- Photoswitchable Magnetic Resonance Imaging Contrast by Improved Light-Driven Coordination-Induced Spin State Switch
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We present a fully reversible and highly efficient on-off photoswitching of magnetic resonance imaging (MRI) contrast with green (500 nm) and violet-blue (435 nm) light. The contrast change is based on intramolecular light-driven coordination-induced spin state switch (LD-CISSS), performed with azopyridine-substituted Ni-porphyrins. The relaxation time of the solvent protons in 3 mM solutions of the azoporphyrins in DMSO was switched between 3.5 and 1.7 s. The relaxivity of the contrast agent changes by a factor of 6.7. No fatigue or side reaction was observed, even after >100 000 switching cycles in air at room temperature. Electron-donating substituents at the pyridine improve the LD-CISSS in two ways: better photostationary states are achieved, and intramolecular binding is enhanced.
- Dommaschk, Marcel,Peters, Morten,Gutzeit, Florian,Schütt, Christian,N?ther, Christian,S?nnichsen, Frank D.,Tiwari, Sanjay,Riedel, Christian,Boretius, Susann,Herges, Rainer
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supporting information
p. 7552 - 7555
(2015/07/02)
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- Pyridobenzoxazepine and pyridobenzothiazepine derivatives as potential central nervous system agents: Synthesis and neurochemical study
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In order to characterize the pharmacological profile of the different chemical classes of pyridobenzazepine derivatives, a series of N- methylpiperazinopyrido[1,4]- and -[1,5]- benzoxa- and benzothiazepine derivatives were prepared. The affinities for D2, D1, 5-HT2, and cholinergic (M) receptors were measured. In comparison to dibenzazepine reference compounds, a strong decrease of the affinities was observed, less pronounced, however, for the substituted analogues. Oxazepine and thiazepine analogues like clozapine (except 8-chloro-6-(4-methylpiperazin-1-yl)- pyrido[2,3-b][1,4]benzoxazepine (9) and 8-chloro-6-(4-methylpiperazin-1- yl)pyrido[2,3-b][1,4]-benzothiazepine (11)) were found to be inactive against apomorphine stereotypies. In the open-field test in rats, different molecules showed a high disinhibitory activity as observed with anxiolytic drugs. Moreover, 8-chloro-5-(4-methylpiperazin-1-yl)pyrido[2,3-b][1,5]benzoxazepine (14) presented a clozapine-like profile that was confirmed in the behavioral model in dogs and showed most of the behavioral characteristics described for antipsychotic drugs. Its neurochemical profile, in particular the 5-HT2/D2 ratio, was also compatible with atypical antipsychotic activity.
- Liegeois,Rogister,Bruhwyler,Damas,Thuy Phuong Nguyen,Inarejos,Chleide,Mercier,Delarge
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p. 519 - 525
(2007/10/02)
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- TITANIUM (O) REAGENTS; 4. A SELECTIVE AND EFFICIENT REDUCTION OF NITROPYRIDINE DERIVATIVES
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Following the successful applications of a titanium (O) slurry in the deoxygenation of aromatic N-oxides, we attempted to achieve this method for the reduction of a nitro- group in pyridine derivatives.In general, only aminopyridine derivates were formed in 85-98percent yield.The advantage of this excellent reducing agent consists in mild reaction conditions and high yields of products, as well as in the selectivity of the reaction.
- Malinowski, Marek
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- Aryl substituted pyrido[1,4]benzodiazepines and their use as antidepressives
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Novel [2-[(aminopyridinyl)amino]phenyl]arylmethanones and their thioxomethyl, ketal or thioketal analogs of the formula: STR1 wherein; R is selected from the group consisting of hydrogen, loweralkyl, --alk1 --halo, --alk1 --NR1 --NR1 R2 or --alk1 --N=CH--OC2 H5 ; R1 and R2 are selected from the group consisting of hydrogen, loweralkyl, --C(O)O-loweralkyl or R1 and R2 taken together with the adjacent nitrogen atom may form a heterocyclic residue selected from the group consisting of 1-piperidinyl, 1-phthalimido, 1-pyrrolidinyl, 4-morpholinyl, 1-piperazinyl and 4-substituted-1-piperazinyl; B is selected from carbonyl, thioxomethyl, ketal or thioketal; Ar is selected from the group consisting of 2, 3 and 4-pyridinyl, 2 or 3-thienyl, phenyl or phenyl substituted by 1 to 3 radicals selected from halo, loweralkyl, loweralkoxy, trifluoromethyl or nitro and may be the same of different; alk1 is a straight or branched hydrocarbon chain containing 1-8 carbon atoms; Z is selected from the group consisting of hydrogen, halogen, loweralkyl, loweralkoxy, hydroxy or nitro; Y is selected from the group consisting of hydrogen or 1-2 radicals selected from loweralkyl, loweralkoxy or hydroxy and may be the same of different, and the acid addition salts thereof. These compounds are intermediates in the preparation of novel aryl substituted pyrido[1,4]benzodiazepines having antidepression activity. Some of these intermediates are useful in treating depression.
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- Aryl substituted pyrido[1,4]benzodiazepines for treatment of depression
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Pyrido[1,4]benzodiazepines having antidepressant activity of the formula STR1 wherein Ar is 2, 3 and 4-pyridinyl, 2 or 3-thienyl, phenyl or a substituted phenyl; R is hydrogen, loweralkyl or an amine on the end of a hydrocarbon chain; Z is hydrogen, halogen, trifluoromethyl, loweralkyl, lower-alkoxy, hydroxy or nitro; and Y is hydrogen, loweralkyl, loweralkoxy or hydroxy; and the pharmaceutical salts are prepared from [2-[(aminopyridinyl)amino]phenyl]arylmethanones which also have antidepressant activity.
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- Aryl substituted pyrido[1,4]benzodiazepines
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Pyrido[1,4]benzodiazepines having antidepressant activity of the formula STR1 wherein Ar is 2, 3 and 4-pyridinyl, 2 or 3-thienyl, phenyl or a substituted phenyl; R is hydrogen, loweralkyl or an amine on the end of a hydrocarbon chain; Z is hydrogen, halogen, trifluoromethyl, loweralkyl, loweralkoxy, hydroxy or nitro; and Y is hydrogen, loweralkyl, loweralkoxy or hydroxy; and the pharmaceutical salts are prepared from [2-[(aminopyridinyl)amino]phenyl]arylmethanones which also have antidepressant activity.
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- PHOTOLYSIS OF PYRIDYL, QUINOLYL, AND ISOQUINOLYL AZIDES IN HYDROHALOGENOIC ACIDS
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Photolysis of 4-azido-pyridine and -quinoline in hydrohalogenoic acids gave the 3-amino-4-halogeno compounds (2) via azirine or azacycloheptatetraene intermediates, whereas their N-oxides (4), under similar conditions, gave the 4-amino-3-halogeno compounds (5) presumably via nitrenium ion intermediates.In the 3-azidoquinoline and 4-azidoisoquinoline series, both free bases (6a, 8a) and N-oxides (6b, 8b) gave similar results to 4-azidopyridine and -quinoline N-oxides (4).
- Sawanishi, Hiroyuki,Hirai, Toyoko,Tsuchiya, Takashi
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p. 1043 - 1046
(2007/10/02)
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