| 摘要 |
To prepare compound (I), a quaternising agent R<3>-X<⊖> is introduced into a solution, in an organic solvent or a mixture of organic solvents, of a compound of formula (III), at a temperature of 35 to 80° C., and the reaction is then allowed to continue at said temperature until compound (III) has disappeared completely or substantially completely, after which water is added and then an aqueous solution of compound (I) is separated and the water removed as necessary.R<1>=H or -CH3; R<2>=one of -CH3, -C2H5, -C3H7 and -C4H9; the two R<3 >are the same or different and each represents one of -CH3, -C2H5, -C3H7, -C4H9 and -CH2C6H5; and the two X<⊖> are the same or different and each represents Cl<⊖> or Br<⊖>. |
