329358-19-2Relevant articles and documents
1,3-Dipolar cycloadditions to (5Z)-1-Acyl-5-(cyanomethylidene)-imidazolidine-2,4-diones: Synthesis and transformations of spirohydantoin derivatives
Groselj,Drobnic,Recnik,Svete,Stanovnik,Golobic,Lah,Leban,Meden,Golic-Grdadolnik
, p. 3403 - 3417 (2001)
Cycloadditions of various 1,3-dipoles to (5Z)-1-acyl-5-(cyanomethylidene)-3-methylimidazolidine-2,4-diones 8 or 9, prepared in 3 steps from hydantoin (1) (Schemes 1 and 2), were studied. In all cases, reactions proceeded regio- and stereoselectively. The type of product depended on the 1,3-dipole and/or dipolarophile employed as well as on reaction conditions. Thus, with stable dipoles under neutral conditions, spirohydantoin derivatives 12-16 were obtained (Scheme 2), while under basic or acidic conditions, pyrazole- or isoxazole-5-carboxamides 18 and 23-26 and carboxylate 27 were formed via aromatization of the newly formed dihydroazole ring, followed by the simultaneous cleavage of the hydantoin ring (Schemes 3-5).
