A Facile Procedure for Halodecarboxylation of Hydroxyaromatic Carboxylic Acids
Zhenbei Zhang∗
a
College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, 453002, P. R. of China
b
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, P. R. of China
,
Wenhui Sun
a
College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, 453002, P. R. of China
,
Zhishan Cao
c
College of Resources and Environment , Henan Institute of Science and Technology, Xinxiang, 453002, P. R. of China
,
Guisheng Zhang
b
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, P. R. of China
,
Olha Bakumenko∗
d
Department of Plant Protection, Sumy National Agrarian University, Sumy, 40021, Ukraine
,
Feng Xue∗
a
College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, 453002, P. R. of China
› InstitutsangabenThis work was supported by the Key Scientific and Technological Project of Henan Province (Nos. 222102310117 and 222102320259) and by a Postdoctoral Research Grant of Henan Province (No. 19030076).
An efficient approach is reported for the direct halodecarboxylation of hydroxyaromatic acids by using a readily available N-halosuccinimide (halo = Cl, Br) as the sole promoter in ethanol at room temperature without any other catalyst or additive. This environmentally friendly route tolerates a wide substrate scope with good to excellent yields under convenient conditions.
15Decarboxylative Halogenation of Hydroxybenzoic Acids; General Procedure
The appropriate hydroxyaromatic carboxylic acid 1 (0.2 mmol) and NXS (0.66 mmol) were stirred in 95% EtOH (2 mL) at r.t. for 24 h. The mixture was then concentrated in vacuum, and the crude product was purified by flash column chromatography [silica gel; PE–EtOAc (50:1)].
2,4,6-Tribromophenol (3a)16
White solid; yield: 60.9 mg (91%) from 1a; 56.2 mg (85%) from 1b; and 63.4 mg (96%) from 8; mp 92–94 °C; (Lit.16 95 °C). 1H NMR (400 MHz, CDCl3): δ = 7.58 (s, 2 H), 5.88 (s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 149.0, 134.3, 112.8, 110.5.
