Table 6.

Summary of results for proton affinity bracketing of Q (4).

Reference compound	PAa	Proton transferb
		Ref. base	Conj. acid
1-methylpiperidine	232.1 ± 2.0	+	–
1-methylpyrrolidine	230.8 ± 2.0	+	–
piperidine	228.0 ± 2.0	+	+
pyrrolidine	226.6 ± 2.0	+	+
4-picoline	226.4 ± 2.0	+	+
3-picoline	225.5 ± 2.0	+	+
pyridine	223.8 ± 2.0	–	+
n-octylamine	222.0 ± 2.0	–	+

^aPAs are in kcal mol⁻¹.³¹

^bA “+” indicates the occurrence and a “–” indicates the absence of proton transfer