Cyclic acetal forming reactions of some carbohydrate diols and triols.
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Cyclic acetal forming reactions of some carbohydrate diols and triols.

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Published by University of Birmingham in Birmingham .
Written in English

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Thesis (Ph.D.) - University of Birmingham, Department of Chemistry.

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Open LibraryOL19633779M

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  Kinetic control in the benzylidenation of some 1-alkylcyclohexane-cis-1,2-diols. Carbohydrate Research , , DOI: /(85) Some reactions of acetal derivatives of arabinose. CARBOHYDRATE CYCLIC ACETAL FORMATION AND MIGRATION. Chemischer Informationsdienst , 11 Cited by: Cyclic acetals and ketals are of particular importance in carbohydrate chemistry. They can be formed by the reaction of the diol and a carbonyl component in the presence of an acid or a Lewis acid. 2, Also transacetalization of a ketal or acetal with the diol can be carried out. Finally geminal dibromides and dichlorides can be used as introducing reagents.   Cyclic and acyclic carbohydrates react with aldehydes and/or ketones, in the presence of catalysts (hard or Lewis acids), to give cyclic acetals and/or ketals (1,3-dioxolanes 3 or 1,3-dioxanes 5, respectively) (Fig. ).This reaction is routinely used in carbohydrate chemistry for the protection of hydroxyl groups in a sugar in order to prevent their interference in chemical transformation(s Cited by: 2. 2,3-O-Methylene-L-threitol (Thx) is a cyclic carbohydrate-based diol prepared by acetalization and subsequent reduction of the naturally occurring tartaric acid.

  Acetal derivatives have been prepared by acid-catalyzed reactions with benzaldehyde and acetone. As a rule, benzaldehyde forms six-membered cyclic acetals, whereas acetone prefers to form five-membered acetals. The top equation shows the formation and some reactions of the 4,6-O-benzylidene acetal, a commonly employed protective group. Acetal formation is a characteristic reaction of aldehydes and ketones, but not of carboxylic acids. Show how you could advantageously use a cyclic acetal protecting group in . 1. EVALUATION Introduction. The Committee evaluated a group of 31 flavouring agents 1 that included aliphatic acyclic diols, triols, and related substances (see Table 1) using the Procedure for the Safety Evaluation of Flavouring Agents (see Figure 1, Introduction). All members of this group are aliphatic acyclic primary alcohols, aldehydes, acids, or related esters with one or more. Reactions of nucleophiles with carbonyl groups are among the most important reactions in organic chemistry. They are widely used in organic synthesis to make C-C bonds, and we will see them in fundamental bioorganic reactions of carbohydrates, proteins, and lipids. Overview (A).

Periodic acid attacks the vicinal diols in carbohydrates and oxidizes these groups to form carbonyl compounds. The mechanism of this reaction involves a cyclic periodate ester that reacts with two neighboring alcohol functional groups which are oxidized to carbonyl functional groups. How is a sugar degraded through periodic acid degradation?   The terms 'acetal' and 'ketal' have had varied use over the years. Back in the day, acetals were diethers of geminal diols (ie. 1,1-diols), with a formula R 2 C(OR') 2 (R' ≠ H) where at least one R = H, and were therefore derived from aldehydes. Whereas, when neither R = H, they were called ketals and were obviously derived from ketones. A carbohydrate that reacts with an oxidizing agent to form an aldonic acid is classified as a _____ Oxidation to Aldonic Acids (Reducing Sugars) This reaction is . Scheme 8 depicts one of several instances in which some level of regiochemical complementarity was Clode DM () Carbohydrate cyclic acetal formation and migration. Chem Rev 79 Kluger R () Biomimetic monoacylation of diols in water. Lanthanide-promoted reactions of methyl benzoyl phosphate. J Am Chem Soc