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Margareta Zehnder 《Helvetica chimica acta》1981,64(1):251-257
The X-ray structures of the compounds 4 and 2 have been determined by direct methods and refined by least squares techniques. Crystals of C22H27NO5 and C27H27NO5 are triclinic, space groups Pī with lattice parameters a = 13.652 (5) Å, b = 10.926 (3) Å, c = 7.755 (2) Å, a = 111.554 (4) Å, β = 85.541 (3) Å, γ = 104.813 (4) Å, and a = 15.394 (4) Å, b = 9.674 (3) Å, c = 8.522 (3) Å, a = 111.04 (4) Å, ß = 93.65 (4) Å, γ = 95.01 (4) Å, respectively. 相似文献
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The thermal cyclodimerization of 5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene assisted by Fe2 (CO)9 gives the title complex 1 , a precursor for the synthesis of antitumoral anthracyclinones. The crystal structure of 1 has been determined by X-ray diffraction: a = 11.188 (1); c = 26.968 (3) Å; space group tetragonal, P41212, Z = 8; R = 0.041; RW = 0.033. The tricarbonyliron group is in the exo-position and the coordination polyhedron is tetragonal pyramidal. The NMR coupling constants are well-related to the observed dihedral angles between the non-aromatic protons and now give a reliable criterion for assigning the stereochemistry of the metal in d8-complexes of 2,3-dimethylidene-7-oxanorbornane derivatives. 相似文献
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Pezdirc L Bevk D Groselj U Meden A Stanovnik B Svete J 《Journal of combinatorial chemistry》2007,9(4):717-723
Combinatorial solution-phase cycloadditions of (1Z,4R*,5R*)-4-benzoylamino-5-phenylpyrazolidin-3-on-1-azomethine imines 3 to beta-keto esters 4 afforded a library of 26 bicyclic pyrazolidinones 5 in 6-89% yields and in 14-100% de. All products were isolated in >90% purity according to 1H NMR, and 25 of them were analytically pure. The structures of cycloadducts were confirmed by NMR and X-ray diffraction. Most of the products were isolated as mixtures of the major (1S*,2S*,3R*,5R*,6R*)-epimers 5 and the minor (1R*,2S*,3R*,5R*,6R*)-epimers 6. Epimerization of cycloadducts 5/6 at the anomeric position 1 in solution was confirmed by 1H NMR. 相似文献
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Guliya G. Bizhanova Kyrill Yu. Suponitsky Yulia V. Vakhitova Rail R. Gataullin 《Tetrahedron》2017,73(2):109-115
We synthesized methyl ester of N-(1-methylbut-2-en-1-yl)-N-phenylglycine which underwent acid catalyzed aromatic amino Claisen rearrangement to provide methyl-N-[2-(1-methylbut-2-en-1-yl)phenyl]glycinate. A mixture of syn- and anti-atropisomeric methyl-N-acetyl-N-[4-methyl-2-(1-methylbut-2-en-1-yl)phenyl]glycinates was obtained either by the reaction of this ester with acetyl bromide or by the reaction of the sodium salt of N-acetyl-2-(1-methylbut-2-en-1-yl)-4-methylaniline with methyl bromoacetate. Upon saponification of the synthesized ester mixture the syn-atropisomer of N-acetyl-N-[4-methyl-2-(1-methylbut-2-en-1-yl)phenyl]glycine was isolated by fractional crystallization. Treatment of the obtained acids with acetic anhydride, ethyl chloroformate, dicyclohexylcarbodiimide or isopropenylacetate leads to compounds of 4,5-dihydro-3aH-methano[1,3]oxazolo[3,2-a]quinolin-2-one structure. 相似文献
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Goverdhan Mehta Saikat Sen Siddharth Dey 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):o358-o360
In the title compound, C6H12O4·H2O, 1,4/2,5‐cyclohexanetetrol and water molecules are seen to possess twofold symmetry. All four hydroxyl groups of the tetrol participate in extensive intermolecular O—H⋯O hydrogen bonding to form molecular tapes propagating along the a axis. Translationally related tapes along the c axis are held together by four coordinated water molecules. 相似文献
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