N.[Na].[C:3]1([P:9](C2C=CC=CC=2)[C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.Br[C:23]1[N:28]=[C:27]([NH2:29])[CH:26]=[CH:25][CH:24]=1>C1(C)C=CC=CC=1>[C:10]1([P:9]([C:3]2[CH:4]=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:23]2[N:28]=[C:27]([NH2:29])[CH:26]=[CH:25][CH:24]=2)[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1At −78° C., 200 ml of ammonia were condensed in and 5.00 g of sodium (216.8 mmol) were dissolved therein within 5 min. The resulting dark blue solution was admixed with 11.70 g of triphenylphosphine (108.4 mmol) in portions, stirred at −78° C. for approx. 2 h and then admixed with 15.00 g (86.7 mmol) of 6-bromo-2-aminopyridine from example 14.1. After 250 ml of toluene had been added, the cold bath was removed and the ammonia evaporated off overnight. The residue was hydrolyzed with 150 ml of dist. H2O and admixed with 150 ml of saturated NaCl solution, the resulting phases were separated and the aqueous phase was extracted once with 200 ml of toluene. The combined organic phases were dried over MgSO4 and concentrated under reduced pressure. The product was purified by column chromatography (first with dichloromethane to remove diphenylphosphine, then with 9:1 dichloromethane/ethyl acetate). Resulting mixed fractions were purified by sublimation at 180° C. and 10−2 mbar. 14.26 g (51.2 mmol, 59%) of 6-(diphenylphosphino)-2-aminopyridine were obtained as a white solid.
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