Anthranils rearrangements

Interestingly, preliminary studies indicate that some o-azidoaryl ketone - anthranil decompositions are very sensitive to the presence of certain metals.132 For example, although 2-(o-azidobenzoyl)-4,5-dimethylthiophene in boiling chlorobenzene yields 3-(4,5-dimethyl-3-thienyl)anthranil (94%), in the presence of reduced iron powder only thienoquinolone (140), i.e., the anthranil rearrangement product, is obtained in 67.5% yield. The nature and scope of this metal catalysis is currently under study. 

Nitro-3-(2,5-dimethoxyphenyl)anthranil rearranges to 1,4-dimethoxy-acridone, whereas the 6-nitro-3-(3,4-dimethoxyphenyl) derivative yields a mixture of rearranged and unrearranged dimethoxyacridones.165... 

Figure 4.6 The bifunctional enzyme PRA-isomerase (PRAI) IGP-synthase (IGPS) catalyzes two sequential reactions in the biosynthesis of tryptophan. In the first reaction (top half), which is catalyzed by the C-terminal PRAI domain of the enzyme, the substrate N-(5 -phosphoribosyl) anthranilate (PRA) is converted to l-(o-carboxyphenylamino)-l-deoxyribulose 5-phosphate (CdRP) by a rearrangement reaction. The succeeding step (bottom half), a ring closure reaction from CdRP to indole-3-glycerol phosphate (IGP), is catalyzed by the N-terminal IGPS domain.

S-Formylbenzofuroxan has been prepared, but the 4-acetyl compound rearranges under the conditions used for its jDreparation, to an anthranil derivative (see Section VIII). 

New rearrangements of 2-imino-2//-l-benzopyran-3-carboxamides under the action of anthranilic acid as an N-nucleophile have been revealed. Depending on the conditions 2-(2-oxo-2//-l-benzopyran-2-yl)-3//-quinazolin-4-ones or 2-oxo-2//-l-benzo-pyran-3-((V-2-carboxyphenyl)carboxamides were found to be the products. 

The yellow crystalline azaberbinone (388) has been prepared by several, closely related methods. Dehydrogenation of betaine 378 (Section III,E,2) with dichlorodicyanoquinone gives compound 388 directly. Alternatively, this compound (388) has been prepared in three ways from 6 -nitropapaverine (385) (Scheme 15) (i) Treatment of compound 385 with triethyl phosphite gives a low yield of betaine 388 directly (ii) compound 385 in methanolic KOH at reflux temperature gives the anthranil 386 which rearranges to the betaine 388 in hot triethyl phosphite and (iii) iodine oxidation of 6 -nitro-papaverine (385) generates the A-oxide 387 which is reduced to the betaine 388 by sodium bisulfite. The chemistry of compound 388 remains unexplored. 

C N-( 5 -phosphoribosyl) anthranilate isomerase none Amadori rearrangement... 

In the diaryl amine series 191 (Scheme 47), additional, synthetically valuable, anionic pathways provide routes to anthranilates 190, oxindoles 192, and dibenzazepinones 194. Although not explored in terms of its scope [75c], the lateral metalation-cydization, 191 -> 192, is extensively precedented [69] but harbors intriguing potential for subsequent DreM chemistry. The rearrangement 191 —> 190 is an N —> ortho C anionic Fries equivalent of the aryl O-carbamate migration (Scheme 3E) [75c] and after N-methylation, 190 may be transformed into 1,2,3-trisubstituted systems 193 [76]. In another appealing manifestation of CIPE, the efficient conversion of 191 into dibenzazepinone 194 has been applied in an effective synthesis of the antiepileptic drug oxcarbazepine (Trileptal ) 195 [77] and may also be... 

The conversion of anthranilic acid to tryptophan by cell-free extracts involves, initially, a reaction with 5-0-phospho-a-D-ribosyl pyrophosphate (XX, see Fig. 8). On the basis of the known enzymic reactions of XX, the formation of X-(o-carboxyphenyl)- 9-D-ribofuranosylamine 5-phosphate (XXI) would be expected. However, the first identifiable compound is the unphosphorylated, Amadori-rearrangement product XXII which is formed... 

While the acylanthranils belong to another ring system, examples of 3-acyl-substituted anthranils are known (Section III,C, 6, a) one of them (3-benzoylanthranil) rearranges on heating into the isomeric 2-phenyl-3,l-benzoxazin-4-one [Eq. (19)].165... 

The eighth volume of this serial publication comprises eight contributions from international authors. Four of these deal with well-defined groups of compounds thiopyrones (R. Zahradnik, R. Mayer, and W. Broy), phenoxazines and phenothiazines (M. Ionescu and H. Mantsch), diazepines (F. D. Popp and A. Catala Noble), and benz-isoxazoles (anthranils and indoxazenes) (K.-H. Wiinsch and A. J. Boulton). J. M. Tedder has surveyed the field of the heteroaromatic diazo compounds which are derived from a variety of heterocyclic ring systems, and M. Schulz and K. Kirschke discuss heterocyclic peroxides. The remaining two chapters survey well-known reactions the Hilbert-Johnson reaction is covered by J. Pliml and M. PrystaS, and heterocyclic Claisen rearrangements by B. S. Thyagarajan. 

Rearrangement reactions of 3-(imidazol-2-yl)anthranils have been described (Section 4.02.3.4.2). 

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