The macrocyclization between buckminsterfullerene, C,,, and bis-malonate derivatives in a double Singe1 reaction provides a versatile and simple method for the preparation ofcovalent bis-adducts of C,, with high regioand diastereoselectivity. A combination of spectral analysis, stereochemical considerations, and X-ray crystallography ( Fig. 2 ) revealed that out of the possible in-in, in-out, and out-out stereoisomers, the reaction of bis-malonates linked by 0-, ni-, or p-xylylene tethers afforded only the out-out ones (Scheme I). In contrast, the use of larger tethers derived from 1,lO-phenanthroline also provided a first example, (*)-19 (Scltemr 2), of an in-out product. Starting from optically pure bis-malonate derivatives, the new bis-functionalization method permitted the diastereoselective preparation of optically active fullerene derivatives (Schemes 4 and 5 ) and, ultimately, the enantioselective preparation (enantiomeric excess ee > 97 YO) of optically active cis-3 bis-adducts whose chirality results exclusively from the addition pattern (Fig. 6). The macrocyclic fixation of a bis-malonate with an optically active, 9,9-spirobi[9H-fluorene]-derived tether to C,, under generation of 24 and ent-24 with an achiral addition pattern (Scheme 4 ) was found to induce dramatic changes in the chiroptical properties of the tether chromophore such as strong enhancement and reversal of sign of the Cotton effects in the circular dichroism (CD) spectra (Figs. 4 and 5). By the same method, the functionalized bis-adducts 50 and 51 (Schemes 10 and If) were prepared as initiator cores for the synthesis of the fullerene dendrimers 62, 63, and 66 (Schemes 12 and 13) by convergent growth. Finally, the new methodology was extended to the regio-and diastereoselective construction of higher cycbpropanated adducts. Starting from mono-adduct 71, a clipping reaction provided exclusively the all-cis-2 tris-adduct (&)-72 (Scheme 14), whereas the similar reaction of bis-adduct 76 afforded the all-cis-2 tetrakis-adduct 77 (Scheme 15). Electrochemical investigations by steady-state voltammetry (Table 2) in CH,CI, ( + 0 . 1~ Bu,NPF,) showed that all macrocyclic bis(niethan0)fullerenes underwent multiple reduction steps, and that regioisomerism was not much influencing the redox potentials. All cis-2 bis-adducts gave an instable dianion which decomposed during the electrochemical reduction. In CH,CI,, the redox potential of the fullerene core in dendrimers 62, 63, and 66 is not affected by differences in size and density of the surrounding poly(ether-amide) dendrons. The all-cis-2 tris-and tetrakis(methano)fullerenes (5)-72 and 77, respectively, are reduced at more negative potential than previously reported all-e tris-and tetrakis-adducts with methano bridges that are also located along an equatorial belt. This indicates a larger perturbation of the original fullerene rr-chromophore and a larger raise in LUMO energy in the former derivatives.') Present address: Groupe des Matkriaux Organiques,

A versatile and simple method provides access to covalent bisadducts of C60 with high regio‐ and diastereo‐selectivity. Starting from optically pure bis(malonate) derivatives and C60, a double Bingel reaction afforded optically active cis‐3 bisadducts (ee > 97%), whose chirality results exclusively from the addition pattern.

NR1/NR2A is a subtype of N-methyl-D-aspartate receptors (NMDARs), which are glutamate and glycine-gated Ca 2ϩ -permeable channels highly expressed in the central nervous system. A high-throughput screening (HTS) campaign using human osteosarcoma (U-2 OS) cells transiently transduced with NR1/NR2A NMDAR subunits, tested in a specifically designed fluorometric imaging plate reader (FLIPR)/Ca 2ϩ assay, identified sulfonamide derivative series, exemplified by,4-thiadiazol-2-yl}thio)acetamide (compound 13) as novel NR1/NR2A receptor antagonists. Compounds 1 and 13 displayed submicromolar and micromolar potency at NR1/NR2A receptor, respectively, although they did not show activity at NR2B-containing receptor up to 50 M concentration. Addition of 1 mM glycine, but not 1 mM L-glutamate, was able to surmount compound 1 and 13 inhibitory effects in FLIPR NR1/NR2A assay. However, compounds 1 and 13 displaced a glutamate site antagonist,519), in rat brain cortex binding assay. Results of FLIPR cell-based, electrophysiological, and biochemical binding assays suggest that compounds 1 and 13 are the prototypes of novel classes of NMDAR ligands, which to the best of our knowledge are the first selective antagonists at NR1/NR2A over NR1/NR2B receptor, and might constitute useful tools able to elucidate the relative role of the NR2A subunit in physiological and pathological conditions.

The amphiphilic C60-dendrimer conjugates 1 and 2 with one and two glycodendron headgroups, respectively, form stable, ordered monomolecular Langmuir layers at the air−water interface. The bulky glycodendron headgroups in 1 and 2 are very effective in suppressing fullerene aggregation, resulting in reversible compression and expansion behavior. The absence of fullerene aggregation was also revealed by the UV−vis spectra of the Langmuir monolayers and by Brewster angle microscopy. The monolayers of 1 and 2 were transferred successfully as X-type Langmuir−Blodgett films onto quartz slides; such films could have potential applications in optical technology and as biosensors for glycoproteins.