I am trying to react quercetin and poly(allylamine) to form imine on the repeating units. Poly(allylamine) is dissolved in water. The problem is the choice of solvent. Poly(allylamine) is soluble in water, lower alcohols, formamide, and ethylene glycol. Quercetin is insoluble in water, and soluble in DMF and DMSO. Quercetin also dissolves in lower alcohols, but very small amounts (approximately 2 mg in 1 mL). What solvent can I choose? Should I try reaction in heterogeneous phase? Or, it is known that DMF is miscible with methanol or ethanol, so should I try cosolvent of these?