- The discovery and development of a safe, practical synthesis of ABT-869
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The discovery, development and implementation of two chemical routes to ABT-869 is reported. Optimization of the first-generation heterocycle formation and Suzuki coupling is briefly described. Key features of the second-generation synthesis include the development of a safe hydrazine condensation by utilizing an inorganic base to increase the onset temperature of exothermic decomposition. The second-generation Suzuki reaction is discussed in detail, culminating in the use of an oxygen monitor as a PAT to maximize reproducibility on scale.
- Kruger, Albert W.,Rozema, Michael J.,Chu-Kung, Alexander,Gandarilla, Jorge,Haight, Anthony R.,Kotecki, Brian J.,Richter, Steven M.,Schwartz, Albert M.,Wang, Zhe
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- Safe Scale-Up of a Hydrazine Condensation by the Addition of a Base
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Herein we describe an observation where an exothermic event encountered during the safety evaluation of the scale-up of the synthesis of 4-chloro-1H-indazol-3-amine was mitigated upon the addition of a base. The 100 C adiabatic temperature rise was attributed to the hydrazine condensation reaction, which could cause the batch to self-heat beyond the onset temperature of the exothermic decomposition of the reaction mass. Switching from 1-methyl-2-pyrrolidinone to a lower-boiling-point solvent was explored, but that alone did not guarantee the safe operation in the event cooling is lost. The reaction byproduct, HCl, was identified as a possible cause for the decreasing onset temperature of hydrazine monohydrate. The addition of a base to the reaction mixture increased the onset temperature and decreased the severity of the observed decomposition of the reaction mass. By the introduction of sodium acetate as a base in combination with a lower-boiling-point solvent, safe operating conditions for the process were identified. This base-stabilizing effect has been observed with other hydrazine condensation reactions in our laboratory.
- Wang, Zhe,Richter, Steven M.,Gandarilla, Jorge,Kruger, Albert W.,Rozema, Michael J.
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Read Online
- Synthesis and structure-activity relationships of indazole arylsulfonamides as allosteric CC-chemokine receptor 4 (CCR4) antagonists
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A series of indazole arylsulfonamides were synthesized and examined as human CCR4 antagonists. Methoxy- or hydroxyl- containing groups were the more potent indazole C4 substituents. Only small groups were tolerated at C5, C6, or C7, with the C6 analogues being preferred. The most potent N3-substituent was 5-chlorothiophene-2-sulfonamide. N1 meta-substituted benzyl groups possessing an α-amino-3-[(methylamino)acyl]- group were the most potent N1-substituents. Strongly basic amino groups had low oral absorption in vivo. Less basic analogues, such as morpholines, had good oral absorption; however, they also had high clearance. The most potent compound with high absorption in two species was analogue 6 (GSK2239633A), which was selected for further development. Aryl sulfonamide antagonists bind to CCR4 at an intracellular allosteric site denoted site II. X-ray diffraction studies on two indazole sulfonamide fragments suggested the presence of an important intramolecular interaction in the active conformation.
- Procopiou, Panayiotis A.,Barrett, John W.,Barton, Nicholas P.,Begg, Malcolm,Clapham, David,Copley, Royston C. B.,Ford, Alison J.,Graves, Rebecca H.,Hall, David A.,Hancock, Ashley P.,Hill, Alan P.,Hobbs, Heather,Hodgson, Simon T.,Jumeaux, Coline,Lacroix, Yannick M. L.,Miah, Afjal H.,Morriss, Karen M. L.,Needham, Deborah,Sheriff, Emma B.,Slack, Robert J.,Smith, Claire E.,Sollis, Steven L.,Staton, Hugo
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supporting information
p. 1946 - 1960
(2013/05/09)
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- 3-[(Imidazolidin-2-yl)imino]indazole ligands with selectivity for the α2-adrenoceptor compared to the imidazoline I1 receptor
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A series of 3-[(4,5-dihydroimidazolidin-2-yl)imino]indazoles has been synthesized as positional analogues of marsanidine, a highly selective α2-adrenoceptor ligand. Parent compound 4a and its 4-chloro (4c) and 4-methyl (4d) derivatives display α2-adrenoceptor affinity at nanomolar concentrations (Ki = 39.4, 15.9 and 22.6 nM, respectively) and relatively high α2/I1 selectivity ratios of 82, 115 and 690, respectively. Evidence was obtained that these compounds act as partial agonists at α2A-adrenoceptors. Compound 4d with intrinsic activity comparable with that of marsanidine, but lower than that of clonidine, elicited pronounced cardiovascular effects in anesthetized rats at doses as low as 0.01 mg/kg iv.
- Sczewski, Franciszek,Kornicka, Anita,Hudson, Alan L.,Laird, Shayna,Scheinin, Mika,Laurila, Jonne M.,Rybczyńska, Apolonia,Boblewski, Konrad,Lehmann, Artur,Gdaniec, Maria
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scheme or table
p. 321 - 329
(2011/02/26)
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- NOVEL COMPOUNDS
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Indazole compounds, processes for their preparation, intermediates usable in these processes, pharmaceutical compositions containing such compounds and their use in therapy.
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Page/Page column 25
(2010/09/05)
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- New practical synthesis of indazoles via condensation of o-fluorobenzaldehydes and their O-methyloximes with hydrazine
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The reaction of o-fluorobenzaldehydes and their O-methyloximes with hydrazine has been developed as a new practical synthesis of indazoles. Utilization of the methyloxime derivatives of benzaldehydes (in the form of the major E-isomers) in this condensation effectively eliminated a competitive Wolf-Kishner reduction to fluorotoluenes, which was observed in the direct preparations of indazoles from aldehydes. Reaction of Z-isomers of methyloximes with hydrazine resulted in the formation of 3-aminoindazoles via a benzonitrile intermediate.
- Lukin, Kirill,Hsu, Margaret C.,Fernando, Dilinie,Leanna, M. Robert
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p. 8166 - 8172
(2007/10/03)
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