tert-butyl (S)-(6-oxotetrahydro-2H-pyran-3-yl)carbamate synthesis

Yield:125982-23-2 37.2%

Reaction Conditions:

with acetic acid in toluene; for 5 h;Reflux;

Steps:

4.3 Step 3

A solution of compound of A4-3 (25g, O. lmol, l .Oeq) in toluene (300mL) and acetic acid (150mL) was heated to reflux for 5hrs and then cooled, concentrated under vacuum. The residual was added saturated sodium bicarbonate solution to pH 7-8 in ice-bath. Then the mixture was extracted three times with ethyl acetate, and the combined extracts was washed with brine, dried over anhydrous sodium sulfate, concentrated and recrystallized by ethyl acetate and PE to give compound A4-4 as a white powder (8.0g, yield 37.2%). GC-MS: 215

References:

WO2018/67422,2018,A1 Location in patent:Page/Page column 47; 48