Here, we report the systematic synthesis and characterization of simple phenols bearing a trialkyl(aryl)silyl or trialkyl(aryl)germyl functional group as a hydrophobic substituent. These silicon and germanium analogues exhibited higher hydrophobicity than the corresponding carbon analogues, with a difference in log P value of approximately 0.6, independent of the alkyl(aryl) species. Trimethylsilylphenol and trimethylgermylphenol exhibited smaller pK(a) values than the corresponding carbon analogue or unsubstituted phenol, indicating that trialkylsilyl and trialkylgermyl functional groups have a negative substituent constant (sigma). The trialkylsilyl- and trialkylgermylphenols exhibited more potent estrogenic activity as compared with the carbon analogues. The substituent parameters and structure-activity relationship reported here may be helpful for drug discovery utilizing the heavier group 14 elements.
KOBAYASHI M.; KOBAYASHI MASANORI, BULL. CHEM. SOC. JAP., 59,(1986) N 9, 2807-2810
作者:KOBAYASHI M.、 KOBAYASHI MASANORI
DOI:——
日期:——
<i>cis</i>-Selective Hydrogenation of Aryl Germanes: A Direct Approach to Access Saturated Carbo- and Heterocyclic Germanes
reported via the hydrogenation of readily accessible aromatic germanes (2D framework). Among the numerous catalysts tested, Nishimura’s catalyst (Rh2O3/PtO2·H2O) exhibited the best hydrogenation reactivity with an isolated yield of up to 96%. A broad range of substrates including the synthesis of unprecedented saturated heterocyclic germanes was explored. This selective hydrogenation strategy could tolerate