1,3-Pentadiene with acetaldehyde

The material is prepared by Diels-Alder reaction of 1,3-pentadiene and mesityl oxide and subsequent aldol condensation of the resulting acetyl trimethyl cyclohexene with acetaldehyde [99]. 5-Damascone is used in perfumes to create masculine notes. 

In this manner, self-condensation of acetaldehyde is rninimi2ed and yields in the range of 77—85% are obtained. However, even with these precautions a detectable amount of 5-phen5l-2,4-pentadienal [13466-40-5] is invariably formed. 

The results of pyrolysis of polypropylene in air depends on the pyrolysis heating rate because the pyrolysis process competes with the oxidation [108], By heating between 120° C and 280° C in air, polypropylene is reported to generate ethene, ethane, propene, propane, isobutene, butane, isobutane, pentadiene, 2-methyl-1-pentene, 2,4-dimethyl-1-pentene, 5-methyl-1-heptene, dimethylbenzene, methanol, ethanol, 2-methyl-2-propene-1-ol, 2-methylfuran, 2,5-dimethylfuran, formaldehyde, acetaldehyde, acrolein, propanal, methacrolein, 2-methylpropanal, butanal, 2-vinylcrotonaldehyde, 3-methylpentanal, 3-methylhexanal, octanal, nonanal, decanal, ethenone, acetone, 3-buten-2-one, 2-butanone, 1-hydroxy-2-propanone, 1-cyclopropylethanone, 3-methyl-2-buten-2-one, 3-penten-2-one, 2-pentanone, 2,3-butanedione [109]. 

It is an a,3-unsaturated aldehyde with a substitution at the y-carbon. To synthesize this compound, one can begin with an aldol condensation of two acetaldehydes. Dehydration of the product gives crotonaldehyde, which can undergo another aldol condensation with benzaldehyde and then dehydrate to give 5-phenyl-2,4-pentadienal. The total synthesis is shown below ... 

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