Production process and intermediate of tetrazole compound

A process for producing a tetrazole compound of general formula (1):

• wherein R1 is as defined below, characterized in that a nitrile of general formula (2):
• R1CN (2)
• wherein R1 is a 4-oxo-4H-benzopyranyl group substituted with R2, or a phenyl group substituted in its 2-position with X, in which R2 is an R3CONH group;
• R3 is a C1-C20 alkyl group, a phenyl group, a phenyl-substituted (C1-C20) alkyl group, a phenyl-substituted (C1-C20) alkoxyphenyl group or a (C1-C20) alkoxyphenyl group;
• X is a phenyl group optionally substituted with Y;
• and Y is a C1-C20 alkyl group, a C1-C20 alkyl group substituted with one or more hydroxy groups whereby optionally the hydrogen atom in the hydroxy group is replaced for protection, a C1-C20 alkyl group substituted with one or more amino groups whereby optionally at least one hydrogen atom in the amino group is replaced for protection, a C1-C20 alkyl group with at least one hydrogen atom being replaced by a halogen atom, a C1-C20 alkoxy group, a C1-C20 alkoxy group substituted with one or more hydroxy groups whereby optionally at least one of the hydrogen atom(s) in the hydroxy group(s) is replaced for protection, a C1-C20 alkoxy group substituted with one or more amino groups whereby optionally at least one hydrogen atom in the amino group is replaced for protection, or a C1-C20 alkoxy group with at least one hydrogen atom being replaced by a halogen atom, is reacted with anhydrous hydrazine or a salt thereof in the presence of a catalyst which is at least one selected from alkoxides, alkali metals, alkali metal amides, alkali metal hydrides, alkaline earth metal hydrides, sulfides or salts thereof, thiocyanoates, pyridine compounds, alkylamines, aromatic amines, diamines and organic quarternary ammonium salts, followed by reaction with a nitrous acid compound of general formula (3):
• ANO2 (3)
• wherein A is a hydrogen atom, an alkali metal, an alkaline earth metal or a C1-C20 alkyl group.