Veratric Acid → Veratroyl chloride

2.9 g of 3,4-dimethoxybenzoic acid and 4 ml of thionyl chloride were heated for 4 hours at reflux and concentrated under reduced pressure to obtain 3,4-dimethoxybenzoyl chloride. The 3,4-dimethoxybenzoyl chloride was dissolved in 10 ml of anhydrous benzene, and the resulting solution was added dropwise to a solution of 4.0 g of N-ethyl-N-(4-hydroxybutyl)-6-methoxy-1,2,3,4-tetrahydro-2-naphthylamine and 2.2 g of triethylamine in 50 ml of anhydrous benzene. After the addition, the resulting solution was stirred for 30 minutes at room temperature (about 25° C.) and heated for 3.5 hours at reflux. The reaction solution was washed with water, a 2 N-NaOH aqueous solution and water in this order, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue obtained was purified through silica gel chromatography to obtain N-ethyl-N-[4-(3,4-dimethoxybenzoyloxy)butyl]-6-methoxy-1,2,3,4-tetrahydro-2-naphthylamine as a colorless oily product. To this oily product was added an ethanolic solution of hydrogen chloride having a concentration of about 18% and the resulting solution was concentrated under reduced pressure to obtain a residue. The residue was dissolved in a mixed solvent of acetone and diethyl ether, and the solution was left at a temperature of about 2° to 3° C. to form crystals. By collecting the crystals through filtration and recrystallization from a mixed solvent of acetone and diethyl ether, 3.0 g of N-ethyl-N-[4-(3,4-dimethoxybenzoyloxy)butyl]-6-methoxy-1,2,3,4-tetrahydro-2-naphthylamine hydrochloride was obtained as colorless crystals having a melting point of 139°-140° C. The melting point, the infrared spectra and other physical data of this product corresponded to the date of the compound obtained in Example 2 (ii).

1. temperatureat reflux
2. concentrationconcentrated under reduced pressure

ORD record

ord-9e12f4b98ee8482b85e510f625c709c0

Source dataset

uspto-grants-1980_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04239903