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Selective Syntheses of β-Aryl-α,β-diamino Esters,

Keywords: Stereo-Selective Synthesis; 2-Substituted Norbornene; Isomerization; Kinetically Selective Hydrolysis

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Stereo-selective synthesis of Erythro-3-methyl-hexyn …

A new and one-pot synthesis of oxazolines has been accomplished by K5[PW11ZnO39].23H2O—catalyst acylation followed by C–N ring opening/C–O bond formation in NH ketoaziridines. This regio- and stereo-selective reaction presumably proceeds via a domino sequence resulting in the in situ generation of acyl aziridine which undergoes a ring expansion reaction via an initial C–N rupture of aziridine ring followed by ring closure to the oxazolines. The methodology provided novel one-pot procedure for the synthesis of trans-2,5-diaryl-4-aroyloxazolines.

First stereo selective synthesis of 5-O-feruloyl-2-deoxy …

Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.

STEREO SELECTIVE SYNTHESIS OF NOVEL LIGNAN …

Synthesis, optical stability, stereo-selective and -specific reactions of chiral triorganotin hydrides

In this thesis, the writer describes the whole synthesis of average product Maoecrystal V intimately. within the first a part of the thesis, the writer introduces the examine historical past and studies the study growth in overall synthesis of Maoecrystal V. within the moment half, the writer develops a unique and concise technique for the stereo selective development of the tetracyclic version process of Maoecrystal V. The version process is entire in eight steps with 20% yield. within the 3rd half, the writer describes the 1st profitable overall synthesis of Maoecrystal V and investigates 4 techniques for developing the most important tetrahydrofuran oxa-bridge skeleton. the entire synthesis begins from a identified compound and is complete in 17 steps with 1.2% yield. The winning overall synthesis of Maoecrystal V will give a contribution to the advance of effective artificial suggestions for traditional items and different compounds with complicated structures.

In this thesis, the writer describes the whole synthesis of average product Maoecrystal V intimately. within the first a part of the thesis, the writer introduces the examine historical past and studies the study growth in overall synthesis of Maoecrystal V. within the moment half, the writer develops a unique and concise technique for the stereo selective development of the tetracyclic version process of Maoecrystal V. The version process is entire in eight steps with 20% yield. within the 3rd half, the writer describes the 1st profitable overall synthesis of Maoecrystal V and investigates 4 techniques for developing the most important tetrahydrofuran oxa-bridge skeleton. the entire synthesis begins from a identified compound and is complete in 17 steps with 1.2% yield. The winning overall synthesis of Maoecrystal V will give a contribution to the advance of effective artificial suggestions for traditional items and different compounds with complicated structures.

STEREO SELECTIVE SYNTHESIS OF NOVEL ..

Sharpless, Catalytic Osmylation of Conjugated Dienes: A One-Pot Stereoselective Synthesis of Polyols., , 32, 1003, (1991).

In this paper, simple, effective, and stereo-selective syntheses of 5-norbornene-2-carboxylic acid (NBCA) and its derivatives were reported. The properties as a resist material were also investigated. In order to obtain exo-rich isomer at high yield, methyl 5-norbornene-2-carboxylate (MNBC) was synthesized via Diels-Alder reaction as a starting material at first. Then, the isomerization and exo-selective hydrolysis of MNBC were performed in a basic condition to synthesize exo-rich NBCA. Exo-rich t-butyl 5-norbornene-2-carboxylate (tBNBC) was prepared by non-selective esterification. After purification, exo-tBNBC was isolated. The random copolymers consisting of exo- or endo-rich tBNBC (endo-rich tBNBC was synthesized by classic Diels-Alder reaction) and maleic anhydride were synthesized as resist materials via free radical polymerization. The resulting copolymers were characterized by GPC and 1H NMR. Furthermore, the acidic deprotection behavior of exo- and endo-tBNBC was monitored using 1H NMR for the model reaction of resist system. In this study, it is suggested that the endo/exo ratio of norbornene derivatives affect reactivity, rate of reaction, property of polymer and monomer, and lithographic performance.

Total synthesis of (±) -solavetivone (1), a spirovetivane phytoalexin, was achieved. The metal catalyzed decomposition of the phenolic diazoketone (8) gave the spiro-dienone (6), selective reduction of which afforded the hydroxy-enone (5). The regio-and stereo-selective Birch reduction of 5 provided a high yield of the hydroxy-spiro-enone (9), whose structure was determined by X-ray crystal analysis. Compound 9 was transformed to (±) -1 and the aglycone A3 in several steps.

The first lectures revise many of the important principles we require in order to allow us to tackle stereoselective synthesis.
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  • Stereo-Selective Synthesis of exo-Norbornene …

    Selective Syntheses of α,β-Diamino Esters, α-Sulfanyl-β-amino Esters, Ψ-Lactams and 1,5-Benzodiazepin-2-one,

  • Advanced Organic Chemistry: Stereoselective synthesis

    Sharpless, Enantioselective Synthesis of Juvenile Hormone III in Three Steps from Methyl Farnesoate, , 8, 777 (1993).

  • and stereo-selective organic synthesis.

    stereo selective synthesis of novel lignan intermediates as antimicrobial agents

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