Diamidino Yellow

Keizer, K. Kuypers, H. G. J. M. Huisman, A. M. Dann, O. Diamidino yellow dihydrochloride (DY-2HC1) a new fluorescent retrograde neuronal... 

Preparation of 2-Hydroxy-4,4 -Diamidinostilbene Dihydrochloride 10 grams of 2-hydroxy-4,4 -dicyanostilbene were suspended in 250 cc of absolute ethyl alcohol and the mixture saturated with dry hydrogen chloride at 0°C. The whole was left for eight days at room temperature. The imino-ether hydrochloride formed was filtered off, washed with dry ether and dried in the air for a short time. It was then added to 250 cc of 10% ethyl alcoholic ammonia and the whole heated for 5 hours at 45°C. The 2-hydroxy-4,4 -diamidino-stilbene dihydrochloride which separated was crystallized from 10% hydrochloric acid. It forms pale yellow needles, MP 357°C (decomposition). 

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