ChemicalBook CAS DataBase List Imidazole

Imidazole synthesis

11synthesis methods

Product Name:Imidazole
CAS Number:288-32-4
Molecular formula:C3H4N2
Molecular Weight:68.08

Imidazole is formed by reacting glyoxal with formaldehyde in the presence of ammonium acetate in acetic acid. The driving energy is microwave radiation. More generally, this reaction is used to produce substituted imidazoles.
synthesis of Imidazole

Although there had been discoveries of various derivatives of imidazole in 1840, it was first reported in 1858. The synthesis process of imidazole follows the reaction between formaldehyde in ammonia and glyoxal. This process gives low yield of imidazole but it is still used to form imidazole with C-substitution (Wolkenberg et al., 2004).

49761-82-2 Synthesis

49761-82-2
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288-32-4
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Yield:288-32-4 98%

Reaction Conditions:

with sodium tetrahydroborate in ethanol at 20; for 3.5 h;

Steps:

General procedure of the reaction of the substrates with NaBH4 in dry or 95% EtOH (Table 1)

General procedure: To a stirring solution of the organic substrate (1 mmol) in dry EtOH or 95% EtOH (3 mL), NaBH4 [57.0 mg, 1.5 eq, 1.5 mmol, (in case of compound 2, 114.0 mg, 3 eq, 3 mmol)] was added in small portions and the reaction mixture was left stirring at rt. The reaction was followed by TLC (or mass spectroscopy) and upon completion, it was quenched by the dropwise addition of a 3N solution of HCl at 0 °C, until gas production ceased (pH ~7). The organic solvent was evaporated in high vacuo and the residue was dissolved in CHCl3 (3 mL) and dried with Na2SO4. After evaporation of the solvent, the product was isolated and appropriately purified.Imidazole (13) was isolated as white solid. Mp 90-91 °C (mp25 89-91 °C); 1H NMR (CDCl3) δ 9.62 (br s, 1H, NH), 7.70 (s, 1H, NCHN), 7.11 (d, J 0.84 Hz, 2H, Ar-H); 13C NMR (CDCl3) δ 135.28, 121.92; MS (ESI) m/z (%), 69.25 (100) ([M+H]+).

References:

Gerokonstantis, Dimitrios-Triantafyllos;Apostolidi, Eugenia;Moutevelis-Minakakis, Panagiota [Arkivoc,2020,vol. 2020,# 8]

4238-71-5 Synthesis