Crystal structure and Hirshfeld surface analysis of 4-allyl-2-methoxy-6-nitrophenol

Abstract

The asymmetric unit of the title compound, C10H11NO4, which was synthesized via nitration reaction of eugenol (4-allyl-2-methoxyphenol) with a mixture of nitric acid and sulfuric acid, consists of three independent molecules of similar geometry. Each molecule displays an intramolecular hydrogen bond involving the hydroxide and the nitro group forming an S(6) motif. The crystal cohesion is ensured by intermolecular C—H...O hydrogen bonds in addition to π–π stacking interactions between the aromatic rings [centroid–centroid distances = 3.6583 (17)–4.0624 (16) Å]. The Hirshfeld surface analysis and the two-dimensional fingerprint plots show that H...H (39.6%), O...H/H...O (37.7%), C...H/H...C (12.5%) and C...C (4%) are the most important contributors towards the crystal packing.

Regioselectivity in the Nitration of Eugenol Is Independent of Inorganic Reagents: An Experimental and Theoretical Investigation with Synthetic and Mechanistic Implications

“…In this way, the presented data and the 1 H– 13 C HSQC, 1 H– 13 C HMBC, and 13 C NMR experiments (Figures S8, S12, and S13) made it possible to assign all signals to 6-nitroeugenol (Table ) and unequivocally confirm its structure. It is also noteworthy that according to the best of our knowledge, unlike what we observed, all the spectra presented in the literature show the 6-nitroeugenol hydroxyl signal as a singlet, regardless of the intensity of the magnetic field of the NMR equipment. ,,− …”

“…Table and Figure compare the 1 H NMR spectra for 5-nitroeugenol 2 and 6-nitroeugenol 3 . This study was necessary because there are significant discrepancies in the described NMR data for 5-nitroeugenol (at least three different chemical shift sets for 1 H and 13 C NMR in the literature), ,− , and for 6-nitroeugenol, there are described different multiplicities for the same 1 H NMR signals. ,,, For instance, the meta-coupling between aromatic hydrogens (H-3 and H-5) of 6-nitroeugenol 3 is not observed, in fair contrast with the result herein described. In addition, there are reports of straightforward nitration of eugenol whose NMR data to 5-nitroeugenol 2 and 6-nitroeugenol 3 are identical. − …”

“…According to the available protocols, 6-nitroeugenol 3 can be prepared by straightforward nitration of eugenol, ,− while for the 5-nitroeugenol synthesis, there are two approaches, the three-step route involving acetylation/nitration/solvolysis and the straightforward synthesis of 5-nitroeugenol 2 by nitration with Bi­(NO 3 ) 3 ·5H 2 O, Scheme . The latter is a scarce case of inorganic nitrating reagent reversed regioselectivity in the electrophilic aromatic substitution reaction, Scheme .…”

Synthesis, Antioxidant and Antituberculosis Evaluation of Eugenol Derivatives from Mannich Condensation

“…The ortho-substitution of eugenol seems simple and suitable way to introduce various functional groups of pharmacological interest. [24] Rajput et al [25] developed novel dihydroxy derivatives of eugenol (B) containing azomethine function, which have excellent anticancer effect on cell lines pancreatic cancer (MIAPaCa-2) and colon cancer (HCT-15). Mastelic et al [26] have achieved remarkable antioxidant properties through simple hydroxymethylation reactions on ortho position of eugenol.…”

“…Eugenol enters in the elaboration of many interesting bioactive compounds and co‐drugs. The ortho‐substitution of eugenol seems simple and suitable way to introduce various functional groups of pharmacological interest [24] . Rajput et al [25] .…”