The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Ninhydrin-positive components derived from cystine during the cyanide-nitroprusside test》. Authors are Hambraeus, Leif; Reio, Lembitu.The article about the compound:2-Amino-4,5-dihydrothiazole-4-carboxylic acidcas:2150-55-2,SMILESS:O=C(C1N=C(N)SC1)O).Name: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid. Through the article, more information about this compound (cas:2150-55-2) is conveyed.
NaCN used in the cyanide-nitroprusside test of Brand et. al to determine cystine (I) in urine (CA 24, 3555) could be effectively replaced by NaBH4 which yielded about the same color intensity as when NaCN was used. However, the color produced by NaBH4 faded very quickly. Studies were made to obtain some qual. and quant. data regarding the ninhydrin-pos. components during the reaction between NaCN, I, and Na nitroprusside by means of an automatic amino acid analyzer. When freshly prepared com. NaCN was used, 2 peaks were obtained (one of I and cysteine). With the addition of NaCN and I, no addnl. peak was found, but a new peak appeared which corresponded to 4-carboxythiazolidinon-2-imide (II) formed due to the cleavage of I. With pure I, peaks of II and another peak of 2-aminothiazoline-4-carboxylic acid appeared.
Although many compounds look similar to this compound(2150-55-2)Name: 2-Amino-4,5-dihydrothiazole-4-carboxylic acid, numerous studies have shown that this compound(SMILES:O=C(C1N=C(N)SC1)O), has unique advantages. If you want to know more about similar compounds, you can read my other articles.