Ethaverine is an analogue of Papaverine (P190500), an antispasmodic. An isoquinoline derivative with the potential for antimicrobial, antimalarial and cytotoxic antiviral agents.
(1) 1 part of 2-(3,4-diethoxy-phenyl)-N-[2-(3,4-diethoxy-phenyl)-2-hydroxyethyl]acetamide (homoveratroyl hydroxyhomo-veratrylamine), prepared from
2-amino-1-(3,4-diethoxy-phenyl)ethanol and (3,4-diethoxy-phenyl)acetyl
chloride, is dissolved in a neutral solvent, such as, for example, chloroform or
benzene. Thereupon, 1 to 3 parts of phosphorus oxychloride are added to the
resulting solution and the no whole is heated for some hours under a reflux
condenser. It should be pointed out here that it is also possible to occur by
allowing the amide solution to flow on to the phosphorus oxychloride with the
application of heat or in the cold. Instead of this, it is also possible to carry
out the reaction in such a way that the reaction mixture is first allowed to
stand in the cold. Then it completed by heating. The base produced in both
cases is obtained by shaking with chloroform after distilling off the solvent and
after alkalization. MP: 145°-147°C.
(2) 1 part of 2-(3,4-dimethoxyphenyl)ethylamine is dissolved in 2 parts of
benzene, 1 to 2 parts of phosphorus pentachloride are added thereto and the
whole is heated to boiling. After heating for several hours, the base, which is
formed can be isolated as above described. MP: 147°C.
(3) 1 part of N-(3,4-diethoxyphenylacetyl)-β-oxy-β-(3,4-
diethoxyphenyl)ethylamine is dissolved in benzene or chloroform, mixed with
1 to 3 parts by weight of phosphorus oxychloride and boiled under a reflux
condenser for 3 hours whereupon 6,7-diethoxy-1-(3',4'- diethoxybenzyl)isoquinoline base can be isolated in the usual way. MP: 99°-
101°C.
