Proton NMR spectra of ethyl acetate derivatives of benzo[b) thiophenes, benzo[b) furans and quinolines show that there is a strong long range coupling between H3 and H7 (51). The coupling magnitude in benzo[b)thio~henes and benzo[b)furans was 0.73 ± 0.1 Hz. The observed coupling values between H4 and Hg ( J) H2 and h7 (6J) in quinolines were 0.73 ± 0.1 and 0.36 ± 0.1 . Hz respectively. Long range spin-spin coupling of ca. 0.73 ± 0.1 Hz over four bonds between ring proton and adjacent methine proton of ethylacetate group is observed for a wide variety of the title compounds.
I M A NAJJAR ,H B AMIN ,S S AL SHOWIMAN ,
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