Water → HCID 20279774, compound

Participants

Reaction Steps

A solution of 3-amino-2-methyl propan-1-ol (4) (0.400 g) in dry benzene (10 ml) was treated with cyclohexanone (0.450 g) and heated at reflux in an apparatus with provision for water removal for 5 hours. The product was concentrated to give the crude 3-methyl-1-oxa-5-azospiro[5.5]undecane (5) as a yellow oil; νmax. (CH2Cl2) 3450, 1660 (weak, Schiffs base); 1460, 1450, 1160, 1040 cm-1. This material was redissolved in dry benzene (10 ml) and stirred and cooled in an ice-bath, treated with diketene (0.37 ml) and stirring continued at 0° C. for 1 h followed by room temperature for 1 h. The solvent was evaporated and the residue chromatographed on Kieselgel 60 (<230 mesh ASTM) eluting with hexane grading to 1:1 ethyl acetate/hexane, to give 1-[3-methyl-1-oxa-5-azaspiro[5.5]undecan-5-yl]butan-1,3 -dione (6) (0.400 g) as a yellow oil; νmax (CH2Cl2) 1725, 1640, 1450, 1410, 1550 cm-1 ; δ (ppm, CDCl3) 0.96 (3H, d, J=7 Hz, CH3CH); 1.25-2.70 (10H, m, cyclohexyl); 2.10-2.20 (1H, m, CH3CH); 2.27 (3H, s, C(O)CH3); 3.10 (1H, dd, J=12, 7 Hz, CHaHbN); 3.27 (1H, dd, J=11, 7 Hz, CHaHbO); 3.34 (1H, dd, J=12, 7 Hz, CHAHb N); 3.50 (2H, d, J=2.5 Hz, COCH2CO); 3.94 (1H, dd, J=11, 7 Hz, CHaHbO).

Provenance & Evidence