Table 1.

¹H chemical shifts of CH₂, CH, and OH protons and enol percentage. From [24] with permission from the American Chemical Society.

Compound/Chemical Shifts a and % Enol	Diketo	Enol	OH	% Enol
2,4-Pentanedione	3.58	5.50	15.34	79
2,4-Hexanedione	3.18 b	5.08 b	13.46 b	81
5-Methyl-3,5-hexanedione	3.57	5.50	14.92	80
2,2-Dimethyl-3,5-hexanedione	3.56	5.60	15.58	94
3,5-Heptanedione	3.66	5.66	15.04	76
3,5-Heptanedione	3.18 b	5.12 b	14.30 b	76
2-Methyl-3,5-heptanedione	3.57	5.50	14.92	88
2,2-Dimethyl-3,5-heptanedione	3.56	5.58	15.88	92
2,6-Dimetyl-3,5-heptanedione	3.60	5.50	15.50	94
2,2,6-Trimethyl-3,5-heptanedione	3.54 b	5.28 b	15.52 b	96
2,2,6,6-Tetramethyl-3,5-heptanedione	3.74	5.86	c	c

^a Chemical shifts in ppm from internal TMS. ^b Chemical shifts in ppm from external TMS. ^c No data given.