Formation of [M − H]⁺ ions in electron impact mass spectra of nitrosocarbonyl compounds α‐ and γ‐nitrosocarbonyl compounds

Abstract

The presence of the [M + HI+ ions and the absence of the monomer molecular ions M" in the mass spectra of some tertiary a-and y-nitrosocarbonyl compounds is reported. This effect is caused by the rearrangement of the mobile hydrogen in the a-carbonyl position in the fragmentation pattern of the dimer molecular ions 2M". $ EtONO CH,COCI

5-Methyl-5-nitrosohexan-2-one, reexamined

“…The literature lacks any data indicating the physical state of 2. 4 Compound 2 is colorless oil that turned into a low melting solid (mp 8-10 °C) upon storage in the refrigerator. Nitro ketal 2 was reduced with aluminum amalgam 7 in ethanol/water yielding the hydroxylamine derivative 3, a low-melting solid (the literature 4 does not provide any data referring to its physical state); in the solid state 3 is stable but solutions rapidly turn green due to air oxidation.…”

“…4 Compound 2 is colorless oil that turned into a low melting solid (mp 8-10 °C) upon storage in the refrigerator. Nitro ketal 2 was reduced with aluminum amalgam 7 in ethanol/water yielding the hydroxylamine derivative 3, a low-melting solid (the literature 4 does not provide any data referring to its physical state); in the solid state 3 is stable but solutions rapidly turn green due to air oxidation. The hydroxylamine 3 was oxidized with mercuric oxide, 8 the turquoise-blue color of the reaction solution is indicative of the nitroso functionality of 4; the isolated product was the crystalline colorless dimer, the diazene 1,2-dioxide 4a.…”

“…The collected product was recrystallized from pentane to yield colorless prisms 4a (600 mg, 1.59 mmol, 75%); mp 57-58 °C (pentane), lit. 4 5 and (E,Z)-1,2-bis(1,1-dimethyl-4-oxopentyl)diazene 1,2-dioxide 4 (5a). A mixture of nitroso dimethyl ketal dimer 4a (529 mg, 2.75 mmol) in moist acetonitrile (10 mL, 3% H2O) and p-toluenesulfonic acid monohydrate (10 mg) was stirred at ambient temperature for 5 min.…”

“…The preparation of the nitroso compound 5 by conversion of 5-methyl-5-nitrohexan-2-one 1 in the course of a multi-step synthesis has been reported 4 in the context of a study of the mass spectral fragmentation mechanism of the nitroso ketone dimer 5a; the rather cursory synthetic procedures are lacking some physical data, and part of the spectroscopic data ( 1 H NMR) have not been unambiguously assigned. This prompts us to describe the detailed preparation of the title compound and its precursors; furthermore, all physical and NMR spectroscopic data including signal assignments based on two-dimensional NMR techniques are provided.…”

“…The residual blue oil upon cooling in the refrigerator and scratching in the presence of little pentane turned into a colorless crystalline solid 5a (320 mg, 1.12 mmol, 81%); mp 54-55 °C (pentane), lit. 4 …”