Relaxation Processes in Aromatic Methyl Groups. II. Methyl-Methyl Nuclear Overhauser Enhancements

Abstract

A range of compounds with methyl groups disposed ortho and peri on heteroaromatic frameworks have been prepared, and T1 values and methyl-methyl Overhauser effects measured for them. Most of the n.O.e . Values were ≤6%, but two examples of methyls flanked by two others exhibited values of 9% (6-hydroxy-4,4,5,7-tetramethyl-3,4-dihydro-2H-benzopyran-2-one) and 15% (1,4,5,8,9-pentamethylcarbazole).