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Leucine, N-(diphenylMethylene)-4-fluoro-, ethyl ester synthesis
- Product Name:Leucine, N-(diphenylMethylene)-4-fluoro-, ethyl ester
- CAS Number:848949-86-0
- Molecular formula:C21H24FNO2
- Molecular Weight:341.42
Yield:848949-86-0 220 g
Reaction Conditions:
Stage #1: ethyl N-diphenylmethylene glycinewith potassium tert-butylate in N,N-dimethyl-formamide at 0; for 0.5 h;
Stage #2: (2-fluoro-2-methylpropyl) trifluoromethanesulfonate in N,N-dimethyl-formamide at 25; for 12 h;
Steps:
2B.2 Step 2: ethyl 2-((diphenylmethylene)amino)-4-fluoro-4-methylpentanoate
To a solution of KOtBu (97.0 g, 864 mmol, 1.05 eq) in DMF (1.10L) was added ethyl 2- ((diphenylmethylene)amino)acetate (220 g, 823 mmol, 1.00 eq) at 0 °C. After stirring for 0.5 hr, 2- fluoro-2-methylpropyl trifluoromethanesulfonate (214 g, 955 mmol, 1.16 eq) was added. The reaction solution was warmed to 25 °C and stirred for 12 hrs. The reaction was poured into 5% aqueous NH4Cl (0.80 L) and extracted with EtOAc (2.00 L and 1.00 L). The combined organic layers were washed with brine, dried over Na2SO4and concentrated under vacuum to give the crude product. The crude product was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 100: 1 ~ 0 : 1) to provide ethyl 2-((diphenylmethylene)amino)-4-fluoro-4-methylpentanoate (220 g) as a light yellow oil.
References:
WO2021/76890,2021,A1 Location in patent:Page/Page column 239; 320