4-Chloro-7-nitro-2,l,3-benzoxadiazole

The acid-base equilibrium constants of 3-oxy-7-nitrobenzofurazans were determined with the help of UV spectroscopy [1106, 1234], Kinetics of the reaction of methoxydegalogenization and hydrolysis of 4-chloro-7-nitro-2,l,3-benzoxadiazole has been investigated [1106], UV-spectra of some nitrobenzofurazan derivatives are described [1242-1244],... 

UV-visible spectra of porphyrin systems obtained on the base 4-nitro-, 4-chloro-7-nitro-2,l,3-benzoxadiazoles or 4-nitro-2,l,3-benzoselenadiazole have been studied in detail [1241],... 

Dipping sointion II Dissolve 0.1 g NBD-chloride (7-chloro-4-nitrobenzofurazan, 7-chloro-4-nitro-2,l,3-benzoxadiazole) in 50 ml ethanol. 

Although derivatives of 2,1,3-benzoxadiazole have been used extensively to make quinoxalines (see Section 1.6.7), the corresponding selena and thia systems have been paid scant attention for that purpose. However, 5-chloro-4-nitro-2,l,3-benzoselenadiazole (456) has been used as a convenient source of 4-chloro-3-nitro-1,2-benzenediamine (457) (HCl + HI, 20°C, 2 h 88%), which was then converted into 6-chloro-5-nitro-2,3(l//,4//)-quinoxalinedione (458) (oxalic acid, 2M HCl, reflux, 2.5 h 23%). ° In addition, irradiation of 2,1,3-benzoselenadiazole (460, X = Se) or 2,1,3-benzothiadiazole (460, X = S) with dimethyl acetylenedicarboxy-late afforded, among other products, dimethyl 2,3-quinoxalinedicarboxylate (459)... 

A Sep-Pak Cig cartridge coated with 900 pg of phosphoric acid is used for sampling C1-C4 alkyl primary and secondary amines. A 5-1001 volume of air is sampled through the cartridge at 0.8-1.21 min The trapped substances are eluted with 5 ml of methanol and derivatized by mixing with 4mg of 7-chloro-4-nitro-l,2,3-benzoxadiazol (NBD-Cl) and 2 mg of potassium hydroxide. The... 

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