β-(het)aryl-β-fluoroalkyl β-aminoacids and their α-hydroxy derivatives can be readily obtained using a decarboxylative Mannich-type reaction without protection/deprotection steps. This protocol utilizes lithium hexamethyldisilazide and (het)arylfluoroalkyl ketones to generate NH-ketimine intermediates. The mild reaction conditions allow the preparation of original fluorinated β-aminoacids as useful building
One-pot tethering of organic molecules through non-symmetric malonate derivatives
作者:Daniel Sherman、Rimma Shelkov、Artem Melman
DOI:10.1016/j.tetlet.2005.05.044
日期:2005.7
A new method for one-pot chemoselective beterobifunctional cross-linking of organic molecules is described. The method is based on tert-butyldiphenylsilyl malonate and involves two sequential carbodiimide couplings with two different molecules possessing a hydroxy or an amino functionality with one intermediate one-pot fluoride deprotection. (c) 2005 Elsevier Ltd. All rights reserved.
Modulation of doxorubicin activity in cancer cells by conjugation with fatty acyl and terpenyl hydrazones
作者:K. Effenberger、S. Breyer、R. Schobert
DOI:10.1016/j.ejmech.2010.01.037
日期:2010.5
Doxorubicin N-acylhydrazones derived from saturated, unsaturated and terpene-terminated fatty acids were tested for anticancer activity in cells of human HL-60 leukaemia, 518A2 melanoma, MCF-7/Topo breast and KB-V1/Vbl cervix carcinomas. In the latter, the N-heptadecanoyl hydrazone was more cytotoxic than its unsaturated C(18)-fatty acyl analogues and even three times more than doxorubicin. The (menthoxycarbonyl)undecanoyl hydrazone was twice as active as doxorubicin in these multidrug resistant KB-V1/Vbl and in the 518A2 cells and also more efficacious in KB-V1 and MCF-7 cells that had been desensitised for doxorubicin. All hydrazones induced apoptosis albeit by slightly different mechanisms. While apoptosis induction by the menthoxymalonyl hydrazone was characterized by an upfront increase in caspase-8 activity, all other hydrazones elicited a hike in caspase-9 activity. Treatment of HL-60 and 518A2 cells with doxorubicin or its heptadecanoyl, linolenoyl, (menthoxycarbonyl)undecanoyl or menthoxymalonyl hydrazones also led to diverging increases of the ratio of bax to bcl-2 mRNA expression, of reactive oxygen species and of mitochondrial membrane damage. (C) 2010 Elsevier Masson SAS. All rights reserved.
Stereochemical studies. XV. Ferrocene studies. XXII. Planar elements of stereochemistry