Celiprolol hydrochloride, a β-blocker drug, has been synthesised from 4-chloronitrobenzene. The route involved hydrolysis of the chloride and acetylation of the phenol, reduction of the nitro group, and acylation of theamine. This was followed by Fries rearrangement of the acetyl group, Williamson etherification with epichlorohydrin, followed by opening of the epoxide ring and salt formation. The overall yield of celipropol was 39.1% on the basis of 4-chloronitrobenzene. The Fries rearrangement was substantially improved. The process is suitable for industrial application because of its convenient and environmentally friendly reaction conditions.
