Synthesis and Spectral Characterisation of (E)-3-(3-(4 (Dimethylamino)Phenyl)Acrylo-yl)-4-Hydroxy-2H-Chromen-2-One and Their Antibacterial Activity and Acetylcholinesterase Inhibition

Table 5

The ketol/enol ratios when coumarin 3 was dissolved in solvents with different polarities and dielectric constants (ɛ).

Solvent	Dielectric constant (D)	Δf	Enol form (%)	Keto form (%)
n-hexane	1.9	0.13	83.0	17.0
n-heptane	1.9	0.12	90.6	9.4
cyclohexane	2.0	0.15	91.0	9.0
dioxane	2.2	0.12	93.8	6.2
CCl4	2.2	0.12	92.8	7.2
benzene	2.3	0.12	90.4	9.6
CHCl3	4.8	0.25	87.3	12.7
CH2Cl2	9.1	0.32	70.0	30.0
BuOH	17.8	0.36	83.5	16.5
IsoPrOH	18.3	0.37	83.5	16.5
EtOH	24.6	0.38	60.9	39.1
EG	31.7	0.30	38.9	61.1
MeOH	32.6	0.39	61.0	39.0
ACN	35.9	0.39	90.7	9.3
DMF	38.3	0.38	46.1	53.9
Acetone	39.3	0.28	72.6	27.4
Glycerol	42.5	0.32	64.3	35.7
DMSO	46.5	0.37	9.7	90.3
H2O	78.4	0.36	78.3	21.7