The invention provides compounds that inhibit epoxide hydrolase in therapeutic applications for treating hypertension. A preferred class of compounds for practicing the invention have the structure shown by Formula 1 wherein Z is oxygen or sulfur, W is carbon phosphorous or sulfur, X and Y is each independently nitrogen, oxygen, or sulfur, and X can further be carbon, at least one of R1-R4 is hydrogen, R2 is hydrogen when X is nitrogen but is not present when X is sulfur or oxygen, R4 is hydrogen when Y is nitrogen but is not present when Y is sulfur or oxygen, R1 and R3 is each independently C1-C20 substituted or unsubstituted alkyl, cycloalkyl, aryl, acyl, or heterocyclic.