Conversion of Some 2(3H)‐Furanones into Pyrrolinotriazine and Oxazolopyrimidine Derivatives

2(3H)‐Furanones 1 were utilized for the construction of pyrrolinotriazine and oxazolopyrimidine derivatives 4 and 9 . Thus, 1 reacted with glycine in ethanol at 70°C to give the acids 2 , which were cyclized into the pyrrolin‐5‐one derivatives 3 by the action of HCl/AcOH. The later compounds 3 were also obtained by refluxing the furanones 1 with glycine in glacial AcOH for 10 h. The carboxy functionality in 3 was used for the construction of a triazinone ring by treatment with thionyl chloride followed by refluxing the acid chloride with hydrazine in ethanol. The conversion of the furanones 1 into the oxazolopyrimidine derivatives 9 involved the following steps: (i) ring opening of the lactone ring with hydrazine hydrate to give the acid hydrazides 5 , (ii) conversion of the hydrazides 5 into the corresponding acyl azides 6 by action of NaNO2/AcOH, (iv) base‐catalyzed decomposition of the azides in the presence of glycine, (v) ring closure of the urea derivatives 7 into the pyrimidine derivatives 8 , and finally (vi) condensing 8 with benzaldehyde in the presence of NaOAc/AcOH mixture.