Ketal structure

This process, which predominates at low temperatures, causes migration of internal ketal structures along a chain but does not involve the dissociation to separate aryloxy radicals that occurs during the redistribution process. 

Plants. Extensively metabolized by oxidation, desalkylation and cleavage of the ketal structure, the resulting metabolites bearing a hydroxylated /-butyl group or an aminodiol were further conjugated... 

Title Monomer Having Fluorine-Containing Acetal or Ketal Structure, Polymer Thereof, and Chemical-Amplification-Type Resist Composition as Well as Process for Formation of Pattern with Use of the Same... 

The possibility that olefin-carbon monoxide copolymers can exist in the isomeric poly-spiro ketal structure (Scheme 8.5) was recognized soon after the first synthesis of the copolymers of propene. Using dialkyl diphosphines as the modifying ligands [27], copolymers were obtained with blocks with the spiroketal form [28]. 

Ketal structures have been built into cross-linked polymers for cleavage by acid to permit recycling. Compound 14.4 has been used to make cleavable epoxy resins.182... 

The lipoidal characteristic of the GC steroids needed to facilitate epidermal entry can be achieved by various derivatizations of OH functions at C-16, C-17, and C-21, specifically esters and ketals (structures B and C). Derivatization of even one hydroxyl can be useful. Table 14-4 gives examples of the type and positions of derivatives that impart increased lipoidal characteristics to steroids to enhance their local antiinflammatory activity. 

Dichloromethyl ketal structure affects the expression of glutathione S-transferase isoforms in maize (I. Jablonkai, Inst, of Biomolecular Chemistry, Hungary)... 

In a second study we have compared the performance of three commercial photolnltlators for surface cure in a commercial urethane acrylate formulation. The following photoinitiators were utilized in this study HCPK - alpha-hydroxy-alpha-cyclohexylphenylketone (Structure II), BDMK - benzil-dimethyl-ketal (Structure III), and AAP (Structure IV). The extinction spectra of these initiators are in Figure 8. 

Ketal structure of the copolymer of CO and propene formed In the absence of protic component. 

The final difference in the copolymerization of carbon monoxide with propene or styrene is the overall connectivity of the initial polymer generated under some conditions. The polymer generated from the copolymerization of carbon monoxide and propene in protic solvents consists of the fused tetrahydrofuran ketal structure shown in Figure 17.17. This polymer reopens to the polymer shown in Figure 17.13 upon addition of acid in alcohol. Several mechanisms for formation of this product have been proposed, and the origin of the ketal structure remains unresolved. Polymers formed in aprotic solvents form the acylic polymer. 

In the amine-catalyzed reactions, a Knoevenagel addition/ketalization/ intramolecular retro-Claisen cascade is detected (Scheme 2.32). The retro-Claisen step is enabled by the ketalization of the Knoevenagel addition product Q. The ketalization of the Knoevenagel product (Q S) is initiated by the hydroxyl groups of the carbohydrate moiety, as in-house NMR-experiments suggest (formation of intermediate ketal structure K in Knoevenagel condensation/ketalization/oxa-Michael cascade reaction Scheme 2.16). Products derived from this reaction sequence (Scheme 2.16)... 

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