Preparation of Heteroarenecarbonitriles by Reaction of Haloheteroarenes with Potassium Cyanide Catalyzed by Sodium p-Toluenesulfinate
摘要:
Several heteroarenecarbonitriles were prepared by reaction of haloheteroarenes with potassium cyanide catalyzed by sodium p-toluenesulfinate (1) or sodium methanesulfinate (2). In the reaction pathway, the cyanation proceeds through the formation of the sulfonylheteroarenes.
Studies on pyrazolo(3,4-d)pyrimidine derivatives. XVII. Reactions of 5-benzoyl-4,5-dihydro-6-methyl-1-phenyl-1H-pyrazolo(3,4-d)pyrimidine-4-carbonitrile (The 6-methylpyrazolopyrimidine Reissert compound).
Acid hydrolysis of the 6-methylpyrazolopyrimidine Reissert compound (6) gave the ring-opened product (12) and the oxazole (13). Alkaline hydrolysis of 6 afforded the 6-methylpyrazolopyrimidine (7) and benzoic acid (15). The anion (1) of 6 mainly underwent both aromatization and rearrangement, resulting in the formation of the 6-methylpyrazolopyrimidinecarbonitrile (20) and the 4-benzoyl-6-methylpyrazolopyrimidine (21) together with by-products such as 7, the dimer (22), the benzoate (23a), and O-benzoylbenzoin (24a). The anion I added to the carbonyl carbon of aromatic aldehydes (8a-c), giving the benzoates (23a-c) together with 7, the O-benzoylaroins (24a-c), and the O-benzoylcyanohydrins (27a, c).
The oxidative [3+2+1] annulation reaction of aldehydes, 5-aminopyrazoles, and nitriles is achieved under the oxidation of I2/O2, affording various valuable pyrazolo[3,4-d]pyrimidines in 27%–91% yields. The salient feature of this reaction is transition-metal free, operationally simple, broad substrate scope, good functional group tolerance, and gram-scalable. Remarkably, the corresponding products