Process for producing benzo[f]quinoxaline compounds

A process for producing a v-coelenteramine compound represented by formula (XIV):

• (wherein R1 is hydrogen;
• a halogen;
• an aryl which may optionally be substituted with at least one selected from the group consisting of a halogen, hydroxy, an alkyl having 1 to 6 carbon atoms, an alkoxy having 1 to 6 carbon atoms, an amino and a dialkylamino having 1 to 6 carbon atoms;
• an arylalkyl which may optionally be substituted with at least one selected from the group consisting of a halogen, hydroxy, an alkyl having 1 to 6 carbon atoms, an alkoxy having 1 to 6 carbon atoms, an amino and a dialkylamino having 1 to 6 carbon atoms;
• an arylalkenyl which may optionally be substituted with at least one selected from the group consisting of a halogen, hydroxy, an alkyl having 1 to 6 carbon atoms, an alkoxy having 1 to 6 carbon atoms, an amino and a dialkylamino having 1 to 6 carbon atoms;
• an alkyl which may optionally be substituted with an alicyclic group;
• an alkenyl which may optionally be substituted with an alicyclic group;
• an alicyclic group, a heterocyclic group;
• or an alkynyl which may optionally be substituted with an alicyclic group), which comprises:
• (1) reacting a compound represented by formula (VIII):
• (wherein R1 is the same as defined above and R4 is a protecting group selected from the group consisting of methyl, methoxymethyl, tetrahydropyranyl, benzyl, 4-methoxybenzyl, tert-butyldimethylsilyl, trimethylsilyl, triethylsilyl, phenyldimethylsilyl, tert-butyldiphenylsilyl and triisopropylsilyl) with a methyltriphenylphosphonium salt in the presence of a solvent and a base to give a compound represented by formula (IX):
• (wherein R1 and R4 are the same as defined above), and,
• (2) performing a ring-closing metathesis reaction on any one selected from the group consisting of the compound represented by formula (IX) and a compound represented by formula (X) which is prepared by protecting the amino in formula (IX) with R5:
• (wherein R1 and R4 are the same as defined above and R5 is a protecting group selected from the group consisting of acetyl, benzoyl, p-tosyl, tert-butoxycarbonyl and benzyloxycarbonyl) in the presence of a solvent and a catalyst, and then deprotecting R4 and, if any, R5.