Synthesis of coelenterazine synthesis intermediate
Disclosed herein are synthesis methods for coelenterazine and intermediates. Also disclosed are articles including the coelenterazine and coelenterazine derivatives. Representative absorbent articles include disposable diapers and adult incontinence products.
1. A method of making 3-(4-(benzyloxy)phenyl)-2-oxopropanal, comprising
providing 1-(benzyloxy)-4-(chloromethyl)benzene, and
reacting the 1-(benzyloxy)-4-(chloromethyl)benzene in two steps to provide 3-(4-(benzyloxy)phenyl)-2-oxopropanal,
wherein a first step of the two steps comprises reacting the 1-(benzyloxy)-4-(chloromethyl)benzene with methyl 2,2-dimethoxyacetate under Grignard conditions to provide 3-(4-(benzyloxy)phenyl)-1,1-dimethoxypropan-2-one; and
wherein a second step of the two steps comprises reacting the 3-(4-(benzyloxy)phenyl)-1,1-dimethoxypropan-2-one with aqueous acid to provide the 3-(4-(benzyloxy)phenyl)-2-oxopropanal.
2. The method of claim 1 , wherein the method does not include more than one palladium-catalyzed reaction.
3. The method of claim 1 , wherein reacting the 1-(benzyloxy)-4-(chloromethyl)benzene with methyl 2,2-dimethoxyacetate under Grignard conditions comprises reacting the 1-(benzyloxy)-4-(chloromethyl)benzene with methyl 2,2-dimethoxyacetate, ethyl bromide, magnesium, and a catalytic amount of iodine.
4. The method of claim 3 , wherein the 3-(4-(benzyloxy)phenyl)-1,1-dimethoxypropan-2-one is purified by silica column chromatography.
5. The method of claim 1 , wherein the aqueous acid is aqueous HCl.
6. The method of claim 1 , wherein the 3-(4-(benzyloxy)phenyl)-2-oxopropanal is isolated in a yield of 60 to 75% at a purity of 85 to 95% relative to 1-(benzyloxy)-4-(chloromethyl)benzene.