Phosphite-imidazole catalyzed N-formylation and N-acylation of amines

One-pot synthesis of N-sulfonylamidines from N-acylsulfonamides enabled by a metal triflate-mediated nonhydrolytic N-deacylation

A triflate salt-catalyzed nonhydrolytic method for the deacylation of N-acylsulfonamides and subsequent one-pot condensation of the newly formed sulfonamides with N,N-dimethylformamide dimethyl acetal to provide N-sulfonylamidines is presented. A range of aliphatic and aromatic N-acylsulfonamides bearing various N-acyl groups such as acetyl, propionyl, butyrl, isobutyryl, octanoyl, benzoyl, 2-phenylacetyl, and sterically hindered pivaloyl are readily transformed into the corresponding N-sulfonylamidines in good to excellent yields. A variety of functional groups including halogeno, keto, nitro, cyano, hydroxyl, ether, and carboxylic ester are tolerated intact.

K2S2O8-Mediated Denitrogenative Formal Transformylation of Amines with Formylhydrazine in Water

A new approach for direct formylation of various amines has been disclosed using a novel formylating agent, formylhydrazine, to afford N-formylamines in significant yields with application in the gram-scale synthesis of chlorothiazide. This transformylation (transfer of a formyl group from hydrazine to amines) occurs via denitrogenation in the presence of K2S2O8 as the exclusive reagent with water as the solvent. Two reaction pathways involving extremely underexplored formyl or hemiaminal radicals have been postulated, which require further investigation.

Direct additive-free N-formylation and N-acylation of anilines and synthesis of urea derivatives using green, efficient, and reusable deep eutectic solvent ([ChCl][ZnCl2]2)

In the current report, we introduce a simple, mild efficient and green protocol for N-formylation and N-acetylation of anilines using formamide, formic acid, and acetic acid as inexpensive, nontoxic, and easily available starting materials just with heating along stirring in [ChCl][ZnCl2]2 as a durable, reusable deep eutectic solvent (DES), which acts as a dual catalyst and solvent system to produce a wide range of formanilides and acetanilides. Also, a variety of unsymmetrical urea derivatives were synthesized by the reaction of phenyl isocyanate with a range of amine compounds using this benign DES in high to excellent yields. [ChCl][ZnCl2]2 showed good recycling and reusability up to four runs without considerable loss of its catalytic activity.