Synthesis of 2, 6-Naphthalenedicarbaldehyde from 2, 6-Naphthalenedicarboxylic Acid

Abstract

In connection with the utilization of 2, 3-naphthalenediscarboxylic acid (2, 3-NDCA) as a new industrial raw material, 2, 6-naphthalenedicarbaldehyde was prepared by the reduction reaction of 2, 6-NDCA which in turn was obtained by the Henkel rearrangement of K2-2, 3-NDCA.
Conversion of 2, 6-NDCA to the acid chloride, followed by the reaction with N-methylaniline gave 2, 6-naphthalenedicarbon-N-methylanilide (1). Reduction of (Z) with Li[AIH] (1.2 molar ratio to (1)) in THF for 2 hr at OeC, and cleavage of the resultant complex with dilute hydrochloric acid without previous isolation produced 2, 6-naphthalenedicarbaldehyde (2). The yields depend sharply on the reaction temperature and on the amount of Li[AIH] used At higher reaction temperatures, the yie1d of (2) decreases and 2, 6-bis(hydroxymethyl)naphthalene is formed as a side product.