Synthesis and Conformational Assignment of N-(E)-Stilbenyloxymethylenecarbonyl-Substituted Hydrazones of Acetone and o-(m- and p-) Chloro- (nitro-) benzaldehydes by Means of ¹H and ¹³C NMR Spectroscopy

Table 13

¹H and ¹³C NMR data of cis/trans conformers of N-(E)-4-X-stilbenyl-4′-oxymethylenecarbonyl substituted hydrazones of acetone (19, 20); 19 X = Cl. 20 X = NO₂.

Compound	^1H NMR	Conformer	^13C NMR	Conformer	* Δ %
	–OCH2–	cis %	–OCH2–	cis %
	s(𝛿, ppm) [height]	trans %	s(𝛿, ppm) [height]	trans %
19	5.00 [62.0]	57.78	64.86 [25.5]	60.00	2.22
	4.66 [45.3]	42.22	66.00 [17.0]	40.00
20	5.02 [60.5]	59.66	64.03 [37.2]	58.49	1.17
	4.69 [40.33]	40.33	65.94 [26.4]	41.50

*The difference between the percentage of the conformers calculated from the ¹H NMR and ¹³C NMR data.