One‐pot three‐component reaction; synthesis of new symmetrically bridge 4,4′‐(1,4‐phenylene)di‐pyrimidines under solvent free conditions

Abstract

The present article describes a facile one-pot synthesis of a new series of 4,4 0 -(1,4-phenylene)-dipyrimidines (6a-c and 10a, b) by the reaction of terephthalaldehyde (1), 2-acetylthiophene, and/or nitriles with Sbenzylthiouronium chloride 3a. And also, the di-pyrimidinones 13a-d were obtained by the reaction of different amidines 3a-d and ethyl cyanoacetate (11) with terephthalaldehyde (1) under solvent-free conditions in the existence of sodium hydroxide which is found to be a more efficient base for these reactions. The final products were characterized by spectral data and elemental analysis, IR, MS, 1 H, and 13 C NMR spectroscopy.

Recent advances in polyethylene glycol as a dual‐functional agent in heterocycle synthesis: Solvent and catalyst

“…(Scheme 2). 29 This is an example of many reactions, although several reported areas show that PEG has been an excellent phase transfer catalyst and a green solvent; the reaction listed above shows that choosing the solvent has little to do with the nature of the solvent and a lot to do with its compatibility of contents in the reaction mixture and reaction conditions. Thus, choosing a solvent must be done only after checking the affinity of the former with the reaction; after all, one solvent cannot be a solution for all solutions.…”

“…While PEG-400 may not universally catalyze every step in a stepwise synthesis, it can strategically stimulate specific reactions within the sequence. 29 This targeted approach minimizes the requirement for diverse catalysts throughout the process. PEG-400 often enables reactions to proceed efficiently at lower temperatures and pressure than traditional catalysts.…”

“…The visual depiction of the greener aspects of PEG is represented in Figure 1. While PEG‐400 may not universally catalyze every step in a stepwise synthesis, it can strategically stimulate specific reactions within the sequence 29 . This targeted approach minimizes the requirement for diverse catalysts throughout the process.…”