Hydrochloric Acid → (2S)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(4-hydroxyphenyl)propanoic acid

To a stirring suspension of L-tyrosine O-t-butyl ester (1.00 g, 4.21 mmol) and NaHCO3 (354 mg, 4.21 mmol) in 1,4-dioxane/water (1:1, 20 mL) was added 9-fluorenylmethyl-N-succinimidyl carbonate (1.42 g, 4.21 mmol) and the resulting mixture was stirred for 18 hr at room temperature. The solvent was reduced to 10 mL followed by the addition of 50 mL of cold 1N HCl. The product was extracted with ethyl acetate (3×). The organic extracts were washed with H2O and saturated aqueous NaCl then dried over Na2SO4. The solution was then concentrated after filtration to give the colourless solid 83 (1.94 g, 100%) which was used without purification: 1H NMR (400 MHz, CDCl3) δ 1.43 (s, 9H), 2.97-3.06 (m, 2H), 4.21 (bt, J=7.1, 1H), 4.33 (dd, J=7.1, 10.5, 1H), 4.41-4.53 (m, 2H), 5.01 (bs, 1H), 5.30, (d, J=8.2, 1H), 6.73 (d, J=8.5, 2H), 7.00 (d, J=8.5, 2H), 7.31 (t, J=7.5, 2H), 7.40 (t, J=7.5, 2H), 7.57 (dd, J=3.3, 7.3, 2H), 7.76 (d, J=7.5, 2H).

1. extractionThe product was extracted with ethyl acetate (3×)
2. washThe organic extracts were washed with H2O and saturated aqueous NaCl
3. dry with materialthen dried over Na2SO4
4. concentrationThe solution was then concentrated
5. filtrationafter filtration

ORD record

ord-ddd0366ddea54e6589c73b50d84504c8

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08524691B2