ChemicalBook CAS DataBase List (S)-ethyl 2-aMino-4-fluoro-4-Methylpentanoate

(S)-ethyl 2-aMino-4-fluoro-4-Methylpentanoate synthesis

6synthesis methods

Product Name:(S)-ethyl 2-aMino-4-fluoro-4-Methylpentanoate
CAS Number:156047-39-1
Molecular formula:C8H16FNO2
Molecular Weight:177.22

2743-40-0 Synthesis

2743-40-0
240 suppliers
$5.00/5g

(S)-ethyl 2-aMino-4-fluoro-4-Methylpentanoate

156047-39-1
49 suppliers
$90.00/5mg

Yield:97 % ee

Reaction Conditions:

with tetrakis(tetrabutylammonium)decatungstate(VI);N-fluorobis(benzenesulfon)imide in water;acetonitrile; for 66 h;Inert atmosphere;Sealed tube;UV-irradiation;Solvent;Concentration;Time;

Steps:

1

[0078] On a larger scale, a solution of (L)-leucine ethyl ester hydrochloride salt (100 mg, 0.51 mmol), TBADT (37 mg, 2%) and NFSI (193 mg, 0.61 mmol) in CH₃CN/H₂0 (2: 1, 6.0 mL) was purged with nitrogen (10 minutes) then sealed. The resulting solution was then placed between two 15 watt UVB (365 nm) lamps and irradiated for 18 hours. At this time, another aliquot of solid NFSI (75 mg) was added to the solution and it was purged with nitrogen for another 10 minutes. The resulting solution was irradiated between two 15 watt UVB (365 nm) lamps for another 24 hours. At this time more solid NFSI (50 mg) was added to the solution and it was purged with nitrogen for another 10 min, and irradiated for a further 24 hours, and then worked up as follows: The blue solution was diluted with CHC1₃ and water/potassium carbonate was added to pH >10. The solvent was removed via rotary evaporator and the resulting white solid was suspended in CHCI₃ and dried over MgSC>4. The solution was cooled in a freezer and then filtered over celite, washing with cold CHCI₃. Concentration of the filtrate yielded an orange oil (68 mg) that was -75% pure based on H NMR analysis. The approximate isolated yield of (XH (600 MHz, CDCI₃): δ = 4.18 (q, J = 7 Hz, 2H), 3.69 (m, 1H), 2.14 (ddd, J= 23.6, 14.8, 4.8 Hz, 1H), 1.85 (ddd, J= 25.5, 14.8, 7.9 Hz, 1H), 1.44 (d, J = 21.5 Hz, 3H), 1.43 (d, J= 21.4 H, 3H), 1.28 (t, J = 7.1 Hz, 3H); ¹³C (150 MHz, CDC1₃): δ = 175.8, 95.2 (d, J = 165.8 Hz), 61.2, 51.7, 45.9 (d, J = 21.3 Hz), 27.3 (d, J= 90.5 Hz) 27.2 (d, J= 90.8 Hz), 14.3; HRMS m/z [M+H]⁺ calcd for C₈Hi₇FN0₂: 178.1238; found: 178.1222; enantiomeric excess (ee) determined by chiral GC (CDX cyclodextrin chiral column, 100°C isothermal, retention time (major): 23.04 min, retention time (minor): 22.32 min): 97% ee. The ee of the product establishes that the reaction does not effect racemization or epimerization of the amino acid starting material or product - that is, the stereochemistry of the starting material is carried over to the product without loss of enantiomeric purity.