Evidences of some unusual behaviours of 2‐aminothiazol and 2‐aminobenzothiazol in reactions with formaldehyde and glyoxal

Abstract

In contrast to the previously reported acid‐catalyzed reaction of 2‐aminothiazole with aqueous formaldehyde in water at 0‐5 °C which afforded N,N′‐bis(2‐thiazolyl)methanediamine (4), 5,5′‐methylenebis(2‐aminothiazole) (5) is obtained as the unique product under reflux conditions. Reaction of 2‐aminobenzothiazole with aqueous formaldehyde in acetonitrile at 0‐5 °C or under reflux conditions produces (2‐benzothiazolylamino)methanol (6) or N,N′‐bis(2‐benzothiazolyl)methanediamine (7), respectively. Heating monoamine 6 in acetonitrile remarkably yields the symmetric diamine 7. While cyclocondensation of 2‐aminothiazole with aqueous glyoxal in acetonitrile gives 3,4,8,9‐tetrahydroxy‐7,10‐bis(2‐thiazolyl)‐2,5‐dioxa‐7,10‐diazabicyclo[4.4.0]decane (8), reaction of 2‐aminobenzothiazole with glyoxal fails to produce similar results; In the presence of aqueous formaldehyde, although the former reaction leads to the formation of 4‐hydroxy‐5‐(thiazolylamino)‐1,3‐bis(2‐thiazolyl)imidazolidine (9), utilization of 2‐aminobenzothiazole gives 4,5‐dihydroxy‐1,3‐bis(2‐benzothiazolyl)imidazolidine (10). Condensation of either 6 or 7 with aqueous glyoxal affords compound 10. Details of the reactions will be discussed in this presentation.

Polymer/clay nanocomposites based on aliphatic–aromatic polyamide containing thiazole ring and new organomodified nanosilicate layers: Synthesis, characterization, and thermal properties study

“…DA was synthesized according to a reported procedure . A 100 mL round‐bottom flask was charged with a mixture of 2‐aminothiazole (2 g, 20 mmol), formaldehyde 37% (0.8 g, 10 mmol), formic acid 98% (0.08 g, 1.76 mmol), and distillated water (40 mL).…”

“…The increased compatibility between the polymer and clay was achieved by production of the OC. The effects of two organo modified clays were described in the optical and thermal properties of PA. DA was synthesized according to a reported procedure [37]. A 100 mL round-bottom flask was charged with a mixture of 2-aminothiazole (2 g, 20 mmol), formaldehyde 37% (0.8 g, 10 mmol), formic acid 98% (0.08 g, 1.76 mmol), and distillated water (40 mL).…”

Synthesis and Dynamic NMR Studies of Some New Symmetrical Podands of Dithiocarbamates Formed from Bis(N‐thiazol)chloroacetamides

“…The diamines ( Ia , Ib ) were obtained from condensation of thiazoles with formaldehyde or thiourea [36, 38] which upon reaction with chloroacetyl chloride at room temperature led to dichlorodiamides ( IIa , IIb ) in 2 h. The dichloro compounds ( IIa , IIb ) easily reacted with dithioate salts at room temperature and produced the podands Va , Vb , Vc , Vd , Ve , Vf (Scheme and Table ).…”

“…Because of the importance of carbamothioates, we were encouraged to synthesis two series of DTCs ( Va , Vb , Vc and Vd , Ve , Vf ) using the reacting diamine ligands ( Ia , Ib , see Scheme ) which were already synthesized in our laboratory and converted to their corresponding bis‐Schiff's base .…”

Synthesis of novel symmetrical bis‐schiff bases of 5,5′‐methylenebis(2‐aminothiazole)

“…For example, treatment of the above mixture has been studied at room temperature, refluxing in heptane as solvent in the presence of acetic acid as catalyst [13], or forming an azeotropic mixture of benzene and water in the presence of acid and using a Dean-Stark [14] apparatus to remove the water. Based on investigations in literature, it appears that the reaction of carbonyl compounds with bis-amine of 5,5'-methylenebis(2-aminothiazole) (1) [15] for the synthesis of symmetrical diimino Schiff bases have not been studied before.…”