252723-16-3

35808-68-5

Synthesis of compound 18.3. A mixture of potassium tert-butoxide (450 mg, 4 mmol) and 7-benzenesulfonyl-4-chloro-6-methyl-7H-pyrrolo[2,3-d]pyrimidine (250 mg, 0.8 mmol) in tetrahydrofuran (7.5 mL) was stirred for 16 hours at room temperature. After completion of the reaction, saturated sodium bicarbonate solution was added to the reaction mixture. The reaction mixture was extracted with ethyl acetate (3 × 100 mL), the organic layers were combined, washed sequentially with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by fast column chromatography with petroleum ether/ethyl acetate (100/0 to 0/100, v/v) as eluent to afford 4-chloro-6-methyl-7H-pyrrolo[2,3-d]pyrimidine (Compound 18.3, 118 mg, 87% yield).1H NMR (200 MHz, DMSO-d6) δ 12.5 (br s, 1H) 8.47 (s, 1H), 6.29 (s, 1H), 2.42 (s, 3H). Mass spectrum (MS) m/z 168 [M + H]+.