The acid-catalysed hydrolysis and protonation behaviour of hydroxamic acids

Investigation of the acid-catalyzed hydrolysis and reaction mechanisms ofN,N′-diarylsulfamides using various criteria

“…10.00–11.00 M), and finally increase again (after 11.00 M). Similar rate maxima have been observed for acid‐catalyzed hydrolysis of other compounds such as sultams, amides, hydroxamic acids, primary acetate esters, and N ‐acetylsulfonimidic esters . These rate maxima were attributed to an A2 mechanism in which extensive protonation of the sulfamides occurs in the regions of acidity in which the activity of the water is falling.…”

Acid‐catalyzed hydrolysis of 5‐substituted‐1H,3H‐2,1,3‐benzothiadiazole 2,2‐dioxides (5‐substituted benzosulfamides): kinetic behavior and mechanistic interpretations

“…While 1a , 1b show a clearly defined rate maximum at 9.00 M (for 1c , 1d at 8.00 M), after that the rates decrease, pass a minimum for 1a , 1b around 10.00–12.00 M (for 1c , 1d around 10.00–14.00 M) and finally increase again for 1a , 1b after 12.00 M (for 1c , 1d after 14.00 M). Similar rate maxima have been observed for acid‐catalyzed hydrolysis of other compounds such as sultams, N‐arylsulfinylphthalimides, hydroxamic acids, primary acetate esters, N‐acetylsulfonimidic esters and N,N'‐diarylsulfamides . The initial downward curvatures, which were exhibited are typical of an A2 reaction in which extensive protonation of the 5‐substituted benzosulfamides occurs in the regions of acidity in which the activity of the water is falling.…”

Lossen Rearrangements under Heck Reaction Conditions

“…N ‐Hydroxy‐4‐methylbenzamide (8b) (R=CH 3 ): White needles; yield: 4 g (86%); R f =0.02 (ethyl acetate/ n ‐hexane, 50%); mp 143–145 °C (reported: mp 143–144 °C);25 1 H NMR (300 MHz, DMSO): δ =11.43 (bs, 1 H), 9.42 (bs, 1 H), 7.87 (d, 2 H, J =7.85 Hz), 7.43 (d, J =7.87 Hz, 2 H), 2.50 (s, 3 H); 13 C NMR (75 MHz, DMSO): δ =164.58, 141.21, 129.57, 128.90, 126.81, 20.82.…”