3-Oxo-N-[4-[4-(-3oxobutanoylamino) phenoxy]phenyl]butanamide Gulten,  Gulten, S, SyntheticPages, 2011, 499
Benzaldehyde (Acros Organics)
Thiourea (Acros Organics)
37% HCl (Merck)

A mixture of 3-oxo-N-[4-[4-(-3oxobutanoylamino) phenoxy]phenyl]butanamide (300 mg, 0.814 mmol), thiourea (185 mg, 2.44 mmol), benzaldehyde (0.25 mL, 2.44 mmol) and catalytic amoun of conc. HCl (4 drops) in EtOH (10 mL) was refluxed overnight. After the completion of reaction, the reaction mixture was allowed to cool. The solid product formed was filtered, washed with water (5 mL) and cold ether (3x5 mL) to remove the unreacted thiourea or benzaldehyde or 3-oxo-N-[4-[4-(-3oxobutanoylamino) phenoxy]phenyl]butanamide and dried. The title compound was obtained as a light yellow solid (486 mg, 94% yield).

This reaction was carried out with catalytic amount of pTSA to give the corresponding bis Biginelli product in good yield.
This reaction was carried out by Nilüfer Hamarat in the  final year research project under my supervision.

IR-ATR:  3380, 3190,  2973, 2873, 1669, 1646, 1602, 1495, 1178, 828 cm^-1.
¹H NMR (400 MHz, DMSO-d₆): ppm = 2.07 (s, 6H, CH₃), 5.40 (s, 2H, CH) 6.90 (d, 4H, J= 8.9 Hz,  CH_Ar), 7.25-7.38 (m, 10H, CH_Ar), 7.5 (d, 4H, J= 8.9 Hz, CH_Ar), 9.42 (s, 2H, NH), 9.73 (s, 2H, NH), 9.98 (s, 2H, NH).
¹³C NMR (100 MHz, DMSO-d₆): ppm = 174.63, 165.22, 153.10, 143.53, 135.81, 134.91, 129.09, 128.16, 126.83, 121.79, 119.01, 107.70,  55.57, 16.96.

Vijay Virsodia, Raghuvir R.S. Pissurlenkar, Dinesh Manvar, Chintan Dholakia, Priti Adlakha, Anamik Shah, Evans C. Coutinho, Synthesis, screening for antitubercular activity and 3D-QSAR studies of substituted N-phenyl-6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydro-pyrimidine-5-carboxamides, European Journal of Medicinal Chemistry, 43, 2008, 2103-2115. doi:10.1016/j.ejmech.2007.08.004

B.R. Prashantha Kumar, Gopu Sankar, R.B. Nasir Baig, Srinivasan Chandrashekaran, Novel  Biginelli dihydropyrimidines with potential anticancer activity: A parallel synthesis and CoMSIA study, European Journal of Medicinal Chemistry, 44, 2009, 4192-4198. doi:10.1016/j.ejmech.2009.05.014