2220 (m), 1595 (m), 1440 (s), 1150 (s); MS, m/e 285 (El); exact mass caled for 016 01 02 285.0556, found 285.0553. 2-Chloro-4-cyano-3-ethoxy-l-hydroxydibenzofuran (37).A solution of 0.25 g (0.70 mmol) of 33d and 0.10 mL (0.77 mmol) of trimethylsilyl chloride in 75 mL of dry CCI4 was added dropwise to 300 mL of refluxing CC14. The solution was heated at reflux for 1.5 h and then concentrated. The residue was absorbed on to silica gel and subjected to flash chromatography (1:1 hex-anes/ethyl acetate) to give 0.15 g (76%) of off-white crystals (37): mp 214-215 °C;
A regioselective oxidation of N-indan-4-yl-acetamide or N-(5,6,7,8-tetrahydronaphthalen-1-yl)acetamide with potassium permanganate followed by acidic hydrolysis gave 7-aminoindan-1-one or 8-aminotetral-1-one in good yield. The amino ketones were converted to the corresponding 7-haloindanone or the 8-halotetralone. Another method to prepare 7-haloindan-1-ones was completed by a cyclization of 3-chloro-1-(2-halophenyl)propan-1-one under Friedel-Crafts conditions to produce the product in gram quantity.
Mammalian flavin-containing monooxygenase (FMO) is active towards many drugs with a heteroatom having the properties of a soft nucleophile. Thiocarbamides and thiones are S-oxygenated to the sulfenic acid which can either react with glutathione and initiate a redox-cycle or be oxygenated a second time to the unstable sulfinic acid. In this study, we utilized LC-MS/MS to demonstrate that the oxygenation by hFMO of the thioureas under test terminated at the sulfenic acid. With thiones, hFMO catalyzed the second reaction and the sulfinic acid rapidly lost sulfite to form the corresponding imidazole. Thioureas are often pulmonary toxicants in mammals and, as previously reported by our laboratory, are excellent substrates for hFMO2. This isoform is expressed at high levels in the lung of most mammals, including non-human primates. Genotyping to date indicates that individuals of African (up to 49%) or Hispanic (2–7%) ancestry have at least one allele for functional hFMO2 in lung, but not Caucasians nor Asians. In this study the major metabolite formed by hFMO2 with thioureas from Allergan, Inc. was the sulfenic acid that reacted with glutathione. The majority of thiones were poor substrates for hFMO3, the major form in adult human liver. However, hFMO1, the major isoform expressed in infant and neonatal liver and adult kidney and intestine, readily S-oxygenated thiones under test, with Kms ranging from 7–160 μM and turnover numbers of 30–40 min−1. The product formed was identified by LC-MS/MS as the imidazole. The activities of the mouse and human FMO1 and FMO3 orthologs were in good agreement with the exception of some thiones for which activity was much greater with hFMO1 than mFMO1.
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