Eine neue Synthese von Isothiazol aus 3-Thioacroleien

One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na2S2O3

The concise and efficient one-pot synthesis of 2-R-naphtho[2,3-b]thiophene-4,9-diones from 2-bromo-1,4-naphthoquinone and alkynes has been developed. The reaction proceeds through the formation of 2-(R-ethynyl)-1,4-naphthoquinones, which undergo transformation with Na₂S₂O₃ to 2-R-naphtho[2,3-b]thiophene-4,9-diones via C-H sulfuration, accompanied by the formation of the aromatic Bunte salt, followed by its air oxidation and 5-endo-dig cyclization. The protocol is characterized by simplicity, good tolerance for functional groups, relatively mild conditions, and commercially available starting compounds.

(15-Crown-5-κO)[S-(E)-1,2-dichloro-vinyl thio-sulfato-κO]sodium

In the title complex, [Na(C₂HCl₂O₃S₂)(C₁₀H₂₀O₅)], there are two independent complex units in the asymmetric unit, one of which has a 55:45% disorder in the 15-crown-5 component. The coordination sphere about the Na atom in each complex unit comprises five bonds to O atoms of the crown ether [Na—O = 2.390 (7)–2.466 (6) Å] and one to a thio­sulfate O atom [Na—O = 2.305 (4) and 2.447 (3) Å].