Acetaldehyde dimethylacetal

For this reaction, soluble monomers are needed, e.g. a mixture of N AT-methylene bisacrylamide as crosslinker, methacrylamide as an inert comonomer, methacrylic acid as ionic comonomer for stabilization [309] and methacryl ami-do-AT-acetaldehyde-dimethylacetal as functional comonomer. The coupling with proteins is only possible if the free aldehyde groups are accessible, i.e. if they are not located in the interior of the microgel. This condition can only be fulfilled by a careful choice of the comonomer composition in the reaction mixture [291]. 

Fig. 56. Dependence of Mwof the microgels on the polymer yield in the anionic polymerization of EDMA in toluene by n-BuLi [254] (see Figure 53 caption for the reaction conditions). Reduced viscosity vs concentration of microgels a) Composition (mol %) N,N -methyl-enebisacrylamide (55%), methacrylamide (33%), methacrylic acid (2%), methacrylamido acetaldehyd-dimethylacetal (10%),measured at 20 °C in water, b) Composition (mol %) 1,4-DVB (35%), propenic acid amide-2-methyl-N-(4-methyl-2-butyl-l,3-dioxolane prepared by emulsion copolymerization and measured in dimethylformamide.

Fig. 21. Hydrolysis of acetals at 20°C on a Dowex 50W X10 resin catalyst [513]. Rate coefficients of the resin-catalysed reaction (feres) versus rate coefficients of the reaction catalysed by dissolved inorganic acid (fehom)- 1 Formaldehyde dimethylacetal 2, formaldehyde diethylacetal 3, formaldehyde di-2-propylacetal 4, acetaldehyde ethyleneacetal 5, acetone ethyleneacetal 6, acetaldehyde dimethylacetal 7, acetaldehyde diethylacetal. The slope for acetals 1—3 is 1, for the acetals 3—7 0.5.

O Meara and Shepherd1 found the reagent useful for the conversion of aldopyran-oses into ethylidene derivatives. Thus 2.5 ml. of coned, sulfuric acid was added dropwise to a stirred suspension of 58 g. of methyl /3-n-glucopyranosidc (I) in 250 ml. of acetaldehyde dimethylacetal. The mixture was shaken for 48 hrs., filtered, and the solid product (2) collected and crystallized twice from ethanol. Methyl 4 6-... 

Ally Isulfamy 1-5 chloro-4-sulfamylaniline Acetaldehyde Dimethylacetal... 

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