Diisopropylamine → Ethyl 1-benzyl-4-(N,N'-di-tert-butyloxycarbonylhydrazino)piperidin-4-ylcarboxylate

Participants

Reaction Steps

A solution of diisopropylamine (8.8 ml, 0.063 mol) in ether (400 ml) at -70° C. under nitrogen was treated with 1.6M n-butyllithium in hexane (37.5 ml, 0.060 mol) and stirred for 10 minutes. A solution of ethyl 1-benzylpiperidin-4-ylcarboxylate (13.6 g, 0.055 mol) in ether (70 ml) was added over 5 minutes and the resulting mixture then stirred at -70° C. for 40 minutes, before adding a solution of di-tert-butylazodicarboxylate (13.5 g, 0.058 mol) in ether (80 ml). The reaction mixture was allowed to warm to room temperature over 0.5 h, then stirred for a further 2 h before adding dilute potassium carbonate solution (150 ml). The ether layer was separated, dried (Na2SO4) and concentrated in vacuo to leave an orange oil. This was chromatographed on silica gel eluting initially with 20% ether/60-80 petrol, then with neat ether to afford the title compound (D26) (14.2 g, 54%) as a yellow oil.

Provenance & Evidence