Acetylation of 2-bromo-3-methyl- and 3-bromo-2-methylthianaphthene and the Schmidt reaction of the products was written by Matsuki, Yasuo;Ito, Ichi. And the article was included in Nippon Kagaku Zasshi in 1967.Safety of 3-Bromo-2-methylbenzo[b]thiophene This article mentions the following:
2-Bromo-3-methylthianaphthene (11.4 g.) in 35 ml. PhNO2 was treated with 4.35 g. AcCl and 7.35 g. AlCl3 at 10° to give 9.2% 4-acetyl-2-bromo-3-methylthianaphthene (I), m. 123-4°, 2,4-dinitrophenylhydrazone m. 278° (decomposition), 67.4% Ia (R1 = Br, R2 = Me, R3 = Ac) (II), m. 114-15°; 2,4-dinitrophenylhydrazone m. 270-1°, and 19.1% Ia (R1 = Ac, R2 = Me, R3 = H) (III). Reaction at 25° gave 9.9% I, 72.7% II and 26.6% III. Similar reaction of 3-bromo-2-methylthianaphthene gave 94.1% Ia (R1 = Me, R2 = Br, R3 = Ac), m. 96-7°, 2,4-dinitrophenylhydrazone m. 282° (decomposition), at 0° and 80.6% 3-acetyl-2-methylthianaphthene at 10°. The results were attributed to the electron density at 3 position. II (1 g.) was dissolved in 80 ml. MeOH containing 0.23 g. NaOH and hydrogenated over Pd-C to yield 0.66 g. Ia (R1 = H, R2 = Me, R3 = Ac), m. 42-3°; 2,4-dinitrophenylhydrazone m. 282° (decomposition). II (2.7 g.) was treated with KClO (3.8-4 g.) in 30-5 ml. H2O and 20 ml. dioxane at 55-60° and then at 80° to give 2.62 g. Ia (R3 = CO2H) (Ib, R1 = Br, R2 = Me) (IV), m. 261-2°; Me ester m. 131-2°. Similarly the following Ib were obtained (R1, R2, m.p. and m.p. of Me ester given): H, Me, 226-7°, -; Me, Br (V), 272-3°, 98-9°; Me, H, 228-9°, 48-9°. Heating IV with Raney Ni yielded p-iso-PrC6H4CO2H. Similarly V gave p-PrC6H4CO2H. II (4.04 g.) in 19.5 ml. AcOH and 1.95 g. H2SO4 was treated with 1.95 g. NaN3 at 65-70° to give 63% Ia (R1 = Br, R2 = Me, R3 = AcNH) (VI), m. 196-7°, and 13% Ia (R1 = Br, R2 = Me, R3 = NH2) sulfate, m. 234°. Similarly the following Ia were obtained (R1, R2, R3, % yield, m.p. of the acetamido derivative, % yield and m.p. of amine sulfate given): Me, Br, AcNH, 71, 181.5-2°, 19, 272° (decomposition); AcNH, Me, H, 50, 180-1°, -, -; Me, AcNH, H, 82, 184-5°, -, -. Reduction of VI with Na-Hg gave 6-acetamido-3-methylthianaphthene. 2-(N-Methylcarbamoyl)-3-methylthianaphthene, m. 139-40°, and 3-(N-methylcarbamoyl)-2-methylthianaphthene, m. 166-7°, were prepared In the experiment, the researchers used many compounds, for example, 3-Bromo-2-methylbenzo[b]thiophene (cas: 10243-15-9Safety of 3-Bromo-2-methylbenzo[b]thiophene).
3-Bromo-2-methylbenzo[b]thiophene (cas: 10243-15-9) belongs to benzothiophene derivatives. Benzothiophene is relatively a stable molecule. The core structure is a part of various pharmaceutical substances and natural products. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization.Safety of 3-Bromo-2-methylbenzo[b]thiophene
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem