Geminal oxygen–nitrogen–halogen systems.N-Halohydroxylamine derivatives

N-Chloro-N-alkoxyureas: synthesis, structure and properties

“…This nitrogen pyramidality is a consequence of n O -σ* N-Cl anomeric effect dominant in N-chloro-N-alkoxyamides, 4,5 which must stabilise the sp 3 hybridization of nitrogen as predicted. 4,5 Some elongation of the N-Cl bond in ureas 1, 2 is observed: up to 1.757(1) Å for 1, and 1.7572(5) Å for 2. For comparison, the N-Cl bond lengths are 1.71-1.72 Å in 2-Cl mono-, di-and trisubstituted N-chloro-N-phenylacetamides, 6 which have almost planar configurations of the nitrogen atom.…”

“…The pyramidality of dialkoxyamide nitrogen in ureas Me 2 N-C(O)N(OR)OR' has been demonstrated by a DNMR method (∆G ¹ inv = 9.8-10.5 kcal mol -1 at 25°C), The configuration stability of nitrogen in O-N-X geminal systems [X = OC(O)R, OR, Cl] has been studied theoretically, 4,5 and for N-chloro-N-alkoxyamides it was predicted that N-C(O) and N-O rotation barriers are much higher than nitrogen inversion barriers 2,4(a) (∆G ¹ inv = = 2.52 kcal mol -1 ). 4(a) In N-chloro-N-alkoxyureas, the N-C(O) rotation barrier was determined using the DNMR method (∆G ¹ inv = 19.2 kcal mol -1 at 25°C).…”

“…N(2) C (1) O (1) N (1) Cl (1) O (2) C(2) Figure 2 Molecular structure of 2. Selected bond lengths (Å) and bond angles (°): Cl(1)-N(1) 1.7572 (5), O(1)-C(1) 1.2103 (7), N(1)-O(4) 1.4204 (7), N(1)-C(1) 1.4719(8), N(2)-C(1) 1.1354(8), N(2)-C(2) 1.4000 (8) (9), O(4)-C(8) 1.4549 (7), O(5)-C(11) 1.2144 (7), O(6)-C(11) 1.3252 (7), N(3)-C(5) 1.4618(8), C(2)-C(3) 1.4007(8), C(2)-C(7) 1.4059(8), C(3)-C(4) 1.3881 (9), C(4)-C(5) 1.3866 (9), C(5)-C(6) 1.3903 (9), C(6)-C(7) 1.3827 (9), C(8)-C(9) 1.5223 (9), C(8)-C(10) 1.5290 (9), C(8)-C(11) 1.5316 (9); O(4)-N(1)-C(1) 108.35 (5), O(4)-N(1)-Cl(1)-108.97(4), C(1)-N(1)-Cl(1) 108.51(4), N(1)-O(4)-C(8) 113.37(8), O(1)-C(1)-N(1) 121.39 (6). O(2) N (3) O (3) C (5) C (4) C (3) C (2) C (6) C (7) N (2) C(1) O (1) N (1) Cl (1) O(4) C(10) C(8) C (9) C (11) O (5) O (6) C(12) N-alkoxy-N'-methylureas 5,7(b) was found to proceed in the same manner.…”

N‐Chloro‐N‐alkoxyureas: Synthesis, Structure and Properties.

“…The pyramidality of dialkoxyamide nitrogen in ureas Me 2 N-C(O)N(OR)OR' has been demonstrated by a DNMR method (∆G ¹ inv = 9.8-10.5 kcal mol -1 at 25°C), 2 and XRD studies in N-acyloxy-N-alkoxybenzamide, 3 N-acyloxy-N-alkoxyureas and N-acyloxy-N-alkoxycarbamates. 1 The configuration stability of nitrogen in O-N-X geminal systems [X = OC(O)R, OR, Cl] has been studied theoretically, 4,5 and for N-chloro-N-alkoxyamides it was predicted that N-C(O) and N-O rotation barriers are much higher than nitrogen inversion barriers 2,4(a) (∆G ¹ inv = = 2.52 kcal mol -1 ). 4(a) In N-chloro-N-alkoxyureas, the N-C(O) rotation barrier was determined using the DNMR method (∆G ¹ inv = 19.2 kcal mol -1 at 25°C).…”