1,3-Dipolar Cycloaddition of Arylnitrile Oxides to Some Exocyclic Alkenes and Regioselective Synthesis of Spiro Isoxazolines

Synthesis of spiro-pyrazole-3,3′-thiopyrano[2,3-b]pyridines and azolo[a]pyrido[2′,3′:5,6]thiopyrano[3,4-d]pyrimidines as new ring systems with antifungal and antibacterial activities

“…Pyrazole derivatives have also exhibited diverse pharmacological properties [3]. In addition, many investigations concerning the synthesis of spiro heterocycles utilizing nitrilimines were discussed [4][5][6][7]. We have previously described several routes to fused polyheterocyclic ring systems [8][9][10], we here intend to report our results on the synthesis of the so far unreported 3-benzylidene-4oxothiopyrano [2,3-b]pyridines 2a,b and their 3-(N,Ndimethylamino)-methylene analog 3 as well as their applications in the synthesis of the novel spiro-pyrazolo-3,3'thiopyrano [2,3-b]pyridines 6a,b, 6H-2-phenylpyrazolo [1,5-a]pyrido [2',3':5,6]thiopyrano [3,4-d]pyridine (12) and 7H-pyrido[2",3":6',5']thiopyrano [4',3':4,5]pyrimido-[1,2-a]benzimidazole (14) as new ring systems.…”

Simple regioselective synthesis of spiro[2<I>H</I>-indene-2,3'-[3<I>H</I>]pyrazoles]

“…12,13 The stereo configuration of 3 (3'R, 4'S or its enantiomeric form) was established through nuclear Overhauser effect difference technique (nOe-difference) of 3h as a representative example. 1 H-NMR spectra of 3a-i exhibit the presence of singlet signals at (δ) = 4.91-5.27 assignable to the pyrazole H-4'.…”

“…The structure of 6 was established through IR, 1 H-NMR, 13 C-NMR as well as elemental analysis data. The structure of 6 was established through IR, 1 H-NMR, 13 C-NMR as well as elemental analysis data.…”

Synthesis of hydroxylated 3,5-diaryl-2-pyrazolines by the reaction of hydroxychalcones with hydrazines

“…Formation of 2-pyrazolines by the reaction of α,β-unsaturated ketones and hydrazines may take place under various reaction conditions using ethanol, 18 acetic acid [8][9][10]16,21,[25][26][27] or pyridine 28,29 as solvent. After some preliminary experiments, acetic acid was found to be a convenient solvent in our present case.…”