Benzothiophenes. II.Ultraviolet and nuclear magnetic resonance (N.M.R.) spectra of some methoxybenzothiophenes was written by Angeloni, Annino Sante;Tramontini, Maurilio. And the article was included in Annali di Chimica (Rome, Italy) in 1963.Reference of 90560-10-4 This article mentions the following:
Ultraviolet spectra of 3-, 4-, 5-, 6-, and 7-methoxybenzothiophenes are presented. They are essentially similar to those of the Me derivatives Spectra of the methoxythioanisoles are presented in terms of their possible contribution to the benzothiophene chromophore. In the N.M.R. spectra, τ MeO = 5.79-6.22, and the Me derivatives have τ Me = 7.43-7.63. The o-, m-, and p-methoxythiophenetoles show a singlet from the MeO at about 6.20 τ, a CH2 quadruplet at about 7.20 τ, and a Me triplet at about 8.70 τ. Similarly, the methoxythioanisoles have r MeO of ∼6.2 and τ Me of ∼7.6. In 5-methoxybenzothiophene, the MeO group has τ = 5.79; this is clearly lower than the other derivatives, which are about the same as the τ values for MeO in the methoxythioanisoles and closer to τ = 5.92 of anisole itself. Distillation of the crude mixture from the cyclization of m-methoxyphenyl 2,2-dimethoxyethyl sulfide gave ∼35% of a mixture of 4- and 6-methoxybenzothiophene, b16 = 105-144°. The mixture was chromatographed on alumina. The 1st fractions gave the picrate of 4-methoxybenzothiophene, m. 108-9° (10%) (alc.). The same compound was obtained by the methylation of 4-hydroxybenzothiophene. The last fractions gave 15% of 6-methoxybenzothiophene, m. 38-9°. o-Methoxythiophenetole was prepared (66%) by treating an alk. solution of o-MeOC6H3SH with (EtO)2SO2. Repeated distillation at 123° at 12 mm. gave the product, m-Methoxythiophenetole, b12 125° (65%), was prepared similarly. In the experiment, the researchers used many compounds, for example, 6-Methoxybenzo[b]thiophene (cas: 90560-10-4Reference of 90560-10-4).
6-Methoxybenzo[b]thiophene (cas: 90560-10-4) belongs to benzothiophene derivatives. Benzothiophene is relatively a stable molecule. The electrophilic substitution of benzothiophene systems is much less regioselective than that of indoles. It is found within the chemical structures of pharmaceutical drugs such as raloxifene, zileuton, sertaconazole, and also BTCP.Reference of 90560-10-4
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem