biostudies-literatureUnknown31(3)Chen WControl of process-related impurities is of critical importance for developing an efficient and suitable synthetic process of an active pharmaceutical ingredient. In the study of a key intermediate of silodosin (KIS), two process-related impurities including the benzaldehyde impurity (BAI) and indole impurity (IDI) were prepared and fully characterized to determine their downstream fate. Under optimized conditions, BAI was formed in a yield of ~48% by treating KIS with 10% hydrogen peroxide at 60 °C. Interestingly, BAI would not be expected to be the major product under the apparent Baeyer-Villiger oxidative condition. Furthermore, by adding 20 mM FeCl₃ into the above 10% hydrogen peroxide solution, IDI became the major product in a yield of ~43% under this Fenton reaction-like Molecules (Basel, Switzerland)462https://www.ebi.ac.uk/biostudies/studies/S-EPMC12898569biostudies-literaturePreparation of Two Process-Related Impurities of a Key Intermediate of Silodosin Under Baeyer-Villiger and Fenton Conditions.PMC12898569Xi JZhou QZhang JChen WBai ZJin JLi MfalsePreparation of Two Process-Related Impurities of a Key Intermediate of Silodosin Under Baeyer-Villiger and Fenton Conditions.Control of process-related impurities is of critical importance for developing an efficient and suitable synthetic process of an active pharmaceutical ingredient. In the study of a key intermediate of silodosin (KIS), two process-related impurities including the benzaldehyde impurity (BAI) and indole impurity (IDI) were prepared and fully characterized to determine their downstream fate. Under optimized conditions, BAI was formed in a yield of ~48% by treating KIS with 10% hydrogen peroxide at 60 °C. Interestingly, BAI would not be expected to be the major product under the apparent Baeyer-Villiger oxidative condition. Furthermore, by adding 20 mM FeCl₃ into the above 10% hydrogen peroxide solution, IDI became the major product in a yield of ~43% under this Fenton reaction-like 2026-01-01T00:00:00Z2026 Jan2026-07-09T13:12:01.426Z2026-07-09T13:09:13.422ZS-EPMC128985694168343910.3390/molecules31030462