The present invention are novel amino acid amide compounds of the following general formula which inhibit the enzyme acylcoenzyme A:cholesterol acyltransferase:
wherein R is phenyl or 1- or 2-naphthyl which are unsubstituted or may be substituted; R₁ is hydrogen or a straight or branched alkyl group having from 1 to 6 carbon atoms; R₂ is hydrogen, an aliphatic group, an aromatic group, an aralkyl or diarylalkyl group or R₁ and R₂ form a carbocyclic group; R₃ is hydrogen, an aliphatic group, an aralkyl group wherein the alkyl moiety may contain a carbocyclic entity; R₄ is hydrogen, an aliphatic group, SO₂R₁₄, -C(=S)NHR₁₅, -CO₂R₁₅, -COR₁₈, or -C(=O)NHR₁₅ wherein R₁₄ is morpholino, phenyl or substituted phenyl; R₁₅ is an alkyl group, phenyl or phenylalkyl wherein the phenyl group may be substituted; and R₁₈ is the same is R₁₅ or is halo-substituted alkyl, 9-fluorenylmethylene or pyrrolidino.