Synthesis ans nitration of 1,3- and 1,4- bis(nitrofuroxanyl)benzenes

摘要

In this research 1,3- and 1,4-bis(3-nitrofuroxan-4-yl)benzenes were prepared by nitrosyla-tion of tetrapotassium salts of 1,3- and 1,4-bis(2,2-dinitro-1-hydroximinoethyl)benzenes with NaNO_2 in AcOH and thermally isomerized to 1,3- and 1,4-bis(4-nitrofuroxan-3-yl)benzenes. Initial salts, in turn, were prepared by an interaction of bis(hydroximoyl) chlorides with an excess of dinitromethane sodium salts at low temperature in DMF fol-lowed by acidification and treatment with AcOK in MeOH. Nitration of isomeric bis(nitrofuroxanyl)benzenes with a mixture of equal volumes of 100% HNO_3 (10 moles) and concentrated H_2SO_4 at 50 -55 °C resulted in mononitro derivatives in yields 80-90%. It was found that 4-nitrobenzene derivatives had been obtained at nitration of l,3-bis(4-nitrofiroxan-3-yl)benzenes whereas nitration of their isomer, viz.1,3-bis(3-nitrofuroxan-4-yl)benzene, only resulted in the 5-nitroisomer. Both 1,4-bis(nitrofuroxanyl)benzenes can be nitrated only in position 3 irrespective of the nitrofuroxanyl fragment structure. The nitro group position in the 5-methyl-1 ,3-bis(nitrofuroxanyl)benzene nitration products relies solely on the methyl groups influence.