7,8-dimethoxy-2,3,4,5-tetrahydro-1H-benzo[c]azepine hydrochloride and preparation method thereof

The invention discloses 7,8-dimethoxy-2,3,4,5-tetrahydro-1H-benzo[c]azepine hydrochloride and a preparation method thereof. The method comprises the following steps: taking 3,4-dimethoxyhydrocinnamic acid as a starting material, catalyzing by thionyl chloride and then carrying out aminolysis treatment to obtain 3,4-dimethoxyphenyl propanamide; carrying out reductive treatment by boron trifluoride diethyl etherate and sodium borohydride to obtain 3,4-dimethoxy-amphetamine; carrying out reaction on the 3,4-dimethoxy-amphetamine in sulfuric acid and paraformaldehyde to obtain N-acetyl-7,8-dimethoxy-2,3,4,5-tetrahydro-1H-benzo[c]azepine after acetyl protection; carrying out acetyl deprotection and Boc deprotection to obtain N-Boc-7,8-dimethoxy-2,3,4,5-tetrahydro-1H-benzo[c]azepine; introducing hydrochloric acid gas to obtain the 7,8-dimethoxy-2,3,4,5-tetrahydro-1H-benzo[c]azepine hydrochloride. The preparation method is relative mild in conditions, and a product is easy to process and purify, and is suitable for