ExperimentaldetailsHa toms were located by difference fourier techniques, but refined with fixed individual displacement parameters, using ariding model with d(C-H) ranging from 0.93 to 1.00 Å. Hatoms of hydroxyfunctions were refined free, because of their relevance in hydrogen bond interactions. In addition,the methyl groupisallowedtorotatebut nottotip.The Flackparameteris0.01(4) [7], which is in accordance with the absolute configuration resulting from the synthetic pathway. DiscussionThe title compound (figure, top) crystallizes with one independent ion pair in the asymmetric unit of the acentric space group P2 1 2 1 2 1 .Asexpected, the piperidine ring system shows achair conformation. The packing diagram (figure, bottom)s hows a complex network of intermolecular hydrogen bonds, where the chloride anion works as threefold acceptor. The H1×××Cl1 distance is 2.22 Åand the related angle N1-H1×××Cl1 is 151°. The distances of H2A×××Cl1 and H4A×××Cl1 are 2.23(2) Åand 2.32(2) Åand the related angles O2-H2A×××Cl1 and O4-H4A×××Cl1 are 177(2)°and 165(2)°, respectively. Twomore intermolecularhydrogen bonds are built up between two hydroxy functions, with distances H1C×××O3 of 1.80(2) Åand H3A×××O2 of 2.06(2) Å. The related angles O1-H1C×××O3 and O3-H3A×××O2 are 175(2)°and 158(2)°, respectively.The bc-view of the cell plot ( figure, bottom)shows an alternate layer-type organization of the structure, built up by the piperidine moieties and the chloride anions. The layers have a diagonal orientation in the ab-plane and the stacking vector extends along the bc-diagonal.
Source of materialThe title compound was obtained as the major product by fragmentation of 6-deoxy-6-iodo-1,2:3,4-di-O-isopropylidene-a-Lgalactose with zinc, ammonium chloride and vitamin B 12 in methanol [1][2][3][4][5]. Isolation by column chromatography (ethyl acetate/petroleum ether) followed by crystallization of the anomeric mixture from ethyl acetate gave the title 5-hexenose compound in the form of colourless crystals Experimental detailsHatoms were located in difference fourier map, but refined with fixed individual displacement parameters using ar iding model with d(C-H) ranging from 0.93 to 0.98 Å,e xcept H3A of the hydroxy group which is refined free, because of its relevance for the intermolecular hydrogen bond. In addition, the methyl groups were allowed to rotate but not to tip. DiscussionThe alkenyl bond of the side-chain C7=C8 is verified by the distance of 1.316(6) Å.Both dioxolane rings show an envelope conformation with C3 and C4 out-of-plane. This results in a cis configuration of the hydrogen. An intermolecular hydrogen bond is present between the hydroxy group O3−H3A as donor and the oxygen O1 of adioxalane moiety as acceptor. This interaction is nearly linear indicated by an angle ∠O3−H3A···O1 of 175(4)°a nd d(H3A···O1) =1.86(5) Å.
Source of materialThe title compound was prepared by reacting (S)-l-phenylethylamine with 2-chloro-l,3-dimethyl-imidazolinium chloride [1,2], The crude product was recrystallized from acetonitrile to give colourless crystals (m.p. 480 K) [1]. The enantiomerically pure compound has = -41 (c = 1.04, CH3CN). Experimental detailsΗ atoms were located on difference fourier map, but refined with fixed individual displacement parameters using a riding model with d(C-H) ranging from 0.93 to 0.98 Â, except for H3 of the ammonium ion which is refined free because of its relevance for the intermolecular hydrogen bond. In addition, the methyl groups were allowed to rotate but not to tip. DiscussionThe absolute configuration of the tide compound, as known from the starting material (S)-1 -phenyl-ethylamine, was confirmed by the absolute structure determination by X-ray data indicated by the Flack parameter of χ = 0.01(11). The imidazolidine ring is showing a flat conformation forced by the guanidinium system C1, Ν1, N2 and N3 and is characterized by a r.m.s. ¿=0.0344 À of the best plane formed by the atoms NI, CI, N2, C2 and C3. N1 and N2 are showing a slight pyramidalization, where the methyl group C4 lies 0.43 A above and the methyl group C5 -0.34 Â below this plane. A strong intermolecular hydrogen bond between the ammonium ion N3-H3 as donor and the chlorine ion Cll as acceptor is evident. The H3-C11 distance is 2.32(3) Λ and the angle N3-H3-C11 is 174(3)°.
Experimental detailsHatoms were located on difference fourier map, but refined with fixed individual displacement parameters using ar iding model with d(C-H) ranging from 0.93 to 0.98 Å,except for H3 of the ammonium ion which is refined free because of its relevance for the intermolecular hydrogen bond. In addition, the methyl groups were allowed to rotate but not to tip. DiscussionThe absolute configuration of the title compound, as known from the starting material (S)-1-phenyl-ethylamine, was confirmed by the absolute structure determination by X-ray data indicated by the Flack parameter of x=0 .01(11). The imidazolidine ring is showing af lat conformation forced by the guanidinium system C1, N1, N2 and N3 and is characterized by ar.m.s. d =0.0344 Å of the best plane formed by the atoms N1, C1, N2, C2 and C3. N1 and N2 are showing aslight pyramidalization, where the methyl group C4 lies 0.43 Å above and the methyl group C5 −0.34 Å below this plane. Astrong intermolecular hydrogen bond between the ammonium ion N3−H3 as donor and the chlorine ion Cl1 as acceptor is evident. The H3···Cl1 distance is 2.32(3) Å and the angle N3−H3···Cl1 is 174(3)°.
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