反应详情

To a solution of the product from step (a) (4.18 g) in methanol (250 ml) under argon was added p-toluenesulphonic acid monohydrate (2.99 g) followed by 10% Pd on C (1.8 g). The argon was replaced by hydrogen and the reaction mixture was stirred under a blanket of hydrogen for 6 hours. The catalyst was filtered off through a pad of diatomaceous earth and washed with methanol. The blue-coloured filtrate and washings were evaporated to near dryness and excess ether was added. On storage overnight at -10° C. a solid crystallised which was collected, washed with ether and dried to give t-butyl 4-amino-3-methylphenoxyacetate, p-toluenesulphonate salt (2.93 g) as an off-white solid: NMR Spectrum (DMSO-d6) 1.42 (9H, s), 2.28 (3H, s), 2.30 (3H, s), 4.63 (2H, s), 6.82 (1H, dd), 6.88 (1H, d), 7.12 (2H, d), 7.24 (1H, d), 7.48 (2H, d), 9.50 (3H, br s); Mass Spectrum m/Z 260 (M+Na)+.

1. filtrationThe catalyst was filtered off through a pad of diatomaceous earth
2. washwashed with methanol
3. customThe blue-coloured filtrate and washings were evaporated
4. additionwas added
5. customOn storage overnight at -10° C. a solid crystallised which
6. customwas collected
7. washwashed with ether
8. customdried