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:

Identification and synthesis of N-(thiophen-2-yl) benzamide derivatives as BRAF(V600E) inhibitors. The V600E BRAF kinase mutation, which activates the downstream MAPK signaling pathway, commonly occurs in about 8% of all human malignancies and about 50% of all melanomas. In this study, we employed virtual screening and chemical synthesis to identify a series of N-(thiophen-2-yl) benzamide derivatives as potent BRAF(V600E) inhibitors. Structure-activity relationship studies of these derivatives revealed that compounds b40 and b47 are the two most potent BRAF(V600E) inhibitors in this series.
{"Chemical": ["N-(thiophen-2-yl) benzamide"]}