Trifluoroacetic acid → HCID 87403533, compound

N-tert-butoxycarbonyl α,α-dimethylglycyl α,α-dimethylglycine methyl ester 3 (10.79 g, 35.69 mmol) was dissolved in 50% (v/v) TFA in CH2Cl2 (100 mL). The reaction mixture was stirred for 2 h 30 min at room temperature before the solvent and bulk of excess TFA were evaporated at 50° C. over 1 h 30 min. The residue was left standing overnight, dissolved in CH2Cl2 (100 mL) and the bulk of solvent evaporated. More CH2Cl2 (2×100 mL) was added and evaporated. The residue was washed with Et2O (3×60 mL) and the Et2O decanted off. The residue was dissolved in CH2Cl2 (30 mL). Upon standing a solid precipitated and was collected by filtration. The residue was washed with Et2O (3×60 mL) under suction and dried under vacuum affording the title compound as a white solid (10.17 g, 90%), with spectral characteristics in accordance with literature data5,6; 1H NMR (300 MHz, DMSO-d6) δ 8.45 (s, 1H, NH), 8.20 (br s, 3H, NH3+), 3.57 (s, 3H, OCH3), 1.47 (s, 6H, CH3), 1.39 (s, 6H, CH3); 13C NMR (75 MHz, DMSO-d6) δ 174.1, 171.4, 158.3 (q, JCF=33 Hz), 116.7 (q, JCF=295 Hz), 56.4, 55.9, 52.1, 24.8, 23.3; HRMS (m/z): M+ calcd. for C9H19N2O3, 203.1395. found, 203.1396; Anal. Calcd. for C11H19F3N2O5: C, 41.77; H, 6.06; N, 8.86. Found: C, 41.8; H, 6.1; N, 8.7.

1. customwere evaporated at 50° C. over 1 h 30 min
2. waitThe residue was left
3. dissolutiondissolved in CH2Cl2 (100 mL)
4. customthe bulk of solvent evaporated
5. additionMore CH2Cl2 (2×100 mL) was added
6. customevaporated
7. washThe residue was washed with Et2O (3×60 mL)
8. customthe Et2O decanted off
9. dissolutionThe residue was dissolved in CH2Cl2 (30 mL)
10. customprecipitated
11. filtrationwas collected by filtration
12. washThe residue was washed with Et2O (3×60 mL) under suction
13. customdried under vacuum

ORD record

ord-a21e21350c184d36a96287b16ea30a3d

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09227995B2