Synthesis and characterization of a novel imidazole cyclic trimer

Synthesis, Crystal Structures, and Biological Activity Evaluation of Novel Xanthine Derivatives Containing a Pyrethroid Moiety

“…The key intermediates 2-iodoethyl 2,2,3,3-tetramethylcyclopropane-1-carboxylate ( 1) and 2-iodoethyl (1 R ,3 R )-3-(( Z )-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate ( 2 ) were prepared in high yields (61–72%) from the esterification of 2-iodoethanol with chrysanthemum acid and bifenthrin acid, respectively, in the presence of EDCI and DMAP at room temperature (Scheme ). Referring to similar procedures in the literature, − 1-substituted-7-methyl-3,7-dihydro-1 H -purine-2,6-diones ( 5a–5c ) were successfully synthesized via multistep reactions from the starting material triethyl orthoformate (Scheme ). Theophylline, 8-chlorotheophylline, and theobromine are commercially available, while other xanthine intermediates such as 8-bromotheophylline ( B1 ), 8-trifluorotheophylline ( B2 ), 8-chlorotheobromine ( B3 ), and 8-chloroparaxanthine ( B4 ) (Schemes , , and ) were prepared from their corresponding xanthine precursors A1 , A4, and 5a using the known/similar protocols. , Ultimately, these various xanthine intermediates were reacted with iodo-ester 1 or 2 using anhydrous K 2 CO 3 as the base in DMF solvent at 70 °C to afford the title compounds Ia–Is with satisfactory yields (Schemes –).…”

“…Preparation of the Intermediates 1-Substituted-7-methyl-3,7-dihydro-1H-purine-2,6-diones (5a−5c). Using a known literature procedure, 31 intermediate 3, which was prepared from triethyl orthoformate and cyanamide, 32 was reacted with sarcosine ethyl ester in toluene, and the reaction mixture was then treated with sodium ethoxide in ethanol to afford the intermediate 4-amino-1methylimidazole-5-carboxylate ethyl ester (4) in 60% yield. Adopting a similar literature protocol, 33 intermediates 5a−5c were successfully synthesized.…”