Isopropanol → [2-(9-Oxa-3,7-diazabicyclo[3.3.1]non-3-yl)ethyl]carbamic acid tert-butyl ester 2,4,6-trimethylbenzenesulfonic acid salt

Participants

Reaction Conditions

Reaction Steps

[2-(7-Benzyl-9-oxa-3,7-diazabicyclo[3.3.1]non-3-yl)ethyl]carbamic acid tert-butyl ester 2,4,6-trimethylbenzenesulfonic acid salt (150 g; see Preparation P above), isopropanol (IPA; 225 mL) and water (75 mL) were combined in a metal hydrogenation vessel. Solid 5% Pd/C catalyst (4.7 g, 61% water wet, Johnson Matthey type 440) was added. Hydrogen was introduced to the vessel and stirring was started. The mixture was hydrogenated under 2.5 bar of hydrogen pressure and was simultaneously heated to 55° C. (temperature overshot to 73° C.). Gas uptake measurement showed the reaction to be complete after 1 hour. After cooling to 47° C. the catalyst was removed by filtration through a glass fibre filter paper. The catalyst was washed on the filter with IPA (75 mL) and the combined filtrate and washings used in the next step.

Provenance & Evidence