PRODUCTION OF 1,4-DIHYDROXY-2-NAPHTHOIC ARYL ESTER

摘要

PROBLEM TO BE SOLVED: To easily and industrially obtain the subject compound in high purity and yield with no need of any special purification operation by reaction between a 1,4-dihydroxy-2-naphthoic acid and a triaryl phosphorous ester in the presence of trifluoromethanesulfonic acid as catalyst to suppress formation of dimer by-products. SOLUTION: This compound of formula III is obtained by reaction of a 1,4-dihydroxy-2-naphthoic acid of formula I (R1 is H, a lower alkyl or the like) with a triaryl phosphorous ester of formula II (R2 is H, a halogen or the like) (e.g. triphenyl phosphite) in the presence of trifluoromethanesulfonic acid pref. at 25-35 deg.C; wherein it is preferable that the molar ratios: the compound of formula II/the compound of formula I and the trifluoromethanesulfonic acid/the compound of formula I are 2-3.5 and 0.01-0.1, respectively.