José J. Cordero-Pérez, Sandra L. de Ita-Gutiérrez, Nayely Trejo-Carbajal, Myriam Meléndez-Rodríguez, Maricruz Sánchez-Zavala, Nury Pérez-Hernández, Martha S. Morales-Ríos, Pedro Joseph-Nathan and Oscar R. Suárez-Castillo.,?Complete 1H NMR assignment of 3-formylindole derivatives? Magn. Reson. Chem., 52, 789?794, (2014).
-Formylindoles including indolylglyoxylate esters andindolylglyoxylamides are widely found in nature as alkaloids,andare important building blocks or synthetic intermediates for drugdiscovery,and for the synthesis of natural products.Acarefulin-spection of the1H NM R data of these moleculesreveals that multi-plicities for H4 and H7 are reported as broad doublets,[4a,4b]asdoublet of doublets-like,[4b]as a combination of doublet of doubletsand multiplets,[4a,4b]or simply as doublets.[4c,4d]InthecaseofH5andH6, they are reported as triplet of doublets,[4a,4b]as triplets,[4c]or as dou -blet of triplets[4d]despite the fact that in most cases, their chemicalshifts are claimed to be unambiguously assigned. In addition, incorrectcoupling constant values for the incorrect multiplicities for H4?H7 arealso reported. A prudent signal description of the H4?H7 system israrely given as multiples without reporting coupling constant values.[4e