“…It has been demonstrated that polyetherols with perhydro‐1,3,5‐triazine,1–3 1,3,5‐triazine,4–8 and purine9, 10 rings can be used as polyol components to obtain polyurethane foams with improved thermal stability. The foams with improved thermal stability can also be synthesized by the introduction of 1,3‐pyrimidine ring 11, 12. Polyetherols with 1,3‐pyrimidine ring have been obtained in reactions of 6‐aminouracil (6‐AU) with excess of oxiranes13 or alkylene carbonates 14, 15.…”