| 摘要 |
<p>Stable concentrated solutions of basic dyestuffs of the formula <IMAGE> wherein R denotes the remaining part of a 5- or 6-membered heterocyclic ring, R1 denotes optionally substituted alkyl, alkenyl, cycloalkyl, aralkyl or aryl, R3 denotes alkyl and A denotes an aromatic or heterocyclic radical are prepared by reacting bases of the formula <IMAGE> with dialkyl sulphates of the formula (R3-O-)2SO2 in organic solvents which are completely or partially miscible with water and which do not react with the dialkyl sulphates or react with these more slowly than the dye bases.</p> |
