Dissectic acid

Fig. 58. A Bellidiflorin, An. Bar lOiLim. B Materia rubra [an unidentified compound from Usnea baileyi (Stirt.) Zahlbr.], GE. Bar 100 pm. C Dissectic acid with atranorin, An. Bar 10 pm. Dissectic acid is an unidentified PD+ Substance from Heterodermia dissecta (Kurok.) Awas. D a-Acetylsalazinic acid, oT. Bar 10 pm...

Elix JA, Wardlaw JH (1996) The Structure of Dissectic Acid, a p-Orcinol mela-Depside from the Lichen Heterodermia dissecta. Aust J Chem 49 539... 

The antibiotic aplasmomycin serves as a receptor or transporter for borate. Retrosynthetic simplification of the boron-free macrocycle to identical hydroxy acid subunits is clearly appropriate. Further retrosynthetic dissection produced fragments A, B and oxalate and provided a workable synthetic plan. 

Zechel DL, Withers SG (2001) Dissection of nucleophilic and acid-base catalysis in glycosidases. Curr Opin Chem Biol 5 643-649... 

Substantial progress can be expected in the near future concerning the structure of amino acid transporters, their functional dissection, and their evolutionary filiation. 

Many years ago, doisynolic acid (39), a steroid degradation product, was shown to have such activity. Over the years many simple compounds have been synthesized following the idea of molecular dissection. One of these is fenesti-el (38). Hageman s ester (35) is alkylated to 36 by t-BuOK and ethyl-bromide. The regioselectivity observed is generally... 

A molecular dissection of the alkaloid vasicine (52) ultimately resulted in the expectorant and mucolytic agent bromhexine (54). The synthesis starts with displacement of halogen on 2-nitrobenzyl-bromide (53) by N-methyl cyclohexylamine, followed by Raney nickel and hydrazine reduction of the nitro group. Bromination in acetic acid then affords bromhexine. 

Arava, Y., Boas, F. E., Brown, P. O., and Herschlag, D. (2005). Dissecting eukaryotic translation and its control by ribosome density mapping. Nucleic Acids Res. 33, 2421-2432. 

A young Louis Pasteur observed that many salts of tartaric acid formed chiral crystals (which he knew was related to their ability to rotate the plane of polarization of plane-polarized light). He succeeded in solving the mystery of racemic acid when he found that the sodium ammonium salt of racemic acid could be crystallized to produce a crystal conglomerate. After physical separation of the macroscopic enantiomers with a dissecting needle, Pasteur... 

Fig. 6. Structural stability of major ampullate silk protein in constrained Nephila edulis. The graph shows a time series of circular dichroism spectra of major ampullate (MA) protein at 1% w/v in distilled water. The spiders prior to dissection were prevented from spinning, but fed and watered for at least 2 weeks. With time, the secondary structure of silk protein is becoming more and more disordered. The arrow indicates increasing time (days). Note that the amino acid composition of the silk protein was similar to that of a native N. edulis spider. Interestingly, silk protein extracted from the constrained spider did not respond to denaturing conditions (detergents, alcohols, pH, and salts Dicko et al, 2004a, 2005).

Boileau AJ, Kucken AM, Evers AR, Czajkowski C. 1998. Molecular dissection of benzodiazepine binding and allosteric coupling using chimeric y-aminobutyric acid receptor subunits. Mol Pharmacol 53 295. 

The discovery of the sedative/hynoptic activity of derivatives of barbituric acid has led to very extensive dissections of that molecule. One outcome of this work is the realization that acylurea and acylamide derivatives often exhibit CNS depressant activity. A fair number of such molecules have been prepared that contain a succinimide or glutarimide pharmacophore. For example, Michael addition of cyanide to the stereochemically xmdefined cinnamate... 

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