Compound containing oxo-pyrido-aliphatic ring or aliphatic heterocyclic structure, and medical use thereof

A compound as represented by the following formula I, or an isomer, pharmaceutically acceptable salt or solvate thereof:

• wherein,
• X1 and X2 are respectively independently CH or N, and X2 is preferably N;
• X3 and X4 are respectively independently C, CH or N;
• X5 is C, CH, CH2, NH or N;
• Y1 is CH2, O or NH, and Y1 is preferably O or NH;
• Y2 is O or S, and Y2 is preferably O;
• R2 is independently —H, —(C1-C6)alkyl or —(C3-C8)cycloalkyl when occurring each time, and n is 0, 1, 2, 3, 4, 5 or 6,
• or, two R2 form a 3-6 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which R2 attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which R2 attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S,
• or, —(R2)n forms a 3-6 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which —(R2)n attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which —(R2)n attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S;
• R3 is independently —H, —(C1-C6)alkyl or —(C3-C8)cycloalkyl when occurring each time, and o is 0, 1, 2, 3, 4, 5 or 6,
• or, two R3 form a 3-6 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which R3 attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which R3 attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S,
• or, —(R3)o forms a 3-6 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which —(R3)o attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which —(R3)o attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S;
• A has a structure as represented by the following formula II:
• a G-chain group forms a 5-7 membered aliphatic ring or aliphatic heterocyclic ring together with two carbon atoms to which the G-chain group attaches, and ring-forming heteroatoms in the aliphatic heterocyclic ring are —O—, —S— or
• R1 is independently —H, —(C1-C6)alkyl or —(C3-C8)cycloalkyl when occurring each time, and m is 0, 1, 2, 3, 4, 5 or 6,
• or, two R1 form a 3-8 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which R1 attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which R1 attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S,
• or, —(R1)m forms a 3-6 membered aliphatic ring or aliphatic heterocyclic ring together with atoms to which —(R1)m attach, the aliphatic ring or aliphatic heterocyclic ring optionally forms a spiro structure, a fused ring structure or a bridged ring structure with the ring to which —(R1)m attach, and heteroatoms in the aliphatic heterocyclic ring are O, N or S.