Thiophene and furan selenides. 2. Metal plating and acylation of alkyl-(2-thienyl)selenides was written by Sukiasyan, A. N.;Litvinov, V. P.;Gol’dfarb, Ya. L.. And the article was included in Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya in 1970.Application of 29421-99-6 This article mentions the following:
Me 2-thienyl selenide (I) b15 80-2°, n20D 1.6175; Me 5-methyl-2-thienyl selenide (II) b14 94-5°, 1.5985. I (7.08 g) and 4 ml POCl3 mixed in DMF at below 20° and heated 5 hr at 100° gave, after quenching in ice, 85% 5-methylseleno-2-thiophenecarboxaldehyde (III), b3 125-6°, m. 18°; semicarbazone m. 177.5-8.5°. Oxidation of III with Ag2O gave 5-methylseleno-2-thiophenecarboxylic acid (IV), m. 108-9°. II similarly treated with POCl3 in DMF gave 26% 2-methylseleno-5-methyl-3-thiophenecarboxaldehyde (V), m. 34-5° (semicarbazone m. 196.5-7°), which also oxidized to the carboxylic acid, m. 188-9°, with Ag2O. 5-Methyl-3-thiophenecarboxaldehyde (VI) treated with HC(OEt)3 in the presence of concentrated HCl in EtOH 20 hr gave the di-Et acetal of VI, b10 105-8°, 1.4892, which, with BuLi at -20°, then refluxed in Et2O, treated with powd. Se at -20°, refluxed 2 hr, and refluxed with MeI 1 hr gave 28% V di-Et acetal, b2 117-20°, 1.5579, which, heated with concentrated HCl 10 hr gave 85% V. I and AcCl in PhCl treated with SnCl4 at 0°, and kept 1 hr at 20° gave, after aqueous HCl treatment, 75% 5-methylseleno-2-acetothienone, m. 35.5° (semicarbazone m. 200-1.5°), which oxidized with iodine in pyridine to IV. Similarly prepared was 25% 2-methylseleno-5-methyl-3-acetothienone, m. 91.5-2.5°, which oxidized with iodine-pyridine to the corresponding acid, m. 188-9°. 4-Bromo-2-thiophenecarboxaldehyde, m. 46-7°, was reduced with N2H4 to 90% 4-bromo-2-methylthiophene, b22 77-8°, 1.5727, which was conventionally converted into 5-methyl-3-thiophenecarboxaldehyde, b10 80-1°, 1.5672. 2-Methyl-3,5-dibromothiophene, b8 93°, 1.6068, treated at -70° with BuLi in Et2O under N, followed by Me2Se2 and holding 1 hr gave after aqueous treatment 75.4% 4-bromo-2-methylseleno-5-methylthiophene, b8 123-6°, 1.6340, which, with BuLi in Et2O at -70° 2 hr, followed by 2 hr with added DMF, gave, after aqueous treatment, 70.9% 4-bromo-5-methyl-2-thiophenecarboxaldehyde, b1 90-2°, m. 55°, which with Ag2O oxidized to the corresponding acid, m. 198.5-9.5°. I and BuLi at -70° in Et2O 2.5 hr gave, after acidification following treatment with Dry Ice, 80.6% 2-thiophenecarboxylic acid, m. 125.5-6.5°. BuLi and thiophene under such conditions gave no such acid and yielded only unchanged thiophene. BuLi and mixed I and 2-methylthiophene gave after similar treatment 66.4% 2-thiophenecarboxylic acid only. Acetylation of mixed I and 2-(methylthio)thiophene with AcCl in PhCl with SnCl4 gave 5-methylseleno-2-acetothienone and 5-(methylthio)-2-acetothienone in 1:1.6 ratio with much unreacted starting material. In the experiment, the researchers used many compounds, for example, 4-Bromo-5-methylthiophene-2-carboxylic acid (cas: 29421-99-6Application of 29421-99-6).
4-Bromo-5-methylthiophene-2-carboxylic acid (cas: 29421-99-6) belongs to organobromine compounds. Organo bromine compounds are versatile compounds and are widely used in diverse fields. Organo bromine derivatives are used in the dye sector, as an indicator in analytical chemistry (Bromothymol blue is a popular indicator). The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of reactivity and cost.Application of 29421-99-6
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary