Synthesis of Trans-4a,12b/3,4-Dihydrodibenzo[f,h]quinolin-2(1H)-Ones and Dibenzo[f,h]quinolin-2(1H)-Ones via Irradiation of 6-Biphenylpyridine-2(1H)-Ones

The synthesis of trans-4a,12b-dihydrodibenzo[fh]quinolin-2(1H)-ones (2), dibenzo[f,h]quinolin-2(1H)-ones (3) and 3,4-dihydrodibenzo [f,h] quinolin-2(1H)-ones (4) via photo-induced annulation of 6-( [1, 1'-biphenyl]-2-yl)pyridine-2(1H)-ones (1) under irradiation of a 313 nm UV light was described. Compounds 2 were obtained in 82-95% yields when the irradiation time was 3 h. Products 3 were obtained by irradiating 1 for 12 h in the presence of iodine. Heating the solutions of 2 in DMF at 130 degrees C for 24 h gave compounds 4 via a double 1,3-H shift. The demonstrated protocols showed the diversity of photo-induced cyclization of compounds 1.

Automated summary

The synthesis of three types of quinoline compounds, including trans-4a,12b-dihydrodibenzo[fh]quinolin-2(1H)-ones (2), dibenzo[f,h]quinolin-2(1H)-ones (3) and 3,4-dihydrodibenzo[f,h]quinolin-2(1H)-ones (4), was achieved through photo-induced annulation of 6-([1,1'-biphenyl]-2-yl)pyridine-2(1H)-ones (1) under 313 nm UV light. The highest yield reached 95%.