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:

Novel naphthoquinone derivatives: synthesis and activity against human African trypanosomiasis. A series of naphthoquinone derivatives has been synthesized and tested for its biological activity against human African trypanosomiasis. The use of reverse micellar medium not only enhanced the conversion rate, but also showed selectivity towards mono-coupled product in aryl chloride-aniline coupling reactions. Two derivatives of naphthoquinone (9b and 9c) exhibited potent activity against Trypanosoma brucei in vitro with low cytotoxicity.
{"Chemical": ["aniline", "naphthoquinone", "aryl chloride"]}