Synthesis of quinoxalin-2(1H)-ones^a.

Entry	1, R1, R2	4, R5	5, yielda (%)
1	1a, H, Bn	4a, i-Pr	5a, 78
2	1a, H, Bn	4a, i-Pr	5a, 81b
3	1b, Me, Bn	4a, i-Pr	5b, 57
4	1c, F, Bn	4a, i-Pr	5c, 61
5	1a, H, Bn	4b, n-Pr	5d, 71
6	1b, Me, Bn	4b, n-Pr	5e, 55
7	1c, F, Bn	4b, n-Pr	5f, 57
8	1a, H, Bn	4c, n-Bu	5g, 55
9	1b, Me, Bn	4c, n-Bu	5h, 56
10	1c, F, Bn	4c, n-Bu	5i, 57
11	1a, H, Bn	4d, Cy	5j, 71
12	1b, Me, Bn	4d, Cy	5k, 55
13	1c, F, Bn	4d, Cy	5l, 51
14	1d, H, Me	4a, i-Pr	5m, 71
15	1e, Me, Me	4a, i-Pr	5n, 52
16	1f, F, Me	4a, i-Pr	5o, 56
17	1d, H, Me	4b, n-Pr	5p, 67
18	1e, Me, Me	4b, n-Pr	5q, 65
19	1f, F, Me	4b, n-Pr	5r, 71
20	1d, H, Me	4c, n-Bu	5s, 66
21	1e, Me, Me	4c, n-Bu	5t, 61
22	1f, F, Me	4c, n-Bu	5u, 63
23	1d, H, Me	4d, Cy	5v, 53
24	1e, Me, Me	4d, Cy	5w, 54
25	1f, F, Me	4d, Cy	5x, 51

^aReaction conditions: a mixture of 1 (0.6 mmol), 4 (0.6 mmol) and CF₃COOH (0.6 mmol) in MeCN (2.0 mmol) while stirring in open flask at room temperature.

^bN₂ balloon (1.0 atm).