6results about "Preparation by halogen elimination" patented technology

The application discloses a preparation method of a key intermediate of a montelukast sodium side chain acid, belongs to the technical field of pharmaceutical intermediates, and relates to a key intermediate of a montelukast sodium side chain acid, i.e. 1-bromomethylcyclopropylacetonitrile, which is characterized by the preparation method of the 1-bromomethylcyclopropylacetonitrile. The preparation method is as follows: taking tribromoneopentyl alcohol as a starting material, and obtaining 1-bromomethylcyclopropylacetonitrile through a cyclization reaction, an iodination reaction and a cyano substitution reaction. The 1-bromomethylcyclopropylacetonitrile is prepared by using a brand-new synthesis process, starting from tribromoneopentyl alcohol, through a cyclization reaction, an iodination reaction and a cyano substitution reaction. The method solves the blank of the preparation method of 1-bromomethylcyclopropylacetonitrile in the prior art, and also solves the defects of a long reaction theoretical cycle and a low actual yield and a large amount of impurities in the reaction of preparing 1-bromomethylcyclopropylacetonitrile by first preparing 1-hydroxymethylcyclopropylacetonitrile and then reacting phosphorus tribromide with the 1-hydroxymethylcyclopropylacetonitrile.

The present invention provides a mechanochemical reaction method and reaction apparatus that allows for operations such as adding reagents during the reaction, removing reaction products, and adding substrates for the next reaction without removing the lid of the reaction vessel, while preventing a decrease in reaction efficiency and ensuring safety. Furthermore, it allows for checking the state inside the reaction vessel, and improves operability and workability, while shortening (accelerating) the reaction process. [Solution] A mechanochemical reaction method using a reaction apparatus A comprising a reaction vessel 11 having an opening and a lid 12 that seals the opening 13 of the reaction vessel in an openable and closable manner, wherein one or more through holes 21 are provided in the reaction vessel other than the opening and / or in the lid, communicating the inside of the reaction vessel with the outside of the reaction vessel.

Stereoselective methods of producing a stereoisomer of p-menthane-3,8-diol are disclosed, the methods comprising the steps of: hydrating the alkene group of isopulegol, or performing a ring opening reaction on verbenol and hydrogenating and deprotecting the resulting diol. Also disclosed are compositions comprising 95mol% or greater of a stereoisomer of p-menthane-3,8-diol and insect repellents, flavourings or fragrances comprising such compositions. Also disclosed are methods of reducing resistance of a target insect or tick species to a p-menthane-diol repellent.

The invention relates to a method for removing chloropropylene glycol in epichlorohydrin wastewater, which comprises the following steps: in a hydrogen atmosphere, contacting the epichlorohydrin wastewater with a hydrodechlorination catalyst to carry out catalytic hydrodechlorination reaction, so that the chloropropylene glycol in the epichlorohydrin wastewater is converted into propylene glycol; wherein the hydrodechlorination catalyst comprises an activated carbon carrier and an active metal component; the active metal component comprises Ru. According to the method provided by the invention, the chloropropylene glycol in the epichlorohydrin wastewater can be efficiently removed, a propylene glycol product with higher value is obtained, and the treatment cost of the chloropropylene glycol is reduced.

In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein is versatile polyene cyclization strategy that exploits conjugated b-ionyl derivatives. Photomediated disruption of the extended p-system within these chromophores unveils a contra-thermodynamic polyene that engages in a Heck-type cyclization to afford [4.4.1]-propellanes. The connectivity of overbred polycycles generated from this process is controlled by the position of the requisite C–Halide bond. Thus, compared to conventional biomimetic polyene cyclization, this approach allows for complete control of regiochemistry and facilitates incorporation of both electron-rich and electron-deficient (hetero)aryl groups. This strategy was successfully applied to the total synthesis of abietanes such as, for example, taxodione and salviasperanol, two isomeric abietane-type diterpenes that previously could not be prepared along the same synthetic pathway.

This invention discloses a method for preparing 6-bromo-6,6-difluoro-1-hexanol, belonging to the field of organic synthesis. The method uses 4-penten-1-ol as a starting material, reacting it with dibromodifluoromethane via an addition reaction to prepare 4,6-dibromo-6,6-difluoro-1-hexanol; then, a dehalogenation reaction is carried out using a second metal reagent to obtain 6-bromo-6,6-difluoro-1-hexanol. In this method, the reactants and reagents are inexpensive and readily available, the reaction steps are short, and production control is convenient; the reaction conditions are mild, ensuring high safety; the process is simple, and the product has high purity.