Abstract: | Pyrimithate (2-dimethylamino-6-methylpyrimidin-4-yl diethyl phosphorothio-nate) decomposes when exposed to u.v. light in the presence of air to a complex mixture of products, some of which inhibit esterases directly or indirectly. Separation of the mixture by thin-layer and liquid chromatography gave five pure components in sufficient quantity for spectroscopic identification. A sixth was tentatively identified. The structures ( II-VII ) show that oxidative attack occurs at the dimethylamino group and at the sulphur atom. |