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Synlett 2011(11): 1573-1578  
DOI: 10.1055/s-0030-1260766
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Facile Synthesis of Spiropyrans from Chromene Hemiacetal Esters and Bifunctional Nucleophiles

Yan-Chao Wu*a,b, Hui-Jing Lia, Li Liua, Nicolas Demoulinb, Zhe Liua, Dong Wanga, Yong-Jun Chen*a
a Beijing National Laboratory for Molecular Science (BNLMS), CAS Key Laboratory for Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. of China
Fax: +86(10)62554449; e-Mail: ycwu@iccas.ac.cn; e-Mail: yjchen@iccas.ac.cn;
b Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif-sur-Yvette Cedex, France
Further Information

Publication History

Received 13 February 2011
Publication Date:
26 May 2011 (online)

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Abstract

Facile synthesis of several new kinds of spiropyrans has been accomplished through the condensation of chromene hemi­acetal esters with bifunctional nuclephiles, in which previously nonpractical amination and amidation processes help each other and all become practical processes of the corresponding tandem reactions.

Key words

spiropyran - tandem reaction - hemiacetal ester - chromene - bifunctional nucleophile

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CCDC 800884 contains the supplementary crystallographic data of spiropyran 3i for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.

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Synthetic Procedure for Spiropyrans 3
A solution of (1R,2R)-1,2-diphenylethane-1,2-diamine (1h, 42.5mg, 0.2 mmol) and hemiacetal esters 2a (67.7mg, 0.2 mmol) in CH2Cl2 (2 mL) was stirred at reflux for 3 d. The mixture was concentrated, and the residue was purified
by column chromatography over silica gel to afford 2H-chromene-piperazin-2-one spiropyran 3c (85.1 mg) in 85% yield as a single diastereomer. White solid; mp 136-137 ˚C. [α]D ²4 +101.27 (c 2.0, MeCO2Et). ¹H NMR (300 MHz, CDCl3): δ = 7.43-7.05 (m, 18 H), 5.95 (s, 2 H), 4.67 (s, 2 H), 2.98 (br s, 1 H), 1.18 (s, 9 H). ¹³C NMR (75 MHz, CDCl3): δ = 167.2, 148.1, 144.1, 138.0, 137.9, 137.8, 137.6, 129.0, 128.6, 128.5, 128.4, 128.4, 128.3, 128.2, 128.1, 127.7, 126.6, 123.3, 120.4, 120.2, 117.0, 86.9, 65.8, 58.6, 34.3, 31.4. FT-IR (KBr): 3350, 3033, 2361, 1693, 1489, 1245, 921, 700 cm-¹. Anal. Calcd for C34H32N2O2: C, 81.57; H, 6.44; N, 5.60. Found: C, 81.43; H, 6.67; N, 5.82.