Reaction #1018

Reaction equation

sodium ethoxide

4-pyridine carboxaldehyde

(3-cyclopentyloxy-4-methoxyphenyl)-methyltriphenylphosphonium chloride

→

compound

Yield 11.9%

(Z)-4-[2-(3-Cyclopentyloxy-4-methoxyphenyl)ethenyl]pyridine

Yield 11.9%

Solvents

ethanol

ethanol

Conditions

Workup

1. 1
   ConcentrationAfter 2h, the reaction mixture was concentrated in vacuo
2. 2
   Otherthe residue partitioned between EtOAc (75 ml) and brine (50 ml)
3. 3
   OtherThe organic layer was separated
4. 4
   Dryingdried (MgSO4)
5. 5
   Concentrationconcentrated in vacuo
6. 6
   workup.ADDITIONconsisted of a 3:2 mixture of (Z)

Procedure

A solution of sodium ethoxide [prepared from sodium (0.10 g, 4.50 mmol)] in ethanol (50 ml) was added over 5 min to a stirred mixture of 4-pyridine carboxaldehyde (0.44 g, 4.10 mmol) and (3-cyclopentyloxy-4-methoxyphenyl)-methyltriphenylphosphonium chloride (2.00 g, 4.08 g) in ethanol (30 ml). After 2h, the reaction mixture was concentrated in vacuo and the residue partitioned between EtOAc (75 ml) and brine (50 ml). The organic layer was separated, then dried (MgSO4) and concentrated in vacuo. A 1H n.m.r. spectrum indicated that the mixture consisted of a 3:2 mixture of (Z): (E)title compound (and triphenylphosphine oxide). A portion (0.6 g) of the mixture was subjected to chromatography (SiO2 ; hexane to EtOAc) to afford pure/Z-title compound (0.14 g) as a pale yellow solid m.p. (Found: C, 77.18; H, 7.16; N, 4.63. C19H21NO2 requires C, 77.26; H, 7.17; N, 4.74%); δH (300 MHz; CDCl3) 1.5-1.55 (2H, br m, cyclopentyl H's), 1.65-1.9 (6H, br m, cyclopentyl H's), 3.83 (3H, s, OMe), 4.44 (1H, br m, OCHCH2), 6.40 (1H, d, J 12.2 Hz, CH=CH), 6.65-6.80 (4H, m, ArH ortho to OMe+2×ArH meta to OMe+CH=CH), 7.15 (2H, ca. d, J 6.0 Hz, pyridine H2, H6); m/z 295 (M+, 22%), 228 (15), 227 (100), 226 (94), 198 (35), 184 (15), 166 (12), 43 (19), and 41 (29).

Source