Asymmetrical nitrogen. 52. Nucleophilic substitution at nitrogen in N-chloro-N-alkoxyamines

Bis-aziridinomethanes: synthesis, structure and properties

“…1 H NMR (C 6 D 6 ) d: 1.10, 1.19, 1.47 and 1.64 (m, 8H, ring protons, ABCD spectrum, ∆n AB 43.0 Hz, n CD 35.5 Hz, 3 J AB cis 5.4 Hz, 3 J CD cis 7.1 Hz, 3 J AD trans = 3 J BC trans = 3.8 Hz, 2 J AC gem = 2 J BD gem = 0.7 Hz), 1.77 (s, 1H, HC), 2.55 (s, 6H, Me 2 N). 13 C NMR (C 6 D 6 ) d: 22.0 (ddm) and 24.6 (ddm) (ring carbons, 1 J 165.0 Hz, 1 J 175.0 Hz), 39.9 (qq, MeN, 1 J 133.3 Hz, 3 J 4.0 Hz), 105.2 (dm, CH, 1 J 153.0 Hz). ‡ Crystallographic data for 1: at 293 K, crystals of C 9 H 14 N 4 O are triclinic, space group P1, a = 6.309 -3 , m = 0.83 cm -1 , F(000) = 208.…”

“…1(g) It can be demonstrated by comparing 1-dimethylaminomethylaziridine and its 2,2-dimethyl analogue. 13 The transformation of the former compound into methyl iodide leads to a great decrease in the nitrogen inversion barrier (by 3.5 kcal mol -1 ) due to the anomeric effect n(N) ® σ*(C-N + ), whereas upon a similar transformation of the latter compound the inversion barrier remained unchanged due to steric hindrances for the anomeric effect. Finally, according to an X-ray database, the anomeric effect is also observed in 1-alkoxyaziridine (+)-G 11 where it is strengthened by steric strain which is favourable to lengthening the C-O bond [bond lengths:…”