1-Bromo-4-(methylsulphonyl)benzene → 6-chloro-N-(4-methylsulfonylphenyl)pyrazin-2-amine

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_1-bromo-4-(methylsulfonyl)benzene (1410 mg, 6.00 mmol)_ _then_ _cesium carbonate (2540 mg, 7.80 mmol)_ _ were successively added to a solution of __6-chloropyrazin-2-amine (777 mg, 6.00 mmol)_ _ _ _1,4-dioxane (20 ml)_ _into a microwave reactor._ _The mixture was purged by bubbling nitrogen for 5 minutes, then_ ___(9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine) (278 mg, 0.48 mmol)_ _and_ _diacetoxypalladium (53.9 mg, 0.24 mmol)_ _were added , the mixture was degassed by vacuum/nitrogen three times, then heated to _ _75 °C_ _in an heating block( internal temperature )for 1 hr then at_ _85 °C_ _ and finally at __90 °C_ _for 30 min_ _After cooling the mixture was diluted with ethylacetate , filtered , the solid washed with ethyl acetate, and the organic solution washed with water, pre-dried with brine and dried over MgSO4 , filtrated and concentrated in vacuo.The solid was taken up with ethylacetate ( 20 ml) stirred 15 min , and diluted with diethylether until some trouble occured; the solid was filtered and the procedure was repeated.The solid was dried under vacuum ( 1 mmHg/1 hr /50°C ) to afford 6-chloro-N-(4-(methylsulfonyl)phenyl)pyrazin-2-amine (1000 mg, 58.8%)_ _. The filtrate was concentrated and the above purification procedure was repeated three times to afford a second batch __6-chloro-N-(4-(methylsulfonyl)phenyl)pyrazin-2-amine (0.200 mg, 11.75 %) of the same purity . The 2 batches were combined to afford _ _6-chloro-N-(4-(methylsulfonyl)phenyl)pyrazin-2-amine (1200 mg, 70.5 %)_ _as a beige solid_

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