The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The present invention relates to a preparation method of a long-chain compound, which includes the following steps: (1) carrying out condensation reaction on HR.sub.2 and R.sub.5N-Glu(OR.sub.4)OR.sub.3, wherein, R.sub.3 is a carboxyl protecting group, R.sub.4 is a carboxyl activating group, and R.sub.5 is an amino protecting group; obtaining a compound of formula II; (2) removing carboxyl protecting group R.sub.3 and amino protecting group R.sub.5 of the compound shown in formula II to obtain a compound of formula III; (3) carrying out condensation reaction on the compound shown in formula III and

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to obtain a compound shown in formula I. The method reduces the time of deprotection, and all the reactions can be carried out in a solvent with low boiling point. The post-processing requires only simple washing and recrystallization to obtain the product with higher purity, so the method is suitable for large-scale production.

Solid mixed catalysts and methods for use in conversion of triglycerides and free fatty acids to biodiesel are described. A batch or continuous process may be used with the catalysts for transesterification of triglycerides with an alkyl alcohol to produce corresponding mono carboxylic acid esters and glycerol in high yields and purity. Similarly, alkyl and aryl carboxylic acids and free fatty acids are also converted to corresponding alkyl esters. The described catalysts are thermostable, long lasting, and highly active.

Solid mixed catalysts and methods for use in conversion of triglycerides and free fatty acids to biodiesel are described. A batch or continuous process may be used with the catalysts for transesterification of triglycerides with an alkyl alcohol to produce corresponding mono carboxylic acid esters and glycerol in high yields and purity. Similarly, alkyl and aryl carboxylic acids and free fatty acids are also converted to corresponding alkyl esters. The described catalysts are thermostable, long lasting, and highly active.

A process for the oxidation of an organic carbonyl compound comprising reacting the compound, optionally in the presence of a solvent, with hydrogen peroxide in the presence of a catalyst comprising a tin-containing zeolitic material and at least one potassium salt.

A process for the oxidation of an organic carbonyl compound comprising reacting the compound, optionally in the presence of a solvent, with hydrogen peroxide in the presence of a catalyst comprising a tin-containing zeolitic material and at least one potassium salt.

The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The invention relates to bismuth perfluoroalkylphosphinates as Lewis acid catalysts, the compounds, and processes for the preparation thereof.

Ar.sub.xBi[OP(O)(R.sub.f).sub.2].sub.3-x(Ia),

Ar.sub.3Bi[OP(O)(R.sub.f).sub.2].sub.2(Ib).

The present disclosure is directed to fatty-acid glycerol ester derivative compounds containing a targeting bisphosphonate group. The disclosure further include pharmaceutical or biomedical compositions comprising these compounds, and methods of using these compounds and compositions forming microbubbles. The microbubbles have affinity for metal-containing, especially calcium-containing, bodies and/or biological targets. In certain embodiments, these compositions are useful for providing targeted placement of microbubbles capable of cavitation on application of high frequency energy.