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:

Asymmetric synthesis and anti-protozoal activity of the 8,4'-oxyneolignans virolin, surinamensin and analogues. The asymmetric synthesis of 8,4'-oxyneolignans (-)-virolin, (-)-surinamensin and a number of analogues has been achieved. A divergent synthesis was used, with all compounds being elaborated from a single chiral aldehyde derived from ethyl lactate. In the 15 compounds that were tested, the level of substitution on the A-ring was found to directly influence the activity against Leishmania donovani whilst the activity against Plasmodium falciparum was influenced by numerous substitution and stereochemical factors.
{"Chemical": ["aldehyde", "ethyl lactate", "(-)-surinamensin", "(-)-virolin", "8,4\u0027-oxyneolignans", "surinamensin", "virolin"]}