Aldehydes reaction with diamines

Determination of carbonyl groups by reaction with hydroxylamine hydrochloride and titration of the liberated hydrochloric acid, or determination of aldehyde groups by oxidation with hypoiodite or chlorous acid and by reaction with diamines and subsequent fixation of dyes. 

Figure 1.98 Aldehydes may be transformed into primary amines by reaction with ammonia or a diamine in the presence of a reducing agent.

Diamines, aminothiols, and aminoalcohols are well suited for quantitative solid-state cyclizing condensations with simple aldehydes and ketones. As yet only quantitative gas-solid reactions with acetone and solid-solid reactions with paraformaldehyde (that will monomerize upon the milling) have been profited from. An early remarkable reaction type involving two molecules of... 

Schiff bases having two nitrogen atoms as donors may be derived either from condensation of dialdehydes and diketones with two molecules of an amine, or from reaction of diamines with aldehydes or ketones. In Section 20.1.2.1, it has been pointed out that coordination through the N atom may occur only under particular circumstances. However, in the case of diimines the formation of chelate rings stabilizes the metal-nitrogen bond. Thus, they can form both mono-41 and bis-chelate42 complexes. 

As noted already, the reactions of oc,(3-unsaturated ketones with or /zo-diamines are often accompanied by various rearrangements and side processes. For instance, the o-PDA condensation with chalcone in the presence of an acid catalyst or during overheating of the reaction mixture produces a final product of 2-phenylbenzimidazole [2, 7] a similar phenomenon is also observed for 2,3-diaminopyridine [54]. Owing to the existence of much more suitable approaches to the synthesis of 2-aryl derivatives of benzimidazole and their heteroannelated analogues (e.g., proceeding from diamines and acids or aldehydes [121]), such a trend in the interaction of chalcones with diamines is unlikely to have any application for this purpose. 

Amine-aldehyde condensations. Sometimes known as a Schiff base condensation, the reaction of dialdehydes with diamines has been used extensively in the preparation of macrocyciic ligands for metal cations. Reduction of the resulting imine (C = N) group with NaBH4 gives the corresponding aliphatic amine (Section 3.10.6). 

A hydroformylation-cyclocondensation of iV-alkenylpropane-1,3-diamines, such as 159 (prepared by reductive amination of the appropriate unsaturated aldehyde with either propane-1,2-diamine or 2-aminoethanol and subsequent borohydride reduction), in the presence of PPh3 and BIPHENPHOS as ligand provided different reaction products depending on the H2/CO ratio <1999AJC1131>. The bicyclic system 160 was accompanied by 10% branched 162 when H2/CO was 1 1 (Scheme 66). Reaction with H2/CO in a 1 5 ratio provided solely the bicyclic system, while only a mixture of monoalcohols 161 and 162 was isolated when the reaction was performed in the absence of PPh3. 

The hydroxy-binaphthyl functionalised saturated imidazolium salt is readily available from 1-amino-I -hydroxy-binaphthyl in a reaction with a ( oc-protected mesitylamine aldehyde [86] (see Figure 4.24). The resulting Schiff base is reduced to the diamine by Na(OAc)3BH. Subsequent deprotection and ring closure reaction with triethyl orthoformate yields the corresponding hydroxy-binaphthyl functionalised saturated imidazolium salt. Reaction with silver(I) carbonate and subsequent carbene transfer to the ruthenium(II) precursor yields the asymmetric olefin metathesis precatalyst. 

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