N-acyl anthranilic acid derivative or salt thereof

An N-acyl anthranilic acid derivative of formula (I) or a salt thereof:

• wherein
• R1 represents an optionally protected carboxyl group or an optionally protected 1H-tetrazol-5-yl group;
• R2 represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, an optionally protected hydroxyl group, an optionally protected amino group, an optionally protected or substituted alkylamino group, an optionally substituted dialkylamino group, an optionally substituted alkyl group or an optionally substituted alkoxy group;
• R3 represents an optionally substituted aryl group or an optionally substituted heterocyclic group;
• X1 represents a carbonyl group;
• X2 represents a bond;
• X3 represents a bond;
• X4 represents an oxygen atom, an optionally protected imino group, an optionally substituted alkylene group or a bond;
• and
• A represents a group of formula (II):
• wherein
• R4 represents a hydrogen atom or a phenolic hydroxyl protecting group;
• one of R5, R6, R7, and R8 represents a group of formula —Y—R9:
• wherein
• R9 represents a cyano group, a nitro group, an optionally protected hydroxyl group, an optionally protected amino group, an optionally protected or substituted alkylamino group, an optionally substituted dialkylamino group, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group, an optionally substituted aryloxy group, an optionally substituted heterocyclic group, an optionally substituted heterocyclic oxy group, an optionally substituted acyl group, or an optionally substituted acyloxy group;
• Y represents an optionally substituted alkylene group, an optionally substituted alkenylene group, an optionally substituted alkynylene group, a bond, a group of formula —(CH2)m—O—(CH2)n—, or a group of formula —(CH2)m—NR10—(CH2)n—,
• wherein m represents an integer of 0 to 4, and n represents an integer of 1 to 4,
• wherein R10 represents a hydrogen atom, an optionally substituted lower alkyl group or an imino protecting group, and m represents an integer of 0 to 4, and n represents an integer of 1 to 4, and
• remaining moieties identically or differently each represent a hydrogen atom, a halogen atom, an optionally protected hydroxyl group, an optionally protected amino group, an optionally protected or substituted alkylamino group, or an optionally substituted dialkylamino group;
• or
• R5 and R8 identically or differently each represent a hydrogen atom, a halogen atom, an optionally protected hydroxyl group, or an optionally protected amino group, and
• R6 and R7 each represent, together with carbon atoms to which they bind, an optionally substituted 5- to 7-membered heterocyclic group, or
• A represents a group of formula (III):
• wherein
• one of Z1, Z2, Z3, Z4, and Z5 represents a nitrogen atom,
• one of the remaining four represents a group of formula C—R11,
• wherein R11 represents an optionally substituted aryl group, an optionally substituted nitrogen-comprising 6-membered aromatic heterocyclic group, an optionally substituted oxygen-comprising 5-membered aromatic heterocyclic group, an optionally substituted nitrogen-comprising oxygen-comprising 5-membered aromatic heterocyclic group or an optionally substituted nitrogen-comprising sulfur-comprising 5-membered aromatic heterocyclic group,
• the remaining three identically or differently each represent a group of formula C—R12,
• wherein R12 represents a hydrogen atom or a halogen atom.