Benzyl 1,4-dioxa-7-azaspiro[4.4]nonane-7-carboxylate → 1,4-Dioxa-7-azaspiro(4.4)nonane

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Reaction Steps

A mixture of 1d (34.8 g, no more than 124 mmol) and 10% Pd—C (14 g) in EtOH (90 mL) was hydrogenolyzed (60 psi) in a Parr shaker apparatus at room temperature for 1.5 h. The catalyst was filtered off, the solvent was evaporated in vacuo and the residue was pumped under high vacuum for 20 min to yield 1e (15.9 g, quant. yield). Rf 0.14 (EtOAc-iPrNH2, 95:5, v/v); 1H NMR (200 MHz, CDCl3) δ 4.00 (s, 4H), 3.10 (t, J 7 Hz, 2H), 2.90 (s, 2H), 2.00 (t, J 7 Hz, 2H); 13C NMR (50 MHz, APT, CDCl3) δ 64.5 (+), 55.0 (+), 45.5 (+), 37.0 (+); IR (film) 3292 cm−1.

Provenance & Evidence