4-Diethylamino-2-hydroxybenzaldehyde

Polymer-bound 5-(2-bromoacetyl)pyrroles were converted into benzofurylpyrrolylketones through the addition of o-hydroxybenzaldehydes under basic conditions. Several bases were tested for this purpose, for example potassium tert-butoxide, BEMP (2-tert-bu-tylimino-2-diethylamino-l,3-dimethyl-perhydro-l,3,2-diazaphosphorine), sodium ethox-ide, and DBU.The best results were obtained with BEMP in NMP at 60°C (Fig. 6.18), the products being cleaved from the resin with 20% TFA/CH2C12. 

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