No abstract

No abstract

Materials Restwch, Central Research I)ivision, The National Cash Register Company ' l~t i r w dif'f'erent 3,iE-diacylfuroxans (1) are shown to give :i-substituted-J -phenyl-4,5-dioximino-2-pyrazolines (2) upon reaction with phenylhydrazine. The compounds 2 were dehydrated t o O-sut~stitutt:d-4-phenyl-~~~f-pyrazolo~:~,4~] furazaris. (3) and thermally converted t o :{-substituted .. 5-iminoanilino-iE-acylfurazans (10).l'c.rkin ( 1) trt:att:d methyl dimethy1acc:toacetate with nitric: acid to obtain a "glyoximc: peroxide" that with phenylhydrazine gave "methyl phenylaminoisotriazoxole-tJimethylmalonylate"; this in turn upon treatment with aqueous hase gave an acid of semi-empirical constitution ( l 6 t I 5 [ ( : 3 N 4 0 ] ( :~l e 2 ( ; 0 2 t 1 to which it was "difficult to assign a satisfactory formula". Perkin suggested a structure containing a I ,5 -dehydro (valence -bridged)-I Jdihydro-I ,?J,iE-tetrazine nucleus, whose improbability has previously been noted (2). Our curiosity as to the structure of the acid led us to rcirivtstigate these arid related reactions. h ' e assumed that tht: "glyoxime peroxide" was in fact Ic, a ;i,il.-diacylf'uroxan ( 3 ) , and thus for comparison purposes we began liy rt:-examining the reported reactions of' the diacetyl and dilttxizoyl furoxans. 1)iacetylfuroxan (Ib) has been reported (4) to give with 1iniitt:d or excess phenylhydrazine merely the monophenylhydrazone (m.p. I f) I -162") o r the diphenylhydrazone (1n.p. 176"), rt:spectively. liowevt:r, neither elemental analyses nor any chemical evidence for these assignments were given. 1)itwizoylfuroxan ( l a ) reportedly reacts with phenylhydrazine to give benzoylphenylhydrazine and a yellow material (2a) of empirical formula 5 I1 N 4 0 2 , which upon heating in acetic acid or acetic anhydride affords a diff'erent substance (3a) heretofore formulated as an isomer of 2a (5) o n the basis of a single nitrogen analysis.Formulas A , H, and (; have been proposed as structures for 2a and 3a, and thert: has been extensive discussion as t o which formula should be assigned to which compound (5-8).1 he initial unstahle reaction product of l a and phenyl-r .The compounds 1 react with aniline to give :Ihydrazine was presumed to have structure 4 (5Jj). This formula, which implies addition of one molecule of phenylhydrazine t o a carbonyl group and one to the ring (;=N+O function, could readily give A and H, and lead t o C after a single Heckmann rearrangement.

Bromination of isatoic anhydride in acetic acid gives N-dibromoacetyl-3,5-dibromoanthranilic acid. Three new anthranils a r e described.In connection with another problem we desired a series of anthranils substituted with halogen and nitro groups. Lesser and Weiss reported (1) that bromination of isatoic anhydride (I) in acetic acid gave a "tribromoanthranilic acid" (II), which with acetic anhydride was ' I dehydrated" to a tribromoanthranil" (III). Such a dehydration is unlikely, for the reaction of anthranilic acids with acyl anhydrides gives 4 -0x0 -4H -3 , l -benzoxazines (2) rather than anthranils.W e now show that I1 and III a r e N-dibromoacetyl-3,5-dibromoanthranilic acid and 2-dibromomethyl-6,8-dibromo-4-oxo-4H-3,l-benzoxazine, respectively.Elemental analyses and molecular weight determinations support the C, rather than the C, formulations. Spectral data (Table I) further support these assignments. The infrared spectrum of I1 shows N-R, 0-H, and two C=O absorptions. Both the infrared and ultraviolet spectra are similar to those of C H A R T 3 , 5 -dibromo -Nacetylanthranilic acid (IV). The n.m.r. spectrum of I1 in dimethyl sulfoxide 4 shows two aromatic protons situated meta to each other and one proton a t 6.51 p.p. m. assigned to the single proton of the dibromoacetyl group. Possibly the carboxyl proton is lost by exchange with water in the solvent, and probably the amide NH proton resonance i s so broad and weak a s to be unobservable ( 3 ) . The 6.51 p. p. m. assignment is in reasonable accord with the signals observed for the corresponding proton in cup-dibromoacetanilide (5.96 p.p.m.), ethyl dibromoacetate (5.89 p. p. m. ), and dibromoacetic acid (5.90 p.p.m.). The infrared spectrum of 111 has strong, sharp bands a t 1795 and 1645 cm-' attributable to the O=C-0-C=N grouping, is very simil a r to spectra of several authentic 4-oxo-m-3,1benzoxazines, and is very different from spectra of authentic anthranils (4) which have only moderate absorption near 1650 cm-'. The ultraviolet spectrum IV. R = A C V I V, R = H / / , . i i / / 111 Br Br V I I V l l l I X

No abstract