Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

Abstract

Exhaustive Michael-type alkylations of amines and ammonia with azoalkenes (generated from α-halohydrazones) were demonstrated as an efficient approach to poly(hydrazonomethyl)amines – a novel class of polynitrogen ligands. An intramolecular cyclotrimerization of C=N bonds in tris(hydrazonomethyl)amine to the respective 1,4,6,10-tetraazaadamantane derivative was demonstrated.

Recent Advances in the Chemistry of Conjugated Nitrosoalkenes and Azoalkenes

“…This umpolung strategy was well illustrated by the divergent preparation of pyrazoles via base-promoted conjugate addition of Narylhydrazone anions to azoalkenes, 122 domino or sequential reactions of azoalkenes with vinyl malononitriles 123 and pyridine-like heterocycles, 124 and multicomponent reaction with amines and iso(thio)cyanate 125 Conjugate addition of amines and ammonia to azoalkenes allowed the preparation of bis-, tri-, and tetrahydrazones in good to excellent yields, as illustrated in Scheme 57. 126 The addition of primary amines to azoalkenes gave bishydrazones 281 with 2 equiv of hydrazone 280. By a similar strategy, trihydrazones 282 were obtained by the reaction of ammonia with 3.1 equiv of hydrazone 280.…”

“…Conjugate addition of amines and ammonia to azoalkenes allowed the preparation of bis-, tri-, and tetrahydrazones in good to excellent yields, as illustrated in Scheme . The addition of primary amines to azoalkenes gave bishydrazones 281 with 2 equiv of hydrazone 280 .…”

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

“…Several of the obtained TAAD derivatives were characterized by X-ray analysis (namely, 4a, 4a•HCl, 4b [35], 4c•HCl, Bn-4c, 8a, 19e•3HCl, 21 and 21•HCl, see Figure 2 and Supporting Information File 2). The geometrical parameters of the 1,4,6,10tetraazaadamantane cage in these products are close to that observed in 3 O-TAADs of type 2 [21].…”

“…Here, we wish to report the synthesis of TAADs decorated with N -amino(amido) groups ( 3 N -TAADs) by cyclization of the corresponding tris-hydrazones, as well as the assembly of unsymmetrically substituted TAADs having both amino(amido) and hydroxy groups at bridge nitrogen atoms ( 2 N , 1 O -TAADs and 1 N , 2 O -TAADs) via a hitherto unknown co-trimerization of oxime and hydrazone units [ 35 ]. Also, structural studies of the obtained TAAD derivatives were performed, and the formation of boron chelates and host–guest complexes having an unusual intramolecular H-bonded network was showcased in this work.…”

2,4,9‐Triazaadamantanes with “Clickable” Groups: Synthesis, Structure and Applications as Tripodal Platforms

“…Recently, our group introduced 1,4,6,10‐tetraazaadamantane (TAAD) as a readily available, stable, and easy‐to‐modify multifunctional platform (Scheme 1, chart c). [ 17c,19c,21 ] Our group and others have shown the application of TAAD derivatives in the design of fluorophore‐labelled natural molecules, [ 22 ] biodegradable polymers, [ 22 ] polymer‐bound organocatalysts, [ 22 ] scavengers for boronic acids, [ 22 ] water‐soluble phthalocyanines, [ 23 ] capped metal complexes, [ 24 ] and dynamic combinatorial libraries. [ 22 ] Surprisingly, 2,4,9‐triazaadamantane (TRIAD), which is a simpler analog of TAAD, has received much less attention and was not considered for applications as a molecular platform (Scheme 1, chart c).…”