Synthesis of pyrrole derivatives of serinol for functionalization of carbon allotropes

N-Pyrrole-based heterocycles are present in many natural products,[1] medicinal agents,[2] and functional materials,[3,4] therefore substantial attention has been paid to develop efficient methods for pyrroles synthesis. Moreover, they are precursors for the synthesis of poly N-alkyl pyrroles which have wide ranging applications in electronics and sensors due to their tunable optoelectronic properties. We present here one operationally simple, practical and economical Paal-Knorr pyrrole condensation of serinol (2-amino-propan-1,3-diol, 1) with beta-dicarbonyl compounds 2 (and related acetal/ketals or enolesters), under neat conditions in the absence of any catalysts, which allows the synthesis of N-serinopyrrole derivatives (3) in good to excellent yield. Depending on substituents, compounds 3 show quite interesting amphiphilic polar/unpolar and variable -interaction properties. The mechanistic conclusion reached in the study, allowed to identify a direct method for the preparation of the precursor serinol-pyrrole from sugar derivatives. Typical examples of this reaction is the dehydrative condensation of galactaric acid (4) with serinol (1) (i.e. its serinol salt or other derivatives). Methods for the derivatization of carbon allotropes (CNT, Graphenes and Carbon Black) by the prepared pyrroles were investigated and the good dispersion properties of the resulting material proved.