Chemistry of the thiazoles

Advances in the synthesis of neonicotinoids

“…According to that scheme, initial S-methyl-N-nitroisothiourea (95) reacted with phthaloyl dichloride to give N-[methylsulfanyl(nitroimino)methyl]phthalimide (118). The reaction of (118) with 5-aminomethyl-2-chlorothiazole (119) led to thiazole 120, and the latter was converted into clothianidin (7) by treatment with methylamine (Scheme 46).…”

“…Aminothiazole 71 was first treated with sodium nitrite in hydrochloric acid to obtain the corresponding diazonium salt whose subsequent decomposition afforded 2-chlorothiazole (72). Compound 72 was then chlorinated with N-chlorosuccinimide to give 73 [94][95][96][97] An alternative procedure, which also involves isothiocyanates, was described in [96,[101][102][103][104][105]. It implies initial reaction of 2,3-dichloro-1-propene (75) with potassium thiocyanate on heating, which leads to isothiocyanate 76.…”

“…A special scheme was developed for the synthesis of 6 [32,108,[133][134][135][136] starting from S-methyl-N-nitroisothiourea (95). Compound 95 reacted with methylamine in ethanol to give 94% of N-methyl-N'-nitroguanidine 115.…”

“…Several procedures for the synthesis of 2-nitroiminoimidazolidine were developed. Hafner and Evans [116] obtained this compound in 72.1% yield by reaction of S-methyl-N-nitroisothiourea (95) Presumably, the most convenient procedure for the synthesis of 2-nitroiminoimidazolidine (97) is that proposed by McKay and Wright [118,119]. According to the authors, compound 97 is formed by reaction of nitroguanidine (99) with ethylenediamine dihydrochloride (100) and potassium hydroxide in water on heating (Scheme 37).…”

Thiazolecarboxylic Acids, Thiazolecarboxaldehydes, and Thiazolyl Ketones

“…The Mannich reaction can be realized with formaldehyde and seconketones (28,80,(115)(116)(117). The haloform reaction is realized in good yield (28,82, 112,119, 120).…”