Improved glucose tolerance in rats treated with oxazolidinediones.

5-(2-Chloro-6-methoxyphenyl)oxazolidine-2,4-dione (49) is the most potent agent selected from a series of 5-substituted oxazolidinediones that were found to cause improvements in glucose tolerance in previously fasted rats and potentiation of insulin release in response to a glucose challenge. These compounds were unique in not producing hypoglycemia below the normal fasting glycemia levels. Substituent effects at positions 2-6 of the phenyl ring were investigated.