Abstract
The nucleophilic substitution of substituted o-nitrochlorobenzenes with substituted methanethiolates, catalysed with triethylamine or pyridine, has been used to prepare a series of appropriately substituted methyl-o-nitrophenylsulfides. The prepared compounds were identified by their 1H- and 13C-NMR spectra. The base catalysed ring closure of methyl 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylate only results in an attack of carbanion on the ester group, not on a nitro group as with the other compounds prepared. The cyclisation product is methyl 3-hydroxy-5,7-dinitro-benzo[b]thiophene-2-carboxylate (11).
Highlights
Wagner et al [1] have described the base-catalysed reaction of substituted 2-nitrochlorobenzenes with esters of sulfanylethanoic acid giving the correspondingly substituted 2-alkoxycarbonylbenzo[d]thiazol-3-oxides
We have found that the attack on the ester group is so fast that the carbanion attacks this group exclusively
Compound 9 was prepared in a “roundabout” way: the nucleophilic substitution with anion of methyl sulfanylethanoate was carried out on the 2-chloro-3,5-dinitrobenzenecarboxylate anion that was formed by adding 1 equivalent of triethylamine to 2-chloro-3,5-dinitrobenzenecarboxylic acid
Summary
Wagner et al [1] have described the base-catalysed reaction of substituted 2-nitrochlorobenzenes with esters of sulfanylethanoic acid giving the correspondingly substituted 2-alkoxycarbonylbenzo[d]thiazol-3-oxides. In the reaction of methyl sulfanylethanoate with methyl 2-chloro-3,5-dinitrobenzenecarboxylate in the presence of a base, the primary methyl 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylate (9) produces a carbanion, which can attack either the nitro group (to give the substituted benzo[b]thiazol-3-oxide) or the ester group (to give methyl 3-hydroxy-5,7-dinitrobenzo[b]thiophene-2-carboxylate (11); Scheme 3).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
