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Polar [3+2] cycloaddition between N-methyl azomethine ylide and trans-3,3,3-trichloro-1-nitroprop-1-ene

Żmigrodzka Magdalena, Sadowski Mikołaj, Kras Jowita, Dresler Ewa, Demchuk Oleg M., Kula Karolina

Scientiae Radices

2022

Vol. 1, Iss. 1

26--35

Pyrrolidines are important heterocyclic organic compounds which show biological effects. Many of them are successfully used in medicine. These compounds can also be applied in industry, for example as dyes or agrochemical substances. Therefore, the study of pyrrolidines chemistry is important for modern science. In this paper the pyrrolidines synthesis in [3+2] cycloaddition between Nmethyl azomethine ylide and trans-3,3,3-trichloro-1-nitroprop-1-ene was studied. The reaction was carried out experimentally and based on computational research. The obtained results show the reaction may be of a polar nature, and proceed under mild conditions leading to (3SR,4RS)-1-methyl-3-nitro-4-(trichloromethyl)pyrrolidine as a single reaction product. Probably, a similar protocol can be applied for analogous reactions involving other 2-substituted nitroethene analogues.

Acidity of the N+Ch2 Protons in N-Phenacyl-R-pyridinium Bromides

Szafran M., Szwajca A.

Polish Journal of Chemistry

2004

Vol.78 /nr 11-12

2131-2140

UV-Vis, FTIR, 1H and 13C NMR and MS spectra of 19 N-phenacyl-R-pyridinium bromides and their ylides were measured and analysed. In crystals the investigated salts appear as keto-tautomer, but in water solutions in a keto-enol tautomeric equilibrium. In most salts, the N+CH2 hydrogens, undergo fast hydrogen-deuterium exchange in neutral D2O at room temperature, which confirms the presence of some amount of enolic tautomers in aqueous solutions. The intensity of the ylide bands in the 385-480 nm region is substituent and time dependent and reflects the rates of their formation and decomposition. The ylides with electron-withdrawing substituents form and decompose much faster than those with electron-donating ones.