Synthetic reactions in polyethylene glycol. Diazotization and sandmeyer reactions of anilines in polyethylene glycol–methylene dichloride

Abstract

Diazotization and the Sandmeyer reactions of representative arylamines proceed smoothly in polyethylene glycol-CHzClz and have been found to be effective for the preparation of aryl halides and cyanides.Chemistry in cyclic polyethers (crown ethers) has attracted widespread interest because of the rather high selectivity of many reactions of activated anion species. The properties of polyethylene glycol (PEG) make it an excellent substitute for crown ethers in many reactions,lJ and its use as a co-solvent has been reported. We have now found that diazotization of arylamines and Sandmeyer substitution reactions of the resulting diazonium compounds take place with NaN02-HCl in PEG-CH2C1&4 and with Cu2X2, Cu-MX, or K2[ Cu( CN)4.NH3] in PEG-CH2C12 systems, respectively, providing the first example of the cyano substitution of diazonium salts using the isolated solid K2[Cu(CN)4.NH3] complex (Scheme 1).Ar-NH2 & Ar-Nl Y-5 Ar-X + other products (1) (2) (3) a; Ar = Ph b; Ar = p-PhCOC,H, c; Ar = or-naphthyl d; Ar = p-CIC,H, e; Ar = p-MeOC,H, f; Ar = o-MeOC,H, g; Ar = m-MeOC,H, h; Ar = p-PhGCC6H4 X = C1, Br, I, or CN Y = C1, Br, or I Scheme 1. Reagents: i, NaN0,-HY in PEG-CH,C& at 0 "C; ii, MX in PEG-CH2Cl2 at 0 "C to room temperature.

Diazotization–cyanation of aromatic amines with crosslinked poly(4‐vinylpyridine)‐supported cyanide ions

“…In general, aryl nitriles are synthesized from aryl halides and stoichiometric amounts of copper(I) cyanide (Rosemmund–von Braun reaction)15, 16 on an industrial scale via the amoxidation of the corresponding toluene and its derivatives17 or from aniline18 via diazotization and a subsequent Sandmeyer reaction. Nickel‐19–21 and palladium‐catalyzed22–27 methods have been developed as milder alternatives to the classical Rosemmund–von Braun nitrile synthesis, but these transition‐metal‐catalyzed reactions take several hours.…”

Tunable Redox Potential Photocatalyst: Aggregates of 2,3-Dicyanopyrazino Phenanthrene Derivatives for the Visible-Light-Induced α-Allylation of Amines

“…The synthesis of halogen-substituted 9,10-phenanthrenequinone was performed according to the reported literature. , …”

“…The synthesis of halogen-substituted 9,10-phenanthrenequinone was performed according to the reported literature. 27,28 2,7-Dibromo-9,10-phenanthrenequinone. To a solution of 9,10phenanthrenequinone (1.25 g, 6.0 mmol) in 98% sulfuric acid (40 mL) was added N-bromosuccinimide (2.14 g, 12 mmol), and the mixture was stirred at room temperature for 8 h. The reaction mixture was added to an ice−water bath and filtered to afford an orange solid with a quantitative yield.…”

Palladium‐catalyzed cyanation reaction of aryl halides using K4[Fe(CN)6] as non‐toxic source of cyanide under microwave irradiation

“…Most often aryl nitriles are prepared from aryl halides using stoichiometric amounts of CuCN by Rosenmund–Von Braun reaction 11. These compounds have been produced industrially via amoxidation of the corresponding toluene derivatives12 or from aniline via diazotization followed by Sandmeyer reaction 13, 14…”