Phthalazine analogs of a Lisofylline (LSF) and synthetic methods for preparation of such analogs are provided. Compounds of the invention have structural formula III: wherein 1) R3a is hydrogen and R3b is selected from C5-22alkyl, C2-22alkenyl, or C2-22alkynyl; or a pharmaceutically acceptable salt thereof; or 2) R3b is hydrogen and R3a is selected from C9alkyl, C15-22alkyl, C9-22alkenyl, or C2-22alkynyl; or a pharmaceutically acceptable salt thereof; or 3) R3a and R3b are the same or different and are selected from C9alkyl, C15-22alkyl, C4-22alkenyl, or C2-22alkynyl; or a pharmaceutically acceptable salt thereof. The analogs of LSF provided have the ability to protect cell viability, particularly the ability to protect pancreatic β-cells, to induce insulin secretion.