5-chloro-2,8,9-triazabicyclo[4.3.0]nona-1,3,5,7-tetraene

Used as an intermediate in organic synthesis.

4-chloro-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine (1.506 g, 5.502 mmol) was dissolved in neat TFA (8.478 ml, 110.0 mmol) and the reaction mixture was stirred at 75°C for 2 hours. The reaction mixture was concentrated to a dark yellow oil and MeOH was added to give a thick white precipitate that was filtered and washed with MeOH. The filtrate, which contained the desired product, was concentrated to a yellow oil that was dried in vacuo overnight to yield a yellow waxy solid. The crude solid was partitioned between EtOAc and saturated NaHCO3. The phases were separated, and the aqueous layer was re-extracted with EtOAc (1x). The combined organic phases were dried over Na2SO4, filtered and concentrated to yield the desired product 5-chloro-2,8,9-triazabicyclo[4.3.0]nona-1,3,5,7-tetraene(0.845 g, 100%) as a yellow solid. LRMS (APCI pos) m/e 154, 156 (M+, Cl pattern).