Novel Photoinduced Electorn Transfer-Initiated Cyclization of 1,2,4-Triazole-Substituted α-Dehydronaphthylalaninamides in the Presence of Triethylamine
摘要:
The irradiation of the title compounds [(Z)-1] in nitrogen-saturated methanol containing triethylamine (TEA) at room temperature was found to quantitatively afford 2(1H)-benzo/[f]quinolinone (2) and 3,4-dihydro-3-(3-methyl-5-substituted 1,2,4-triazol-4-yl)-2(1H)-benzo[f]quinolinone (3) derivatives, which were described as being formed via electron transfer from TEA to the excited-state (E)-1. Analysis of solvent and substituent effects on the composition ratio of 2 to 3 confirmed that this ratio is increased from 0.2 to 9.0 with an increase in the proton-donating ability and polarity of solvent as well as in the electron-withdrawing ability of substituent bonded to the triazole ring.
Novel Photoinduced Electorn Transfer-Initiated Cyclization of 1,2,4-Triazole-Substituted α-Dehydronaphthylalaninamides in the Presence of Triethylamine
摘要:
The irradiation of the title compounds [(Z)-1] in nitrogen-saturated methanol containing triethylamine (TEA) at room temperature was found to quantitatively afford 2(1H)-benzo/[f]quinolinone (2) and 3,4-dihydro-3-(3-methyl-5-substituted 1,2,4-triazol-4-yl)-2(1H)-benzo[f]quinolinone (3) derivatives, which were described as being formed via electron transfer from TEA to the excited-state (E)-1. Analysis of solvent and substituent effects on the composition ratio of 2 to 3 confirmed that this ratio is increased from 0.2 to 9.0 with an increase in the proton-donating ability and polarity of solvent as well as in the electron-withdrawing ability of substituent bonded to the triazole ring.
Substituent Effects on the Electron Transfer-Initiated Photochemical Transformation of 1,2,4-Triazole-Substituted α-Dehydroarylalaninamides into 2(1H)-Quinolinone Derivatives
An investigation was undertaken to elucidate substituent effects on the photoreactivity of 1,2,4-triazole-substituted alpha-dehydroarylalaninamides [(Z)-1] as well as on the selectivity of 2(1H)-quinolinone derivatives (2) from a synthetic point of view. It was found that photoinduced electron transfer-initiated cyclization of (Z)-1 bearing a meta-substituted phenyl or a 4-substituted naphthalen-1-yl group in methanol proceeds with a moderate to good efficiency affording the corresponding product 2 in a selectivity ranging from 33 to 100%.
Novel Photoinduced Electorn Transfer-Initiated Cyclization of 1,2,4-Triazole-Substituted α-Dehydronaphthylalaninamides in the Presence of Triethylamine
The irradiation of the title compounds [(Z)-1] in nitrogen-saturated methanol containing triethylamine (TEA) at room temperature was found to quantitatively afford 2(1H)-benzo/[f]quinolinone (2) and 3,4-dihydro-3-(3-methyl-5-substituted 1,2,4-triazol-4-yl)-2(1H)-benzo[f]quinolinone (3) derivatives, which were described as being formed via electron transfer from TEA to the excited-state (E)-1. Analysis of solvent and substituent effects on the composition ratio of 2 to 3 confirmed that this ratio is increased from 0.2 to 9.0 with an increase in the proton-donating ability and polarity of solvent as well as in the electron-withdrawing ability of substituent bonded to the triazole ring.