Fullerene bisadduct regioisomers containing an asymmetric diamide tether

Abstract

Four macrocyclic bis(pyrrolidino)fullerene regioisomers with e-edge, e-face, trans-4 and cis-2 addition patterns were synthesized from the corresponding monoadduct by Prato's cycloaddition in a yield of 50%, and fully characterized by spectroscopic techniques. Bisadduct regioisomers were isolated easily in a pure form using dry-flash column chromatography. The relative ratio of the isolated regioisomers e-edge/e-face/trans-4/cis-2 was 1.0:1.9:1.5:4.9. Morphology of selfassembled structures of the four bisadduct regioisomers in solution was characterized using scanning electron microscopy.

Synthesis of Carbapenems Containing Peptidoglycan Mimetics and Inhibition of the Cross‐Linking Activity of a Transpeptidase of l,d Specificity

“…Deprotection of the methyl ester was performed with LiOH, leading to the corresponding acid 16 in 63 % yield (Scheme 4 A). The synthesis of dipeptide derivative 20 started with the formation of the amino benzyl ester 17 as previously described [39] . Coupling with Boc‐ l ‐Ala‐OH was achieved by using TBTU (2‐(1 H ‐benzotriazole‐1‐yl)‐1,1,3,3‐tetramethylaminium tetrafluoroborate) as the coupling agent.…”

“…The synthesis of dipeptide derivative 20 startedw itht he formation of the amino benzyl ester 17 as previously described. [39] Coupling with Boc-l-Ala-OHw as achieved by using TBTU (2-(1 H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate) as the coupling agent. Compound 18 was treated with TFAt or emove the Boc group and reactedw ith (2R)-2-methoxypropanoica cid, affording compound 19 in 71 %y ield.…”

Analytical and preparative separation and isolation of functionalized fullerenes by conventional HPLC stationary phases: method development and column screening

“…In contrast to planar aromatic compounds where a new substituent will affect the reactivity even at remote p-conjugated positions, fullerenes react at multiple positions leading to complex hardto-separate mixtures of mono-, bis-and more highly functionalized fullerenes. [16][17][18][19] Due to poor solubility in most solvents, purication of product mixtures with isolation of the desired components and assessment of purity are major challenges. [20][21][22][23] Already in 1990, Kroto et al 24 identied liquid chromatography (LC) as a purication method that could provide C 60 and C 70 as clean fractions from their complex synthesis soot mixtures.…”