Andreas Terpin

Resolution and Kinetic Stability of a Chiral Supramolecular Assembly Made of Labile Components

The importance of chirality for recognition processes in nature is impressively exemplified by the different tastes of (R)and (S)-asparagine,[1] and the vastly different pharmacological effects of the two enantiomers of thalidomide.[2] Chirality is not the exclusive domain of organic chemistry, many metals can also serve as centers of chirality.[3] The most frequent case is an octahedral arrangment of three bidentate ligands around a metal center to form D or L absolute configurations. Chirality at metal centers has been found to play an important role in nature, for example, for the siderophore-mediated iron uptake in many organisms.[4] D/L Isomerization of tris-bidentate complexes of the labile high-spin ferric ion or its closely related gallium(iii) analogues is rapid in aqueous solution. Tris(catecholate)gallium(iii) complexes, model compounds of iron siderophores, usually racemize fast. Racemization rates of 10(1) sÿ1 for a mononuclear complex[5] and 0.10(1) sÿ1 for a dinuclear helix[6] were determined by NMR studies. The isomerization was found to

Synthesis and cyclisation of didemnimide C and its imidazol-1-yl isomer ☆

Abstract A key step in the synthesis of the marine alkaloid didemnimide C (1c) is the Stille coupling between the urethane protected 3-bromo-4-(indol-3-yl)-1-methylmaleimide 3 and 5-tributylstannyl-1-methylimidazole (4). In this manner 1c can be obtained in four steps in 29% overall yield. Treatment of 3 with imidazolyl magnesium bromide affords the imidazol-1-yl compound 7 which can then be converted to the cyclo derivatives 8 and 10 upon irradiation with a halogen lamp.

BIOMIMETIC TOTAL SYNTHESIS OF POLYCITRIN A

Abstract The synthesis of the marine alkaloid polycitrin A ( 1a ) is described. The synthesis is based on the formation of 3,4-bisarylpyrrole-2,5-dicarboxylic acids from 3-arylpyruvic acids by oxidative coupling and consecutive pyrrole ring formation. The pyrrole dicarboxylic acids are then converted into 3,4-bisaryl maleimides by treatment with hypochlorite. The synthesis is completed by bromination and introduction of the N-alkyl substituent, 1a is thus obtained in 6 steps from 3-(4-methoxyphenyl)pyruvic acid ( 6 ) with 26% overall yield.

A concise synthesis of storniamide A nonamethyl ether [1]

(E,E)-Storniamide A nonamethyl ether is obtained from 3-(3,4,5-trimethoxyphenyl)-pyruvic acid and 2-(4-hydroxyphenyl)ethylamine in three steps with an overall yield of 19%.

Metal Complexes of Biologically Important Ligands, CLXXI [1]. Incorporation of the cis-Dichloroplatinum Group into Amides of 3,4-Diarylpyrrole-2,5-dicarboxylic Acids

3,4-Bisarylpyrrole-2,5-dicarboxylic acids were coupled with rac-N1,N2-di-Boc-1,2,4-triaminobutane to give the corresponding diamides, which were deprotected and converted into the bis(cis-dichloroplatinum) complexes by treatment with K2PtCl4 Graphical Abstract Metal Complexes of Biologically Important Ligands, CLXXI [1]. Incorporation of the cis-Dichloroplatinum Group into Amides of 3,4-Diarylpyrrole-2,5-dicarboxylic Acids