Observation of intermediates during the reaction of linear alkanesulfinyl chlorides with activated zerovalent zinc

Abstract

H, m). m/e(%) 146 (36.0), 131 (22.3), 105 (100.0), 77 (50.3), 69 (44.6). This product was not purified (lit.18 bp 90-95 °C (2 mmHg)).2-(2-Benzoyl-l-methylethyl)-3,5-diphenylpyrrole (29a).The sublimed product from the pyrolysis of 15a and 16 (0.12 g) was dissolved in CDC13 (0.5 mL) and the reaction was monitored by NMR. After 5-6 days at 25 °C the formation of 28a was completed. Addition of HBF4 (48%, 2 drops) gave 29a in 1 h. Removal of the solvent gave the adduct as a viscous oil: IR (CHBr3) 3430 m (NH), 1672 s (C=0) cm"1; NMR (CDC13) 1.5(3 H, d, J = 7 Hz), 3.4 (2 H, m), 3.6-4.S (1 H, m), 6.5 (1 H, d, J = 3 Hz), 7.0-8.1 (15 H, m), 8.6 (1 H, d, NH); 13C NMR (CDC13) 20.3 (q), 27.4 (d), 45.0 (t), 106.35 (d), 123.5-137.1 (aromatic C), 200.4 (s); m/e (%) 365 (24.7), 246 (100.0), 105 (48.0); high-resolution MS, m/e caled for C26H23NO, 365.1772; found, 365.1776. 2-(2-Benzoylethyl)-3,5-diphenylpyrrole (29b). Pyrolysis of 15b (0.3 g, 0.85 mmol) as above at 170-190 °C (1-5 mmHg) gave 0.18 g of a mixture of 27 and 29b. The adduct 29b (50 mg, 17%) was isolated by fractional recrystallization from EtOH: needles; mp 132-133 °C; IR (CHBr3) 3450 m (NH), 1680 s (C=0) cm'1;

The mechanism of radical-trapping antioxidant activity of plant-derived thiosulfinates

“…Spectral data are in accordance with those reported elsewhere. 49 (E)-Ethyl 3-(allylsulfinyl)acrylate (4). Ethyl propiolate (0.66 mL, 3.3 mmol) was added dropwise to a solution allicin (0.25 g, 1.5 mmol) in 30 mL of benzene and the mixture was stirred at 37 • C under N 2 for 24 h. The solvent was removed under reduced pressure and the resulting oil was purified by flash chromatography (70 : 30 hexanes-ethyl acetate) to afford a colourless oil (74%).…”

vic-Disulfoxides and OS-sulfenyl sulfinates

“…The water generated in the reaction can react with 30, 39, and/or 50 (eq 21,22,30). [4][5][6]10 Warming the reaction mixture to 0 °C leads to the reaction of 47 with 59 to afford 21 and 58.4-6,180-82 The absence of 47, 58, and 59 in the final product mixture is consistent with eq 31 and 32.10 4-CICsH4-S-S-CsH5 (36) 66 mation of thiosulfonate 64. Although formation of sulfinyl radicals with subsequent transfer of negatively charged oxygen has been proposed to account for the exchange of sulfenyl groups (eq 37, 38), this mechanism does not account for the absence of mixed thiosulfonates or diphenyl disulfide in the product mixture.…”

Exploring the synthetic application of sulfinyl radicals

“…This pathway was first proposed by Topping et al in 1962. 11 Despite the lack of direct experimental evidence, this pathway gained support from a number of chemists over the next two decades, including Oae, 12,41 Kice, 13,14,42 Miller, 15 Koch, 16 Howard, 40 Iino, 43 Freeman, [44][45][46][47] Singleton, 48 Bennett 49 and so on. Harpp et al designed a class of cyclic thiosulfinates (1a and 1b) and used nuclear magnetic resonance (NMR) to detect their oxidation in real time, which provides the first direct experimental evidence for the sulfinyl radical self-termination via the S-O coupling pathway (Table 3).…”

“…This pathway was first proposed by Topping et al in 1962. 11 Despite the lack of direct experimental evidence, this pathway gained support from a number of chemists over the next two decades, including Oae, 12,41 Kice, 13,14,42 Miller, 15 Koch, 16 Howard, 40 Iino, 43 Freeman, 44–47 Singleton, 48 Bennett 49 and so on.…”