Diazomethane and its participating reactions (2)

3.

There are many methods for preparing diazomethane .

Where R is a sulfonyl group, a carbonyl group or a similar electron withdrawing group, the chemical structure is as follows:

example 1

The potassium hydroxide (18g, 0.

Example 2

It is prepared by the reaction of bis(N-methyl-N-nitroso) terephthalamide and 30% sodium hydroxide solution, and the operation is the same as in Example 1.

The above two methods involve strong carcinogenic nitrosamine intermediates, these intermediates need to be self-made, unstable and difficult to store, and the raw material has a large molecular weight, so the efficiency of preparing diazomethane is not high

Example 3

The method for preparing diazomethane with higher atom utilization is to react with chloroform and hydrazine hydrate in a strong alkaline environment in the presence of a phase transfer catalyst

In view of the multiple hazards of diazomethane, trimethylsilanated diazomethane n-hexane solution (such as 2mol/L) or ether solution, which is used as a methylating agent, rearrangement and ring expansion, etc.

Diazomethane is widely used as a methylating agent in organic synthesis.