With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.556-90-1,2-aminothiazol-4(5H)-one,as a common compound, the synthetic route is as follows.
General procedure: The desired compounds, (Z)-5-(substituted benzylidene)-2-iminothiazolidin-4-one analogues (1a- 1l) (Figure 1), were prepared by Knoevenagel condensation.With one exception, refluxing a solution of appropriate benzaldehydes and pseudothiohydantoinin acetic acid in the presence of NaOAc produced (Z)-5-benzylidene-2-iminothiazolidin-4-ones as a single stereoisomer in yields of 41.4-94.1%. A Knoevenagel condensation between 2,4-dimethoxy benzaldehyde and pseudothiohydantoin under the same conditions gave amixture of (E)- and (Z)-5-(2,4-dimethoxybenzylidene)-2-iminothiazolidin-4-ones. These compounds could not be easily separated by conventional silica gel column chromatography. Milder reaction conditions capable of accomplishing the Knoevenagel condensation were needed to synthesize only (Z)-stereoisomer. Interestingly,heating a solution of 2,4-dimethoxy benzaldehyde and pseudothiohydantoin in ethanol:H2O (1:1) in the presence of 1.0 equiv. of piperidine as a base catalyst at 80 C afforded the corresponding (Z)-stereoisomer(1l) as a sole product. A suspension of an appropriate benzaldehyde (300 mg, 1.53-2.46 mmol), pseudothiohydantoin(1.1 eq.), and sodium acetate (3.0 eq.) in acetic acid (1 mL/1 mmol of benzaldehyde) was refluxed for 3-7 h. The reaction mixture was cooled and water was added. The resulting precipitates were filtered, and washed with water and, if necessary, a small amountof methylene chloride or ethyl acetate, to produce (Z)-5-(substituted benzylidene)-2-iminothiazolidin-4-oneproducts (1a – 1k) in 41.4-94.1% yields. The resulting precipitates were filtered, and washed with water,ethyl acetate and methylene chloride to give (Z)-5-(2,4-dimethoxybenzylidene)-2-iminothiazolidin-4-one (1l) all final products were confirmed by 1H and 13C NMR spectroscopy and mass spectroscopy.
As the paragraph descriping shows that 556-90-1 is playing an increasingly important role.
Reference£º
Article; Jung, Hee Jin; Lee, Min Jung; Park, Yeo Jin; Noh, Sang Gyun; Kyoung; Moon, Kyoung Mi; Lee, Eun Kyeong; Bang, Eun Jin; Park, Yun Jung; Kim, Su Jeong; Yang, Jungho; Ullah, Sultan; Chun, Pusoon; Jung, Young Suk; Moon, Hyung Ryong; Chung, Hae Young; Bioscience, Biotechnology and Biochemistry; vol. 82; 5; (2018); p. 759 – 767;,
Thiazole | C3H3NS – PubChem
Thiazole | chemical compound | Britannica