2,6‐Bis(2‐Alkoxypropan‐2‐yl)Pyridines as Inexpensive Alternatives to Sterically Hindered 2,6‐Di‐ tert ‐Butylpyridines

Sterically encumbered pyridines such as 2,4,6‐tri‐ tert ‐butylpyrimidine (TTBP), 2,6‐di‐ tert ‐butylpyridine (DTBP), and its 4‐substituted analogs (such as 2,4,6‐tri‐ tert ‐butylpyridine (TTBPy)) are routinely used as proton trapping agents by organic chemists. Contrary to their practical use, these bulky pyridines exhibit unusually low basicity in aqueous solution, reflected in their unexpectedly low p K a values. The observed low p K a values of these bulky pyridines have been attributed to their solvation insusceptibility in polar solvents due to the steric shielding by the bulky tert ‐butyl groups around the cationic [N–H] + site. In the present work, we report the synthesis of a series of 2,6‐disubstituted pyridine derivatives in which one of the methyl groups of the tert ‐butyl substituent has been replaced with methoxy, ethoxy, or benzyloxy groups. We demonstrate that these new, cost‐effective classes of hindered pyridines retain the properties of non‐nucleophilic bases and can serve as potential alternatives to TTBPy, DTBP, and TTBP.