2-Iodopyrimidine

The coupling of two azinyl halides, in the presence of an appropriate electron source, also leads to the formation of diaryl compounds. 2-Iodopyrimidine and its derivatives were converted into the symmetrical 2,2 -bipyrimidines (7.88.) using activated copper. This method was found to give superior results,111 compared to the earlier reported nickel chloride-zinc system.112... 

Couplings in 5-bromo-2-chloropyrimidine would be expected to proceed preferentially in the 5-bromo position (Scheme 75). This order of preference has been changed by an initial exchange of the chloro with an iodo substituent. The prodnct from the halogen exchange, 5-bromo-2-iodopyrimidine, is selectively conpled in the 2-position with a wide... 

Iodopyrimidine (66, 15.00 g, 72.8 mmol) and activated copper powder (17.50 g, 275 mmol, 3.98 eq.) were placed in a 250 ml double-necked flask fitted with a reflux condenser, a N2 inlet, and a magnetic stirrer. Absolute DMF (60 ml) was added, and the flask was flushed with N2 for 10 min. The reaction mixture was heated to 80 °C with vigorous stirring at the temperature kept between 80 and 85 °C. After 3.5 h, activated copper powder (4.00 g, 63.0 mmol) was added to the mixture, and the N2 inlet was replaced with a calcium chloride tube. After another 3.5 h, the temperature was increased to 120-130 C and the stirring was continued for 2 h. The suspension was then cooled to 0 C, carefully drowned into a solution of potassium cyanide (23.00 g) in 115 ml of 25% aqueous solution of ammonia, and filtered. The solid residue was... 

---