1,3,5‐Triazapenta‐1,3‐dienes: Useful Building Blocks for the Synthesis of1,2‐Dihydro‐1,3,5‐triazines and Oligonitriles

Abstract

Keywords: 1,3,5-Triazapenta-1,3-dienes / Tautomerism / Triazines / Oligonitriles / DFT calculations 1,3,5-Triazapentadienes 1, prepared from amidines and imidoyl chlorides 2, have been used as nucleophilic building blocks for the reactions with various electrophilic reagents. With aldehydes 4 1,2-dihydrotriazines 3 were obtained, whereas ketones 5 gave 3 or 1,3,5-triazahexa-1,3,5-trienes 6, depending on the substitution pattern of 1. Acyl chlorides 7 reacted with 1 to give 1-oxa-3,5,7-triazahepta-1,3,5-trienes 8; in a similar manner imidoyl chlorides 2 gave rise to the formation of the new 1,3,5,7-tetraazahepta-1,3,5-trienes 9. Treatment of N-benzoylbenzimidoyl chloride 10 with 1 afforded the 1-oxa-3,5,7,9-tetraazanona-1,3,5,7-tetraenes 11, or, depending on the substitution pattern, their ring-tautomeric compounds 12 with 1,2-dihydrotriazine structures.

Fluorescent benzene-centered mono-, bis- and tris-triazapentadiene–boron complexes

“…Mono-triazapentadiene ligands 6a,b: the synthesis of the hitherto unknown secondary triazapentadiene ligand 6a, which bears two hydrogen atoms at the terminal nitrogen atom, was achieved by following a procedure developed by Heße et al,4,5 whereas the novel tertiary triazapentadiene ligand 6b (with one hydrogen atom at the terminal nitrogen atom) was synthesized by adapting a procedure of Häger et al…”

“…Although 1,3,5-triazapentadienes are known since 1907, [1][2][3][4] relatively little is known about their coordination chemistry compared to their carbon analogues β-diimine-and the wellknown β-diketone ligands (Scheme 1).…”

PdII‐Promoted Single‐Pot Template Transformations of Benzonitriles, Cyanoguanidine and Sodium Dicyanamide with the Formation of Symmetrical and Asymmetrical (1,3,5‐Triazapentadienate)palladium(II) Complexes

“…phenyls, and can be synthesized by the reaction of primary amines, RNH 2 , with the fluorinated imine C 3 F 7 -CF=N-C 4 F 9 [6] or by the Ley and Muller method [23] where amidine is treated with an N-imidoyl chloride. [3][4][5]12] Another route to tap-Pd complexes involves template transformations of cyanopyridines [10,16] through lithium amidinate, which is produced in situ from LiN(SiMe 3 ) 2 [10] or via an oxime-mediated process. [16] In the latter case, the synthesized complexes were shown [16] to display catalytic activity towards Suzuki-Miyaura and Heck cross-coupling reactions.…”

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These compounds are triaza isoelectronic analogues of the well known and widely used O,O-β-diketonates R-C(=O)-CH-C(=O)-R, and usually coordinate to a metal ion as chelating N,Nbidentate ligands, forming stable complexes with a square planar core. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] On the other hand, it was noted [9] that these ligands resemble bis(pyrazolyl)borates, another important class of ligands. Thus, tap can also potentially impact areas in which O,O-β-diketonates or bis(pyrazolyl)borates find application, such as in organic synthesis, catalysis, the preparation of optical recording materials, enzyme inhibition, analytical chemistry, etc.…”

Synthesis of Secondary, Tertiary and Quaternary 1,3,5‐Triazapenta‐1,3‐dienes and Their CoII, ZnII, PdII, CuII and BF2 Coordination Compounds

“…[3] Subsequently, this method was modified by our group. [4,5] Tertiary 1,3,5-triazapenta-1,3-reacting 2b with boron trifluoride-diethyl ether. From the tertiary triazapentadiene 3c and CoCl 2 or ZnCl 2 the six-membered 1:1 chelate complexes 3c·CoCl 2 and 3c·ZnCl 2 , respectively, were obtained.…”