Anhydrobiisatic acid

The chemistry of isatoic anhydride derivatives: electrophilic reactions of 2-amino-3,1-benzoxazin-4-one

“…Hereby it was found that in the reaction with the anions from diethyl malonate and ethyl cyanoacetate ring cleavage and recyclisation did occur, but in these cases N-3 of the urea group participated in the reaction, not N-1 as with azide (Scheme 2). The products from these transformations were identified as the quinazolones ( 6) and (7). The infrared frequencies of compound (7) support the structure whereby one ester carbonyl group is in plane as a cis-enamino carbonyl system, with its inherent high carbonyl frequency at 1 655 cm-', whereas the other ester group is twisted out of plane and more closely resembles a saturated ester with a frequency at 1 720 cm-'.…”

“…The products from these transformations were identified as the quinazolones ( 6) and (7). The infrared frequencies of compound (7) support the structure whereby one ester carbonyl group is in plane as a cis-enamino carbonyl system, with its inherent high carbonyl frequency at 1 655 cm-', whereas the other ester group is twisted out of plane and more closely resembles a saturated ester with a frequency at 1 720 cm-'. Similarly the ester group of the cyano-derivative (6) is in a similar in-plane environment with a carbonyl frequency at 1664 cm-'.…”

Epoxydibenzo[b,f][1,5]diazocines: From a Hidden Structural Motif to an Efficient Solvent-Free Synthetic Protocol

“…Rather surprisingly, application of excess of KOH at reflux afforded epoxydibenzodiazocine 24 directly from isatin 23a in an excellent 94% yield. Further investigation proved unambiguously the chemical inertness of the epoxydiazocine skeleton, and simple post-functionalization was performed, including methyl ester formation (26a,b), N-methylation (28), and neutralization (25), leading to the desired products in very high yields (Scheme 6). Furthermore, the authors also proved that the condensation is fully reversible, and hydrolysis of bisaminal 28 performed under acidic conditions in water at reflux provided starting isatin 23b in virtually quantitative yield.…”

“…Exceptional progress in the field has been achieved by Lorenc and co-workers in the course of their research on isatin (Scheme 6 ). 25 Treatment of unprotected isatin ( 23a ) with 20% aqueous KOH at room temperature led to the expected potassium isatate (not shown). Rather surprisingly, application of excess of KOH at reflux afforded epoxydibenzodiazocine 24 directly from isatin 23a in an excellent 94% yield.…”

The Metabolism of 14C-Labeled Isatin and Anthranilate in Pisum Stem Sections

“…3 Institute of Experimental Botany, Czechoslovak .\cadeniv of Sciences, Prague 6, C.S.S.R. (19). Benzene ring labeled isatin-14C was syntliesized as described by Marvel and Hiers (12 Identification of the fl-glucoside of anthr-anilic acid was performed, as follows: 1) The substance showed a bluish fluorescence in UV light on chromatograms which was less intense than that of -anthranilic acid.…”