Syntheses of heterocyclic compounds of nitrogen. CV. Benzothiazole derivatives. 9 was written by Takahashi, Torizo;Okada, Jutaro;Yamamoto, Yasuo. And the article was included in Yakugaku Zasshi in 1957.Category: thiazole The following contents are mentioned in the article:
A mixture of 12 g. 3-ClC6H4NH2, 15 g. NH4SCN, and 75 ml. AcOH at 5° treated dropwise with 16 g. Br in 32 g. AcOH, the product diluted with 4 volumes H2O, neutralized with Na2CO3, the precipitate filtered off, taken up in 10% HCl, the HCl layer made alk. with NH4OH, and the product recrystallized from C6H6 gave 6 g. 3,4-Cl(NCS)C6H3NH2 (I), columns, m. 75°. Or, reducing 0.6 g. 3,4-Cl(NCS)C6H3NO2 in 6 ml. concentrated HCl with 6 g. SnCl2.2H2O, suspending the precipitate in H2O, alkalinizing with NaOH, and extracting with Et2O gave C6H6-soluble I and C6H6-insoluble [2,4-Cl(H2N)C6H3]2S2, m. 136-8°. 3-ClC6H4NHCSNH2 (50 g.) in 150 ml. CHCl3 treated dropwise with 44 g. Br in 30 ml. CHCl3, heated 1 hr. on an H2O bath, the solvent removed, the residue in 800 ml. H2O and 5 ml. 48% HBr treated with a small amount of Na2SO3, made alk. with Na2CO3, and the precipitate recrystallized from dilute EtOH gave 28 g. 2-amino-5-chlorobenzothiazole (II), needles, m. 198°; the filtrate from II made alk. with K2CO3 and the precipitate recrystallized from dilute EtOH gave 16.5 g. 7-Cl analog (III) of II, needles, m. 145-50°. Or, the reduction of 0.6 g. 5,2-Cl(NCS)C6H3NO2 with 6 g. SnCl2.2H2O gave 0.4 g. II, m. 196-8°. A mixture of 1 mole RC6H3.S.C(NH2):N [R = 6-MeO (IIIA), 6-EtO (IV), 6-BuO (V), 4-Cl (VI), 5-Cl (VII), or 6-Cl (VIII)] (2 moles used in the case of III) in CHCl3, 1 mole C5H5N (no addition in the case of III), and 1 mole 2-bromoacyl bromide or (ClCH2CO)2O heated 0.5-1 hr. on an H2O bath, the solvent removed, and the product recrystallized from solvent gave RC6CH3.S.C(NHCOCHXR1):N (IX) (R, R1, X, and m.p. given): IIIA, H, Br, 164-5°; III, Me, Br, 148°; III, Et, Br, 123°; III, Me2CH, Br, 128-8.5°; IV, H, Cl, 181°; IV, Me, Br, 145°; IV, Et, Br, 139°; IV, Me2CH, Br, 115°; V, H, Br, 162-3°; V, Me, Br, 122°; V, Et, Br, 99-100°; V, Me2CH, Br, 129°; VI, Me, Br, 152°; VII, H, Br, 178°; VII, Me, Br, 160°; VII, Et, Br, 182-3°; VII, Me2CH, Br, 156-7°; VIII, H, Cl, 218°; VIII, Me, Br, 149°; VIII, Et, Br, 146°; VIII, Me2CH, Br, 150°. A mixture of 1 mole IX and a C6H6 solution containing more than 2 moles Me2NH in a sealed tube heated 1 hr. at 100°, kept overnight, and the solvent removed gave RC6H3.S.C(NHCOCHR1NMe2):N (X) (R, R1, and m.p. given): III, H, 113-14°; III, Me, 113°; IV, H, 126° (as HCl salt); IV, Me, 178° (picrate); IV, Et, 91°; V, H, 96-7°; V, Me, 76-7°; VI, Me, 106-7°; VII, H, 144-5°; VII, Me, 163-4°; VII, Et, 120-1°; VIII, H, 136°; VIII, Me, 255° (decomposition) (as HCl salt); VIII, Et, 260° (decomposition) (as HCl salt). This study involved multiple reactions and reactants, such as 6-Butoxybenzo[d]thiazol-2-amine (cas: 14372-65-7Category: thiazole).
6-Butoxybenzo[d]thiazol-2-amine (cas: 14372-65-7) belongs to thiazole derivatives. Thiazoles are a class of five-membered rings containing nitrogen and sulfur with excellent antitumor, antiviral and antibiotic activities. The nitrogen in thiazole is sp2 hybridized and the lone pair of electrons localized on the nitrogen is less reactive due to increased aromatic character and decreased basicity. It is protonated and alkylated/acylated at nitrogen forming hydrochloride and quaternary thiazolium salt.Category: thiazole
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica