Diperoxycarboxylic anhydrides and their urea adducts as peroxy acid precursors

During our studies of urea and thiourea adducts, we noticed that no adducts with unsubstituted pyridine had been structurally investigated. The 1:1 adduct of pyridine and urea, C5H5N·CH4N2O, crystallizes in the P21/c space group with Z = 4. The structure is of a standard type for urea adducts, whereby the urea molecules form a ribbon, parallel to the a axis, consisting of linked R 2 2(8) rings, and the pyridine molecules are attached to the periphery of the ribbon by bifurcated (N—H...)2N hydrogen bonds. The 1:1 adduct of pyridine and thiourea, C5H5N·CH4N2S, crystallizes in the P21/n space group, with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct. There are two independent ribbons parallel to the b axis at z ≃ 0 and 1 \over 2, and three at z ≃ 1 \over 4 and 3 \over 4; the latter are crosslinked to form a layer structure by additional long N—H...S interactions, which each formally replace one branch of a bifurcated hydrogen-bond system.

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On the mechanism of enzyme action. XLVIII. Investigation of the fat of Fusarium lini Bolley by means of urea adducts

Archives of Biochemistry and Biophysics ◽

10.1016/0003-9861(52)90044-1 ◽

1952 ◽

Vol 38 (1) ◽

pp. 377-383 ◽

Cited By ~ 5

Author(s):

J.A. Maselli ◽

F.F. Nord

Keyword(s):

Enzyme Action ◽

Urea Adducts

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Evidence for production of oxidizing radicals by the particulate O-2- forming system from human neutrophils

Blood ◽

10.1182/blood.v53.4.666.bloodjournal534666 ◽

1979 ◽

Vol 53 (4) ◽

pp. 666-676

Author(s):

AI Tauber ◽

TG Gabig ◽

BM Babior

Keyword(s):

Hydrogen Peroxide ◽

Superoxide Dismutase ◽

Ethylene Production ◽

Human Neutrophils ◽

Peroxy Acid ◽

Radical Scavengers ◽

Alkyl Peroxide ◽

Acyl Peroxide

The particulate O-2-forming system from human neutrophils was found to oxidize methional and 2-keto-4-methylthiobutyric acid (KMB) to ethylene, indicating the formation by this system of strongly oxidizing radicals. Conforming this interpretation was the observation that ethylene production was inhibited by the radical scavengers benzoate, ethanol, and mannitol. Ethylene production was also sharply reduced by superoxide dismutase, implicatin O-2 as a precursor of oxidizing radicals. In our system catalase only partially inhibited ethylene generation from either methional or KMB, suggesting that oxidizing radicals are generated at least in part by the reacton of O-2 with compounds other than H2O2. We propose that in neutrophils oxidizing radicals are formed in a reaction between O-2 and a peroxide according to the following equation: O-2 + ROOH leads to RO . + OH- + O2, in which ROOH may be hydrogen peroxide, an alkyl peroxide, or an acyl peroxide (i.e., a peroxy acid).

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