Crystal structure of 2-hy-droxy-3-(prop-2-yn-1-yl)naphthalene-1,4-dione.

Isidório Raquel Geralda,Alves Ricardo José,Speziali Nivaldo Lúcio,Ottoni Flaviano Melo

doi:10.1107/s2056989018011647

Isidório Raquel Geralda, Alves Ricardo José + Show 2 more

Open Access

https://doi.org/10.1107/s2056989018011647

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Abstract

The naphtho-quinone unit of the title compound, C13H8O3, is essentially planar, with an r.m.s. deviation of 0.013 Å for the non-H atoms. The essentially linear propargyl group is tilted by ca 113° relative to the naphtho-quinone plane. In the crystal, mol-ecules are linked via a pair of O-H⋯O hydrogen bonds, forming an inversion dimer. The dimers are further linked via pairs of C-H⋯O hydrogen bonds into a tape structure along [20]. No π-π stacking is observed in the present case as it could be expected for naphtho-quinone derivatives.

Highlights

The naphthoquinone unit of the title compound, C13H8O3, is essentially planar, with an r.m.s. deviation of 0.013 Afor the non-H atoms
The essentially linear propargyl group is tilted by ca 113 relative to the naphthoquinone plane
No – stacking is observed in the present case as it could be expected for naphthoquinone derivatives

Summary

Chemical context

Lawsone (2-hydroxynaphtalene-1,4-dione), 1, shows promising in the synthesis of analogues of atovaquone, 2, an antimalarial drug (Nixon et al, 2013) used in immunosuppressed patients affected by pneumonia caused by Pneumocystis carinii (Cirioni et al, 1995; Comley et al, 1995). 2-hydroxy-3-(prop-2-yn-1-yl)naphthalene1,4-dione (3) was obtained in a two steps one-pot procedure by reacting 1 with propargyl iodide, prepared in situ from propargyl bromide and potassium iodide. It opens the possibility for the synthesis of triazoles at the C3 position of 1 by [2 + 3] alkyne–azide 1,3-dipolar cycloaddition enabling the preparation of 3-substituted lawsone derivatives with potential pharmacological activity, including atovaquone (2) analogues. When 1 was reacted with propargyl bromide and sodium carbonate in DMF the 2-O-propargyl derivative was obtained in 20% yield (Valenca et al, 2017). After evaluating the influence of organic and inorganic bases, protic and aprotic solvents, alkylating agents, temperature and reaction time, we obtained 3 in 28% yield. No product of O-alkylation was observed in the reaction mixture

Structural commentary

Database survey

Synthesis and crystallization

Supramolecular features

Findings

Refinement