145071-76-7Relevant academic research and scientific papers
Alkylation of nitroaromatics with trialkyborane
Palani,Jayaprakash, Karamil,Hoz, Shmaryahu
, p. 4388 - 4391 (2007/10/03)
When p-dinitrobenzene is reacted with Et3B in t-BuOH or THF in the presence oft-BuOK, it yields p-nitroethylbenzene. In this report we examine the scope of this transformation by monitoring the effect of various parameters on the reaction. It has been found that the reaction is extremely sensitive to temperature and rather insensitive to the base-solvent combination used. It is also insensitive to the steric hindrance of the base: good yields were obtained using sodium 2,6-diisopropylphenoxide or when using NaH. Alkylation was obtained With a large variety of alkylboranes ranging from linear to polycyclic. Yields drop significantly if one of the nitro groups is replaced by another electron-withdrawing group. In all cases studied (CHO, PHCO, SO2Ph, and CN), it is the latter group which was preferentially displaced by the alkyl group. According to the suggested mechanism, the radical anion of the substrate combines with the alkyl radical released from the boranyl radical to form a Meisenheimer complex. The reaction takes place at the ring carbon bearing the highest spin density in accordance with ab initio calculations at the B3LYP/ 6-31+G level.
Synthesis and evaluation of 4-alkylanilines as mammary tumor inhibiting aromatase inhibitors
Hartmann,Batzl
, p. 537 - 544 (2007/10/02)
The 4-alkylanilines 1-20 were synthesized to elucidate the importance of the glutarimide moiety for the aromatase inhibiting activity of aminoglutethimide [3-(4-aminophenyl)-3-ethylpiperidine-2,6-dione, AG], the only non-steroidal aromatase inhibitor which is commercially available at present. The most interesting compounds were the (4-aminophenyl)cycloalkanes 4-6 (4, c-pentyl; 5, c-hexyl; 6, c-heptyl) and the 1-alkyl-1-(4-aminophenyl)cyclohexanes 1-3 (1, CH3; 2, C2H5; 3, n-C3H7). Derivatives 1-6 are stronger inhibitors of human placental aromatase than AG exhibiting relative potencies from 1.5 to 2.7 (AG≡1). For selectivity of action, the inhibition of desmolase (cholesterol side chain cleavage enzyme) was determined. Compounds 1-3 showed an inhibition comparable to AG, whereas compounds 4-6 exhibited no effect on desmolase. Being more potent and selective aromatase inhibitors in vitro, compounds 4-6, however, were not superior to AG in vivo, when the reduction of plasma estradiol concentration and the tumor inhibiting activity (PMSG-primed SD rats and DMBA-induced mammary carcinoma of the SD rat, postmenopausal model) were concerned.
