| In general, these newer drugs have been based on the structure of chlorin, purpurin, phthalocyanine or naphthalocyanine. |
| The purpurin, like some of the murices, when mutilated, exude a reddish-purple fluid. |
| The only dyes in this group which appear somewhat behind the rest in point of fastness are purpurin and alizarin maroon. |
| These chemists isolated two compounds which they named alizarin and purpurin. |
| Madder contains two closely allied colouring matters, namely, alizarin and purpurin. |
| Alizarin is the main colourant molecule, but the extract also contains a closely related compound called purpurin, which imparts an orange colour. |
