Spectroscopic Indicators of Diaminomaleonitrile Bisubstitution: A Review

Abstract

Diaminomaleonitrile (DAMN) is an electron-rich ligand which is commonly used in the synthesis of purines, amides and Schiff base ligands. In the last case lies the interest in this molecule, given its symmetry and apparent facility to form various ligands and complexes of interest in fields such as organic solar cells and catalysis among others. Nevertheless, its bisubstitution with aldehydes displays certain difficulty due to the double conjugated presence of the nitrile group (C≡N) in its structure, which significantly affect its coordination behavior by modulating the chemical reactivity of its amines. In addition to presenting a practical resume of guidelines for the preparation of different bisubstituted compounds from DAMN, this paper reviews the possibility of attaining a precise characterization by simple spectroscopic techniques. We provide an additional discussion for one of these techniques (commonly reported but often overlooked), given its potential to provide both the symmetry and E/Z configuration of the product. We hope the comprehensive evidence discussed and shown in this review will be helpful to further develop and understand the products derived of this interesting molecule in their broad applications.

A Three‐Way Regioselective Synthesis of Amino Acid Decorated Imidazole, Purine and Pyrimidine Derivatives by Multicomponent Chemistry Starting from Prebiotic Diaminomaleonitrile

“…synthesis of pyrimidine 6a was confirmed by the presence of the bathochromic effect associated to the conversion of DAMN (λmax 295 nm) to DAFN (λmax 304 nm) (Supporting Information, section 2, Figure S2.4-S2.5), [39] as well as by the appearance of characteristic IR bands at 2197 and 2242 cm À 1 (vibrations of CN), 1602 cm À 1 (C=C stretching band), and 3434-3000 cm À 1 (NÀ H stretching bands) (Supporting Information, section 3, Figure S3.2). [40] The reaction repeated with α-amino acid derivatives 3 b-3 f afforded amino-acid decorated pyrimidines 6 b-6 f from good to high yield, confirming the generality of the procedure (Table 2, entries 4-8). The formation of pyrimidine 6 a-6 f probably occurred by the initial reaction of DAFN with compound 2 to yield the imino ether derivative 5 (that we effectively isolated from the reaction mixture), followed by addition of amino acid derivatives 3 a-3 f, and successive internal displacement of methanol molecule, to yield the sixring closure of the pyrimidine ring (DAFN pathway, Supporting Information, section 1).…”