solvent and then cooled to room temperature. TBME (2 L) was added to the solution and the mixture was stirred at room temperature overnight. The mixture was filtered and the wet cake was dried in vacuum to give compound 90 as a white solid 60 g (53%).
With hydrogenchloride; In tetrahydrofuran; sodium hydroxide; ethyl acetate;
EXAMPLE 1 (R)-(4-Chlorobiphenylsulfonyl)citrulline Prepared according to process variant a): 1.7 g (9.7 mmol) of <strong>[13594-51-9]R-citrulline</strong> are dissolved in 19.4 ml of 0.5 N NaOH and, after addition of 40 ml of THF, slowly treated at 0 C. with a further 19.4 ml of the sodium hydroxide solution and at the same time 9.7 ml of a 1 molar solution of 4-chlorobiphenylsulfonyl chloride. After stirring at room temperature for 16 hours (h), the reaction mixture is concentrated on a rotary evaporator and treated with 20 ml of ethyl acetate. On acidification with 1 M HCl, a white precipitate is deposited, which is filtered off with suction and dried. Yield: 2.26 g (54% of theory) 1 H-NMR (DMSO-d6): 1.2-1.7 (2m, 4H); 2.9 (dd, 2H); 3.7 (dd, 1H); 5.4 (s, 2H); 5.9 (t, 1H); 7.5-7.9 (2 d, s, 8H); 8.2 (d, 1H)
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
For Research Only
110K+ Compounds
Competitive Price
1-2 Day Shipping
