Studies On The Base-promoted N- Alkylation And C – Alkenylation With Alcohols

Nitrogen-containing compounds play a core role in organic chemistry. Mostly nitrogen-containing heterocyclic compounds are bioactive molecules and they have been widely used in medicine and pesticide. So synthesis of them has aroused great interest of organic chemists and has became a popular field of organic synthesis. Synthesis and researches of these compounds, such as amination, alkenylation have became popular in the field of chemistry organic synthesis.Lots of protocols for the synthesis of amines have been developed, such as Hoffmann N-alkylation reaction, reductive amination reaction, coupling reaction of alcohol and amine, etc..Contrastly, the reaction using alcohols as the N-alkylation reagents is the most green method to synthesize amines. The N-alkylation reaction starting from alcohols have many advantages, alcohols are green agents, easy to obtain, low price, stable nature is easy to save, water is the only byproduct. The typical procedure of N-alkylation reaction of alcohols and amines is "borrowing hydrogen" mechanism by transition metal catalysts. Recently, this field have been deeply studied, and have achieved many good results. But the transition metal catalysts(Ru, Rh, Pd, Ir, etc.) are expensive, toxicity and must performed in harsh conditions. The another way of N-alkylation is the air-promoted aerobic mechanism. With the deeply study of the research, it has been reported that the reaction could happen with cheap metal catalysts like Cu, Fe or even transition metal-free catalysts. It is necessary to develop more green synthesis method, reduce the use of transition metal and try to improve some of transition metal catalysis methods.In this paper, firstly, we have studied the N-alkylation reactions of 2-aminobenzothiazoles, 2-aminopyrimidines, and 2-aminopyrazine with primary or secondary alcohols, The reaction can be achieved without any external catalysts in the nitrogen atmosphere or even in the air condition. In addition, it could also be conducted under solvent-free condition, which could reduce pollution to the environment and low the cost. In a word, it’s a green, practical and efficient method.Secondly, we have studied the alkenylation reaction of six-member containing-N heterocyclic compounds and alcohols. Compared with other methods reported, such as alkenylation of N-oxides compounds or N-iminopyridinium ylides, our rection is “one-pot” and metal-free. The extra step to cleave the N-O or N–N bond is avoided. In general, this method own the characteristic, mild condition, low cost, environment friendly, simple and highly efficiency.