2,2-Dimethyl-2H-chromene-6-carbonitrile

Chemical Properties

Pale Yellow Crystalline Solid

Uses

6-Cyano-2,2-dimethyl-2H-benzo-[b]-pyran (cas# 33143-29-2) is a compound useful in organic synthesis.

Uses

2,2-Dimethyl-2H-1-benzopyran-6-carbonitrile (6-Cyano-2,2-dimethylchromene) may be used in the synthesis of 3,4-epoxy-6-cyano-2,2-dimethylchromene via epoxidation.

Synthesis Reference(s)

The Journal of Organic Chemistry, 37, p. 841, 1972 DOI: 10.1021/jo00971a006

General Description

2,2-Dimethyl-2H-1-benzopyran-6-carbonitrile (6-Cyano-2,2-dimethyl-2H-1-benzopyran) is a substituted 2,2-dimethyl-2H-1-benzopyran. It can be synthesized by the condensation reaction between 1,1-diethoxy-3-methyl-2-butene and 4-cyanophenol in the presence of pyridine.

Synthesis

General procedure for the synthesis of 2,2-dimethyl-6-cyano-2H coumarin from 4-((2-methylbut-3-yn-2-yl)oxy)benzonitrile: 4-((2-methylbut-3-yn-2-yl)oxy)benzonitrile (1.0 g, 5.40 mmol) was dissolved in ethylene glycol (5 mL/g of substrate), and the reaction mixture was heated to 210-215 °C,. maintained for 24 hours. After completion of the reaction, the mixture was cooled to room temperature and diluted with water. The mixture was extracted with ether (2 x 25 mL), the organic layers were combined, dried over anhydrous magnesium sulfate and filtered. The solvent was removed by concentration under reduced pressure to give a bright yellow solid. Recrystallization by petroleum ether gave 2,2-dimethyl-6-cyano-2H coumarin as a yellow powder (1.0 g, quantitative yield) with a melting point of 47-48 °C (literature value: 47 °C). IR spectrum (thin film method, cm^-1): 3054, 2985, 2226, 1605, 1487, 1421, 1369, 1265, 1212, 1148, 1128, 1107, 961, 896, 828, 739, 705. ^1H NMR (400MHz, CDCl3): δ 1.45 (s, 6H). 5.70 (d, 1H, J=11.6Hz), 6.28 (d, 1H, J=11.6Hz), 6.78 (d, 1H, J=8.4Hz), 7.24 (d, 1H, J=4.0Hz), 7.37 (dd, 1H, J=8.4Hz, 4.0Hz). ^13C NMR (100 MHz, CDCl3): δ 28.4, 77.9, 103.8, 117.2, 119.3, 120.6, 121.7, 130.1, 132.2, 133.3, 156.8.

References

[1] Tetrahedron, 2016, vol. 72, # 51, p. 8406 - 8416
[2] Organic Process Research and Development, 2001, vol. 5, # 6, p. 636 - 645
[3] Synthesis, 1995, # 6, p. 707 - 712
[4] Journal of Medicinal Chemistry, 1983, vol. 26, # 11, p. 1582 - 1589
[5] Chemical Communications, 2011, vol. 47, # 9, p. 2586 - 2588