PROCESS FOR PRODUCING v-COELENTERAZINE COMPOUNDS

A process for producing a v-coelenterazine compound represented by general formula (II):

• (wherein:
• R1 is hydrogen, a halogen, a substituted or unsubstituted hydrocarbon group, or a substituted or unsubstituted heterocyclic group,
• each of R2 and R3 independently represents hydrogen, hydroxy, an alkoxyl, a halogen, or a substituted or unsubstituted hydrocarbon group), which comprises:
• (1) the step of reacting a compound represented by general formula (VIII):
• (wherein R1 is the same as defined above and R4 is a protecting group) with a methyltriphenylphosphonium salt in the presence of a base to give a compound represented by general formula (IX):
• (wherein R1 and R4 are the same as defined above),
• (2) the step of performing a ring-closing metathesis reaction on any one selected from the group consisting of the compound represented by general formula (IX) and a compound represented by general formula (X) which is the compound represented by general formula (IX) wherein the amino is protected with R5:
• (wherein R1 and R4 are the same as defined above and R5 is a protecting group), and then deprotecting R4 and, if any, R5 to give a v-coelenteramine compound represented by general formula (XIV):
• (wherein R1 is the same as defined above), and,
• (3) the step of reacting the compound represented by general formula (XIV) with a compound represented by general formula (XV):
• (wherein each of R2′ and R3′ independently represents hydrogen, hydroxy, an alkoxyl, a halogen, a hydrocarbon group, or a hydroxy group protected with a protecting group) to give the compound represented by general formula (II).