Trifluoroacetic acid → L-valyl L-valine methyl ester trifluoroacetate

N-tert-butoxycarbonyl L-valyl L-valine methyl ester (16.47 g, 49.85 mmol) was treated with a 50% (v/v) solution of TFA in CH2Cl2 (130 mL). The reaction mixture was stirred for 2 h at room temperature before the solvent and bulk of excess TFA were evaporated. Portions of CH2Cl2 (3×100 mL) and purified CHCl3 (6×200 mL) were added and evaporated. The residue (19.17 g) was washed with Et2O (2×80 mL) and the Et2O decanted off. An additional 80 mL Et2O was added and the suspension filtered. The collected solid was washed with Et2O (80 mL) and dried; δH (300 MHz; d6-DMSO) 8.62 (1H, d, J 7, NH), 8.17 (3H, br s, NH3+), 4.19 (1H, dd, J 7 and 6, CαH(Val2)), 3.75 (1H, br d, J 5, CαH(Val1)), 3.64 (3H, s, OCH3), 2.16-2.01 (2H, m, CH(CH3)2), 0.96-0.90 (12H, m, CH(CH3)2); δC (75 MHz; d6-DMSO) 171.4, 168.4, 158.4 (q, JCF 31), 117.1 (q, JCF 297) 57.7, 56.9, 51.7, 29.9, 29.6, 18.8, 18.1, 18.1, 17.4

1. customwere evaporated
2. customPortions of CH2Cl2 (3×100 mL) and purified CHCl3 (6×200 mL)
3. additionwere added
4. customevaporated
5. washThe residue (19.17 g) was washed with Et2O (2×80 mL)
6. customthe Et2O decanted off
7. additionAn additional 80 mL Et2O was added
8. filtrationthe suspension filtered
9. washThe collected solid was washed with Et2O (80 mL)
10. customdried

ORD record

ord-f00420c739bb4fdfa5e6255fa35d3a8e

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09227995B2