3,4-Diamino-2-bromopyridine synthesis

Yield: 63%

Reaction Conditions:

with thiophene;hydrogen;platinum on carbon in methanol;di-isopropyl ether at 25;Inert atmosphere;

Steps:

A13.a
MeOH (100 ml) was added to Pt/C 5 % (1 g) under N₂ atmosphere. Subsequently, a 0.4 % thiophene sol. in DIPE (2 ml) and 4-amino-2-bromo-3-nitro-pyridine (3.5 g, 16 mmol) were added. The r.m. was stirred at 25 ⁰C under H₂ atmosphere until 3 eq of H₂ was absorbed. The catalyst was filtered off over diatomaceous earth and the filtrate was concentrated in vacuo. Yield: 1.8 g of intermediate 22 (63 %), which was used as such in the next step.

References:

ORTHO-MCNEIL-JANSSEN PHARMACEUTICALS, INC;GIJSEN, Henricus, Jacobus, Maria;VELTER, Adriana, Ingrid;MACDONALD, Gregor, James;BISCHOFF, François, Paul;WU, Tongfei;VAN BRANDT, Sven, Franciscus, Anna;SURKYN, Michel;ZAJA, Mirko;PIETERS, Serge, Maria, Aloysius;BERTHELOT, Didier, Jean-Claude;DE CLEYN, Michel, Anna, Jozef;OEHLRICH, Daniel WO2010/89292, 2010, A1 Location in patent:Page/Page column 69