Process for preparation of O,O-dimethyl phosphoramidothioate and N-(methoxy-methylsulfanylphosphoryl) acetamide
US10669295B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 2018 |
| Grant date | Jun 2, 2020 |
| Priority date | — |
| Expiry date | Aug 6, 2038 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01N57/28
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Preparation of O,O-dimethyl phosphoramidothioate and O,O-dimethyl phosphoroamidothioate. A process of making O,O-dimethyl phosphoroamidothioate is described including reacting sulfur with PCl3 to form PSCl3, reacting the PSCl3 formed with methanol to form O-methyl phosphorodichloridothioate, and reacting the O-methyl phosphorodichloridothioate formed with methyl lye to form O,O-dimethyl phosphorochloridothioate in solution in CH2Cl2, and reacting the O,O-dimethyl phosphorochloridothioate formed with sodium hydroxide and ammonium hydroxide to form O,O-dimethyl phosphoroamidothioate in solution in CH2Cl2. Reacting the O,O-dimethyl phosphoroamidothioate formed with catalytic dimethyl sulfate to form methamidophos, and reacting the methamidophos formed with acetic anhydride to form N-(methoxy-methylsulfanylphosphoryl) acetamide is also described. Throughout the process, the O,O-dimethyl phosphorochloridothioate and the O,O-dimethyl phosphoroamidothioate formed are maintained in solution in CH2Cl2 at all times.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.