2835-39-4Relevant articles and documents
Allyl isovalerate synthesis method
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Paragraph 0016-0024, (2020/01/08)
The invention discloses an allyl isovalerate synthesis method, which comprises: (1) mixing isovaleric acid, sodium hydroxide and water, carrying out a stirring reaction at a temperature of 70-80 DEG Cfor 2-4 h, carrying out normal pressure distillation to remove 50-55% of water, adding toluene, distilling, and completely removing the water from the system to obtain a toluene suspension of sodiumisovalerate; (2) adding allyl chloride and a phase transfer catalyst into the toluene suspension obtained in the step (1), carrying out a reflux reaction for 6-8 h, and washing the reaction solution with water 1-3 times to obtain crude allyl isovalerate; and (3) distilling the crude allyl isovalerate to recover allyl chloride and toluene, and carrying out pressure reducing distillation to obtain the finished allyl isovalerate. According to the invention, allyl isovalerate is synthesized by using isovaleric acid, sodium hydroxide and allyl chloride as main raw materials without strong acids, such that the equipment is not corroded, the generated wastewater is small in amount and easy to treat, and the highly toxic chemical product allyl alcohol is replaced with allyl chloride so as to reduce the harm to human bodies and the environment and achieve safe and environmentally friendly production.
Synthesis of a spirocyclic seco structure of the principal vetiver odorant Khusimone
Kraft, Philip,Denizot, Natacha
, p. 49 - 58 (2013/02/22)
The three-dimensional structure of tricyclic compounds with a zero-bridge to one bridgehead atom is determined by the underlying spirocyclic framework. (-)-Khusimone (1), the principal odorant of vetiver oil (content up to 2 %), is such a tricyclic norsesquiterpene, and dissection of the 7,8-bond between the methylene and the gem-dimethyl unit of 1 results in a spirocycle extending over an almost identical molecular volume and shape. Given that the vetiver rule postulates that one α-branched carbonyl osmophore in a certain spatial distance to a bulky moiety is responsible for the odor of vetiver, a 7,8-seco structure of 1 could prove or disprove these structural requirements. Therefore, (4R*,5R*)-7-isopropyl-4-vinylspiro[4.4]nonan-1-one [(4R*,5R*)-2] was synthesized in a 10-step synthetic sequence commencing with Steglich esterification of allyl alcohol (15) and isovaleric acid (14). Ireland-Claisen rearrangement of the formed allyl isovalerate (16) with subsequent lithium aluminum hydride reduction of resulting γ,δ-unsaturated acid 18, Appel bromination of corresponding alcohol 19, and ozonolysis provided 4-bromo-3-isopropylbutanal (23) in 19 % overall yield as a building block for the projected spiroannulation reactions. Although attempts on cyclopentanone (7) failed, cyclopent-2-en-1-one, via its TMS-trapped lithium 3-vinylcyclopent-1-enolate 12, turned out to be a successful starting material. Evans' variant of the Mukaiyama aldol reaction with 1-trimethylsiloxy-3-vinylcyclopent-1-ene (12) in the presence of BF 3·OEt2, followed by palladium-catalyzed conjugate tin hydride reduction of resulting enone 28 provided 2-(4′-bromo-3′- isopropylbutyl)-3-vinylcyclopentanone (29) in 50 % overall yield as the anlation precursor. LDA-mediated 5-exo-tet cyclization of 29 concluded the synthesis of the racemic 7,8-seco-/6-epi-7,8-secokhusimone mixture (4R*,5R*)-2, which possessed a floral, rosy, green, geranium-like odor with a threshold of 42.0 ng L-1 air, which is 10 times less intense than that of (-)-khusimone (1). Most importantly, seco structure (4R*,5R*)-2 did not display any woody nor any vetiver character, which proves the postulated vetiver rule wrong. Dissecting the bond between the methylene and the gem-dimethyl unit of khusimone leads to a spirocycle of almost identical shape, which was synthesized by 1,4-conjugate addition of a vinyl Gilman reagent, Mukaiyama aldol condensation of a bromo aldehyde prepared by Ireland-Claisen rearrangement of allyl isovalerate, and subsequent cyclization. Copyright
Mild, rapid, and inexpensive microwave-assisted synthesis of allylic and propargylic esters
Gill, Monica A.,Manthorpe, Jeffrey M.
supporting information, p. 1460 - 1468 (2013/05/09)
A variety of allylic and propargylic esters were rapidly prepared via microwave heating of their corresponding mixed anhydride derived from pivaloyl chloride. The reaction conditions were modified to account for the sterics of the alcohol and the electronics of the carboxylic acid. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
