18156-75-7Relevant articles and documents
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O'Brien,Hrung
, p. 185,186, 188, 191 (1971)
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Indazaboles - Synthesis and molecular structure
Wrackmeyera, Bernd,Shahid, Khadija,Kempe, Rhett,Doering, Christian,Milius, Wolfgang
experimental part, p. 398 - 401 (2010/07/16)
The reaction of 1-trimethylsilyl-indazole with boranes affords indazaboles accompanied by elimination of trimethysilane. Thus, the two isomers of parent indazabole are formed in a 1 : 1 ratio using borane in THF (BH3/THF), characterized by NMR spectroscopy in solution (1H, 11B and 13C NMR). In contrast, the analogous reaction with 1, 2-bis(tetramethylene)diborane(6) proceeds to give a single isomerof the B-alkylated indazabole via symmetric ring cleavage of the diborane(6), as shown by NMR in solution and X-ray structural analysis in the solid state. The molecular structure is fluxional in solution. In the solid state, the central B2N4 ring adopts a distorted boat conformation. Calculated gas phase geometries of the parent indazaboles and of the B-alkylated indazabole were optimized by DFT methods at the B3LYP/6-311+G(d,p) level of theory. Copyright
Alkylation, Acylation and Silylation of Azoles
Begtrup, Mikael,Larsen, Peter
, p. 1050 - 1057 (2007/10/02)
Performing alkylation, acylation and silylation reactions in separate deprotonation and nucleophilic displacement steps allows for better control of reaction conditions and facilitates problem handling in these processes.In the alkylation of azoles the alkylating agents and solvents possess individual reaction capabilities which seem to be approximately additive.Monoalkylation occurs if the sum of the normalized reaction potentials is equal or larger than the pKa value of the azole.Dialkylation is avoided by keeping the sum of the normalized reaction potentials below the pKa value of the alkylazole.The applicability of these principles is demonstrated by the development of effective procedures for the methylation, benzylation, acetylation, methoxycarbonylation and trimethylsilylation of azoles.
