| 摘要 |
The invention comprises cyclic nitroxides of the general formulae <FORM:0983134/C2/1> <FORM:0983134/C2/2> and <FORM:0983134/C2/3> wherein Z is >CH2, >CHCH3, >C=O, >CHBr, >CHCl, >CHI, >CHF, >CHOH, >CHCN, >C(OH)CN, >CHCOOH, >CHCOOCH3, >CHCOOC2H5, >C(OH)COOC2H5 or >C(OH)CHOHC2H5, Z1 is=CH-, =C(CH3)-, =C(COOH)- or =C(COOC2H5)-, Z2 is >CH2, >C=O, >C(CH3)2, >CHCONH2, >CHNH2, >C=NOH, >CHOH, >C(CN)OH, >C(COOCH3)OH or >C(COOC2H5)OH, and Z3 is >CH2; when Z2 is >C=O, Z3 may also be >C=O, >C=CHC6H5, >CBr2 or >C=NOH. The compounds are prepared by reacting an amine of the formula <FORM:0983134/C2/4> <FORM:0983134/C2/5> or <FORM:0983134/C2/6> wherein Z, Z1, Z2 and Z3 are as defined above, with an acyl peroxide in an inert solvent to form the corresponding acyl hydroxylamine, hydrolysing the acyl hydroxylamine with base in an alcohol-water mixture and in the absence of air to form the corresponding cyclic hydroxylamine, oxidising said hydroxylamine with air in the presence of a base and an inert solvent to form the corresponding cyclic nitroxide which is then recovered by evaporating the solvent. The intermediate hydroxylamine may be purified by conversion to its salt with a strong inorganic or organic acid followed by hydrolysis of the salt with a base. Examples are given. The compounds are stable free radicals and as such are useful as polymerization inhibitors, antiknock agents in fuels, antioxidants for rubber, traps for free radicals, and paramagnetic standards for electron spin resonance spectrometry. |
