The Willgerodt reaction in the heterocyclic series. II. Some compounds of the 2- and 3-thienyl series was written by Blanchette, Joseph A.;Brown, Ellis V.. And the article was included in Journal of the American Chemical Society in 1951.Recommanded Product: 2,5-Dichlorothiophene-3-carboxylic acid This article mentions the following:
3-Methylthiophene (55 g.), 95 g. N-bromosuccinimide, and 150 cc. CCl4 refluxed 5 hrs., filtered, and the solvent removed in vacuo yielded 70 g. 3-methyl-2-bromothiophene (I), b13 61-3°, b16 68-70°. Dry CO2 passed 3 hrs. into the Grignard reagent from 0.64 mole I at -7° and the product decomposed with dilute H2SO4 yielded 59 g. 3-methyl-2-thiophenecarboxylic acid (II), m. 147-8° (from water). II (50 g.) and 200 cc. SOCl2 refluxed 3 hrs. yielded the acid chloride, which, added in 100 cc. Et2O to 0.36 mole Me2Cd in an ice bath and the mixture refluxed 0.5 hr., cooled, and decomposed, yielded 43 g. 3-methyl-2-thienyl Me ketone (III), b14 98-9°. Amides from S.CR2: CR3.CR4:CR5 (I); R2, R3, I, R4, R5, Amide, M.p., Yield (%), A, B; Et, Ac, H, Et, 3-acetamide, 116-17°, 52, 40; Ac, H, H, Et, 2-acetamide, 148°, 42, 55; Ac, H, H, Me, 2-acetamide (II), 143-4°, 41, 54; Ac, Me, Me, H, 2-acetamide (III), 152°, 34, 24; Ac, Me, H, H, 2-acetamide (IV), 142°, 27, 29; Me, Me, H, Ac, 5-acetamide (V), 165-6°, 40, 55; H, Ac, H, H, 3-acetamide (VI), 154-5°, 5, 13; AcCH2, H, H, H, 2-propionamide (VII), 99-100°, 20, 28; CH2:CH, H, H, H, 2-acetamide (VIII), 147-8°, 25, 30; CO2H, H, H, H, 2-carboxamide (IX), 179-80°, 63, 70; CH(OH)Me, H, H, H(a), 2-acetamide (X), 147-8°, 22, 35; (a) Semicarbazone m. 193-4° (from 50% alc.-water).; 2,5-Dichloro-3-thienyl Me ketone oxidized with KOCl yielded 75% 2,5-dichloro-3-thiophenecarboxylic acid, which on dehalogenation with 5% Pd-on-C yielded 75% 3-thiophenecarboxylic acid, 30 g. of which by the procedure for III yielded 12 g. 3-thienyl Me ketone, b21 117°; semicarbazone, m. 173-4° (from 33% alc.-water). 2-Cyanothiophene (6 g.) in 20 cc. cold concentrated H2SO4 poured after 15 min. onto ice yielded 4 g. 2-thiophenecarboxamide, m. 179-80°. 2-Thiophenecarboxaldehyde (82 g.) in 50 cc. Et2O added dropwise to 0.73 mole MeMgBr in an ice bath, and the mixture refluxed 0.5 hr., cooled, and poured into ice and dilute H2SO4 yielded 79 g. methyl-2-thienylcarbinol, b5 80-3°; urethan, m. 85-6° (from petr. ether). Ten g. thiophene derivative, 25 g. S, 25 cc. concentrated NH4OH, and 30 cc. dioxane heated 11-12 hrs. at 150-60° in a sealed tube and the product evaporated to dryness and extracted with boiling water yielded (Method A) crude amide. The thiophene derivative (5 g.), 25 g. yellow NH4 polysulfide, 3.5 g. S, and 25 cc. dioxane heated 11-12 hrs. at 150-60° yielded (Method B) crude amides. The amides crystallized from water in white plates or needles. The amides (1-2 g.) refluxed 2-3 hrs. with 70-100 cc. 25% KOH and the solution cooled and acidified with 20% HCl yielded the corresponding acids for which the m.ps. are: II, 54-5°; III, 67-8°; IV, 89-90°; V, 97-8°; VI, 79-80°; VII, 44-5°; VIII, 62-3°; IX, 128°; X, 62-3°. In the experiment, the researchers used many compounds, for example, 2,5-Dichlorothiophene-3-carboxylic acid (cas: 36157-41-2Recommanded Product: 2,5-Dichlorothiophene-3-carboxylic acid).
2,5-Dichlorothiophene-3-carboxylic acid (cas: 36157-41-2) belongs to organic chlorides. Organic chlorides can cause corrosion in pipelines, valves and condensers, and cause catalyst poisoning. The hydrocarbon processing industry (HPI) and others are affected by damage caused by these substances. Alkyl chlorides are versatile building blocks in organic chemistry. While alkyl bromides and iodides are more reactive, alkyl chlorides tend to be less expensive and more readily available.Recommanded Product: 2,5-Dichlorothiophene-3-carboxylic acid
Referemce:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics