A reactive solvent was obtained by reacting 1 mol of cyclohexanone with 5 mol of formaldehyde. The structure of the solvent was studied by using H-1-NMR and IR spectroscopy. It was used for solubilization of melamine and other heterocyclic compounds containing -NH- groups, such as adenine, carbazole, cytozine, guanine, thymine, and uracyl, as well as isocyanuric, barbituric, and uric acids. The solubilization involved the reaction of formaldehyde (liberated at an elevated temperature) with amino groups of the compound. Melamine was the compound with the best solubility in the reactive solvent. Preliminary attempts of curing the solutions have also been made. The oligomers cured at 120degreesC in the presence of acidic catalysts.