Derivatives of alrestatin (1–5) and alconil (6–8) possessing Michael acceptor substituents were synthesized as aldose reductase inhibitors. The alrestatin derivatives demonstrated enhanced aldose reductase inhibitory activity. The most potent reversible inhibitor of the series (compound 3) was 15-fold more active than alrestatin. Additionally, lipophilic analogues of alrestatin selectively inhibited rat lens aldose reductase versus rat kidney ...