59057-30-6Relevant articles and documents
Preparation method of vitamin A acetate
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Paragraph 0007; 0076-0077, (2021/03/11)
The invention provides a preparation method of vitamin A acetate, which comprises the following steps: reacting bromoethanol with acetone to obtain a ketal compound, preparing a Grignard reagent fromthe ketal compound, reacting the Grignard reagent with C5 aldehyde to obtain heptanol, reacting the heptanol with triphenylphosphine to prepare heptacarbon phosphine salt, and further reacting the heptacarbon phosphine salt with ionone to obtain the vitamin A acetate. According to the present invention, a C13 + C7 vitamin A acetate synthesis route is provided, such that the yield of the vitamin Aacetate is improved, the process cost is reduced, and the industrial production is easily achieved.
Longer polyenyl cations in relation to soliton theory
Kildahl-Andersen, Geir,Anthonsen, Thorleif,Liaaen-Jensen, Synnove
, p. 2803 - 2811 (2008/03/12)
The carotene-like polyenes decapreno-β-carotene (C50), C54-β-carotene (C54, first synthesis) and dodecapreno-β-carotene (C60) with 15, 17 and 19 conjugated double bonds, respectively, were synthesized by double Wittig reactions. Introduction of a leaving group in allylic position failed, and cations were obtained by hydride elimination effected by i) triphenylcarbenium tetrafluoroborate-d15, prepared by a new method, or ii) treatment with trifluoroacetic acid-d. Deuterated reagents were employed for product analysis by 1H NMR. Parallel experiments were performed with β,β-carotene (C40). NIR spectra at room temperature and at -15 °C were employed for characterisation and stability studies of the cationic products. In CH2Cl2 λmax in the 900-1350 nm region was recorded. NMR data for the cationic product of β,β-carotene obtained by the two new preparation methods were consistent with the two monocations previously characterised. The cationic products of the longer polyenes provided downfield-shifted, broadened signals, compatible with C50-monocation, mixed C54-mono- and dication and C60-dication. Combined NIR and NMR data suggest that the extent of charge delocalisation is limited by the maximum soliton width for cations obtained from linear polyenes with more than ca. 20 sp 2-hybridized carbon atoms. The Royal Society of Chemistry.
Preparation of higher alpha, beta-unsaturated alcohols
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, (2008/06/13)
Higher α,β-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetatesor diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.
Total Synthesis of C31-Methyl Ketone Apocarotenoids: Sintaxanthin and (3R)-3-Hydroxysintaxanthin
Haugan, Jarle Andre
, p. 657 - 664 (2007/10/02)
The previously undescribed (all-E)-2,7,11-trimethyl-12-oxo-2,4,6,8,10-tridecapentenal has been synthesised in 26percent overall yield in six steps from the readily available 3-methyl-2-penten-4-yn-1-ol and 2,7-dimethyl-2,4,6-octatrienedial.This C16-keto aldehyde was used in the first total synthesis of fully characterised (all-E)-sintaxanthin and optically active (all-E)-(3R)-3-hydroxysintaxanthin.The C16-keto aldehyde is a versatile building block for any C31-methyl ketone apocarotenoid.
A novel regioselective synthesis of allylsilanes
Chan,Labrecque
, p. 1149 - 1152 (2007/10/02)
The anions derived from allyl sulfones were silylated in the α-position. Reductive desulfonylation gave the desired allylsilanes regioselectively
