Novel base-catalyzed acylation of benzene diols with vinyl acetate: A Hirshfeld surface study

The present work describes the facile, fast, and economic base-catalyzed acylation of benzene diols with vinyl acetate. The Hirshfeld surface analysis of benzene-1,4-diol O,Oʹ-diacetate is also described. NaOH, KOH, and K2CO3 were the bases used for the catalyzation of the acylation of benzene-1,x-diols (x = 2, 3, 4) with vinyl acetate to obtain the corresponding O,Oʹ-diacetyl derivatives. The yields were quite good up to 99 % under solvent-free conditions. This method represents an alternative “green” process for the preparation of O-acetyl derivatives of hydroxyaryles. The benzene-1,4-diol O,Oʹ-diacetate crystal structure was obtained and described using the Hirshfeld surface analysis. A noticeable contribution of the C∙∙∙H contacts is shown (16.7 %), despite the insignificant area of the Hirshfeld surface occupied by the carbon atoms (9.4 %). By using 2D fingerprint plots, it was proved that C∙∙∙H contacts were due to the presence of π-stacking. The O∙∙∙H contacts (41.4 %) were the most numerous ones, relating mainly to the typical hydrogen bonds (de + di ≈ 2.6 Å). The high saturation of the C∙∙∙H and O∙∙∙H contacts [enrichment ratios (E) = 1.30 and 1.36 respectively]; despite their smaller contribution to the overall surface as compared to the H∙∙∙H contacts (E = 0.84); is shown. The novelty of this work is the development of a method; based on an inexpensive, safer, and easier-to-use catalyst (K2CO3). This method is fast with high yields. Besides, it may be used for the acylation at an industrial scale.