Abstract: A process for preparing a N-tert-butyl-2-pyrazinecarboxamide having the formula (2): ##STR1## which comprises reacting a cyanopyrazine having the formula (1): ##STR2## with tert-butyl alcohol in the presence of sulfuric acid and a process for preparing a N-tert-butyl-2-piperazine-carboxamide having the formula (3): ##STR3## which comprises hydrogenating of said N-tert-butyl-2-pyrazinecarboxamide having the formula (2) in the presence of Raney nickel or Raney cobalt.

Abstract: A process for preparing a N-tert-butyl-2-pyrazinecarboxamide having the formula (2): ##STR1## which comprises reacting a cyanopyrazine having the formula (1): ##STR2## with tert-butyl alcohol in the presence of sulfuric acid and a process for preparing a N-tert-butyl-2-piperazine-carboxamide having the formula (3): ##STR3## which comprises hydrogenating of said N-tert-butyl-2-pyrazinecarboxamide having the formula (2) in the presence of Raney nickel or Raney cobalt.

Abstract: A process for preparing a tertiary amine-N-oxide which comprises reacting a tertiary amine with a peroxide in the presence of a catalyst comprising an oxide containing silicon and titanium atoms. According to the process of the present invention, a tertiary amine-N-oxide can be obtained in a high yield, and since the catalyst can easily be separated from the reaction mixture, the tertiary amine-N-oxide can be obtained in a high purity without the contamination by the catalyst.

Abstract: This invention is to provide a pyrazine derivative capable of developing excellent therapeutic efficacy in infectious diseases caused by various acid-fast bacteria.The pyrazine derivative of this invention is represented by the general formula ##STR1## wherein R.sub.1 is an octyl group or a pivaloyloxymethyl group.

Abstract: 1,8-Naphthyridine compounds and a process for preparing chelated 1,8-naphthyridine derivatives and 1,8-naphthyridine derivatives which are pharmacautically useful compounds. Chelated 1,8-naphthyridine derivatives of the general formula [I]: ##STR1## wherein X and Y are independently a lower alkyl group, are prepared by subjecting a compound of the general formula [II]: ##STR2## wherein X and Y are as defined above and R is a lower alkyl group, to ring-closing condensation in the presence of boron trifluoride and/or a boron trifluoride complex at an elevated temperature, and 1,8-naphthyridine derivatives of the general formula [III]: ##STR3## wherein X and Y are as defined above, are prepared by treating the chelated 1,8-naphthyridine derivatives with water and/or an alcohol. The desired products can be readily obtained in high yields. The chelated compounds are novel compounds.