engleski

Synthesis and characterization of two dehydroacetic acid derivatives and molybdenum(V) complexes: an NMR and crystallographic study

Two enaminones (Hl1 and HL2) have been prepared by the reactions of tryptamine with 2-hydroxy-4-(4- hydroxy)-6-methyl)-2H-pyrane-2-on-3-yl)-4-oxo- 2butenoate (ehmpb) and dehydroacetic acid (dha) respectively. The NMR spectroscopy confirmed that both tautomeric forms of HL1: endo-enol (tautomer A with hydroxyl group at position 4) and exo-enol form (tautomer B with hydroxyl group at position 7) are present in the solution. The molecular and crystal structures as well as the NMR data of HL2 showed that the condensation of dha and tryptamine occurs at acetyl-carbonyl group. The molecular structure of HL2 can be described as consisting of three structural fragments: (i) 2-pyrone ring ; (ii) N-substituent consisting of 1H-indol ring and (iii) ethyl chain interconnecting parts (i) and (ii). In the crystalline state molecules of compound HL2 are found as two symmetrically independent molecules. Molecules are also characterized by six membered pseudoaromatic chelate ring containing these NH-C=C-C=O (keto- amino tautomer) heterodienic moiety. Rings are formed by intramolecular hydrogen bonds enhanced by  -electron delocalization (resonance assisted hydrogen bond, RAHB ; N11-H11...O13 = 2.578(1) Å ; ; ; ; N21-H21...O23 = 2.570(1) Å ; ; ; )

Enaminones ; Tryptamine ; Dehydroacetic acid

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