9-(2,3,4,6-Tetramethylphenyl)-3,7-dimethyl-nona-2,4,6,8-tetraen-1-oic acid butyl ester 、
2,3,4,6-Tetramethyl-benzyltriphenylphosphonium chloride 、
Butyl 3,7-dimethyl-8-oxoocta-2,4,6-trienoate 以From this product, there is produced by the procedure of Example 15 9-(2,3,4,6-tetra-methyl-phenyl)-3,7-dimethyl-nona-2,4,6,8-tetraen-1-oic acid of melting point 201°-202° C.的产率得到9-(2,3,4,6-Tetra-methyl-phenyl)-3,7-dimethyl-nona-2,4,6,8-tetraen-1-oic acid