N-PHOSPHORYL AMINO ACIDS AND PEPTIDES: PART I. THE CRYSTAL AND MOLECULAR STRUCTURE OF N-(O,O-DIISOPROPYL PHOSPHORYL)-TRANS-4-HYDROXY-D,L-PROLINE |
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Authors: | Ying-Wu Yin Ben-Ming Chen Chu-Biao Xue Yu-Fen Zhao |
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Affiliation: | Institute of Chemistry, Academia Sinica , Beijing , China |
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Abstract: | Abstract The crystal and molecular structure of N-(O,O-diisopropyl phosphoryl)-trans-4-hydroxy-D,L-proline has been determined by X-ray diffraction analysis and is compared with proline or hydroxyproline residue in a peptide chain described in the literature. The compound crystallized in orthorhombic system with space group P212121, a=6.934(2), b=8.694(3), c=26.727(7) Å, V=1611.3(8) Å3, Z=4, Dx=1.22 g/cm3. The structure was solved by direct method and refined by anisotropic least squares to a discrepancy index R=0.072. In the compound, the nitrogen atom is trigonal and its remaining 2p orbital is conjugated with the P?Oπ system; the conformation of the phosphorimidate function is favoured by the trans orientation of the P=O bond with respect to the N-C4 bond. In the pyrrolidine ring moeity, the C2-C1-N-C4 atoms are nearly copolnar and the C3 atom is out of the plane by about 0.47 Å. |
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Keywords: | Wittig reagents (I) 4-cyclohexene-1,2-dicarboxylic anhydride and its N-hydroxy-imide (IIa,b) ethyl 3a,4,7,7a-tetrahydro-3-oxo-Δ1-?-1,3-phthalanacetate (IIIa) diethyl 3a,4,7,7a-tetrahydro-Δ1.3.?-1,3- phthalanacetate (IIIb) 3a,4,7,7a-tetrahydro-3-phenacylidenephthalide (IIIc) 3a,4,7,7a-tetrahydro-1,3-phenacylidenephthalane (IIId) and the new spiro-phosphorane adduct (IV). |
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