9Th Brazilian Symposium on Medicinal Chemistry

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis, is a serious worldwide health problem. In this context, this work describes the synthesis of a series of substances containing the heterocycles pyrazine and benzylpiperazine, these heterocycles are present in substances that have demonstrated antimicobacterial activity. The reaction pathway started with the synthesis of benzyl chlorides from the reduction of benzaldehydes with sodium borohydride in ethanol followed by the reaction of the alcohols with thionyl chloride in dichloromethane. Reaction of benzyl chlorides with piperazine monohydrochloride in ethanol furnished key intermediates benzylpiperazines as a hydrochloride salt. Benzylpiperazines as free bases were generated previously before the last step of the synthesis or in situ. Different synthetic methodologies were tested in the last step of this route, the best methodology was found to be from free base benzylpiperazines with 2-pyrazinoil chlorides and triethylamine in dichloromethane, furnishing the desired products in yields ranging from 11-30%.