Table 1.

Reaction conditions and outcomes for the synthesis of halogenated pyrroles 2b–g.

Conditions	Product (Yield)
SOCl2 (1.2 equiv.), CH2Cl2, 0 °C to r.t., 18 h	R1 = H, R2 = Cl 2b (63%)
SOCl2 (5 equiv.), CH2Cl2, r.t., 4.5 d	R1 = R2 = Cl 2c (85%)
Br2 (1 equiv.), CH2Cl2, 0 °C to r.t., 10 min	R1 = H, R2 = Br 2d (45%)
Br2 (2 equiv.), AcOH, r.t. to 60 °C, 2 h	R1 = R2 = Br 2e (91%)
ICl (1 equiv.), CH2Cl2, r.t., 2 h	R1 = H, R2 = I 2f (64%)
Silver trifluoro acetate (2 equiv.), I2 (2 equiv.), CH2Cl2, r.t., 36 h	R1 = R2 = Br 2g (43%)