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ChemicalBook CAS DataBase List Boc-N-alpha-methyl-O-benzyl-L-tyrosine
64263-81-6

Boc-N-alpha-methyl-O-benzyl-L-tyrosine synthesis

11synthesis methods
-

Yield: 35%

Reaction Conditions:

Stage #1:N-tert-butoxycarbonyl-O-benzyl-(S)-tyrosine methyl ester;methyl iodide with sodium hydride in tetrahydrofuran;mineral oil at 0 - 20;
Stage #2: with water in tetrahydrofuran;mineral oil at 0;

Steps:

N-(Boc)-N-(methyl)(0-benzyloxy)tyrosine (19V)
N-(Boc)-N-(methyl)(0-benzyloxy)tyrosine (19V) Chemical Formula: C^h^NOs Exact Mass: 385.19 To a solution of 18V (1.30g, 3.37mmol) and Mel (1.05mL, 16.86mmol) in dry THF (15mL), cooled to 0°C, was added NaH (60% suspension in oil, 674mg, 16.86mmol) in portions. The resulting mixture was stirred overnight at room temperature and then cooled to 0°C and quenched with ice water. After removal of the THF in vacuo, the residue was taken up in water and washed twice with hexane. The water layer was then acidified to pH 4 with citric acid and extracted with DCM. The combined organic layers washed with brine and water, dried over Na2S04, filtered, and concentrated in vacuo. The crude mixture was flash silica gel column chromatographed (Hexane/EtOAc 6:4), affording 19V as a pale yellow oil (453mg, 35% yield). *H NMR (400MHz, CDCI3) δ (mixture of atropoisomers): 7.44-7.36 (m, 4H), 7.34-7.30 (m, lH), 7.14-7.09 (m, 2H), 6.93-6.89 (m, 2H), 5.04 (s, 2H), [4.76 (dd, J = 10.8, 5.0Hz, lH)/4.56 (dd, J = 10.8, 4.2Hz, 1H] atropoisomers, [3.29-3.21 (m, 2H)/3.07 (dd, J = 14.3, 11.1Hz, 1H), 2.98 (dd, J= 14.3, 11.1, 1H)] atropoisomers , [2.75 (s, 3H)/2.69 (s, 3H)j atropoisomers, [1.41 (s, 9H)/1.35 (s, 9H)] atropoisomers.

References:

THE UNIVERSITY OF BRITISH COLUMBIA;CENTRE FOR DRUG RESEARCH AND DEVELOPMENT;PUTNINS, Edward Ewald;GRIERSON, David Scott;GEALAGEAS, Ronan F., B.;DEVINEAU, Alice Andree Valentine;DULLAGHAN, Edith Mary WO2015/27324, 2015, A1 Location in patent:Page/Page column 47; sheet 2

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