Yield:-

Steps:

Multi-step reaction with 6 steps
1: dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 5 h / 20 °C
2: ammonium acetate; acetic acid / 5 h / Reflux
3: N-Bromosuccinimide / acetonitrile / 20 °C
4: N,N-dimethyl-formamide / 80 °C
5: hydrogen; sodium carbonate / palladium 10% on activated carbon / methanol / 2 h / 20 °C
6: dmap; p-toluenesulfonyl chloride / dichloromethane / 2 h / 60 °C

References:

US2012/28983,2012,A1