Reactions of 3‐isopropyl‐, 3‐isopropenyl‐, and 3‐acetyltropolone methyl ethers with guanidines. Synthesis of 9H‐cyclohepta[d]pyrimidin‐9‐ones and cycloheptimidazoles

3-Isopropyl- and 3-isopropenyltropolone methyl ethers reacted with guanidine, 1-methylguanidine, and 1,1-dimethylguanidine to afford the corresponding 4-isopropyl- and 4-isopropenylcycloheptimidazoles 4a-f, respectively. The reactions of 3-acetyl-2-methoxytropones 2c-e with guanidines afforded 4-methyl-9H-cyclohepta[d]pyrimidin-9-ones 8a-i, while the reactions of 7-acetyl-2-methoxytropones 3c,d produced 4-acetylcycloheptimidazoles 4g-1. From these reactions, several minor products were also isolated.