Detail of "33797-51-2"

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First Nonenzymic Synthesis of Kdo8P through a Mechanism Similar to That Suggested for the Enzyme Kdo8P Synthase

First Nonenzymic Synthesis of Kdo8P through a Mechanism Similar to That Suggested for the Enzyme Kdo8P Synthase. Du, Shoucheng; Plat, Dorit; Belakhov, Valery; Baasov, Timor ( Department of Chemistry, Technion-Israel Institute of Technology, Haifa 32 000, Israel). Journal of Organic Chemistry, 62(4), 794-804 (English) 1997 American Chemical Society. CODEN: JOCEAH. ISSN: 0022-3263. DOCUMENT TYPE: Journal CA Section: 33 (Carbohydrates) Section cross-reference(s): 7 The mechanism of Kdo8P synthase, the enzyme that catalyzes the unusual condensation of D-arabinose 5-phosphate (A5P) with phosphoenolpyruvate (PEP) to form Kdo8P, remains a fascinating subject for bioorg. research. This paper describes the synthesis of two intramol. models, e.g. I (R = Ts, R' = Me)(II); (R = PO3H2, R' = H)(III) bearing an enolpyruvate moiety at C-3 of the arabinose fraction. This means that their open-chain aldehyde forms closely mimic the proposed situation, whereby two substrates A5P and PEP evolve into a ternary complex with the synthase.In this article, certain chemicals are used. Some of their cas registry numbers are 33797-51-2 and 106174-56-5 Examn. of II (in org. solvent) and III (in a water soln.) under Lewis acid conditions establishes that they both undergo highly stereospecific intramol. condensation of the enolpyruvate double bond with the carbonyl of sugar. This results in the required Kdo structure possessing the desired stereochem. Mechanistic studies suggest that the obsd. intramol. condensation process takes place via a stepwise mechanism involving the formation of a transient oxocarbenium ion intermediate. The results obtained, uniquely demonstrate enzyme-like chem. in the stereospecific synthesis of the Kdo system. Further investigation is certainly warranted, in order to facilitate the construction of other 3-deoxy-2-ulosonic acids and sialic acids on the basis of the same general model. This is illustrated here in the case of Kdo. Furthermore, the results support the validity of the mechanism suggested for the Kdo8P synthase action, in particular, the possible role of the enzyme in the catalysis of the initial condensation step. .

Investigation of the Reaction of Allyl(cyclopentadienyl)iron(II) Dicarbonyl with Iminium Salts: Synthesis of Ammonium Salts of Substituted Five-Membered-Ring Iron Complexes

All Rights Reserved. Investigation of the Reaction of Allyl(cyclopentadienyl)iron(II) Dicarbonyl with Iminium Salts: Synthesis of Ammonium Salts of Substituted Five-Membered-Ring Iron Complexes. Ipaktschi, Junes; Halimehjani, Azim Ziyaei; Saidi, Mohammad R. ( Institute of Organic Chemistry and Institute of Inorganic and Analytical Chemistry, Justus-Liebig University, Giessen, Germany). Organometallics, 26(1), 201-203 (English) 2007 American Chemical Society. CODEN: ORGND7. ISSN: 0276-7333. DOCUMENT TYPE: Journal CA Section: 29 (Organometallic and Organometalloidal Compounds) Section cross-reference(s): 27 Series of quaternary ammonium salts of substituted five-membered-ring iron complexes I were prepd. 30822-30-1 is also in the experiment. by reaction of allyl(cyclopentadienyl)iron(II) dicarbonyl with iminium salts. Reaction of [CpFe(CO)2(h1-CH2CH:CH2)] (1) with [R22C:N+R12]X gave ammonium complexes I×X [3, R1 = Me, R2 = H, X = I; 5a,b,d, X = ClO4-, R1-R1 = (CH2)5, (CH2)2O(CH2)2, (CH2)4, R2-R2 = (CH2)5; 5a X = ClO4-, R1 = R2 = Me; 5e,f X = ClO4-, R1-R1 = (CH2)4, R2, R2 = 2-furyl, H; iPr, H]. Also, reactions of allyl(cyclopentadienyl)iron(II) dicarbonyl with in situ prepd. iminium salts by reaction of 1 with ArCHO (Ar = Ph, 4-ClC6H4, 4-NO2C6H4) and pyrrolidine afford the same products in good to excellent isolated yields. .