- Synthesis of analogues of citranaxanthin and their activity in free radical scavenging
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Citranaxanthin and its analogues were synthesised via a C5 unit elongation to substituted conjugated polyenes. Their free radical scavenging activity was measured by 1,1-diphenyl-2-picrylhydrazinyl spectrophotometric methods. Results indicated that the new compounds exhibited antioxidant activities. Three new analogues had stronger antioxidant activity than citranaxanthin.
- Zhang, Shaofeng,Liu, Yuan,Luo, Juan
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- Preparation method of 4-acetoxy-2-methyl-2-butenal
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The invention discloses a preparation method of 4-acetoxy-2-methyl-2-butenal, which takes salifying and wittig reactions as a core and methanol which is cheap and easy to obtain as a reaction initial raw material. The invention provides a new reaction route, the reaction steps are simple, the reaction conditions are mild, and the product yield is high.
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Paragraph 0016; 0042; 0049-0052; 0059-0062; 0069-0072; ...
(2021/09/04)
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- Catalytic oxidation method for preparation of 4-acyloxy-2-methyl-2-butenal
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The invention provides a preparation method of 4-acyloxy-2-methyl-2-butenal. The preparation method comprises the following steps: preparing raw materials, subjecting the raw materials prepared in thestep 1 to reacting, and carrying out after-treatment to obtain the 4-acyloxy-2-methyl-2-butenal. The preparation method of the 4-acyloxy-2-methyl-2-butenal is simple in process and mild in reaction conditions, and is carried out in the presence of a catalyst; the catalyst is good in catalytic activity, has excellent stability and durability, and can obtain a product with relatively high yield; and preparation cost is low, little waste salt and waste water are generated in the preparation process, the concept of green chemistry is accorded with, and industrial amplification feasibility is high.
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Paragraph 0078-0081
(2021/02/06)
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- Preparation method of 4-acetoxy-2-methyl-2-butenal
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The invention discloses a method for preparing 4-acetoxyl-2-methyl-2-butenal, and the method comprises the following steps: forming a catalyst system by using a cobalt acid complex and a metal chloride, mixing 4-acetoxyl-2-methylene butyraldehyde (III) with hydrogen, and performing heating to react to obtain the 4-acetoxyl-2-methyl-2-butenal. In the prior art, precious metal needs to be used as a catalyst in the step, and the yield and the selectivity are not high. The method does not need to use a noble metal catalyst, is lower in cost, high in double-bond isomerization reaction speed and high in reaction yield, and is easy to realize industrial production.
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- Preparation method of chroma-stable 2 -methyl -4 - acetoxy -2 - butenal
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The invention discloses a preparation method of a chromaticity-stable 2 -methyl -4 - acetoxy -2 - butenal, which comprises the following steps: (1) 2 - methylen -4 -acetoxybutyraldehyde and an auxiliary. Under the action of the catalyst, a gas - solid -liquid three-phase hydroisomerization reaction is generated to generate 2 - methyl -4 - acetoxy -2 - butenal. (2) The reaction was terminated after the reaction had been reached, the reaction was terminated and the solid phase catalyst was filtered off. (3) Distillation separation system solvent, hydrogenation by-product, unreacted starting material, obtained product 2 - methyl -4 - acetoxy -2 - butenal. The auxiliary agent in the step (1) is one or more organic compounds with amino and carbonyl functions, based on 2 - methylene -4 - acetoxybutyraldehyde of the raw material, 10 - 100 ppm, methacryloyloxy 2 - butanal provided by the invention is low in chroma, good -4 - in -2 - stability during long-term storage, slow in chroma and capable of meeting the downstream requirement better.
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Paragraph 0057-0073
(2021/11/06)
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- Process for preparation of 4-acetoxy-2-methyl-2-butene-1-aldehyde and intermediates thereof
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The invention relates to the technical field of organic synthesis, and discloses a method for preparing 4-acetoxy-2-methyl-2-butene-1-aldehyde and an intermediate thereof. The method comprises the following steps: (1) in the presence of an esterification reagent, carrying out esterification reaction on 1, 4-butenediol to obtain 1, 4-butenediol diacetate; (2) in the optional presence of a first catalyst, carrying out an isomerization reaction on the 1, 4-butenediol diacetate to obtain 3, 4-diacetoxy-1-butene; (3) in the presence of a phosphorus-containing ligand and a rhodium catalyst and/or a cobalt catalyst, carrying out hydroformylation reaction on the 3, 4-diacetoxy-1-butene, carbon monoxide and hydrogen to obtain 2-methyl-3, 4-diacetoxy-1-butyraldehyde; (4) in the optional presence of a third catalyst, carrying out an elimination reaction on the 2-methyl-3, 4-diacetoxyl-1-butyraldehyde to obtain the 4-acetoxyl-2-methyl-2-butene-1-aldehyde. The method provided by the invention has the advantages of mild reaction conditions, environmental friendliness and high yield.
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Paragraph 0055; 0059-0065; 0069-0072; 0076-0079; 0083-0086
(2021/06/09)
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- Method for preparing 4-acetoxy-2-methyl-2-butenal
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The invention provides a method for preparing 4-acetoxy-2-methyl-2-butenal. The method comprises the following steps: esterifying isopentenol to generate isopentenol acetate; and carrying out illumination oxidation on the isopentenol acetate in the presence of a photosensitizer to generate 4-acetoxy-2-methyl-2-butenal. The method has the advantages of cheap and easily available starting raw material isopentenol, high atom economy of the process route, no use of precious metals, less three wastes, and economic and effective synthesis route.
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Paragraph 0009; 0058; 0062
(2020/04/29)
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- Low-cost preparation method of 2-methyl-4-substituted carbonyloxy-2-butenal
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The invention provides a preparation method of 2-methyl-4-substituted carbonyloxy-2-butenal. The method comprises the following steps: carrying out a hydroformylation reaction on 1, 3-butadiene and synthesis gas (carbon monoxide and hydrogen) under the action of a catalyst to prepare 2-methyl-3-butenal, carrying out an addition reaction on the 2-methyl-3-butenal and halogen to prepare 2-methyl-3,4-dihalogenated butyraldehyde, and carrying out an elimination reaction and a substitution reaction on the 2-methyl-3, 4-dihalogenated butyraldehyde and carboxylate to prepare 2-methyl-4-substituted carbonyloxy-2-butenal. The method has the advantages of cheap and easily available raw materials, simple process flow, easy realization of reaction conditions, safe and simple operation, less wastewater generation amount, environmental protection, stable reaction intermediate product, appropriate reaction activity, high reaction selectivity, less side reactions, high target product yield and purityand low product cost, and is suitable for industrial production.
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Paragraph 0082-0083; 0087-088; 0097-0098
(2020/08/18)
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- Preparation method of 2-methyl-4-acetoxy-2-butenal
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The invention provides a preparation method of 2-methyl-4-acetoxy-2-butenal (I). The method comprises the steps: taking 2,2-disubstituent-4,7-dihydro-1,3-dioxepin (II) and synthesis gas as raw materials, performing hydroformylation reaction to prepare 2,2-disubstituent-5-formyl-4,7-dihydro-1,3-dioxepin (III), then performing reaction with an acetylation reagent to prepare 2-formyl-4-acetoxy-1-butene (IV), and performing double bond isomerization to obtain 2-methyl-4-acetoxy-2-butenal (I). The method has the advantages of cheap and accessible raw materials and low cost; the process flow is short, the reaction is easy to realize, the operation is safe, simple and convenient, the wastewater yield is low, and the green and environment-friendly effects are achieved; the method has the advantages of stable reaction intermediate product, proper reaction activity, high reaction selectivity, few side reactions and high yield, and is suitable for industrial production.
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Paragraph 0095-0103
(2020/02/10)
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- Preparation method of 2-methyl-4-acetoxy-2-butenal with high yield
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The invention provides a preparation method of 2-methyl-4-acetoxy-2-butenal (I) with high yield. The preparation method comprises the steps: with 2,5-dihydrofuran (II) and synthesis gas as raw materials, carrying out hydroformylation reaction under the action of a catalyst to prepare 3-formyl tetrahydrofuran (III); then carrying out a reaction with an acetylation reagent under the action of a catalyst to prepare 2-formyl-4-acetoxy-1-butene (IV); and carrying out double bond isomerization under the action of a catalyst to obtain 2-methyl-4-acetoxy-2-butenal (I). The method has the advantages ofcheap and accessible raw materials and low cost; the process flow is short, the reaction is easy to realize, the operation is safe, simple and convenient, the wastewater yield is low, and the green and environment-friendly effects are achieved; the method has the advantages of stable reaction intermediate product, proper reaction activity, high reaction selectivity, fewer side reactions and highyield, and is suitable for industrial production.
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Paragraph 0064; 0084-0092; 0096-0097
(2020/02/10)
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- Preparation method of 4-acetoxy-2-methyl-2-butenal
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The invention provides a preparation method of a vitamin A intermediate, namely 4-acetoxy-2-methyl-2-butenal. The method comprises the following steps: (1) carrying out ring opening on 3-methyl-1,2-epoxybutane under the action of alkaline acetate to generate 2-hydroxyl-3-butyl methyl acetate; (2) dehydrating 2-hydroxyl-3-butyl methyl acetate to obtain 3-methyl-2-butene acetate; and (3) carrying out one step selective oxidation on 3-methyl-2-butenyl acetate to obtain 4-acetoxy-2-methyl-2-butenal. According to the method, 3-methyl-1,2-epoxybutane is used as an initial raw material, the reactionsynthesis route is short, the atom economy is high, the operation is simple, and the method is an industrially optimized synthesis route.
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- Method for preparing 4-acetoxy-2-methyl-2-crotonaldehyde
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The invention discloses a method for preparing 4-acetoxy-2-methyl-2-crotonaldehyde, and provides a preparation method of five-carbon aldehyde which is an important intermediate of vitamin A. The method comprises the steps: (1) performing a reaction between 4-hydroxybutanal and (N, N-dimethyl) methylene ammonium iodide so as to produce 2-methylene-4-hydroxybutanal; (2) isomerizing 2-methylene-4-hydroxybutanal so as to obtain 4-hydroxy-2-methyl-2-crotonaldehyde; and (3) performing a reaction between 4-hydroxy-2-methyl-2-crotonaldehyde and acetic anhydride so as to obtain 4-acetoxy-2-methyl-2-crotonaldehyde (five-carbon aldehyde). According to the method, 4-hydroxybutanal which is adopted as a starting material is a common fine chemical intermediate, and is cheap and easily available, the method has a short reaction synthesis route, a high reaction yield, low cost, simple operation and little pollution to the environment, and an effective synthetic route is provided.
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Paragraph 0049; 0054-0055; 0056-0062; 0063-0069; 0070-0098
(2019/08/30)
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- Preparation method of 4-acetyloxy2-methyl-2-butenal
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The invention discloses a preparation method of 4-acetyloxy2-methyl-2-butenal. The method includes following steps: (1), feeding isoprene and Cl2 into an organic solvent containing a catalyst 1 and apolymerization inhibitor for addition reaction to obtain reaction liquid containing 1, 4-dichlorinated olefin; (2), enabling dichlorinated olefin obtained in the step (1) to react with an acetylationreagent under action of an acid binding agent, a cocatalyst and a catalyst 2 to obtain chlorinated olefin aldehyde alcohol ester; (3), allowing a product obtained in the step (2) to react with hexamethylenetetramine to generate 4-acetyloxy2-methyl-2-butenal. Isoprene and chlorine are used as starting raw materials, are common chemical raw materials and are low in cost and easy to obtain, and noblemetal catalysts are not needed, so that the preparation method is low in cost, simple to operate and little in environment pollution and is an effective synthetic route.
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Paragraph 0067; 0068; 0071; 0075; 0079; 0083; 0087; 0092
(2018/12/03)
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- Preparation method of 4-acetoxy-2-methyl-2-crotonaldehyde
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The invention provides a preparation method of 4-acetoxy-2-methyl-2-crotonaldehyde. The preparation method comprises the following steps that (1) prenyl chloride is oxidized with oxygen under the effect of a catalyst into 4-chloro-2-methyl-2-crotonaldehyde; and 2) 4-chloro-2-methyl-2-crotonaldehyde and acetate are reacted to obtain 4-acetoxy-2-methyl-2-crotonaldehyde. The method is cheap and available in prenyl chloride as a starting material and short in process route as well as is economic and effective.
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Paragraph 0069; 0073
(2018/11/22)
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- A process for preparing 4 - acetoxy -2 - methyl -2 - butenal new method
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The present invention provides a process for preparing 4 - acetoxy - 2 - methyl - 2 - butenal new method. Comprises the following steps: 1, fed with methanol reaction to generate acetal thing (I); 2, acetal thing (I) under the catalysis of the copper salt with the peroxide tert-butyl acetate is generated by the reaction (II) shrinks the aldehydo-ester; 3, shrinks the aldehydo-ester (II) hydrolyzed under acidic conditions to obtain 4 - acetoxy - 2 - methyl - 2 - butenal. The method of starting material fed in cheap and easy to obtain, the process route is short, three wastes, synthetic route economic and effective.
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Paragraph 0074; 0078
(2019/01/08)
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- Preparation method of 4-acetoxy group-2-methyl-2-butenal
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The invention discloses a preparation method of 4-acetoxy group-2-methyl-2-butenal. The method comprises the following steps: (1) enabling prenyl chloride and acetate to react to produce prenyl alcohol acetate under the catalysis of a phase transfer catalyst; (2) oxidizing the prenyl alcohol acetate obtained in the step (1) by using hydrogen peroxide under the catalysis of selenium dioxide to obtain the 4-acetoxy group-2-methyl-2-butenal. The method takes the prenyl chloride as the starting material, the prenyl chloride is a commonly seen intermediate of a fine chemical, is cheap and is easy to get, the reaction process does not need to use noble metal catalysts, the cost is relatively low, the synthetic route is short, the operation is simple, the environmental pollution is small, and thepreparation method is an effective synthetic route.
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- Preparation method of tiglic aldehyde derivative
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The invention provides a preparation method of a tiglic aldehyde derivative. The preparation method comprises the following step of carrying out catalytic oxidation on an isoamylene derivative represented as the following formula (I) in the presence of a catalyst to produce the tiglic aldehyde derivative represented as the following formula (II), wherein the catalyst is a non-metal oxide, and theR in the formula (I) or the formula (II) is selected from aliphatic hydrocarbyl, aryl, aralkyl, halogens, ester groups, acyloxy, acylamino or alkoxy. The preparation method of the tiglic aldehyde derivative provided by the invention has the characteristics of few reaction step, simple process, cheap and easily available raw materials and the like.
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Paragraph 0054-0056
(2018/06/16)
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- Regioselective rhodium-catalyzed hydroformylation of 1,3-dienes to highly enantioenriched β,γ-unsaturated aldehyes with diazaphospholane ligands
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Regioselective and enantioselective rhodium-catalyzed hydroformylation of 1,3-dienes with chiral bisdiazaphospholane ligands yields β,γ- unsaturated aldehydes that retain a C=C functionality for further conversion. The reaction conditions are mild, featuring low catalyst loadings (0.5 mol %), pressures readily obtained in glass bottles, and convenient reaction times (1.5-12 h). Optimized reaction conditions produce high enantioselectivity (>90% ee), regioselectivity (88-99%), and conversion to β,γ- unsaturated aldehydes (99%) for ten 1,3-dienes encompassing a variety of substitution patterns.
- Watkins, Avery L.,Landis, Clark R.
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supporting information; scheme or table
p. 164 - 167
(2011/04/12)
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