You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A dimeric form of N-methoxycarbonyl-2-amino-1,8-naphthyridine bound to the A-A mismatch in the CAG/CAG base triad in dsRNA. A dimeric form of N-methoxycarbonyl-2-amino-1,8-naphthyridine (MCND) connected at the C2 position with a three-atom linker was examined for the binding to mismatches in double stranded RNA. Despite the fully complementary hydrogen bonding groups to guanine, MCND did not bind to guanine-guanine mismatch but did to adenine-adenine mismatch. The base pairs flanking the mismatch had weak effect on the binding, with showing the strongest binding to the A-A mismatch in the CAG/CAG sequence. The A-A mismatch in the GAC/GAC sequence was a poor substrate for the MCND binding. A monomeric derivative of MCND and another derivative lacking a methylcarbamate group showed negligilble binding to the A-A mismatch and the sequence selectivity. These results are important clues for the better molecular design of RNA binding small molecules.
{"Chemical": ["methylcarbamate", "adenine", "N-methoxycarbonyl-2-amino-1,8-naphthyridine", "hydrogen", "MCND", "guanine"]}