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Synlett 2005(7): 1164-1166  
DOI: 10.1055/s-2005-865199
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Novel and Convenient Synthesis of 3-(Polyhaloacyl)chromones Using Diethoxymethyl Acetate

Vyacheslav Ya. Sosnovskikh*, Roman A. Irgashev
Department of Chemistry, Ural State University, 620083 Ekaterinburg, Russian Federation
Fax: +7(343)2615978; e-Mail: Vyacheslav.Sosnovskikh@usu.ru;
Further Information

Publication History

Received 21 January 2005
Publication Date:
14 April 2005 (online)

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Abstract

The reaction of 2-hydroxy-2-(polyhaloalkyl)chroman-4-ones with diethoxymethyl acetate readily occurs at 140-150 °C for 15 minutes to give 3-(polyhaloacyl)chromones in good yields.

Key words

chroman-4-ones - diethoxymethyl acetate - formylation - 3-(polyhaloacyl)chromones

13

General Procedure for the Synthesis of Chromones 2.
A solution of chromanone 1 (1 mmol) in diethoxymethyl acetate (1.0 g, 6 mmol) was heated at 140-150 °C for 15-20 min. After cooling, the resulting mixture was diluted with hexane (3 mL). The solid product obtained on standing was collected by filtration, washed with hexane, and dried. Spectral and analytical data for selected products follows.
3-(Difluoroacetyl)-4 H -chromen-4-one(2a) and 3-(2,2-difluoro-1,1-dihydroxyethyl)-4 H -chromen-4-one ( 3a): IR (KBr): 3076, 1711, 1654, 1614, 1560 cm-1. 1H NMR (400 MHz, CDCl3/TMS): 2a (99%) δ = 6.97 (t, 1 H, CF2H, 2 J H,F = 53.3 Hz), 7.54 (t, 1 H, H-6, o J = 7.6 Hz), 7.57 (d, 1 H, H-8, o J = 8.4 Hz), 7.79 (ddd, 1 H, H-7, o J = 8.6, 7.2 Hz, m J = 1.6 Hz), 8.30 (dd, 1 H, H-5, o J = 8.0 Hz, m J = 1.6 Hz), 8.68 (s, 1 H, H-2); 3a (1%) δ = 5.47 (s, 2 H, 2 OH), 5.78 (t, 1 H, CF2H, 2 J H,F = 56.1 Hz), 8.35 (s, 1 H, H-2). 19F NMR (376 MHz, CDCl3/C6F6): 2a (98%) δ = 30.81 (d, HCF2, 2 J F,H = 53.3 Hz); 3a (2%) δ = 28.72 (d, HCF2, 2 J F,H = 56.1 Hz). 13C NMR (100 MHz, CDCl3): 2a δ = 109.03 (t, CF2, 1 J C,F = 247.6 Hz), 118.45, 120.25, 124.74, 126.50, 126.97, 135.10, 155.84, 162.85, 174.42, 186.51 (t, COCF2, 2 J C,F = 25.6 Hz). Anal. Calcd for C11H6F2O3: C, 58.94; H, 2.70. Found: C, 58.96; H, 2.67.
3-(Trifluoroacetyl)-4 H -chromen-4-one(2c) and 3-(2,2,2-trifluoro-1,1-dihydroxyethyl)-4 H -chromen-4-one ( 3c): 1H NMR (400 MHz, CDCl3/TMS): 2c (50%) δ = 7.50-7.58 (m, 2 H, H-6, H-8), 7.79 (ddd, 1 H, H-7, o J = 8.6, 7.0 Hz, m J = 1.7 Hz), 8.30 (dd, 1 H, H-5, o J = 8.0 Hz, m J = 1.7 Hz), 8.62 (s, 1 H, H-2); 3c (50%) δ = 6.06 (s, 2 H, 2 OH), 7.50-7.58 (m, 2 H, H-6, H-8), 7.78 (ddd, 1 H, H-7, o J = 8.6, 7.0 Hz, m J = 1.7 Hz), 8.26 (dd, 1 H, H-5, o J = 8.0 Hz, m J = 1.7 Hz), 8.40 (s, 1 H, H-2). 19F NMR (376 MHz, CDCl3/C6F6): 2c (50%) δ = 86.93 (s, CF3); 3c (50%) δ = 74.85 (s, CF3). Anal. Calcd for C11H5F3O3·0.25H2O: C, 53.56; H, 2.25. Found: C, 53.56; H, 2.29.
6-Methyl-3-(trifluoroacetyl)-4 H -chromen-4-one(2d) and 3-(2,2,2-trifluoro-1,1-dihydroxyethyl)-4 H -chromen-4-one ( 3d): IR (KBr): 3309, 3059, 1718, 1664, 1635, 1601, 1558 cm-1. 1H NMR (400 MHz, CDCl3/TMS): 2d (70%) δ = 2.49 (s, 3 H, Me), 7.44 (d, 1 H, H-8, o J = 8.6 Hz), 7.57 (ddq, 1 H, H-7, o J = 8.6 Hz, m J = 2.0 Hz, 4 J H,CH3 = 0.6 Hz), 8.07 (dq, 1 H, H-5, m J = 2.0 Hz, 4 J H,CH3 = 0.6 Hz), 8.59 (s, 1 H, H-2); 3d (30%) δ = 2.49 (s, 3 H, Me), 6.16 (s, 2 H, 2 OH), 7.45 (d, 1 H, H-8, o J = 8.6 Hz), 7.59 (ddq, 1 H, H-7, o J = 8.6 Hz, m J = 2.0 Hz, 4 J H,CH3 = 0.6 Hz), 8.02 (dq, 1H, H-5, m J = 2.0 Hz, 4 J H,CH3 = 0.6 Hz), 8.37 (s, 1 H, H-2). Anal. Calcd for C12H7F3O3: C, 56.26; H, 2.75. Found: C, 55.98; H, 2.78.
3-(2,2,3,3-Tetrafluoropropanoyl)-4 H -chromen-4-one(2g) and 3-(2,2,3,3-tetrafluoro-1,1-dihydroxypropyl)-4 H -chromen-4-one ( 3g): 1H NMR (400 MHz, CDCl3/TMS): 2g (94%) δ = 6.80 (tt, 1 H, CF2CF2H, 2 J H,F = 53.3 Hz, 3 J H,F = 5.8 Hz), 7.54 (ddd, 1 H, H-6, o J = 8.0, 7.2 Hz, m J = 1.0 Hz), 7.57 (ddd, 1 H, H-8, o J = 8.5 Hz, m J = 1.0 Hz, p J = 0.4 Hz), 7.79 (ddd, 1 H, H-7, o J = 8.6, 7.2 Hz, m J = 1.7 Hz), 8.27 (ddd, 1 H, H-5, o J = 8.0 Hz, m J = 1.7 Hz, p J = 0.4 Hz), 8.55 (s, 1 H, H-2); 3g (6%) δ = 6.28 (tt, 1 H, CF2CF2H, 2 J H,F = 53.2 Hz, 3 J H,F = 6.2 Hz), 6.31 (s, 2 H, 2 OH), 7.51 (ddd, 1 H, H-6, o J = 8.0, 7.2 Hz, m J = 1.0 Hz), 7.57 (dd, 1 H, H-8, o J = 8.5 Hz, m J = 1.0 Hz), 8.23 (dd, 1 H, H-5, o J = 8.0 Hz, m J = 1.7 Hz), 8.37 (s, 1 H, H-2). 19F NMR (376 MHz, CDCl3/C6F6): 2g (90%) δ = 24.06 (dt, HCF 2 CF2, 2 J H,F = 53.3 Hz, 3 J F,F = 7.3 Hz), 38.73 (td, HCF2 CF 2 , 3 J F,F = 7.3 Hz, 3 J F,H = 5.8 Hz); 3g (10%) δ = 25.39 (dt, HCF 2 CF2, 2 J F,H = 53.1 Hz, 3 J F,F = 7.7 Hz), 30.78 (q, HCF2 CF 2 , 3 J F,F = 3 J F,H = 7.0 Hz). 13C NMR (100 MHz, CDCl3): 2g δ = 109.07 (tt, CF2, 1 J C,F = 252.0 Hz, 2 J C,F = 30.5 Hz), 110.54 (tt, CF2, 1 J C,F = 262.1 Hz, 2 J C,F = 27.4 Hz), 118.40, 120.85, 124.61, 126.39, 127.03, 135.17, 155.69, 162.30 (t, C-2, 5 J C,F = 2.2 Hz), 173.69, 185.58 (t, COCF2, 2 J C,F = 29.3 Hz). Anal. Calcd for C12H6F4O3: C, 52.57; H, 2.21. Found: C, 52.46; H, 2.24.