- Synthesis method of trans-2-methyl-2-pentenoic acid
-
The invention adopts a Reppe synthesis method to prepare 2-methyl-2-pentenoic acid. The method comprises the following steps: firstly, by taking m-pentadiene, carbon monoxide and water as raw materials, and taking precious metal rhodium salt and an organic phosphine ligand as catalysts, preparing a cis-trans isomeric intermediate of 2-methyl-3-pentenoic acid, and then carrying out isomerization reaction on the obtained intermediate product to generate trans-2-methyl-2-pentenoic acid, namely trans strawberry acid.
- -
-
Paragraph 0062-0067; 0073-0077
(2021/09/04)
-
- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
-
Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
-
supporting information
p. 3931 - 3943
(2018/09/11)
-
- A 2-methyl-2-pentenoic acid synthesis method
-
The invention discloses a synthesis method of a 2-methyl-2-pentenoic acid. The method comprises the following steps: by taking n-propanal as a raw material, synthesizing 2-methyl-2-pentenal by aldehyde-aldehyde condensation; generating 2-methyl-2-pentene aldehyde oxime by the effects of the 2-methyl-2-pentenal and hydroxylamine; dewatering and synthesizing 2-methyl-2-allyl acetonitrile by using the 2-methyl-2-pentene aldehyde oxime under the effect of acetic anhydride; hydrolyzing the 2-methyl-2-allyl acetonitrile into the 2-methyl-2-pentenoic acid under the effect of a sulfuric acid. The reaction formula of the 2-methyl-2-pentenoic acid is shown in the specification. Compared with the prior art, the technology disclosed by the invention has main advantages that the synthesis method is available in synthetic materials, simple to operate, good in process stability, and good in fragrance of synthetic product.
- -
-
-
- Pd/C and NaBH4 in basic aqueous alcohol: An efficient system for an environmentally benign oxidation of alcohols
-
We report the oxidation of a wide range of alcohols using an environmentally benign and economical process. The use of Pd/C heterogeneous catalysts along with NaBH4in aqueous ethanol or methanol and either K2CO3 or KOH as base at room temperature under molecular oxygen or air give the corresponding oxidation products. This protocol is versatile since it is capable of oxidizing alcohols to its desired carbonyl or carboxyl counterpart. Room temperature reaction in aqueous system and recyclability of the catalyst are among the advantages of this manipulation. These advantages make the process safe and cheaper rendering it favorable from both economic and environmental viewpoints. Georg Thieme Verlag Stuttgart New York.
- An, Gwangil,Ahn, Hyunseok,De Castro, Kathlia A.,Rhee, Hakjune
-
experimental part
p. 477 - 485
(2010/06/13)
-
- Thermolysis of 4-Methyl-4-(1-propenyl)malonyl Peroxide: Mechanistic Limits to Chemiluminescence Efficiency
-
The preparation and thermal chemistry of 4-methyl-4-(1-propenyl)malonyl peroxide (3) is described.Thermolysis in acetonitrile at 84 deg C gives 2,4-dimethylbut-2-en-4-olide in 45percent yield and an oligomeric ester derived from an intermediate α-lactone in 55percent yield.The reaction of 3 can be catalyzed by aromatic hydrocarbons such as perylene.Under these conditions weak chemiluminescence results.The mechanism for light generation is identified as chemically initiated electron-exchange luminescence (CIEEL).Application of the CIEEL mechanism to 3 reveals an important limitation to light generation by this path.
- Porter, Judith E.,Schuster, Gary B.
-
p. 4068 - 4071
(2007/10/02)
-
- Novel flavoring compositions and products containing isomer mixtures containing high proportions of 2-methyl-cis-3-pentenoic acid
-
Methods are described for producing mixtures containing greater than 50% 2-methyl-cis-3-pentenoic acid as well as substantially pure 2-methyl-cis-3-pentenoic acid for preparing foodstuffs, flavoring compositions for foodstuffs, chewing gum compositions, flavoring compositions for chewing gum, medicinal product compositions and ingredients for medicinal product compositions by including therein the isomeric mixtures containing greater than 50% cis-2-methyl-3-pentenoic acid produced by the above-stated processes in order to produce in foodstuff flavorings, medicinal product flavorings and chewing gum flavorings, a sweet, fruity, strawberry, winey-cognac, butter-like, rum-like and butterscotch aroma and a sweet, strawberry, nutty-coconut, fatty, butter-like, rum-like and butterscotch-like taste with fruity, coconut-like isovaleric undertones.
- -
-
-