ChemicalBook CAS DataBase List 4-PENTENAL

4-PENTENAL synthesis

12synthesis methods

Product Name:4-PENTENAL
CAS Number:2100-17-6
Molecular formula:C5H8O
Molecular Weight:84.12

79-37-8
461 suppliers
$17.67/10gm:

1972-28-7 Synthesis

1972-28-7
374 suppliers
$15.00/5g

2100-17-6
86 suppliers
$56.20/1g

Yield:-

Reaction Conditions:

with triethylamine;triphenylphosphine;Al₂O₃ in tetrahydrofuran;dichloromethane;dimethyl sulfoxide

Steps:

6.g Example 6
g). The compound of formula XIII 5.4 g of the product of step f) above is added to 3.5 l of tetrahydrofuran at room temperature with stirring, 18.7 ml of diethyl azodicarboxylate is added followed by 31.3 g of triphenylphosphine and the mixture warmed to 50°C in an oil bath and allowed to react overnight. The product mixture is concentrated and the residue is purified using 2 Al₂O₃ columns and elution with hexane/ethyl acetate (2:1). Fractions 6-1 from the first column and fractions 7-20 from the second column together yield 5 g of crude product, which is further purified by silica gel chromatography to yield 3.2 g (62%) of the pure resinous intermediate product, being the product corresponding to the compound of formula XIII in which c is in the CH-OCH₂-O-CH₂-CH₂-OCH₃ protected form. This intermediate product is converted to the further intermediate product in which c is CHOH by treatment with acid. 5.2 g of the above intermediate product is dissolved in 12 ml of tetrahydrofuran, 10 ml of IN HCl is added and the mixture stirred at 45°C for 24 hr after which it is extracted three times with ethyl acetate and washed with saturated brine and NaHCO₃ solutions. The ethyl acetate phases are dried over Na₂SO₄, concentrated and purified by silica gel chromatography (hexane/ethyl acetate 1:1) to give about 3.4 g of the sticky further intermediate product. 2 ml of dichloromethane is stirred at room temperature, 76 μl of oxalyl chloride is added, the mixture cooled to -60°C and a solution of 0.13 ml of DMSO in 1 ml of dichloromethane is added dropwise over 3 min. The resultant evolution of gas is allowed to proceed for 3 min after which a solution of 280 mg of the above further intermediate product in 3 ml of dichloromethane is added dropwise over 5 min with formation of a precipitate. The mixture is stirred for a further 15 min after which 0.56 ml of triethylamine is added over a 5 min period with the resultant precipitation of a paste which is allowed to accumulate at room temperature. The paste is extracted with dichloromethane, the organic phases washed twice with 10% citric acid twice with saturated brine solution, dried over Na₂SO₄, concentrated and purified by silica gel chromatography (dichloromethane) to give the title product of formula XIII in pure form. The pure product has the following characteristics: m. pt.159°C; m/z: 344(M+), 217(80), 189(60), 178(100), 95(60).