Oxidative cyclization of 1-(pyridin-2-yl)guanidine derivatives: a synthesis of [1,2,4]triazolo[1,5-a]pyridin-2-amines and an unexpected synthesis of [1,2,4]triazolo[4,3-a]pyridin-3-amines

N-Halo Reagents: Modern Synthetic Approaches for Heterocyclic Synthesis

“…Oxidative cyclization of 1-(2-pyridyl)guanidine derivatives 287 with NCS in the presence of potassium carbonate was described by Ishimoto and co-workers. 131 The reactions are run in one-pot fashion via chlorination/cyclization process. Interestingly, not only [1,2,4] Yne-tethered ynamides 293 were found to undergo 5exo-dig oxidative cyclization in the presence of NIS in combination with DMSO to produce 1,5-dihydro-2H-pyrrol-2ones 294 and spiro-pyrrolones 296.…”

Synthesis of N‐Bridged 6,8‐Dinitrotriazolo[1,5‐a]pyridines

“…The first group (a) include oxidation or sometimes dehydration of pyridylamidines and their derivatives . Route (b) deals with condensation of 1,2‐diaminopyridines with carboxylic acid derivatives,, while route (c) represents the cycloaddition of pyridinium N‐imines with nitriles ,.…”

Izocianid alapú egyedényes módszerek kidolgozása

“…3-((2,4,4-trimetilpentán-2-il) Fenil-3-((2,4,4-trimetilpentán-2-il) 3-((2,4,4-trimetilpentán-2-il) 2-(3,4-Difluorfenil)-3-((2,4,4-trimetilpentán-2-il) Fluor-3-(trifluormetil)fenil)-3-((2,4,4-trimetilpentán-2-il) 2-(4-fluor-3-(trifluormetil) 2-(2,4,6-trimetoxifenil)-1H-imidazo[1,2-b 16,3, 30,0, 54,6, 65,1, 115,4, 122,8, 126,8, 126,9, 127,6, 128,4, 128,7, 128,9, 136,9, 137,8, 145,1; MS (ESI): 320,1 [M+H] + . 2-(1-Fenilprop-1-én-2-il)-3-((2,4,4-trimetilpentán-2-il) 16,7,28,9,31,3,31,7,55,3,58,6,65,0,115,4,122,5,126,7,126,9,127,8,128,4,128,9,129,3,136,9,137,7,145 Butil)-3-((2,4,4-trimetilpentán-2-il) Etil-6-metil-2-(1-fenilprop-1-én-2-il)-3-((...…”

“…NMR (500 MHz, DMSO-d6) δ 11,33 (s, 1H), 7,92 (s, 1H), 7,40 -7,34 (m, 4H), 7,28 -7,19 (m, 1H), 7,02 (s, 1H), 6,77 (bs, 1H), 4,15 (bs, 1H), 3,40 (bs, 1H), 2,29 (s, 3H), 1,11 (s, 9H); 13 C-NMR (126 MHz, DMSO-d6) δ 164,0,142,2,137,2,136,7,128,9,128,5,128,3,127,2,127,0, 126,6,121,9,93,8,54,5,30,0,16,7; MS (ESI): 338,2 [M+H] + .2-Ciklohexil-3-((2,4,4-trimetilpentán-2-il)amino)-1H-imidazo[1,2-b]pirazol-7karboxamid (286) 1 H-NMR (500 MHz, DMSO-d6) δ 11,15 (s, 1H), 7,81 (s, 1H), 6,96 (bs, 1H), 6,70 (bs, 1H), 3,75 (s, 1H), 2,71 (t, J = 12,2 Hz, 1H), 1,79 -1,68 (m, 4H), 1,67 -1,57 (m, 3H), 1,54 (s, 2H), 1,32 -1,19 (m, 3H), 1,12 (s, 6H), 1,00 (s, 9H); 13 C-NMR (126 MHz, DMSO-d6) δ 164,3, 140,8, 136,9, 130,1, 119,3, 93,6, 57,2, 55,1, 33,9, 31,7, 31,5, 31,3, 29,0, 26,4, 25,3; MS (ESI): 360,3 [M+H] + . 3-(terc-Butilamino)-2-heptil-1H-imidazo[1,2-b]pirazol-7-karboxamid (287) 1 H-NMR (500 MHz, DMSO-d6) δ 11,18 (s, 1H), 7,82 (s, 1H), 7,00 (bs, 1H), 6,69 (bs, 1H), 3,84 (bs, 1H), 1,60 (t, J = 7,7 Hz, 2H), 1,32 -1,18 (m, 10H), 1,09 (s, 9H), 0,88 -0,78 (m, 3H), 13 C-NMR (126 MHz, DMSO-d6) δ 164,4, 140,5, 137,2, 125,5, 120,7, 93,7, 53,6, 31,2, 30,1, 28,8, 28,6, 28,4, 24,2, 22,1, 14,0; MS (ESI): 320,3 [M+H] + .…”

“…H-NMR (500 MHz, DMSO-d6) δ (ppm): 0,98 (s, 9H), 1,10 (s, 6H), 1,27 (s, 3H), 1,58 (s, 2H), 2,26 (s, 3H), 2,39 (s, 3H), 3,97 (s, 1H), 4,20 (s, 2H), 6,92 (s, 1H), 7,26 (s, 1H), 7,38 (s, 4H), 11,28 (s, 1H); 13 C-NMR (126 MHz, DMSO-d6) δ (ppm):14,8,17,3,28,9,31,3,31,6,55,3,58,4,58,6,87,8,121,7, 126,5, 126,7,127,0,128,3,128,9,129,7,137,2,138,4,152,9,162,7; MS (ESI): 437,3 [M+H] + .…”