ChemicalBook CAS DataBase List BOC-VAL-NH2

BOC-VAL-NH2 synthesis

11synthesis methods

Product Name:BOC-VAL-NH2
CAS Number:35150-08-4
Molecular formula:C10H20N2O3
Molecular Weight:216.28

13734-41-3

35150-08-4

General procedure for the synthesis of tert-butyl (S)-(1-amino-3-methyl-1-oxo-2-butyl)carbamate from Boc-L-valine: to a colorless solution of 150 mg (0.50 mmol) of Boc-L-valine in 10 mL of THF was added 67 μL (0.70 mmol, 1.4 eq.) of ethyl chloroformate at 0 °C and 209 μL ( 1.5 mmol, 3.0 eq.) triethylamine. After stirring at 0 °C for 30 min, 0.75 mL of 1.0 M aqueous ammonium chloride (0.75 mmol, 1.5 equiv) was added to the colorless suspension. The mixture was continued to be stirred at 0 °C for 30 min, followed by the addition of 5 mL of water. The colorless clear solution was extracted with 30 mL of ethyl acetate and the aqueous layer was extracted with another 20 mL of ethyl acetate. The organic layers were combined, washed with 5 mL of brine and dried with anhydrous magnesium sulfate. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate) to give 129 mg (86% yield) of tert-butyl (S)-(1-amino-3-methyl-1-oxo-2-butyl)carbamate. The product was a colorless solid, melting point: 149-152 °C; [α]30D = -2.4 (c 1.00, methanol); 1H NMR (400 MHz, CDCl3): δ 0.94 (d, J = 6.8 Hz, 3H, CH3CH), 0.99 (d, J = 6.8 Hz, 3H, CH3CH), 1.45 (s, 9H, (CH3)3C ), 2.16 (ddd, J = 6.7,6.8,6.8 Hz, 1H, CH(CH3)2), 3.96 (dd, J = 6.7,7.8 Hz, 1H, CHCO), 5.03,5.42,5.89 (br, br, br, 1H, 1H, 1H, NH, NH2); 13C NMR (100 MHz, CDCl3) : δ17.8,19.3,28.3,30.8,59.5,79.9,156.0,174.4; IR (KBr, vmax/cm-1): 3386 (CONH), 3345 (CONH), 3205 (CONH), 1680 (CON), 1641 (CON); HRMS (ESI-TOF): Calculated value for C10H20N2O3Na (M + Na)+: 239.1366, measured value: 239.1340. Enantiomeric ratio was determined by HPLC (Chiralcel OD column: hexane/2-propanol = 95/5): retention time 9.4 min.

13734-41-3
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35150-08-4
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Yield: 98%

Reaction Conditions:

Stage #1:t-Boc-L-valine with chloroformic acid ethyl ester;triethylamine in tetrahydrofuran at 0; for 0.5 h;
Stage #2: with ammonium chloride in tetrahydrofuran;water at 0; for 0.5 h;

Steps:

4.3.11 4.3. Typical procedure for the primary amidation of Cbz-l-Phe-OH 3a with NH4Cl
General procedure: To a colorless solution of 150mg (0.50mmol) of Cbz-L-Phe-OH 3a in 10mL of THF were added 67μL (0.70mmol, 1.4equiv) of ClCO₂Et and 209μL (1.5mmol, 3.0equiv) of Et₃N at 0°C.
After stirring for 30min at 0°C, 0.75 ml of a 1.0M aqueous solution of NH₄Cl (0.75mmol, 1.5equiv) were added at 0°C to the colorless suspension.
The mixture was stirred for 30min at 0°C and 5mL of H₂O was added to the resulted mixture.
The colorless clear solution was extracted with 30mL of EtOAc and the aqueous layer was extracted with 20mL of EtOAc.
The organic layers were combined, washed with 5mL of brine, and dried over anhydrous MgSO₄.
The crude product was chromatographed on silica gel with EtOAc to afford 129mg (86% yield) of Cbz-L-Phe-NH₂ 4a. 4.3.11
Boc-l-Val-NH₂ 4f
106?mg (98%); >99% ee; coloress solid; mp: 149-152?°C; [α]³⁰_D?=?-2.4 (c 1.00, MeOH); ¹H NMR (400?MHz, CDCl₃): δ 0.94 (d, J?=?6.8?Hz, 3H, CH₃CH), 0.99 (d, J?=?6.8?Hz, 3H, CH₃CH), 1.45 (s, 9H, (CH₃)₃C), 2.16 (ddd, J?=?6.7, 6.8, 6.8?Hz, 1H, CH(CH₃)₂), 3.96 (dd, J?=?6.7, 7.8?Hz, 1H, CHCO), 5.03, 5.42, 5.89 (br, br, br, 1H, 1H, 1H, NH, NH₂); ¹³C NMR (100?MHz, CDCl₃): δ 17.8, 19.3, 28.3, 30.8, 59.5, 79.9, 156.0, 174.4; IR (KBr, v_max/cm^-1): 3386 (CONH), 3345 (CONH), 3205 (CONH), 1680 (CON), 1641 (CON); HRMS (ESI-TOF): Calcd for C₁₀H₂₀N₂O₃Na (M+Na)⁺: 239.1366, found: 239.1340; The enantiomeric ratio was determined by HPLC (Chiralcel OD: hexane/2-propanol?=?95/5): T_r 9.4?min.