Thermal Rearrangement of 3-Hydroxy-1H,3H-quinoline-2,4-diones to 3-Acyloxy-2,3-dihydro-1H-indol-2-ones
摘要:
3-Alkyl/aryl-3-hydroxy-1H,3H-quinoline-2,4-diones (2) were transformed into isomeric 3-acyloxy-2,3-dihydro-1H-indol-2-ones (3) by thermally induced molecular rearrangement. All products were characterized by their H-1 NMR, C-13 NMR, and IR spectra.
4-Hydroxy-1H-quinolin-2-ones (1) react with thiocyanogen in acetic acid to the corresponding 3-thiocyanato-1H,3H-quinoline-2,4-diones (2) in good yields. In some cases, 3-bromo-1H,3H-quinoline-2,4-diones (4) were isolated as minor reaction products. Compounds 2 are very reactive towards nucleophiles and easily hydrolyze to the corresponding 4-hydroxy-1H-quinoline-2-ones (1).
4-Hydroxy-1 H -quinolin-2-ones(1)在乙酸中与硫氰酸根反应生成相应的3-thiocyanato-1 H,3 H -quinoline-2,4-diones(2),产率高。在某些情况下,3-溴1 H,3 H-喹啉-2,4-二酮(4)被分离为次要反应产物。化合物2对亲核试剂具有很高的反应性,并容易水解为相应的4-羟基-1 H-喹啉-2-酮(1)。
Novel Tandem Hydration/Cyclodehydration of α-Thiocyanatoketones to 2-Oxo-3-thiazolines. Application to Thiazolo[5,4-<i>c</i>]quinoline-2,4(3a<i>H</i>,5<i>H</i>)-dione Synthesis
Novel tandem hydration of alpha-thiocyanatoketones to thiocarbamates followed by in situ cyclodehydration to fused 2-oxo-3-thiazolines is described. The reaction is applied to the synthesis of [1,3]-thiazolo[5,4-c]quinoline-2,4(3aH,5H)-diones (4). Concentrated sulfuric acid was found to be critical for the reaction as both corresponding 2,3-dioxo-1,2,3,4-tetrahydroquinolin-3-yl thiocyanates (2) and S-(2,4-dioxo-1,2,3,4-tetrahydroquinolin-3-yl) thiocarbamates (3) rapidly hydrolyze in the presence of water to 4-hydroxyquinolin-2(1H)-ones (1).
Thermal Rearrangement of 3-Hydroxy-1H,3H-quinoline-2,4-diones to 3-Acyloxy-2,3-dihydro-1H-indol-2-ones
3-Alkyl/aryl-3-hydroxy-1H,3H-quinoline-2,4-diones (2) were transformed into isomeric 3-acyloxy-2,3-dihydro-1H-indol-2-ones (3) by thermally induced molecular rearrangement. All products were characterized by their H-1 NMR, C-13 NMR, and IR spectra.
Synthesis of Novel 3-Acyloxy-1,3-dihydro-2H-indol-2-ones and Isomeric 4-Acyl-1,4-dihydro-3,1-benzoxazin-2-ones: Double Rearrangement of 3-Hydroxyquinoline-2,4(1H,3H)-diones
3-dihydro-2H-indol-2-ones 4 and isomeric 4-acyl-1,4-dihydro-3,1-benzoxazin-2-ones 5. The influence of the substituents and the reaction conditions on the course of the reaction was studied. In the proposed mechanism a double rearrangement takes place; α-ketol rearrangement of 3, leading to α-hydroxy-β-diketone intermediate 8, is followed by a rearrangement to the isomeric α-ketol-esters 4 and 5.