PURPOSE: To obtain the subject compound in high yield industrially and advantageously by using 1,3-dichlorobenzene as a starting raw material, converting it through 1,3-dichloro-4,6-dinitrobenzene into a 3-alkoxy-4,6-dinitrophenyl, reducing and hydrolyzing.
CONSTITUTION: 1,3-Dichlorobenzene is nitrated with concentrated nitric acid in the presence of concentrated sulfuric acid to give 1,3-dichloro-4,6- dinitrobenzene, which is reacted with an alcohol of the formula ROH (R is an alkyl) in the presence of an alkali hydroxide to give a 3 alkoxy-4,6- dinitrophenyl. Then this compound is reduced with hydrogen in the presence of a noble metal catalyst to give a 3-alkoxy-4,6-diaminophenol of formula II. The compound is hydrolyzed with a strong acid to give 4,6-diaminoresorcinol. Hydrochloric acid, hydrobromic acid, sulfuric acid or hydroiodic acid is preferable as the strong acid used in the reaction. Sulfuric acid used in the reaction is filtered to separate the objective compound and the filtrate is mixed with SO3 to preferably use sulfuric acid.
SUZUKI HIDEO
TOKUNAGA KENICHI
SAKOTA RYOZO
