Hydrochloric Acid → 3-(9H-fluoren-9-ylmethoxycarbonylamino)cyclohexane-1-carboxylic Acid

3-Aminocyclohexanecarboxylic acid (10 g, 70 mmol) was added to a solution of sodium hydrogen carbonate (7.6 g, 91 mmol) in water (100 mL). A solution of 1-[[(9H-fluoren-9-ylmethoxy)carbonyl]oxy-2,5-pyrrolidinedione (Fmoc-OSu; 28.3 g, 84 mmol) in tetrahydrofuran (200 mL) was added. The solution was stirred at room temperature overnight and then poured into 3 M HCl (200 mL). The mixture was extracted with ethyl acetate (100 mL then 50 mL) and the combined organic layers were washed with saturated brine (3×100 mL), dried (Na2SO4), filtered, and concentrated to approximately 200 mL. Crystallization occurred on concentration. The mixture was allowed to stand overnight, then the solid was filtered off, washed with ethyl acetate and dried in a vacuum oven at 55° C. to give 3-[N-[(9H-fluoren-9-ylmethoxy)carbonyl]amino]cyclohexanecarboxylic acid (14.66, 57%) as a white solid.

1. extractionThe mixture was extracted with ethyl acetate (100 mL
2. wash50 mL) and the combined organic layers were washed with saturated brine (3×100 mL)
3. dry with materialdried (Na2SO4)
4. filtrationfiltered
5. concentrationconcentrated to approximately 200 mL
6. customCrystallization
7. concentrationoccurred on concentration
8. waitto stand overnight
9. filtrationthe solid was filtered off
10. washwashed with ethyl acetate
11. customdried in a vacuum oven at 55° C.

ORD record

ord-ca089e05d12a4d33a94b1fd48ac172a1

Source dataset

uspto-grants-2007_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07217728B2