The first examples of di- and cis triaryl-3a,4,5,6-tetrahydroimidazo[1,5-b]isoxazoles and their ring-opening reactions

Synthesis and Ring Opening Reactions of Tetrahydroimidazo[1,5- b ][1,2,4]oxadiazol-2(1 H )-thiones

“…Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. 7 We have shown the 1,3-dipolar cycloaddition reactions of cyclic nitrones 1 with dipolarophiles as arylisocyanates, 8,9 styrene, 10 DMAD, 11,12 and β-pinene 13 to proceed regio and in the case of chiral nitrones diastereoselectively. 1 1,3-Dipolar cycloadditions of nitrones with variety of dipolarophiles take an important place among the methods for the synthesis of five membered heterocyclic compounds.…”

“…A number of works either on cycloadditions or incorporating cycloadditions have appeared in recent years. An interesting feature of the adducts from isocyanate 14 and DMAD 11,12 and chiral nitrones 1 was their different behavior in the presence of secondary and tertiary amines. 1−4 Aryl and alkylisothiocyanates also act as dipolarophiles with respect to C N bond but in some cases the cycloaddition may occur at C S in the reaction with different nitrones.…”

“…1 1,3-Dipolar cycloadditions of nitrones with variety of dipolarophiles take an important place among the methods for the synthesis of five membered heterocyclic compounds. 11,12,14 Here we report on the reaction of cyclic nitrones 1 with twentyfold excess of the dipolarophile without solvent, to give a new class of tetrahydroimidazo [1,5-b] [1,2,4]oxadiazole-2(1H)-thiones 3. 4 Nitrones undergo cycloaddition to the C N double bond of phenylisothiocyanates to give corresponding oxadiazole-5-thiones, but in reactions with substituted phenylisothiocyanates and benzoylisothiocyanate the addition to the C S double bond predominates.…”

4‐Isoxazolines: Scaffolds for Organic Synthesis

“…[78,79] On the other hand, diastereoselective rearrangement of 199 in the presence of methoxide gives the tetrahydro-1H-pyrrolo[1,2-c]imidazole-6-olates 201. Acidic hydrolysis of these heterocycles followed by intramolecular transformylation affords the 2,5-dihydro-1H-pyrrole derivatives 203.…”

ZnO NPs: an efficient and reusable nanocatalyst for the synthesis of nitrones from DAG using H2O as a solvent at room-temperature

“…A number of reports have appeared on the chemistry of 1,3-dipolar species, with special emphasis on their cycloaddition reaction with multiple bonds [14]. The cycloadducts of di-and triarylimidazoline 3-oxides [15] with a variety of dipolarophiles [16][17][18][19][20][21] give interesting biologically active heterocyclic compounds. 1 The 1,3-dipolar cycloaddition of imidazolin 3-oxides was shown to proceed regio-and diasteroselectivity and interesting reactions of these adducts under various conditions such as the double cis elimination they undergo in the presence of dialkylamines was reported [22,23].…”