Glycoglycerolipid analogues lacking the glycerol backbone were prepared through a lipase catalyzed transesterification of beta-D-galactosylethylene glycol. The inhibitory effect of the resultant isomeric hexanoates at the primary alcoholic positions, beta-D-galactosylethylene glycol itself and nonyl beta-D-galactopyranoside, was tested on Epstein-Barr virus early antigen (EBV-EA) activation in Raji cells promoted by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), as a primary screening test for inhibitors of tumor promotion. All the compounds assayed were found to be less active than the reference 2-O-beta-D-galactopyranosylglycerol derivatives, of which they are simplified models, indicating that the anti-tumor-promoting activity is very closely related to the presence of a free hydroxymethylene group on the glycerol-like aglycone moiety.