## 2 Results and Discussion
However, structure **3a** appears to be more likely based on the spectral data and similarities to the known behavior of \(\alpha\),\(\beta\)-unsaturated carbonyls toward amino pyrazole [31; 32; 33] in which the addition of ring nitrogen to the activated bond system is assumed to be the first step followed by the elimination of one water molecule, as depicted in Scheme 1, to afford the corresponding 7-(4-fluorophenyl)-5-(furan-2-yl)-2-phenyl-6,7-dihydropyprorazolo[1,5-al]pyrimidine (**3a**) in an almost quantitative yield. Furthermore, \({}^{1}\)H-\({}^{1}\)H NOESY 2D spectrum measurements for the isolated compound revealed the neighborhood of the methine proton and the ortho protons of the 4-fluoro phenyl group (Figure 3). The latter result excluded isomer **5a**. The structures of **3a** are in agreement with spectral data of the reaction product. For example, the IR spectrum of compound **3a** showed a C=N band at 1601 cm\({}^{-1}\). The \({}^{1}\)HNMR analysis of the same compound exhibited two dd signals at \(\delta\) 3.42 and 3.50 ppm due to Ha and Hb, respectively, and another dd signal at \(\delta\) 5.67 ppm due to the Hx proton in addition to a singlet signal at \(\delta\) 6.76 ppm corresponding to pyrazole H-3 and aromatic protons and furan protons as the multiplet at \(\delta\) 6.95-7.82 ppm. (_cf._ experimental part). Figure 3: Selected correlation observed in \({}^{1}\)H-\({}^{1}\)H NOESY 2D spectra. A range of aminopyrazole derivatives **2b,c** were tested under optimized conditions (Scheme 2) to determine the scope and generality of the suggested protocol. The obtained products **3b** and **3c** were in complete agreement with the spectroscopic data. For example, the IR spectrum of compound **3b** showed a C=N band at 1609 cm\({}^{-1}\) and two asymmetric bands at 3193 and 3271 cm\({}^{-1}\) due to the amino group. The \({}^{1}\)HNMR spectrum of the same compound exhibited two dd signals at \(\delta\) 3.99 and 4.18 ppm due to Ha and Hb, respectively, and another dd signal at \(\delta\) 5.58 ppm due to the Hx proton, and one singlet signal (D\({}_{2}\)O-exchangeable) assigned to NH\({}_{2}\) protons at \(\delta\) 6.36 in addition to aromatic protons andfuran protons as a multiplet at \(\delta\) 7.15-7.92 ppm. The applied protocol displayed excellent results (high yields and short reaction time) for both obtained compounds (_cf._ experimental part). Also, we extended our scope to include other nitrogen nucleophiles, such as 3-amino-1,2,4-triazole (**6**) and 2-amino benzimidazolazoles (**7**) under the same optimized reaction conditions (Scheme 3). However, in each case, only one isolable product was obtained with an excellent percentage yield and short reaction time (_cf._ experimental part). The formed product **7** was found in its oxidized form rather than its dihydro form, as proved by \({}^{1}\)H NMR. For example, the \({}^{1}\)H NMR spectrum of compound **7** revealed two singlet signals at 8 7.51 and 8.48 due to the pyrimidine proton CH-6 and triazole-CH-2, respectively, in addition to aromatic protons and furan protons as a multiplet at 8 7.19-8.25. This attitude for such an oxidation process proceeded predominantly for the case of using 3-amino-1,2,4-triazole with chalcone in a basic medium [34]. The structure of compound **9** was in line with obtained spectroscopic data in which the \({}^{1}\)H NMR spectrum exhibited two dd signals at 8 3.29 and 3.52 ppm due to Ha, Hb, respectively, alongside another dd signal at 8 5.60 ppm due to the Hx proton, two doublet signals at 8 5.19 and 6.69 due to the furan protons H-3, H-5, respectively, and aromatic protons and the furan proton H-4 as a multiplet at 8 6.72-7.77 ppm.