合成路线1

The 2-phenylpyridine-3-amine (V), an intermediate in the synthesis of 235944, has been obtained with better yields by three related ways: 1. The acylation of 2-chloropyridine-3-amine (I) with Ac2O and TEA in dichloromethane gives the corresponding acetamide (II), which is condensed with phenylboronic acid (III) by means of Pd(PPh3)4 and Na2CO3 in ethanol/toluene, yielding N-(2-phenylpyridin-3-yl)acetamide (IV). Finally, this compound is hydrolyzed with HCl in methanol to afford the target 2-phenylpyridine-3-amine (V) intermediate. 2. The condensation of 2-chloropyridine-3-amine (I) with benzaldehyde (VI) in refluxing toluene gives the corresponding imine (VII), which is condensed with phenylboronic acid (III) as before to yield the 2-phenylpyridine derivative (VIII). Finally, the imino group of (VIII) is hydrolyzed with aqueous HCl to afford the target intermediate (V). 3. The one-pot condensation of 2-chloropyridine-3-amine (I), boronic acid (III) and benzaldehyde (VI) by means of Pd(PPh3)2Cl2 and Na2CO3 in hot toluene gives the already reported 2-phenylpyridine derivative (VIII), which is hydrolyzed as before to afford the target intermediate (V).