Reactions of Pentafluorosulfanyl Isocyanate and Isothiocyanate

The purification of pentafluorosulfanyl isocyanate (1) is rendered less difficult by isolation of the intermediate (pentafluorosulfanyl)carbamoyl fluoride, while pentafluorosulfanyl isothiocyanate (2) can easily be prepared by the reaction of dichloro(pentafluorosulfanylimino)methane with phosphorus pentasulfide in boiling toluene. Both 1 and 2 react readily with alcohols to give urethanes 3a – e and thiourethane 4, respectively, and with thiols to give thiolurethanes 5a, b and dithiourethane 6. With amines 1 and 2 form a variety of substituted ureas 7, 8a – e, 10a – c, and thiourea 9. Of particular interest is the reaction of 1 with tertiary amines which yields zwitterionic derivatives 11a, b. N‐(Pentafluorosulfanyl)imine derivatives 12a – e, 13a, b, 14 are prepared from the reactions of 1 or 2 with aldehydes and N,N‐disubstituted amides. The reaction of 1 with acetylacetone gives the N‐(pentafluorosulfanyl)amide of diacetoacetic acid (16), which in solution is observed in both the keto form and two distinct enol forms. With trimethyl orthoformate 1 gives not only the expected N‐methyl‐N‐(pentafluorosulfanyl)urethane 18 but also the classical addition product 2,2,2‐trimethoxy‐N‐(pentafluorosulfanyl)acetamide (17).