ChemicalBook CAS DataBase List Boc-N-methyl-L-leucine

Boc-N-methyl-L-leucine synthesis

8synthesis methods

Product Name:Boc-N-methyl-L-leucine
CAS Number:53363-89-6
Molecular formula:C12H23NO4
Molecular Weight:245.32

13139-15-6

74-88-4

53363-89-6

To a solution of Boc-L-leucine (5.0 g, 21.6 mmol) in tetrahydrofuran (THF, 73 mL) at 0 °C was added sodium hydride (NaH, 60% dispersion in mineral oil, 10.0 g, 0.13 mol). After stirring at 0 °C for 30 min, iodomethane (MeI, 4.1 mL, 66.0 mmol) and N,N-dimethylformamide (DMF, 3.7 mL) were added sequentially. The reaction mixture was continued to be stirred at 0 °C for 30 min, followed by 4 h at room temperature. Upon completion of the reaction, the reaction was quenched with deionized water (50 mL). The mixture was extracted with ethyl acetate (EtOAc, 2 x 100 mL). The aqueous phase was acidified to pH 5 with 10% aqueous potassium bisulfate (KHSO4) and extracted again with ethyl acetate. All the ethyl acetate extracts were combined, washed with 5% sodium dithionite (Na2S2O4) solution and saturated brine in turn, dried with anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure to give Boc-N-methyl-L-leucine (5.2 g, 98% yield) as a colorless oil.

13139-15-6
450 suppliers
$7.00/5g

74-88-4
348 suppliers
$15.00/10g

53363-89-6
183 suppliers
$9.00/250mg

Yield:53363-89-6 98%

Reaction Conditions:

Stage #1: N-tert-butoxycarbonyl-L-leucinewith sodium hydride in tetrahydrofuran;mineral oil at 0; for 0.5 h;Inert atmosphere;
Stage #2: iodomethane in N,N-dimethyl-formamide;mineral oil at 0 - 20; for 4.5 h;Inert atmosphere;

Steps:

To a solution of Boc-L-Leu (5.0 g, 21.6mmol) in THF (73 mL) wasadded NaH (60% dispersion in mineral oil, 10.0 g, 0.13 mol) inportions at 0 oC. After stirring at 0 oC for 30 min, MeI (4.1 mL,66.0 mmol) and DMF (3.7 mL) were successively added. Thereaction was stirred for 30 min at 0 oC and additional 4 h atrt, until it was quenchedwith H2O (50 mL). The mixture was extracted by EtOAc (2×100 mL). The aqueoussolution was then acidified with 10% aqueous KHSO4 solution to pH 5 and extractedwith ethyl acetate. The combined EtOAc extracts were washed with 5% Na2S2O4solution and brine, and dried over Na2SO4, filtered and evaporated to give 13 (5.2 g,98% yield) as a colorless oil.

References:

He, Wei;Qiu, Hai-Bo;Chen, Yi-Jie;Xi, Jie;Yao, Zhu-Jun [Tetrahedron Letters,2014,vol. 55,# 44,p. 6109 - 6112] Location in patent:supporting information

13139-15-6
450 suppliers
$7.00/5g