(1s,3s)-3-((tert-butoxycarbonyl)amino)cyclobutyl 4-methylbenzenesulfonate synthesis

Yield:-

Reaction Conditions:

with pyridine;dmap in dichloromethane at 20; for 24 h;Inert atmosphere;

Steps:

33.33a

498 mg (2.59 mmol) p-toluenesulphonic acid chloride were added to a solution of 440 mg (2.35 mmol) trans-tert-butyl-3-hydroxycyclobutylcarbamate and 0.74 ml (9.4 mmol) anhydrous pyridine in 7 ml DCM while cooling with ice under a nitrogen atmosphere and the mixture was stirred at RT. After several hours some more DMAP was added and the mixture was stirred for a further 24 h at RT. The reaction mixture was diluted with EE, extracted once with 20% citric acid solution, washed five times with water and once with saturated sodium chloride solution. The organic phase was dried on magnesium sulphate and the filtrate was evaporated down.C₁₆H₂₃NO₅S (341.42)[M+NH₄]⁺=359analytical HPLC (method 3): retention time=2.50 min

References:

US2011/98282,2011,A1 Location in patent:Page/Page column 64