- Insight into technetium amidoxime complex: Oxo technetium(V) complex of N-substituted benzamidoxime as new basic structure for molecular imaging
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In search of benzamidoxime (BHam) derivatives that provide a single 99mTc-labeled compound of high in vivo stability, we synthesized three N-alkyl compounds of benzamidoxime (BHam) ligand. They provided a single 99mTc-labeled compound by ligand exchange reaction of 99mTc-glucoheptonate in high radiochemical yields (over 95% at MBHam concentration of 1 × 10-5 M). 99mTc-N-methyl benzamidoxime (99mTc-MBHam) showed higher stability than the parental 99mTc-BHam. The complex of this compound with 99gTcO+ ion was prepared, isolated, and characterized by FT-IR and NMR spectra as well as X-ray diffraction.99gTc-MBHam crystallized in an orthorhombic space group Pna2 1 with a = 13.4823(5), b = 15.5410(7), c = 7.7907(3) A, V = 1632.39(11) A3, and Z =4. The 99gTc complex possessed square base pyramid coordination geometry. The equatorial plane was formed by two-amine nitrogen and two-oxime oxygen atoms in trans position, while the oxo core of the technetium(V) occupied the apical position. The 99gTc-MBHam proved to be identical with the 99mTc-MBHam prepared at the no-carrier-added level by comparison of their HPLC profiles.
- Thipyapong, Khajadpai,Uehara, Tomoya,Tooyama, Yuji,Braband, Henrik,Alberto, Roger,Arano, Yasushi
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p. 992 - 998
(2011/04/27)
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- Cycloadditions of nitrile oxides to amidoximes. A general synthesis of 3,5-disubstituted 1,2,4-oxadiazole-4-oxides
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The cycloaddition of nitrile oxides to amidoximes is a general method for the synthesis of 3,5-disubstituted 1,2,4-oxadiazole-4-oxides with the same or different substituents. The yields are only moderate since an equivalent amount of the nitrile oxide is consumed by reaction with the amine released in the fragmentation of the primary cycloadducts and reforms the amidoxime. With excess nitrile oxides the 1,2,4-oxadiazole-4-oxides undergo a disproportionation reaction to yield nitroso carbonyl intermediates and 1,2,4-oxadiazoles.
- Quadrelli, Paolo,Invernizzi, Anna Gamba,Falzoni, Mario,Caramella, Pierluigi
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p. 1787 - 1796
(2007/10/03)
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- Photoinduced Molecular Rearrangements. Some Investigations of the Photochemical Behavior of 3-(Acylamino)-1,2,5-Oxadiazoles (Furazans)
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Mechanistic investigations of the photochemical behavior of some 3-(acylamino)-1,2,5-oxadiazoles (furazans) are reported.Irradiations of 3-(aroylamino)-4-methyl- and 3-(acetylamino)-4-phenyl-furazans at λ = 254 nm in methanol, and in methanol containing pyrrolidine, are considered.Photochemical processes follow different routes depending on the actual chromophore in the photoreaction.In the irradiation of 3-(aroylamino)-4-methylfurazans, two photochemical pathways involving a different multiplicity of excited states suggested: cleavage of the ring O(1)-N(5) bond via a singlet excited state (developing into nitrile oxides or carbodiimides, from which final products arise), or preliminary ring-closure involving the aroylamino group via a triplet excited state, respectively.In the irradiation of 3-(acetylamino)-4-phenylfurazan, photolytic intermediates arising from the cleavage of both the O(1)-N(2) and O(1)-N(5) bonds develop into the final products by reaction with the nucleophilic species present.
- Buscemi, Silvestre,Vivona, Nicolo,Caronna, Tullio
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p. 4096 - 4101
(2007/10/02)
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