The ( R ) -and (S)-enantiomers of 4-(3-phosphonopropyl)piperazine-2-carboxylic acid (D-and L-CPP, resp.; 15 and 16, resp.), and of its unsaturated analogue (E)-4-(3-phosphonoprop-2-enyl)piperazine-2-carboxylic acid (D-and L-CPP-ene, resp.; 13 and 14, resp.) were prepared. The absolute configuration of the enantiomers was determined by a chemical correlation of the menthyl ester 7 with o-asparagine. The affinity of these derivatives for the NMDA receptor was determined by displacement of [3H]CPP in rat cerebral cortical membranes. In two functional tests (the frog hemisected spinal cord preparation and the sodium efflux test from rat brain slices), o-CPP-ene appears to be the most potent, enantiomerically pure, competitive NMDA antagonist known to date.

Oxidation des Glucopyranosylamins (II) liefert je nach Lösungsmittel die Verbindung (I) bzw. das Dimer (III).

A method for the preparation of chain elongated uloses based upon the basecatalyzed addition of 1-deoxy-1-nitroaldoses to aldehydes and Michael acceptors and subsequent solvolytic replacement of the nitro group by a hydroxy group is described. Thus, addition of 1, 3 and 9 to formaldehyde. followed by solvolysis gave the chain elongated ulose derivatives 2, 8 and 10 (63-76%), respectively. The configuration at the anomeric center of the addition products was deduced from 13C-NMR. spectra and mutarotation. In the case of 3, the primary addition products 4 and 6 were isolated and acetylated to 5 and 7. The nitro derivatives 4-7 do not follow Hudson's rule of isorotation. Addition of 1 to benzaldehyde (44%) and to nonanal (74%) proceded with a small degree of diastereoselectivity to give 15a/15b, and 11/12, respectively. The configuration of the secondary hydroxyl group of 12 was determined by correlation with methyl 2-hydroxydecanoate (14). Addition of 1 to the galuctoaldehyde 16 gave a single compound 17 (78%). The structure of this dodecosulose was determined by X-ray crystallography. Solvolysis of the acetylation product 18 in formamide gave the hemiacetal 19 (69%). Michael addition of 1 to acrylonitrile, methyl vinyl ketone and cyclohexenone under solvolytic conditions gave the hemiacetals 27, 30 and 31a,b (49%, 71% and 76%, respectively). Under non-solvolytic conditions (Bu4NF), 1 reacted with acrylonitrile, and crotononitrile to give the anomeric nitro ethers 23 and 24 (67%) and 25 and 26 (84%), respectively. Similarly, 3 added to acrylonitrile to give 28 and 29 (55%, 4: 1). This reaction appears to proceed under kinetic control. Addition of 1 to ethyl propiolate and solvolysis yielded the unsaturated spirolactone 32 (50%) and the ') 2.Mitteilung: [I]. 2, Korrespondenzautor. 00 18-0 19)3/82/7/22S i -22$01 .00/0 0 1982 Schweizerische Chemisehe Gesellschaft 2252 HELVPTICA CHIMICA ACTA -Vol. 65, F a x . 7 (1982) -Nr. 220 hemiacetal33 (17%). Hydrogenation of 32 gave the saturated spirolactone 34 (100%) which was also obtained from 1 and methyl acrylate (63%). Addition of 1 to dimethylmaleate gave the unsaturated ester 35 (48%). 1. Einleitung. -Hohere Zucker sind ausgehend von Aldosen durch Verlangerung der C-Kette am anomeren Zentrum oder am Kettenende zuganglich [2] [3]. Zur Kettenverlangerung vom anomeren Zentrum aus werden beinahe ausschliesslich (gegebenenfalls umgepolte) Carbanionen verwendet. Bei den klassischen Methoden sind dies Aquivalente von Formyl-anionen, wie Cyanid [2], Nitromethananion (21 und Diazomethan [2]. Methoden zur Umpolung der Reaktivitat am anomeren Zentrum sind zur Erweiterung der synthetischen Moglichkeiten ebenfalls erwunscht, mussen jedoch a priori (ausser im Fall von 2-Desoxyzuckern) eine P-Eliminierung vermeiden. Dies ist Paulsen mit der Verwendung von offenkettigen, doppelt deprotonierten, von Monosacchariden abgeleiteten 2-Hydroxydithianen erstmals gelungen [4], wahrend die cyclischen, geschutzten 1 -Desoxy-1 -isocyanaldosen von Descotes et al. [ S ] sich zu diesem Zweck nicht eig...

The 1-deoxy-1-nitro-D-manno-pyranose 4 was transformed into the nitroolefin 5 and hence into the anomeric 1,2-dideoxyl-nitro-3,4,6-tri-O-benzyl-~-arabinohexopyranoses (3 a and 3b; c j the Scheme). Conformational analysis of 1 -benzyloxy-2-nitroethane (6) by 'H-NMR spectroscopy (Fig. 2) showed the synclinal conformation to be more stable than the antiperiplanar one by about 1.4 kcal/mol (attractive gauche-effect). This gauche-effect favours the 1-deoxyl-nitro-2,3,4,6-tetra-Obenzyl-B-D-manno-hexopyranose (1 b) possessing an equatorial nitro group, which is, however, qualitatively the less stable anomer. The relative concentrations of the anorners of 1 and 3, respectively, were determined by 'H-NMR spectroscopy after base catalyzed equilibration at 37" in CHC13-solution (Table). Anomeric effects for the nitro group of approximately 2.4 kcal/mol in 3 and of approximately 3.4 kcal/ mol in 1 were calculated.