Microwave Assisted Oxidation of Benzyl Halides to Aldehydes and Ketones with 4-Hydroxypyridinium Nitrate Functionalized Silica Gel in Aqueous Media.

Aldehydes and ketones, available by numerous methods and from plentiful starting materials, are vital classes of chemicals which serve as precursors and intermediates for the preparation of such divergent products as drugs, vitamins and fragrances.[1],[2] One of the methods for the synthesis of aldehydes and ketones is direct oxidation of organic halides.[3],[4] The oxidation of benzyl halides into aldehydes is a well-known transformation in organic synthesis, although the oxidation of aliphatic halides to aldehydes is not common and is more difficult than the oxidation of benzyl halides.[5],[6] Up to now, several methods have been developed for direct oxidation of halides to their corresponding carbonyl compounds. Recently NaOH-modified graphitic carbon nitride (g-C SB 3 sb N SB 4 sb ),[24] nano-Fe SB 3 sb O SB 4 sb @L-arginine-CD-Cu(II),[25] (NH SB 4 sb ) SB 3 sb [FeMo SB 6 sb O SB 18 sb (OH) SB 6 sb ] with O SB 2 sb [26] and amine-functionalized silica-coated iron-core nanoparticles[27] have been reported for the preparation of aldehydes and ketones from alkyl halides. Oxidation of benzyl halides with 4-hydroxypyridinium nitrate functionalized silica gel under microwave irradiation in aqueous media. [Extracted from the article]