The Preparation and Reactions of Benzoylnitrile Oxide from Dimethylphenacylsulfonium Bromide

Abstract

The nitrosation of dimethylphenacylsulfonium bromide (I) with sodium nitrite and hydrochloric acid in water gave 3,4-dibenzoyl-1,2,5-oxadiazole 2-oxide (II) in a 76% yield. The nitrosation of I in a similar manner in 1 : 1 dioxane-water afforded ω-chloro-ω-isonitrosoacetophenone (III) in an 80% yield. The treatment of III with triethylamine produced II through benzoylnitrile oxide (IX). 1,3-Dipolar cycloadditions of IX generated from III were conducted, using methyl methacrylate, styrene, acrylonitrile, and ethyl chloroformate as dipolarophiles, to yield the expected cycloadducts. The mechanisms of these reactions are discussed.

Synthesis of novel pyrazolo[3,4‐d]pyridazine, pyrido[1,2‐a]benzimidazole, pyrimido[1,2‐a]benzimidazole and triazolo[4,3‐a]pyrimidine derivatives

“…The hydrazonoyl halides 3a-g [9][10][11][12][13], hydroximoyl chlorides 10a-c [14][15][16], 4-acetyl-5-methyl-1-phenyl-1H-pyrazole (1) [17] and 1H-benzimidazol-2-ylacetonitrile (16) [18], were prepared according to procedures reported in the literature…”

Regioselective Synthesis of Some Novel Pyrazoles, Isoxazoles, Pyrazolo[3,4‐d]pyridazines and Isoxazolo[3,4‐d]pyridazines Pendant to Benzimidazole.

“…2-Acetyl-1-methyl-1H-benzimidazole (1) [16] hydrazonyl halides 3a-c [17] hydroximoyl chlorides 10a-c [18] were prepared according to the reported literature.…”

Heterocyclic synthesis via enaminones: Regioselective synthesis of some novel pyrazole, isoxazole, pyrimidine, pyrido[1,2-a]benzimidazole and pyrazolo[1,5-a]-pyrimidine derivatives

“…Hydrazonoyl halides 3a [12], 3b [13], 3c [14], and 3d [15], hydroximoyl chlorides 4b [16], 4c [17], and 4d [18], 2-acetylbenzothiazole (1) [19], 1H-2-benzimidazoleacetonitrile (17) [20], and 5-amino-3-phenylpyrazole (20) [21] were prepared according to procedures in the literature.…”