Acetyl chloride → tert-Butyl 1-acetyl-5-chlorospiro[indoline-3,4'-piperidine]-1'-carboxylate

Participants

Reaction Steps

Acetyl chloride (2.8 ml) was added dropwise to a stirred solution of 5-chlorospiro[indoline-3,4′-piperidine]-1′-carboxylic acid tert-butyl ester (9.8 g) and triethylamine (15 ml) in anhydrous dichloromethane (400 ml) under an atmosphere of nitrogen. The reaction was stirred for 1 h and was then quenched with saturated sodium bicarbonate solution (200 ml). The organic layer was dried over anhydrous sodium sulphate and concentrated in vacuo to yield 9.8 g (87%) of the desired amide as an off-white solid. M.p. 64-66° C. 1H NMR (400 MHz, CDCl3) δ 6:1 mixture of rotamers. Major rotamer 1.5 (9H, s), 1.70 (m, 2H), 1.85 (m, 2H), 2.25 (s, 3H), 2.85 (m, 2H), 3.90 (s, 2H), 4.2 (m, 2H), 6.97 (d, J=1 Hz, 1H), 7.20 (dd, J=7 & 1 Hz, 1H), 8.15 (d, J=7 Hz, 1H). Minor rotamer 1.5 (9H, s), 1.70 (m, 2H), 1.85 (m, 2H), 2.45 (s, 3H), 2.85 (m, 2H), 4.05 (s, 2H), 4.2 (m, 2H), 7.2 (d, J=1 Hz, 1H), 7.25 (dd, J=7 & 1 Hz, 1H), 7.48 (d, J=7 Hz, 1H).

Provenance & Evidence