L-Tyrosinol hydrochloride synthesis

Yield: 22.7 %Chromat.

Reaction Conditions:

with CuZn_0.3Mg_0.1AlO(x);hydrogen in ethanol at 80; under 37503.8 Torr; for 10 h;Autoclave;

Steps:

2.3 Testing of the Catalyst Activity
General procedure: The activity of catalyst for hydrogenation of R-phenylglycinemethyl ester was tested in a 0.5 L stainless steelautoclave under stirring at a speed of 500rpm. After 1g catalyst (20-40 mesh) was put in the reactor, the reactorwas swept with H2 five times to flush out air. Thenthe catalyst was reduced at 1MPa H2and 250 °C for 4h. After the autoclave was cooled in H2atmosphere to roomtemperature, 1.5g R-phenylglycine methyl esters (R-p-m)diluted in 150 mL ethanol was added (R-p-m/Cat = 1.5,wt.). The typical reaction conditions were at 5 MPa of H2 and 80 °C for 10 h. After the reaction was ended, theautoclave was cooled in H2atmosphere to room temperature.Then solid catalyst was separated by centrifugation.The product was purified by column chromatography on silica gel with ethyl acetate/methanol (3/2, v/v) as the eluent.Thus we obtained the light yellow powder product byrotary evaporation. Reactants and products were analyzedby High Performance Liquid Chromatograph (HPLC, Agilent1260 Infinity) equipped with an ultraviolet detector anda column (Eclipse XDB-C18, 150 × 4.6mm, 5mm particlesize), then the conversion of R-phenylglycine methyl ester(X), yield (Y) and chemoselectivity to R-phenylglycinol (S)were calculated [18, 19], in which the yield is the LC yield.And the ee value of products was determined by HPLCequipped with an ultraviolet detector (wavelength 258nm)and a chiral column (CHIRALPAK AY-H, 250 × 4.6mm,5m particle size) [19].

References:

Zhan, Bing;Zhang, Shuangshuang;Yu, Jun;Xiao, Xiuzheng;Guo, Xiaoming;Mao, Dongsen;Lu, Guanzhong [Catalysis Letters,2017,vol. 147,# 8,p. 2160 - 2166]