Malonamide fragmention

The construction of suitable dialdehydes for macrocycle formation by metal template methods has more recently been extended to include a range of oxamides. In the first case, the simple 2,2 -(oxalyldiimino)bisbenzaldehyde underwent rather sluggish template reactions but yielded extremely stable macrocyclic complexes (Scheme 31).167 168 These products could be sulfonated in oleum, without destruction of the macrocyclic structure. This general synthetic route has been extended to include reactions of diketones and the formation of complexes of macrocyclic ligands such as (70) and (71). Attempts to incorporate a malonamide fragment in place of the oxamide... 

Numerous pyridines have been synthesized using cyanoacetamide (or cyanothioacetamide), malononitrile, malonamide and closely related compounds, which provide the N-C(2)-C(3) fragment for reviews see (86H(24)2023,87H(26)205,93CR1991). Principal co-reagents are a,(3-unsaturated ketones, arylidene malononitriles (review (83H(20)519)), and (3-diketones or (3-ketoaldehydes. 

Consequently, Fhb is the difference between the OH barrier calculated in the chelate conformation and the same barrier calculated in a molecule structurally close to the examined compound but hydrogen bond free. In most of our calculations, the reference molecule was attained by substituting the hydrogen bond acceptor fragment with a H atom. When tested on malonaldehyde and acetylacetone the approach worked very well [185]. The method was then applied with discrete success to many other molecules as formazan [186], carbonylamine [187], hexafluoro-acetylacetone [184], glyoxaloxime [188], 2-nitroresorcinol, 4,6-dinitroresorcinol and 2-nitrophenol in vacuum and in solution [189], malonamide and nitromalonamide [158] and ort/zo-halophenols [190]. 

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