Improved synthesis of a C3-symmetrical pyridinophane
作者:Claire Nolan、Thorfinnur Gunnlaugsson
DOI:10.1016/j.tetlet.2008.01.077
日期:2008.3
The formation of the C3-symmetrical 2,11,20-triaza[3.3.3](2,6)pyridinophane 1 was undertaken with the aim of improving the synthesis of this highly desirable macrocycle, with the future aim of functionalizing 1 with amide pendent arms for the recognition of lanthanide ions. The synthesis of 1 involves the stepwise transformation of pyridine-2,6-dicarboxylic acid into two key intermediates; N,N-bis
The present invention relates to 2,2'-bridged bis-2,4-diaminoquinazolines of the general formula (I): ##STR1## in which the indicated substituents are as defined in the description. The invention also provides processes for the preparation of the compounds of the formula (I), their use for the preparation of drugs, and drugs containing said compounds.
Probing the Steric and Electronic Characteristics of a New Bis-Pyrrolide Pincer Ligand
作者:Nobuyuki Komine、René W. Buell、Chun-Hsing Chen、Alice K. Hui、Maren Pink、Kenneth G. Caulton
DOI:10.1021/ic402120r
日期:2014.2.3
A new pincer ligand is synthesized to be dianionic, with the potential to be redox active. It has pyrrrole rings attached to both ortho sites of a pyridine, as the linking element. This H2L, can be doubly deprotonated and then used to replace two chloride ligands in MCl2(NCPh)(2), to form LM(NCPh) for M = Pd, Pt. The acid form H2L reacts with ZnEt2 with elimination of only 1 mol of ethane to yield (HL)ZnEt, a three-coordinate species with one pendant pyrrole NH functionality. This molecule binds the Lewis base p-dimethylaminopyridine (DMAP) to give first a simple 1:1 adduct that eliminates ethane on heating to form four-coordinate LZn(DMAP), which has an unusual structure due to the strong preference of the pincer ligand to bind in a mer (planar) geometry. A molecule with two HL- ligands each bonded in a bidentate manner to FeCl2 is synthesized and shown to contain four-coordinate iron with a flattened-tetrahedral structure. The electrochemistry of LM(NCPh) and (L)Zn(DMAP) shows three oxidation processes, which is interpreted to involve at least two oxidations of the pyrrolide arms;
Efficient Synthesis of 2,11,20-Triaza[3.3.3](2,6)pyridinophane