Under nitrogen protection, 7H-pyrrolo[2,3-d]pyrimidine (6 g, 50.4 mmol) and hexamethylenetetetramine (10.59 g, 76 mmol) were dissolved in a mixed solvent of acetic acid (20.00 mL) and water (40 mL). The reaction mixture was heated to reflux temperature with continuous stirring for 8 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the solid product was collected by filtration. The solid was washed three times with ether to remove impurities. After drying, 5.6 g of 7H-pyrrolo[2,3-d]pyrimidine-5-carbaldehyde was obtained in 76% yield. The product was analyzed by ESI-MS (+) showing m/z 148.1 [M+H]+. 1H NMR (methanol-d4) data were as follows: δ 10.00 (s, 1H), 9.43 (s, 1H), 8.91 (s, 1H), 8.40 (s, 1H).
![7H-Pyrrolo[2,3-d]pyrimidine](/CAS/GIF/271-70-5.gif)
![7H-pyrrolo[2,3-d]pyriMidine-5-carbaldehyde](/CAS/GIF/1060815-89-5.gif)