Decomposition of organic azides

Abramovitch, R. A.; Kyba, Evan P.

doi:10.1002/9780470771266.ch5

Cited by 52 publications

(29 citation statements)

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“…The reaction course of the 6-azidoflavin (3) in concentrated sulfuric acid might thus be envisaged to parallel at least some of the reactions occurring during photolysis and to proceed as shown in Scheme 11. Similar sequences of events are amply documented in the literature (Abramovitch & Kyba, 1971;Reiser & Wagner, 1971). The primary products(s) of ring expansion 7 is (are) likely not to be stable under strongly acidic I I ' I ' 425 i 300 400 500 600 700 WAVELENGTH (nm) FIGURE 6: Spectral course of cuz+ complexation of 3,8-dimethyl-6-carboxy-7-(2-methyl-3-oxobut-2-enyl)lumazine @a).…”

Section: Wavelength (Nrn)supporting

confidence: 58%

“…A multitude of products appears during irradation. Although several types of reaction can be expected upon photolysis of aromatic azides (Abramovitch & Kyba, 1971;Reiser & Wagner, 1971), this finding is in partial contrast to what was observed with 8-azidoflavins where several photoproducts could be identified readily (Ghisla et al, 1984;Fitzpatrick et al, 1985). The ratio of the products also changes upon further irradiation, indicating secondary photoreactions.…”

Section: Wavelength (Nm)mentioning

confidence: 86%

“…Reaction Course of Chemically Generated 3-Methyllumiflavin-6-nitrene (6). The transient nitrene ti derived from 6-azido-3-methyllumiflavin (3a) was generated with concentrated sulfuric acid at 0 "C (Abramovitch & Kyba, 1971). The crystalline product obtained in good yield (75%) was homogeneous by HPLC when analyzed in a weakly acidic system (pH 2.5).…”

Section: Wavelength (Nm)mentioning

confidence: 99%

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Preparation and some properties of 6-substituted flavins as active site probes for flavin enzymes

Ghisla¹,

Massey²,

Yagi³

1986

Biochemistry

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6-Azidoflavins, 6-thiocyanatoflavins, and 6-mercaptoflavins at the lumiflavin, riboflavin, FMN, and FAD level were prepared from the corresponding 6-aminoflavins and some of their properties investigated. They are bound tightly by apoflavin enzymes which bind either riboflavin, FMN, or FAD. 6-Azidoflavins undergo facile photolysis. One major product was identified as 6-aminoflavin. A further product, which was formed also during acid decomposition of the azide, results from opening of the flavin benzene ring and is proposed to have a lumazine structure. 6-Thiocyanatoflavins are easily converted by dithiothreitol to 6-mercaptoflavins. The latter are stabilized against dimerization in the presence of reducing thiols. 6-Mercaptoflavins have a pK of 5.9, which corresponds to ionization of the 6-SH function. The neutral form is yellow, while the anion is green, due to a long-wavelength band ( A , , , -600 nm) extending beyond 700 nm. These properties suggest the use of these 6-substituted flavins for probing the active site of flavin enzymes. Because their reactive substituents are in close proximity to the flavin N(5)-position, these 6-substituted derivatives should also serve as useful probes of the environment around the flavin N(5), a position known to be involved in all flavin-mediated redox processes.

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Section: Wavelength (Nrn)supporting

confidence: 58%

Section: Wavelength (Nm)mentioning

confidence: 86%

Section: Wavelength (Nm)mentioning

confidence: 99%

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Preparation and some properties of 6-substituted flavins as active site probes for flavin enzymes

Ghisla¹,

Massey²,

Yagi³

1986

Biochemistry

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“…The protein concentration varied among different experiments, which resulted in different degrees of turbidity in the membrane preparations and, consequently, different exposure conditions to the light used in photolysis. Thermal inactivation (18) or photoinactivation (19) of the acebutolol azide probably occurred during these experiments. All of the experiments with reticulocytes were performed in the presence of 0.16-0.2 mM dithiothreitol.…”

Section: Discussionmentioning

confidence: 80%

“…This article must therefore be hereby marked "advertisement" in accordance with 18 (11). When reticulocytes were used in an assay, the assay mixture contained 50 mM sucrose, 0.2 mM dithiothreitol, 0.6 mM MgCl2, 0.2 mM EDTA, and 5 mM Tris-HCI in addition to the concentrations of reagents present in a normal assay.…”

mentioning

confidence: 99%

Photoaffinity label for the beta-adrenergic receptor: synthesis and effects on isoproterenol-stimulated adenylate cyclase.

Wrenn¹,

Homcy²

1980

Proc. Natl. Acad. Sci. U.S.A.

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An azide derivative of the ,-adrenergic antagonist acebutolol has been synthesized and its effect examined on the isoproterenol-stimulated adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); EC 4.6.1.1] activity of rat reticulocytes. It behaved as an effective competitive antagonist (Kd = 2 X 10-7 M) prior to photolysis. However, when the reticulocyte preparation pretreated with acebutolol azide was photolyzed, a noncompetitive inhibition of isoproterenol-stimulated adenylate cyclase was obtained. Photolysis-of the azide derivative in buffer alone did not convert it to a product of higher affinity.Labeling of the P-adrenergic receptor appeared to be irreversible; multiple washings could not reverse the inhibition produced during photolysis with the label whereas washing would completely reverse the antagonism produced by the same concentration of label prior to photolysis. The effect appears to be specific for the ,-adrenergic receptor because the inhibition could be blocked stereoselectively by propranolol and there was no inhibition of fluoride-or GMP-P(NH)P-stimulated adenylate cyclase. Furthermore, no effect was observed on the glucagonmediated stimulation of adenylate cyclase of liver membranes, whereas the catecholamine response in the same membranes was inhibited.In this communication, we report on the synthesis of an azide derivative of the f3-adrenergic antagonist acebutolol and its characterization as a photoaffinity label for the ,B-adrenergic receptor by its effect on isoproterenol-stimulated adenylate cyclase activity of rat reticulocytes. Although there are previous reports in which affinity labels for this receptor have been described (1-4), this study demonstrates both the irreversible nature and specificity of such inhibition after light-induced chemical activation. Furthermore, the structure of this ligand is unique in that the reactive functional site is located on the phenyl ring rather than on the ethanolamine side chain which is the structure, common to both agonists and antagonists, that is required for ligand binding to the receptor.Photoaffinity labels offer the advantage over affinity labels of being completely reversible until photoactivation occurs. Thus, reliable affinity constants can be obtained and the labels can be characterized prior to their photolysis and concomitant irreversible binding. Furthermore, the specificity of this ligand is demonstrated by its lack of effect on a second adenylate cyclase-linked receptor system in the same membrane preparation in which covalent binding to the f3-adrenergic receptor had been achieved. Stereoselective protection of the receptor from irreversible labeling was also shown with the stereoisomers of propranolol.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. 4449MATERIALS AND METHODS Materials. Acebutolol amine, RS-1-(2-acetyl-4-amino)-2-hydroxy-3-isopropylaminopropan...

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Phenyl Azide

Pearson¹,

Ramamoorthy²

2001

Encyclopedia of Reagents for Organic Synthesis

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Decomposition of organic azides

Cited by 52 publications

References 228 publications

Preparation and some properties of 6-substituted flavins as active site probes for flavin enzymes

Preparation and some properties of 6-substituted flavins as active site probes for flavin enzymes

Photoaffinity label for the beta-adrenergic receptor: synthesis and effects on isoproterenol-stimulated adenylate cyclase.

Phenyl Azide

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