A process for preparing an oligomeric phenolic detergent composition comprising contacting an oil soluble alkylphenol with an alkaline earth metal base, an alpha amino acid, and a C.sub.1 to C.sub.6 aldehyde, in the in the presence of a C.sub.2 to C.sub.6 alkylene glycol and a C.sub.2 to C.sub.4 carboxylic acid; and reacting under reactive conditions at a temperature of from 150.degree. C. to 225.degree. C. The oligomeric phenolic detergent product can be employed in a lubricating oil.