Antibacterially Active 3-Alkyl-5-(5-Nitro-2-Furyl)-1,3,4-Thiadiazolin-2-Ones and Related Substances

Synthesis and structure-activity relations of a series of antibacterially active 5-(5-nitro-2-furfurylidene)thiazolones, 5-(5-nitro-2-furylpropenylidene)thiazolones, and 6-(5-nitro-2-furyl)-4H-1,3-thiazinones

“…This is atypical of nitrofurans which usually exhibit a slight decrease in the activity when alkyl substituents are lengthened, as exemplified by series 2 in Figure 3. [20][21][22][23][24] Space-filling models of the nitrofurans in series 2-4 show that these compounds have a very rigid structure, in contrast to other nitrofurans, e.g., nitrofurantoin, nitrofuryltriazoles, 6a-d, 7a,b, where the two rings are flexible. Steric effects might therefore be of importance for the activity of nitrofurans in series 2-5.…”

Synthesis of potential antimalarial agents. Preparation of some 6-amino-5,8-dimethoxyquinolines and the corresponding 6-amino-5,8-quinolinediones

“…Anal. (CuHgFsNOs) C, , N. 6-Amino-2,4-dimethyl-5,8-quinolinedione (24). A suspension of 25 (4.68 g, 25.0 mmol) in absolute EtOH (560 ml) was cooled in an ice bath and treated with solid sodium azide (4.88 g, 75.0 mmol) and concentrated HC1 (6.2 ml, ~75 mmol).…”

“…(C11H6F3NO2) C, , N. 6 -Amino -5,8-dihydroxy-2,4-dime thy lquinoline Dihydrobromide (27). In a flask protected with a drying tube, a suspension of 24 (0.16 g, 0.79 mmol) in dry THF (20 ml) was treated with a solution of 1 M borane in THF (3 ml) under N2. The resulting mixture was stirred for 45 min, warmed at 40-45°for 15 min, cooled, and treated with excess MeOH (10 ml).…”