N ‐Hydroxyphthalimide

Abstract image [ 524‐38‐9 ] C 8 H 5 NO 3 (MW 163.11) InChI = 1S/C8H5NO3/c10‐7‐5‐3‐1‐2‐4‐6(5)8(11)9(7)12/h1‐4,12H InChIKey = CFMZSMGAMPBRBE‐UHFFFAOYSA‐N (reagent for the formation of O ‐alkyl hydroxylamines, catalytic precursor to the phthalimido‐ N ‐oxyl radical (PINO), capable of mild and selective abstraction of hydrogen from a wide variety of CH bonds with the formation of free radicals for exploitation in synthetic schemes, oxidation of CH bonds) Physical Data: mp 233 °C; d 1.58 g cm −3 ; refractive index 1.522 (at 589 nm); p K a 6.3 at 25 °C in H 2 O; OH BDE 88 kcal mol −1 ; 1 H NMR (DMSO‐d 6 ) 7.84 (s, 4 H , CH), 10.9 (s, 1 H , OH); 13 C NMR (DMSO‐d 6 ) 168, 134, 128, 123; EPR of the derived radical (PINO) triplet, g = 2.0073, A N = 4.23 G; MASS (EI) ( m/z ) 163 M + , 147, 133, 105, 104, 77, 76, 50. Solubility: 0.33 g L −1 5 °C in benzene; 50.5 g L −1 at 25 °C in H 2 O; soluble in AcOH, CH 3 CN, CH 3 COOEt. Preparative Methods: N ‐hydroxyphthalimide is easily prepared by reaction of phthalic anhydride and hydroxylamine hydrochloride or sulphate in basic conditions. Handling, Storage and Precaution: N ‐hydroxyphthalimide is a white crystalline solid, stable to air, does not need particular precautions for the storage, irritant for the eyes and the skin and very toxic after inhalation.