GB1106277A - Benzofuroxan derivatives - Google Patents

Abstract

Novel benzofuroxan derivatives of the formula <FORM:1106277/C2/1> wherein R1, R2 and R3 are each H, C1-alkyl C1-alkoxy, chloro or nitro, or any two adjacent are a second furoxan ring, and A is a bridging linkage having X valency bonds, each linked to a separate benzo-ring, and X is 2, 3 or 4, are prepared by heating an o-nitro azido compound or oxidizing an o-nitro amine with, e.g. NaOCl. When A is -CH2-, the o-nitro azido compound may be formed by reacting NaCN with the o-nitroamine, which is prepared by the rearrangement of N,N1-methylene bis-o-nitroaniline in concentrated HCl. This is itself formed by reacting o-nitro aniline with formaldehyde. When A is carbonyl, azo, trivalent phosphine oxide, the o-nitro azide is formed from the o-nitro chloro compound with NaN3, these o-nitro chloro compounds having been formed by nitration. The tris-(p-Cl-phenyl) phosphine oxide is prepared by reacting the Grignard reagent of p-chlorobromobenzene with POCl3. When A is ether, the o-nitro amine which is oxidized is formed by nitrating diacetylated di-(p-aminophenyl) ether, followed by deacetylation with KOH in water/methanol. The amino ether is formed by reduction of di-(p-nitrophenyl) ether with H2 over Pd. The compound wherein A is a trivalent arsine oxide group is prepared from tris-(4-chloro-3-nitrophenyl) arsine oxide by treatment with sodium azide followed by heating to form the furazan ring. This p-chlorophenyl arsine oxide is nitrated with a mixture of fuming HNO3 and concentrated H2SO4. It may be formed by oxidation of tris-p-chlorophenyl arsine with H2O2.