By systematic modifications of the canonical propylene carbonate, a family of van der Waals glass-formers with similar chemical structures is generated for dielectric studies of the dynamics of the structural alpha-relaxation with the purpose of critically testing the correlation of dynamic properties with the dipole dipole interaction contribution to the intermolecular potential. With the dielectric strengths at T-g varying over a vast range from 4.2 to 182, the modified propylene carbonates provide strong support of the correlation by themselves and in conjunction with 88 van der Waals glassfonners previously considered (Phys. Rev. Lett. 2016, 116, 025702).