10-HDA(link:https://www.bloomtechz.com/synthetic-chemical/api-researching-only/10-hda-cas-14113-05-4.html), chemical name 10-hydrogen-2-decenoic acid, molecular formula c10h18o3, CAS 14113-05-4, structural formula Ho·CH2·(CH2)6·ch=ch·COOH, melting point 52°C. It is a solid substance, and its common appearance is white to light yellow crystals. Its relative molecular mass is about 202.32 g/mol, which is the total mass composed of carbon, hydrogen, oxygen and other elements in it. This compound is a carboxylic acid and therefore has some acidity. It can react by releasing hydrogen ions and undergoes an acid-base neutralization reaction when present in aqueous solution. In nature, only royal jelly contains this substance. The antibacterial, anti-inflammatory effects of royal jelly are associated with the presence of this substance. The content of 10-Hydroxy-2-decenoic acid in fresh royal jelly was higher; the content of 10-Hydroxy-2-decenoic acid in royal jelly that was not fresh, improperly stored or adulterated was lower. Therefore, the content of 10-Hydroxy-2-decenoic acid is one of the important physical and chemical indicators to measure the quality of royal jelly. The general content should be above 1.4%. The determination method is gas chromatography or liquid chromatography. It has been artificially synthesized, and the properties and functions of the synthetic products are similar to those of natural products.
10-HDA Synthesis:
Because of the similarity of properties and functions, researchers have conducted in-depth research in order to increase yield and purity. There are many methods of artificially synthesizing 10-HDA that have been found so far, which will be introduced in the following descriptions.
method one:
The reaction of 1,8-octanediol in dichloromethane solvent after being adsorbed by quantitative silica-sodium bisulfite system gives 8-hydroxyoctanal, and after Witting reaction with ethyl phosphoroacetate, 10- Hydroxy-2-decenoic acid ethyl ester is hydrolyzed under the catalysis of potassium carbonate to generate 10-hydroxy-2-decenoic acid.
First, let's look at the first step:
The Reaction of 1,8-Octanediol Adsorbed by Quantitative Silica-Sodium Bisulfite System in Dichloromethane Solvent
In this step, 1,8-octanediol (molecular formula C8H18O2) is adsorbed by quantitative silica (SiO2) and sodium bisulfite (NaHSO3) system in dichloromethane (CH2Cl2) solvent. The adsorption process is generally carried out under stirring conditions to promote contact and reaction between reactants. Concrete reaction equation is as follows:
C8H18O2 + SiO2 + NaHSO3 → adsorption product
Next is the second step:
Oxidation to 8-Hydroxyoctanal
In this step, the adsorption product undergoes an oxidation reaction under the action of a suitable oxidant to obtain 8-hydroxyoctanal. Concrete reaction equation is as follows:
Adsorption product + oxidizing agent → 8-hydroxyoctanal
Then comes the third step:
Witting reaction to get 10-hydroxy-2-decenoic acid ethyl ester
In this step, 8-hydroxyoctanal is subjected to a Witting reaction with ethyl phosphoroacetate (PhOCOCH2CH2COOR) to give ethyl 10-hydroxy-2-decenoate. Concrete reaction equation is as follows:
8-Hydroxyoctanal + PhOCOCH2CH2COOR + base → ethyl 10-hydroxy-2-decenoate
And finally the fourth step:
Under the catalysis of potassium carbonate, the hydrolysis reaction produces 10-hydroxy-2-decenoic acid
In this step, ethyl 10-hydroxy-2-decenoic acid is hydrolyzed under the catalysis of potassium carbonate (K2CO3) to produce 10-hydroxy-2-decenoic acid. Concrete reaction equation is as follows:
10-Hydroxy-2-decenoic acid ethyl ester + K2CO3 + H2O → C10H18O3 + CH3CH2OH + KHCO3
Method Two:
To synthesize 10-hydroxy-2-decenoic acid, we need to go through a series of chemical reaction steps starting from suberic acid. The following is the detailed synthesis process and its corresponding chemical equation.
The first step: from suberic acid to 1,8-octanediol
First, suberic acid is reacted with LiAlH4, and a reduction reaction occurs to generate 1,8-octanediol.
LiAlH4 + HOOC(CH2)7COOH → HOH(CH2)7CH2OH + LiAlO2
Step 2: From 1,8-octanediol to 8-hydroxyoctanal
Next, 1,8-octanediol was reacted with Ag2CO3 and diatomaceous earth for selective oxidation to produce 8-hydroxyoctanal.
HO(CH2)7CH2OH + Ag2CO3 → HO(CH2)7CHO + 2Ag + CO2 + H2O
Step Three: From 8-Hydroxyoctanal to 8-Hydroxyoctanoic Acid Methyl Ester
8-Hydroxyoctanoic acid reacts with acetic anhydride to produce 8-hydroxyoctanoic acid methyl ester.
HO(CH2)7CHO + (CH3CO)2O → (CH3CO)2O(CH2)7COOH + CH3CHO
Step 4: From methyl 8-hydroxyoctanoate to ethyl 10-hydroxy-2-decenoate
8-Hydroxy octanoic acid methyl ester reacts with malonic acid to generate 10-hydroxy-2-decenoic acid ethyl ester through condensation reaction.
(CH3CO)2O(CH2)7COOH + CH2(COOH)2 → (CH3CO)2OCH=CH(CH2)7COOH + 2H2O
Step 5: From 10-hydroxy-2-decenoic acid ethyl ester to 10-hydroxy-2-decenoic acid
Finally, 10-hydroxy-2-decenoic acid ethyl ester is hydrolyzed to generate 10-hydroxy-2-decenoic acid.
(CH3CO)2OCH=CH(CH2)7COOH + H2O → CH=CH(CH2)7COOH + 2CH3COOH
In summary, through the above five-step chemical reactions, we successfully synthesized 10-hydroxy-2-decenoic acid using suberic acid as a raw material through reduction, oxidation, acetylation, condensation and hydrolysis steps.
In addition to the preparation methods mentioned above, the following are three other possible synthetic methods for the synthesis of 10-hydroxy-2-decenoic acid:
1. Grignard reaction method:
In this method, an appropriate Grignard reagent, such as the reaction of decane bromide and magnesium powder, is first prepared. The Grignard reagent is then reacted with carbon dioxide to form a carboxylate. Next, the carboxylate is converted to the corresponding carboxylic acid by acid hydrolysis. Finally, the carboxylic acid is converted to 10-hydroxy-2-decenoic acid by hydroxylation.
2. Azo compound method:
In this method, decene is first reacted with azomethane to form a methylenediazo compound. Then, the methylene diazonium compound is dissociated by heating or light to generate carbonyl carbonate. Finally, the carbonyl carbonate was converted to 10-hydroxy-2-decenoic acid by acid hydrolysis.
3. Peroxidation reaction method:
This method involves reacting decene with hydrogen peroxide (H2O2). In the presence of an appropriate catalyst, decene will undergo peroxidation to form hydroxyperoxides. Next, the hydroxyperoxide is ring-opened by acid catalysis to generate 10-hydroxy-2-decenoic acid.
These are possible methods for the synthesis of 10-hydroxy-2-decenoic acid. Note that each synthetic method has its specific reaction conditions and steps and needs to be performed under proper laboratory conditions. For more specific and detailed synthetic methods and reaction mechanisms, please refer to Handbook of Synthetic Organic Chemistry or relevant academic literature.