Kangani, Mehrnoosh, Malek-Taher Maghsoodlou, and Nourallah Hazeri. Chinese Chemical Letters 27.1 (2016): 66-70.
Vitamin B12 was employed as an efficient catalyst for the one-pot, three-component synthesis of 3,4,5-trisubstituted furan-2(5H)-ones through the condensation of aldehydes, amines, and dialkylacetylendicarboxylates at ambient temperature in ethanol. Additionally, the synthesis of N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates was achieved using the same catalyst, under similar conditions, from the condensation of formaldehyde, amines, and dialkylacetylenedicarboxylates. This method offers several advantages, including the use of a green, nonhazardous catalyst, clean workup, short reaction times, high yields, and the absence of the need for column chromatography.
General Procedure for the Synthesis of 3,4,5-Trisubstituted Furan-2(5H)-ones
A mixture of amine 1 (1 mmol), dialkylacetylenedicarboxylate 2 (1 mmol), aromatic aldehyde 3 (1 mmol), and vitamin B12 (0.001 g) in ethanol (2 mL) was stirred at ambient temperature for the required reaction time. Upon completion, as monitored by TLC, water was added to the reaction mixture, resulting in the formation of a solid precipitate. The precipitate was then filtered and washed with ethanol (3 × 2 mL) to yield the pure product.
General Procedure for the Synthesis of N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates
A mixture of amine 5 (1 mmol) and dialkylacetylenedicarboxylate 6 (1 mmol) in ethanol (2 mL) was stirred for 25 minutes. Then, amine 7 (1 mmol), formaldehyde (37% solution, 1.5 mmol), and vitamin B12 (0.001 g) were added successively. The reaction mixture was stirred at ambient temperature for the required time. Upon completion, as monitored by TLC, water was added to induce the formation of a solid precipitate. The precipitate was filtered off and washed with ethanol (3 × 2 mL) to obtain the pure product.