Ring Opening Reactions of β-Propiolactam in Superacidic Media.

ABSTRACT: The reaction of β-propiolactam in the superacidic systems HF/MF₅ (M=Sb, As) led to the formation of monoprotonated 3-aminopropanoyl fluoride in the form of [C(O)F(CH₂ )₂ NH₃ ][SbF₆ ] and [C(O)F(CH₂ )₂ NH₃ ][AsF₆ ]. In the presence of traces of water, the diprotonated species β-alanine [C(OH)₂ (CH₂ )₂ NH₃ ][AsF₆ ]₂ was synthesized for the first time. All salts were characterized by low-temperature infrared and Raman spectroscopy. Additionally, single-crystal X-ray analyses were conducted in the case of [C(O)F(CH₂ )₂ NH₃ ][SbF₆ ] and [C(OH)₂ (CH₂ )₂ NH₃ ][AsF₆ ]₂ . By using SO₂ instead of HF as the solvent, the salt [C(OH)₂ (CH₂ )₂ NHSO][SbF₆ ]₂ was obtained, and single-crystal X-ray analysis of this salt containing a thionylimide moiety was conducted. For the formation of these open-chain compounds, an acyl cationic species as intermediate is assumed, which is formed from N-protonated β-propiolactam. Quantum chemical calculations at the B3LYP/aug-cc-pVTZ and MP2/aug-cc-pVTZ levels of theory were carried out to gain a better understanding of the formation and the structural properties of protonated β-propiolactam.

SUBMITTER: Beck S 

PROVIDER: S-EPMC9302645 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature