H. Nmr-)-° and V. =. , 300 MHz): ? = 204 (s, 1H); 13 C NMR (CDCl 3 , 75 MHz): ? = 17.1, 124, general procedure 2 in 91% yield (a final refinement on F 2 with 2861 unique intensities and 182 parameters converged at wR(F 2 ) = 0.1018 (R(F) = 0.0385) for 2416 observed reflections with I > 2?(I)). The data were deposited to the Cambridge Crystallographic Data Centre, pp.7562-7569, 1254.

C. Nmr-)-° and V. =. , P2 1 /n, a = 148516(17) Å, ? = 103319 g cm -3 , µ = 0.078 mm -1 (a final refinement on F 2 with 3105 unique intensities and 191 parameters converged at wR(F 2 ) = 0.1334 (R(F) = 0.0542) for 1796 observed reflections with I > 2?(I)). The data were deposited to the Cambridge Crystallographic Data Centre (CCDC 1034994). 40 5-Methyl-2-(2-naphthyl)quinoxaline (5'g) was similarly isolated in 5% yield (13 mg) as a pale yellow powder and identified unambiguously by X-ray diffraction); mp 154 °C. Crystal data for 5'g: C 19, a final refinement on F 2 with 3068 unique intensities and 191 parameters converged at wR(F 2 ) = 0.112 (R(F) = 0.0418) for 2388 observed reflections with I > 2?(I), pp.50771145079-1, 1361.

V. ). Mhz, 35 g cm -3 , µ = 0.088 mm -1 (a final refinement on F 2 with 4713 unique intensities and 292 parameters converged at wR(F 2 ) = 01677 (R(F) = 0.0778) for 1926 observed reflections with I > 2?(I)) The data were deposited to the Cambridge Crystallographic Data Centre (CCDC 901747) 40 8-Methyl-2-(2-thienyl)quinoxaline (5i) was prepared from 3-methyl-1,2-phenylenediamine (1b) and 2- thienyl glyoxal (2i) according to the general procedure 2 in 95% yield (0.22 g) as a pale yellow powder: R f 0.26 (CH 2 Cl 2 :pentane 9:1); mp 120 °C86-7.90 (m, 1H), 9.19 (s, 1H); 13 C NMR (CDCl 3 , 75 MHz): ? = 17368 g cm -3 , µ = 0.265 mm -1 (a final refinement on F 2 with 2496 unique intensities and 146 parameters converged at wR(F 2 ) = 0.1249 (R(F) = 0.0535) for 1579 observed reflections with I > 2?(I)). The data were deposited to the Cambridge Crystallographic Data Centre (CCDC 887678). 40 5-Methyl-2-(2-thienyl)quinoxaline (5'i) was similarly isolated in 5% yield (11 mg) as a pale yellow powder and identified unambiguously by Xray diffraction: R f 0.40 (CH 2 Cl 2 :pentane 9:1); mp 178- 180 °C. Crystal data for 5'i: C 13 H 10 N 2 S, M r = 226.29, monoclinic, P2 1 /c, a = 12 (a final refinement on F 2 with 2418 unique intensities and 146 parameters converged at wR(F 2 ) = 0.0936 (R(F) = 0.0352) for 2126 observed reflections with I > 2?(I)). The data were deposited to the Cambridge Crystallographic Data Centre (CCDC 887679)Nitrophenyl))pyrido[2,3-b]pyrazine (6j) was prepared from 2,3-diaminopyridine (1c) and 2- nitrophenyl glyoxal (2j) according to the general procedure 2 in 90% yield (0.23 g) as a pale yellow powder: mp 188 °C, MHz): ? = 2.81 (s, 3H), 7.18 (dd, 1H, J = 5.0 and 3.7), 7.51 (dd, 1H, J = 5.0 and 1.1), 7.52-7.58 (m, 2H), 7.83 (dd, 1H, J = 3.7 and 1.1)) °, V = 554a final refinement on F 2 with 2515 unique intensities and 172 parameters converged at wR(F 2 ) = 0.0987 (R(F) = 0.0390) for 2105 observed reflections with I > 2?(I)). The data were deposited to the Cambridge Crystallographic Data Centre, pp.1279006-9401296, 1099.

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