Isoindole

BONNETT, RAYMOND; Brown, R. F. C.; SMITH, ROY G.

doi:10.1039/p19730001432

Cited by 53 publications

(27 citation statements)

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“…Similarly, benzo proton signals for 2BN (d = 7.37 and 7.20 ppm) appeared at higher field than for 2BS (d = 8.05 and 7.59 ppm), whereas the bproton signals in the spectrum of 2BN (d = 9.34 ppm) were observed at lower field than in the case of 2BS (8.33 ppm). As benzo protons of the parent heterocycles exhibit similar chemical shifts (d = 7.5 and 6.8 for isoindole and d = 7.59 and 7.04 for isothianaphthene), [23] these observed differences can be attributed to differences in the diamagnetic macrocyclic ring currents ( Figure 1).…”

Section: Nmr Spectroscopymentioning

confidence: 86%

Application of MCD Spectroscopy and TD‐DFT to Nonplanar Core‐Modified Tetrabenzoporphyrins: Effect of Reduced Symmetry on Nonplanar Porphyrinoids

Mack

Bunya

Shimizu

et al. 2008

Chemistry A European J

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The optical spectra of a series of core-modified tetrabenzoporphyrins were analyzed to determine the effects of core modification, ligand folding, and partial benzo substitution at the ligand periphery on the electronic structure by using magnetic circular dichroism (MCD) and NMR spectroscopy, X-ray crystallography, cyclic and differential pulse voltammetry, and TD-DFT calculations. Planar 21-carba-, 21-thia-, 21,23-dithia-, and 21-oxa-23-thiatetrabenzo[b,g,l,q]porphyrins reported previously were studied together with the previously unreported 21-oxa- and 21-carba-23-thiatetrabenzo[b,g,l,q]porphyrins. The optical properties of these compounds are compared to those of tetrabenzo[b,g,l,q]-, 5,10,15,20-tetraphenyl-, 5,10,15,20-tetraphenyltetrabenzo[b,g,l,q]-21-thia-, 5,10,15,20-tetraphenyltetrabenzodithia-, 5,10,15,20-tetraphenyldibenzo[g,q]-21,23-dithia-, 5,10,15,20-tetraphenyldibenzo[b,l]-21,23-dithia-, 5,10,15,20-tetraphenyltribenzo[g,q,l]-21-thia-, and 5,10,15,20-tetraphenylbenzo[b]-21-thiaporphyrins. Michl's perimeter model and Gouterman's four-orbital model are used to conceptualize the results and to account for red shifts commonly observed in the spectral bands of nonplanar porphyrinoids.

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Section: Nmr Spectroscopymentioning

confidence: 86%

Application of MCD Spectroscopy and TD‐DFT to Nonplanar Core‐Modified Tetrabenzoporphyrins: Effect of Reduced Symmetry on Nonplanar Porphyrinoids

Mack

Bunya

Shimizu

et al. 2008

Chemistry A European J

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“…Under appropriate conditions the coupled oxidation of hernochromes is rapid and leads t o a good yield of bile pigment. 78 On the other hand, with heme proteins the reaction is slow and in general biliverdin is obtained in very small yield.7 3 , 7 5 High concentrations of oxygen accelerate the coupled oxidation of pyridine h e r n o c h r~m e~~ yet, paradoxically, inhibit the coupled oxidation of h e m~g l o b i n .~~ Most importantly, the two processes show a marked difference in stereospecificity, as described below.…”

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confidence: 99%

The Enzymatic Formation of Bilirubin*

Schmid

McDonagh

1975

Annals of the New York Academy of Sciences

101

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“…An overall yield of 11.1% of the mixture of hematobiliverdin methyl esters was obtained. This yield, although lower than that obtained for the oxidation of hemin IX to the biliverdin IX isomers (42% [9]) is not very different from the yields of the biliverdin methyl esters obtained in the oxidation ofuroheme I11 (8.3% [lo]) or coproheme 111 (12.1%…”

Section: Chemical Oxidation Of Hematohemin To Hematobiliverdinsmentioning

confidence: 95%

“…As a first step in these studies we performed the chemical oxidation ('coupled oxidation' [9]) of synthetic hematohemin IX to the four possible hematobiliverdin isomers (a, p, y and 6). We found that, contrary to the negative previous report [8], the reaction took place in low but similar yield to that reported in the chemical oxidations of other hemins.…”

mentioning

confidence: 99%

The chemical and enzymatic oxidation of hematohemin IX. Identification of hematobiliverdin IXalpha as the sole product of the enzymatic oxidation

et al. 1986

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Oxidative cleavage of hematohemin IX in pyridine solution in the presence of ascorbic acid (coupled oxidation), followed by esterification of the products with boron trifluoride/methanol produced the four possible hematobiliverdin dimethyl esters in 11.1 YO overall yield. Transetherifications took place simultaneously with the esterification reaction and resulted in the formation of the dimethyl ester of hematobiliverdin IXy 8 a,l3 a-dimethyl ether (1.8%), the dimethyl ester of hematobiliverdin IXP 13 a,lSa-dimethyl ether (1.9"/), the dimethyl ester of hematobiliverdin 1x6 8 a-monomethyl ether (1.4%), and the dimethyl ester of hematobiliverdin IXa 18 a-monomethyl ether (0.4%). The latter was the sole product obtained after the enzymatic oxidation of hematohemin with heme oxygenase, after esterification of the reaction product with boron trifluoride/methanol. When the esterification step was omitted hematobiliverdin IXa was obtained from the enzymatic oxidation. The structures of the hematobiliverdin derivatives were secured by their NMR and mass spectra data. Saponification of the dimethyl esters afforded the hematobiliverdin methyl ethers, which were excellent substrates of biliverdin reductase and were readily reduced to the corresponding bilirubins. Hematobiliverdin IXa was also a good substrate of biliverdin reductase. It is concluded that the enzymatic oxidation of hematohemin IX by heme oxygenase is a-selective, while biliverdin reductase shows no selectivity in the reduction of the four hematobiliverdin isomers.Heme IX (or b) is degraded in the general metabolism by a microsomal heme oxygenase, which selectively cleaves the a-meso carbon of the hemin to give biliverdin IX a and the latter is then reduced in mammals by a cytosolic biliverdin reductase to bilirubin IXa. We have extensively studied the substrate specificity of both enzymes and we established, by making use of a large number of synthetic hemins and bi-

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Isoindole

Abstract: 2-( p-phenylethy1)isoindoline 2-oxide (VI) at 105" and 0.02 mmHg gives 2-hydroxyisoindoline (VII). The latter was contaminated with 2-( p-phenylethy1)iso-

Cited by 53 publications

References 0 publications

Application of MCD Spectroscopy and TD‐DFT to Nonplanar Core‐Modified Tetrabenzoporphyrins: Effect of Reduced Symmetry on Nonplanar Porphyrinoids

Application of MCD Spectroscopy and TD‐DFT to Nonplanar Core‐Modified Tetrabenzoporphyrins: Effect of Reduced Symmetry on Nonplanar Porphyrinoids

The Enzymatic Formation of Bilirubin*

The chemical and enzymatic oxidation of hematohemin IX. Identification of hematobiliverdin IXalpha as the sole product of the enzymatic oxidation

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