Darstellung und Reaktionen des Trifluormethylisocyanats

Abstract

Der Curtius‐Abbau zur Synthese von CF3NCO (1) aus Azidotrimethylsilan und Trifluoracetylchlorid wird optimiert. Mit Wasser reagiert 1 zu (FCN)3, F3CNHCOF (3) und F3CNHCONHCF3 (5). Über den tert‐Butylester der (Trifluormethyl)carbaminsäure 6 gelang die Darstellung von F3C  NH2 (2). N‐(Trifluormethyl)harnstoff (9) wird aus Ammoniak erhalten. Mit SF4, OSF4 und XeF2 reagiert 1 zu den bekannten Verbindungen 10, 11 und 13. Cyantrimethylsilan (14) addiert an 1 zum Acetonitril 15, das zum Carbamoylcyanid 16 umgesetzt werden kann. Aus 2 mol 1 und 14 erhält man das Imidazolidin 17, dessen Konstitution durch spektroskopische Daten und Derivatisierung zu 18 und 19 sowie Ringspaltung zu 20 bewiesen wird.

Convenient Access to α‐Fluorinated Alkylammonium Salts

“…Solutions of HCN in anhydrous HF were reported as unstable at 20 °C and to form the [HCF 2 NH 3 ] + cation, which was isolated as the [AsF 6 ] − salt and characterized by NMR and vibrational spectroscopy 8a. 9 While small amounts of CF 3 NH 2 were identified by IR spectroscopy in the reaction products when FCN was added to anhydrous HF at −78 °C,8b it was found that HF catalyzes the explosive polymerization of FCN 1d…”

N–CF3 bonds in a carbamate and a triazene

“…Crystals, which were sealed in glass capillaries, were grown by sublimation from material prepared according to Lutz & Sundermeyer (1979) for (1) and Makarov et al (1968) for (3). Crystal sizes are 0.30x0.35 x0.61mm for (1) and 0.24x0.28x 0.78mm for (3).…”

N‐Trifluoromethyl Hydrazines, Indoles and Their Derivatives

“…[7] In this context, a straightforward method to generate trifluoromethylated and unsymmetrically substituted hydrazines would be particularly impactful, owing to the powerful effects of fluorination on the (metabolic) stabilities as well as physical properties of organic molecules. [8] However, the current methodological repertoire to access N-CF 3 hydrazines is of limited scope [9,10] (see Figure 1, middle), relying on harsh photolysis or unselective oxidations with XeF 2 (to yield I) as well as pyrolysis to yield polytrifluoromethylated hydrazines (III), or low-yielding trifluoromethylation of a single class of diazo compounds (to yield II), for which the feasibility of Boc deprotection and potential derivatizations has not been demonstrated however. [10g] In this context, we envisioned that if we could develop a general method to access pharmaceutically and agrochemically relevant aromatic N-CF 3 hydrazines, this might poten-tially allow us to unlock valuable and currently inaccessible N-CF 3 derivatives, such as N-CF 3 hydrazones, sulfonyl hydrazines, or indoles.…”

“…In our tests for compatibility of alternative functionalities, we found the protocol to be rather general, tolerating electron-rich as well as electrondeficient arenes. The electron-withdrawing nitro-(13), sulfone- (15) and even OCF 3 (11) groups were equally compatible as the donating methoxy (10), sulfide (7) or alkyl substituents (9). In this context, meta-and para-substitution were generally well tolerated, whereas the presence of orthosubstituents considerably slows the reaction, giving for example, 8 in only moderate yield (= 38 %) after microwave irradiation for 36 h (along with unreacted carbamoyl azide).…”