Boc-cyclohexylalanine → (S)-2-(Cyclohexylamino)propanoic acid
Reaction equation
C([N:8]([CH:14]1[CH2:19][CH2:18][CH2:17][CH2:16][CH2:15]1)[C@H:9]([C:11]([OH:13])=[O:12])[CH3:10])(OC(C)(C)C)=O>C(O)(C(F)(F)F)=O.C(Cl)Cl>[CH:14]1([NH:8][C@H:9]([C:11]([OH:13])=[O:12])[CH3:10])[CH2:19][CH2:18][CH2:17][CH2:16][CH2:15]1Participants
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
1 g (0.41 mmol/g) of Boc-cyclohexylalanine-BAH resin was suspended and shaken in TFA/CH2Cl2 (1:1) by volume (3×40 mL) 10 min each time to remove the Boc group. The product was isolated by filtration and washed (3×50 mL each) with CH2Cl2, 8% DIEA in CH2Cl2 and CH2Cl2 to give the free base of cyclohexylalanine-BHA resin. This was subjected to sequential solid phase peptide synthesis using the Fmoc-protocol. All couplings except the last residue were performed using DCC/HOBt procedure. At step 7 the Fmoc amino acid, DCC and HOBt were added with the corresponding times as follows: Fmoc-Asp(OtBu)-OH (615 mg, 1.5 mmol), DCC (310 mg, 1.5 mmol) and HOBt (270 mg, 2 mmol) were dissolved in 20 mL of 1:1 by volume DMF/CH2Cl2 and allowed to couple for 60 min at room temperature. Fmoc-Met-OH (550 mg, 1.5 mmol), DCC (310 mg, 1.5 mmol) and HOBt (270 mg, 2 mmol) were dissolved in 20 mL of 1:1 by volume DMF/CH2Cl2 and allowed to couple for 60 min at room temperature. Fmoc-Trp-OH (650 mg, 1.5 mmol), DCC (310 mg, 1.5 mmol) and HOBt (270 mg, 2 mmol) were dissolved in 20 mL of 1:1 by volume DMF/CH2Cl2 and allowed to couple for 60 min at room temperature.
Workup
- customto remove the Boc group
- customThe product was isolated by filtration
- washwashed (3×50 mL each) with CH2Cl2, 8% DIEA in CH2Cl2 and CH2Cl2
Sources & evidence
- ORD record
- ord-3c601076c43047d5b3a6245cf8626a11
- Source dataset
- uspto-grants-1992_07
- Patent number
- US05128448
Reaction notes
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