ChemicalBook CAS DataBase List 3,4-dimethylcyclopent-2-en-1-one

3,4-dimethylcyclopent-2-en-1-one synthesis

6synthesis methods

Product Name:3,4-dimethylcyclopent-2-en-1-one
CAS Number:30434-64-1
Molecular formula:C7H10O
Molecular Weight:110.15

6284-46-4 Synthesis

6284-46-4
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$78.00/25mL

30434-64-1
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$101.00/100mg

Yield: 84.7%

Reaction Conditions:

with PPA in (2S)-N-methyl-1-phenylpropan-2-amine hydrate

Steps:

P.1.2 (2)
(2) Synthesis of 3,4-dimethyl-2-cyclopentenone 1 L of polyphosphoric acid was added into a 2 L flask, purged with nitrogen, and then refluxed and stirred at 100° C., after which crotonic acid isopropyl ester (76.9 g, 0.6 mol) was slowly added in droplets thereto, and the mixture was stirred for 3 hours and thus turned into dark brown. The mixture thus obtained was mixed with ice water (500 mL) and then neutralized with sodium carbonate, after which the organic layer was extracted with ethylether and then subjected to vacuum distillation (105° C., 40 torr), thus obtaining 56 g (0.51 mol, yield 84.7%) of 3,4-dimethyl-2-cyclopentenone as a colorless transparent liquid. ¹H-NMR (CDCl₃) δ=1.05~1.09 (d, 3H), 1.83~1.87 (q, 1H), 1.98 (s, 3H), 2.45~2.51 (q, 1H), 2.67~2.70 (m, 1H), 5.73 (s, 1H) ppm

References:

SK INNOVATION CO., LTD. US2012/329965, 2012, A1