Sulfur of the thiazole is derived from cysteine. In contrast to the isomeric thiazole, the two heteroatoms are in adjacent positions. Mesoionic carbenes based on isoxazole and thiazole have been reported by Albrecht and Bertrand respectively. The amino acid cysteine is produced industrially from substituted thiazole. Other heterocycles such as nitrothiazoles (thiazole) are also used for this purpose. Bottromycins contain a C-terminal decarboxylated thiazole in addition to a macrocyclic amidine. These thiazole dye are used for dyeing cotton. Thiazole orange does show toxicity at this dose. The thiazole is substituted with methyl and hydroxyethyl side chains. The structure of bottromycin contains a macrocyclic amidine as well as a thiazole ring. Several biosynthesis routes lead to the thiazole ring as required for the formation of thiamine. Thiazoles are structurally similar to imidazoles, with the thiazole sulfur replaced by nitrogen. Thiazole can also be considered a functional group. In addition to vitamin B, the thiazole ring is found in epothilone. Song and his partners did preparate thiazole compound by starting with carboxyl acid.