5-Nitrothiophene-2-carboxylic acid

Solid

III. To a stirred solution of potassium dichromate (35.1 g; 143 mmol) in 5N [H2SO4] (375 ml) at [0°C, ] was added solid [2-FORMYL-5-NITROTHIOPHENE] (50.0 g; 318 mmol). The resulting suspension was heated to [100°C] for 1 hour after which HPLC showed no remaining starting material. The reaction mixture was cooled to room temperature, diluted with water (300 ml) and the resulting precipitate collected by filtration, washed with water (5 x 200 ml) and dried to a constant weight in a vacuum oven at [40°C] to afford 95 (39.5 g) as a light green solid. Yield: 72percent [1H] NMR (DMSO-d6) 7.70 (d, 1H); 8.09 (d, 1H).A mixture of 5-nitrothiophene-2-carbaldehyde (1.685 g, 10.72 mmol) and sulfamic acid (1.249 g, 12.87 mmol) in dioxane (30 ml) was cooled to 0° C., and a solution of sodium chlorite (1.940 g, 21.44 mmol) in water (14 ml) was added drop-wise. Step 1: Preparation of 5-nitrothiophene-2-carboxylic acid (Intermediate 53) A mixture of 5-nitrothiophene-2-carbaldehyde (1.685 g, 10.72 mmol) and sulfamic acid (1.249 g, 12.87 mmol) in dioxane (30 ml) was cooled to 0°C and a solution of sodium chlorite (1.940 g, 21.44 mmol) in water (14 ml) was added drop-wise. The mixture was allowed to warm to T and stirred for 2 h. A second batch of 5-nitrothiophene-2-carbaldehyde (1.966 g, 12.51 mmol) was reacted under the same conditions using the molar ratios described above. The two reaction mixtures were combined and portioned between ethyl acetate and water. The organic layer was extracted twice with 5percent NaHCOIn 100ml three-necked flask was added 32ml fuming nitric acid, Control the temperature ≤ 20 dropwise 24ml concentrated sulfuric acid, Upon completion of the dropwise addition of 22.4 g of 2-thiophenecarboxylic acid, And controlling the temperature does not exceed 20 , plus complete, Control the internal temperature 10 ~ 20 to continue stirring for 3 to 4 hours, The reaction was monitored by TLC (n-hexane: ethyl acetate = 1: 1).The reaction solution was slowly added to 448ml of ice water, Stirring crystallization 1 hour, suction filtration, The filter cake was dried under reduced pressure at 40-45 ° C for 8 hours, 18.2 g of 4-nitro-2-thiophenecarboxylic acid was obtainedAnd 5-nitro-2-thiophenecarboxylic acid, Used directly in the next step without purification.

5-Nitrothiophene-2-carboxylic Acid is a reagent used in the preparation of benzothiophene amides which fuctions as nicotinamide ribosyltransferase inhibitors with potential antitumor and anticancer activities. It also functions as an intermediate in varying organic transformations.

Molecular Weight:173.15
XLogP3:1.6
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:1
Exact Mass:172.97827875
Monoisotopic Mass:172.97827875
Topological Polar Surface Area:111
Heavy Atom Count:11
Complexity:189
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes