{"knowledge_schema": {"broad_category": "Chemistry \u2192 Organic Chemistry \u2192 Stereochemistry", "refinement": "This problem involves analyzing the stereochemical properties of a synthesized peptidic compound based on NMR and LC-MS data.", "specific_scope": "The focus is on understanding the presence of duplicate peaks in the NMR spectrum and the LC-MS analysis indicating a mixture of compounds.", "goal": "Identify the most plausible explanation for the observed spectral data, particularly the duplicate peaks corresponding to the same alpha-proton."}, "summary": "In this analysis, we are examining a synthesized peptidic compound that shows duplicate peaks in the 1H NMR spectrum, indicating the presence of two distinct environments for the same alpha-proton. The equal integrals and similar chemical shifts suggest that these peaks arise from diastereoisomers rather than enantiomers or contamination. The LC-MS analysis further supports this by showing two peaks of equal intensity with the same mass spectrum. Therefore, the most likely explanation for these observations is that the crude compound exists as a mixture of diastereoisomers."}