Trimethyl 2-Hydroxy-2-(2-methoxy-2-oxoethyl)-4-(4-methylphenyl)-6-oxo-1,3,5-cyclohexanetricarboxylate

Edmont V. Stoyanov

Faculty of Pharmacy, Medical University of Sofia, Dunav 2, BG-1000 Sofia, Bulgaria
Tel.: (+359 2) 988 3142; Fax: (+359 2) 987 9874; E-mail: [email protected]

Received: 26 September 2002 / Accepted: 17 October 2002 / Published: 13 April 2003

Keywords: Michael addition, cyclohexanone, dimethyl acetonedicarboxylate, cyclization

Aromatic aldehydes react with dimethyl acetonedicarboxylate in molar ratio 1:2 with spontaneous intermolecular Michael addition to give polysubstituted cyclohexanones [1]. We report now the synthesis of an analogous product from 4-methylbenzaldehyde.

To a solution of 4-methylbenzaldehyde (1.20 g, 10 mmol) and dimethyl acetonedicarboxylate (3.48 g, 20 mmol) in 25 ml ethanol, 0.3 ml piperidine was added. The reaction mixture was left to stay at room temperature for 3 days. The separated crystals were filtered off, washed with cold ethanol, recrystallized from dioxane and air-dried. Yield: 3.18 g (71 %). 

Colorless crystals, m. p. 149-150 ºC (dec.) from dioxane.

¹H NMR (300 MHz, d₆-DMSO): 2.23 (s, 3H, PhCH₃), 2.43 (d, 1H, J=17.0 Hz, HCH), 2.96 (d, 1H, J=17.0 Hz, HCH), 3.44 (s, 3H, OCH₃), 3.52 (d, 1H, J=12.2 Hz, H-3), 3.56 (s, 3H, OCH₃), 3.60 (s, 3H, OCH₃), 3.66 (s, 3H, OCH₃), 3.94 (t, J1=J2=12.2 Hz, H-4), 4.38 (d, 1H, J=12.2 Hz, H-5), 4.67 (s, 1H, H-1), 5.40 (s, 1H, OH), 7.06 (d, 2H, J=8.0 Hz, 2' and 6'H arom.), 7.19 (d, 2H, J=8.0 Hz, 3' and 5'H arom.).

¹³C NMR (75 MHz, d₆-DMSO): 41.4, 42.8, 51.1, 51.5, 51.6, 51.7, 54.3, 61.2, 62.8, 66.3, 74.3, 128.1 (2xC), 128.9 (2xC), 136.2, 136.6 (2xC), 167.7, 168.2, 169.5, 169.8.

FT IR (KBr, cm^-1): 3511, 2953, 1729, 1516, 1495, 1364.

ESI MS [FIA in MeOH, CH₃COONH₄/CH₃COOK]: 468.2 [M+NH₄]⁺, 489.2 [M+K]⁺. 

Reference

1. Haensel, W.; Haller, R. Arch. Pharm. (Weinheim Ger.) 1970, 303, 334-338.

Sample Availability: Available from the authors and from MDPI. 

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