Halogeno-substituted 2- and 3-methylbenzo[b]thiophenes: Use of 1H NMR spectral analysis and 1H{1H} nuclear Overhauser effect for locating the halogen substituent

✍ Scribed by Ma. Rosa Cuberes; Marcial Moreno-Mañas; Francisco Sánchez-Ferrandom

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 582 KB
• Volume: 23
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260231006

✦ Synopsis

Thiiy-seven halogeno-substituted 2and 3-methyl-(or halogenomethyl)-benzo[b]thiophenes, including 17 new compounds, were prepared. The constitution of 14 of these was confirmed by full analysis (LAOCOON) of their 80MHz'HNMR spectra and by 'H{'H} NOE measurements. In this way a by-product from the preparation of 4and 6-bromo-3-bromomethyIbenzo[b]thiophenes was shown conclusively to be 5-bromo-3bromomethylbenzo[b]thiophene. The 3-substituted benzo[b]thiophenes showed greater NOE enhancement factors at H-4 than at H-2 when the 3-methyl or halogenomethyl substituent was irradiated. 'H NMR OF HALOGENO-SUBSTITUTED 2-AND 3-METHYLBENZO[b]THIOPHENES 'Same as footnote j.

"This compound was unexpectedly isolated as a by-product, together with 22 and 24 (see text).