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Nickel chloride catalyzed Biginelli condensation; Allyl 4-(3-bromo-4-hydroxy-5-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

SyntheticPage 489
DOI: 10.1039/SP489
Submitted Mar 22, 2011, published Mar 25, 2011
Sirin Gülten (siringulten@hotmail.com)


			Reaction Scheme: Nickel chloride catalyzed Biginelli condensation

Chemicals Used

Allyl acetoacetate (Acros Organics)

5-bromovanillin (Aldrich)

urea (Merck)

nickel chloride hexahydrate (Merck)

37% HCl (Merck)

Procedure

A solution of allyl acetoacetate (2.5 mmol), 5-bromovanillin (2.5 mmol), urea (3.75 mmol), nickel chloride hexahydrate (0.62 mmol) and conc. HCl (2 drops) in EtOH (5 mL) were heated under reflux for 6h. After cooling to room temperature the reaction mixture was poured onto crushed ice (20 g) and stirred for 10 min. The crude product was filtered, washed with cold water (2x10 mL) and then recrystallized from ethanol afford white solid.  Yield (0.74 g, 75%).

Author's Comments

This reaction was carried out with allyl acetoacetate and thiourea to give the corresponding Biginelli product in good yield. The author thanks Çanakkale Onsekiz Mart University (BAP 2008/28) for financial support.

Data

White solid, Rf= 0.11 (50% ethyl acetate/hexane), m.p. 212-214 ºC.
IR-ATR: 3566, 3221, 3103, 2939, 1701, 1680, 1630, 1579 cm-11H NMR (400 MHz, DMSO-d6): ppm = 7.04 (1H, d, J= 1.69 Hz, Har), 6.76 (1H, d, J= 1.66 Hz, Har), 5.92 (1H, br s, NH), 5.81-5.88 (2H, m, CH2=CH), 5.5 (1H, br s, NH or OH), 5.46 (1H, br s, NH or OH), 5.35 (1H, d, J=2.55 Hz, CH2=CH ), 5.23 (1H, d, J=7.55 Hz, CH2=CH), 5.19 (1H, s, CHNH), 4.57-4.54 (1H, m, CH2O), 3.87 (3H, s, CH3O), 2.37 (3H, s, CH3). 13C NMR (100 MHz, DMSO-d6): ppm = 165.08, 152.58, 147.26, 146.57, 142.89, 136.31, 132.17, 122.81, 118.30, 108.50, 108.29, 100.96, 64.97, 56.37, 55.33, 19.00.

 

 


Lead Reference

J. Lu, Y.Bai, Synthesis 2002, 466-470 doi:10.1055/s-2002-20956

Other References

J. Lu, H. Ma, Synlett 2000, 63-64 doi:10.1055/s-2000-6469

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Keywords: addition, alcohols, alkenes, alkyl/alkenyl/aryl halides, aromatics/arenes, Biginelli reaction, dihydropyrimidine, elimination, esters, ethers, heterocyclic compounds, nickel chloride hexahydrate, nucleophilic, thermal

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