What solvent is used for hydroimide rearrangement? What are the steps?

Ethyl benzoate and decahydro can be used as solvents.

Ethyl benzoate has a relatively large flavor when it is expanded, and decahydrone has almost no taste, anyway, the solvent requires that the amine salt can be dissolved, so that the energy is transferred evenly and the finished product is not dissolved.

Heating to more than 160 degrees under the oil bath, preferably 200 degrees Celsius, turning off the heat source in advance to provide energy with waste heat can improve the yield.

There are only steps, and different reaction steps will also be different, such as:

Hydroimide is added to decahydronaide and heated at 170-180 degrees Celsius for rearrangement.

Hydrogen imide hydrochloride is dissolved into n-undecane and heated and boiled (190 degrees to 195 degrees) for 3-4 hours to rearrange.

The most commonly used solvents are ethyl benzoate and decahydronaphthalen, but each has its own advantages, ethyl benzoate is cheaper, that is, the taste is larger when the ring is expanded; Decahydrogenol is very expensive, but it is similar to water, there is almost no taste, choose by yourself, reaction rearrangement is the only place in the whole process that does not need to understand it, it is recommended to heat it to just 190 degrees under the oil bath, and the relative yield will be higher. In fact, as long as the temperature has reached 165, the reaction has been almost activated, because at this time, even if you immediately turn off the heat source and remove the oil bath device, the reaction will continue to release heat on its own, and the temperature can rise to about 180 degrees. However, there are now more advantages to using solid phase rearrangement.

When your amine rearrangement and ring expansion reaction is over, you should first pump the rate, then add ammonia water to separate the free base, then add activated carbon to decolorize, and then mix with solvent, stir thoroughly, add hydrochloric acid, and form salt. You can't go wrong with this order, and it's not difficult to operate.

The rearrangement solvent used here is not ethyl formate, but silver benzoate, and other solvents such as n-undecane, benzene, tetrahydrofuran, decahydronaphthalene and so on. However, liquid phase rearrangement is not recommended.

The solvent ethyl benzoate of liquid phase rearrangement has a low rate, and it is attached to the product and is not easy to completely remove, and the odor is relatively large and has many disadvantages.

Hydroxyyamine hydrochloride is mainly used as a pharmaceutical intermediate, and the final synthetic product is the medical anesthetic anhydride Luanone, because hydroxyyamine hydrochloride is a precursor chemical, it is listed as a class I chemical controlled by the public security department by the state, and the purchase, sales and use must apply for a hazardous chemicals business license, please be cautious. Now many people can only synthesize it by themselves, and it is expensive on the black market.

Of course, it is very good, in fact, there is no need for this at all, and it is enough to reduce imine with a simpler reducing agent, and NabH4 is easy to reduce the raw material aldehyde.

Try it with palladium, and then try it with nickel, and it is estimated that the activity is worse than platinum.