9-Fluorenylmethyl chloroformate → 3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2,2-dimethylpropanoic acid

To 3-amino-2,2-dimethylpropanoic acid, hydrochloride salt (250 mg, 1.63 mmol, 1 eq.) in dichloromethane (4 mL, 0.4 M) was added diisopropylethylamine (859 μL, 4.88 mmol, 3 eq.) followed by (9H-fluoren-9-ylmethoxy)carbonyl chloride (473 mg, 1.79 mmol, 1.1 eq.) The reaction was stirred for 18 hours and then concentrated in vacuo. The residue was taken up in ethyl acetate (3 mL) and washed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine. The organic layer was dried over sodium sulfate, filtered, and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #93 (250 mg, 45%) as an oil. 1H NMR (400 MHz, DMSO-d6) δ 12.22 (s, 1H), 7.89 (d, J=7.4 Hz, 2H), 7.72 (d, J=7.4 Hz, 2H), 7.38-7.44 (m, 2H), 7.27-7.35 (m, 3H), 4.18-4.30 (m, 3H), 3.16 (d, J=6.2 Hz, 2H), 1.05 (s, 6H).

1. concentrationconcentrated in vacuo
2. washwashed with 1 M aqueous hydrochloric acid solution (2×1 mL) and with brine
3. dry with materialThe organic layer was dried over sodium sulfate
4. filtrationfiltered
5. custompurified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane)

ORD record

ord-e69ad027905349daab7a1ad374bc14e2

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08828401B2