16647-04-4Relevant articles and documents
(4E)-dehydrocitrals [(2E,4E)- and (2Z,4E)3,7-dimethyl-2,4,6-octatrienals] from acarid mite histiogaster sp. A096 (Acari: Acaridae)
Hiraoka, Hiroyuki,Mori, Naoki,Nishida, Ritsuo,Kuwahara, Yasumasa
, p. 2749 - 2754 (2001)
A mixture of two monoterpenes was obtained as the opisthonotal gland secretion from unidentified Histiogaster sp. A096 (Acari: Acaridae), and their structures were elucidated to be (4E)-dehydrocitrals [(2E,4E)- and (2Z,4E)-3,7-dimethyl-2,4,6-octatrienals] by GC/MS, GC/FT-IR, UV and 1H-NMR spectra. Both isomers of (4E)-dehydrocitral prepared by syntheses in 4 steps from 3-methyl-2-butenal with 34.2% yields (based on the ylide) were separated by column chromatography into the (2E,4E)- and (2Z,4E)-3,7-dimethyl-2,4,6-octatrienal. Mass spectra together with GC retention times of the purified natural (4E)-dehydrocitrals were identical with those of synthetic (2E,4E)-3,7-dimethyl-2,4,6-octatrienal and (2Z,4E)-3,7-dimethyl-2,4,6-octatrienal. The geometry at the 2-C position of both synthetic (4E)-dehydrocitrals was confirmed by NOESY analyses. This is the first identification of (4E)-dehydrocitrals from the animal kingdom.
Method for synthesizing methyl heptenone from methyl butynol
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Page/Page column 5-11, (2020/05/02)
The invention provides a method for synthesizing methyl heptenone from methyl butynolwhich. The method comprises the following steps: carrying out a rearrangement reaction on methyl butynol and 2-alkoxy propylene under the action of an acid catalyst to obtain a mixture of allenyl ketone and methylheptadienone; and carrying out selective hydrogenation on the mixture under the action of a hydrogenation catalyst to obtain the methyl heptenone product. The synthesis route is novel, firstly, the rearrangement reaction is firstly carried out to obtain allenyl ketone and methylheptadienone intermediates, and the problem of low selectivity of enol synthesis by alkynol hydrogenation is avoided; sulfonic acid resin and a Lewis acid are used for a synergistic catalytic reaction, so that the rearrangement reaction condition is mild; then hydrogenation of allenyl ketone and methylheptadienone is catalyzed by using a Lindelar catalyst and taking an alkali and quinoline as assistants so as to obtainthe methyl heptenone with high selectivity; and the method has the advantages of readily available starting raw materials, low price, high total yield of the route, good cost advantage and potential application prospect.
Palladium-Catalyzed Cleavage of α-Allenylic Aryl Ether toward Pyrazolemethylene-Substituted Phosphinyl Allenes and Their Transformations via Alkenyl C-P(O) Cleavage
Zhu, Jie,Mao, Mao,Ji, Huan-Jing,Xu, Jiang-Yan,Wu, Lei
supporting information, p. 1946 - 1949 (2017/04/28)
A palladium-catalyzed two-component coupling of allenylphosphine oxides with conjugated N-tosylhydrazones is revealed. For the first time, the cleavage of α-allenylic aryl ether toward pyrazolemethylene-substituted phosphinyl allenes enabled facile synthesis of combined motifs with pyrazole and allene. Moreover, the obtained adducts could be easily transformed to potential bioactive multifunctionalized phosphinates via a novel alkenyl C-P(O) cleavage.
