The synthesis and characterization of the precursor isomers
trans-4-(2-(pyridin-2-yl)vinylbenzaldehyde (
I),
trans-4-(2-(pyridin-4-yl)vinylbenzaldehyde (
II),
trans-4-(2-(pyridin-2-yl)vinylbenzoic acid (
III) and (
E)-4-(2-(pydridin-4-yl)vinylbenzoic acid (
IV) are reported. These compounds were prepared in order to obtain
trans
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The synthesis and characterization of the precursor isomers
trans-4-(2-(pyridin-2-yl)vinylbenzaldehyde (
I),
trans-4-(2-(pyridin-4-yl)vinylbenzaldehyde (
II),
trans-4-(2-(pyridin-2-yl)vinylbenzoic acid (
III) and (
E)-4-(2-(pydridin-4-yl)vinylbenzoic acid (
IV) are reported. These compounds were prepared in order to obtain
trans-4-((
E)-2-(pyridin-2-yl)vinyl)benzamide-TEMPO (
V). Compounds
I and
II were obtained by using a Knoevenagel reaction in the absence of a condensing agent and solvent. Oxidation of the aldehyde group using the Jones reagent afforded the corresponding acid forms
III and
IV. A condensation reaction with 4-amino-TEMPO using oxalyl chloride/DMF/CH
2Cl
2 provided the 4-((
E)-2-(pyridin-2-yl)vinyl)benzamide-TEMPO. Single crystals of compounds
I,
II and
III were obtained and characterized by X-ray diffraction. Compound
I belongs to space group
P21/c,
a = 12.6674(19) Å,
b = 7.2173(11) Å,
c = 11.5877(14) Å,
b = 97.203(13)° and the asymmetric unit was
Z = 4, whereas compound
II was in the space group
P2
1, with
a = 3.85728(9) Å,
b = 10.62375(19) Å,
c = 12.8625(2) Å,
b = 91.722 (2)° and the asymmetric unit was
Z = 2. Compound
III crystallized as single colorless needle crystals, belonging to the monoclinic system with space group
P2
1, with
Z = 2, with
a = 3.89359(7) Å,
b = 17.7014(3) Å,
c = 8.04530(12) Å,
b = 94.4030 (16)°. All compounds were completely characterized by IR,
1H-NMR, EI-MS and UV-Vis.
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