Reaction of 3‐Hydroxyquinoline‐2,4‐diones with Isocyanates and Thermally Induced Transformation of the Reaction Products

Abstract

3-Hydroxyquinoline-2,4-diones 1 react with isocyanates to give novel 1,2,3,4-tetrahydro-2,4-dioxoquinolin-3-yl (alkyl/aryl)carbamates 2 and/or 1,9b-dihydro-9b-hydroxyoxazolo[5,4-c]quinoline-2,4(3aH,5H)-diones 3. Both of these compounds are converted, by boiling in cyclohexylbenzene solution in the presence of Ph 3 P or 4-(dimethylamino)pyridine, to give 3-(acyloxy)-1,3-dihydro-2H-indol-2-ones 8. All compounds were characterized by IR, and 1 H-and 13 C-NMR spectroscopy, as well as by EI mass spectrometry.

Base‐Stabilized Gallium Sulfides and Selenides Supported by a Bis(oxazolinyl)(phenyl)methanide Ligand

“…Inspired by trapping of (NacNac)Ga=S with PhNCS by [2 + 2] cycloaddition, [13] 6 b and 7 b were treated with PhNCO (Scheme 4). Mixing 6 b or 7 b with an excess amount of PhNCO immediately resulted in the formation of the corresponding [2 + 2] cycloadducts 9 or 10 along with 1,3,5-triphenylisocyanurate, which presumably formed by a Lewis base-catalyzed trimerization of PhNCO, [14]…”