Ultrasound-assisted rapid synthesis of 2-aminopyrimidine and barbituric acid derivatives

A practical and cost-effective approach to polysubstituted pyrimidine derivativesviaDBU mediated redox isomerization of propargyl alcohol and subsequent N–C–N fragment condensation

“…Guanidine hydrochloride is another well-known N–C–N coupling partner in pyrimidine synthesis and different approaches towards 2-amino pyrimidine derivatives are well documented in the literature. 28 To broaden the scope of our reaction, we planned to use guanidine hydrochloride as an N–C–N coupling partner under the standard reaction conditions to end up with 2-amino pyrimidine derivatives. Towards this end, our model compound 1a was allowed to react with guanidine hydrochloride 4 under the optimized reaction conditions and we were delighted to observe that the propargyl alcohol 1a was smoothly transformed into 2-amino pyrimidine derivatives 5a though with moderate yield (Scheme 3).…”

Ultrasound-assisted transition-metal-free catalysis: a sustainable route towards the synthesis of bioactive heterocycles

“…A straightforward and energy-efficient green protocol for the construction of various 2-amino substituted pyrimidines was disclosed by Güllü and co-workers in 2019 ( Scheme 32 ). 151 Under ultrasound irradiation, the treatment of different β-diketone compounds 115 with guanidine hydrochloride 116 using various base catalysts including Na 2 CO 3 , NaOH, and NaOEt in an aqueous medium was found to smoothly proceed at 60–70 °C to deliver the corresponding 2-aminopyrimidine derivatives 117 in 72–80% yield. The presence of various substituents on the β-diketone ring plays a crucial role in this reaction as well as in the yield of the products.…”

Synthetic Strategies of Pyrimidine-Based Scaffolds as Aurora Kinase and Polo-like Kinase Inhibitors

“…Additionally, the molar ratio of the respective substrate to base were determined, different ratios of base proportion versus 2-aminopyrimidine derivatives were evaluated and significantly better results were attained by using 1:1 equivalents. In the conventional synthesis of 2-aminopyrimidines, it is necessary to keep the temperature around 100 °C for about 5–8 h, whereas in the ultrasonic-assisted reactions temperature range of 60–70 °C is sufficient and the reaction time period is reduced to 30 min [ 38 ].…”