Isatins spectra

In 1882 Baeyer and Oekonomides advanced formula 72 (R = H) for isatin on chemical grounds, but shortly thereafter the dioxo structure 73 (R H) was proposed since the ultraviolet spectrum of isatin resembled that of the N—Me derivative (73, R Me) and not that of the O—Me derivative (72, R = Me). " It was later shown, despite a conflicting report, that the ultraviolet spectrum of isatin is very similar to the spectra of both the O— and N—Me deriva-tives - the early investigators had failed to take into consideration the facile decomposition of the O—Me derivative. Although isolation of the separate tautomers of isatin has been reported, - these claims were disproved. A first attempt to determine the position of the mobile hydrogen atom using X-ray crystallographic techniques was inconclusive, but later X-ray work," dipole moment data, and especially the infrared spectrum demonstrated the correctness of the... 

The infrared spectrum of isatin shows two strong bands at 1740 and 1620 cm 1 corresponding to the carbonyl stretching vibrations. A broad band occurs at 3190 cm 1 due to the A-H stretching, and it is accompanied by many sub-bands, all of which are moved to a lower frequency on deuteration, which also affects several bands in the region of 1400-1100 cm, associated with A-H in-plane bending . Although the vC=0 values are not modified... 

Uyeo and co-workers provided independent confirmation of these two structural possibilities (6). They found that tuberostemonane, an important product from the dehydrogenation (Pd, charcoal) of tubero-stemonine, had a U V-absorption spectrum similar to that of indole. When oxidized with chromic acid it gave a product having an isatin-like absorption spectrum. 

Isatin is the privileged lead molecule for designing potential bioactive agents, and its derivatives have been shown to possess a broad spectrum of bioactivity as many of which were assessed anti-HIV, antiviral, antitumor, antifungal. 

Two reports on pentathiepines have been published. In the first, pentathiepino[6,7-Z ]indole (59) has been prepared by the reaction of isatin with P4S]o <94TL5279>. In a second paper the NMR spectrum of the natural product varacin (60) is discussed 94TL7185>. It had been previously noted that the NMR spectrum of the side chain was unusually complex, which was attributed to... 

The mass spectrum of isatin (2,3-indoledione), a monoamine oxidase inhibitor, as its oxime—TBDMS derivative... 

Figure 8. Electron ionization mass spectrum of the Af-t-butylmethylsilyl-3-oxime-t-butyldimethylsilyl derivatives of (a) isatin and (b) 5-methylisatin. Reproduced from Reference 76 with permission.

A series of N-acyl and N-acyloxymethyl isatin thiosemi-carbazones was synthesized in an attempt to expand the spectrum.These compounds were not inhibitors of influenza WSN or rhinovirus strains. N-methylisatin-P-4 4 -dibutyl-thiosemicarbazone was shown to be an inhibitor of poliovirus RNA synthesis.The compound directly inhibits cell-free polio RNA polymerase. 

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