Acetoxy styrene

Regarding linear polymers, rearrangements can involve the main chain, as in the case of a polycarbonate (see Scheme 7.24), or pendant groups, as in the case of poly(4-acetoxy styrene), which is converted into poly(3-acetyl-4-hydroxy sty-... 

Scheme 7.25 Photo-rearrangement of poly(4-acetoxy styrene).

Vinylidene cyanide/4-acetoxy, a-acetoxy styrene copolymer 21.48 11.25 7.16 21.89 [149]... 

Reaction of AT-fluorobis(trifluoromethylsulfonyl)amine (Id) with alkenes gives various products, depending on the reaction conditions and the structure of the substrate. In solvents of higher nucleophilicity such as water, acetic acid, aqueous hydrochloric acid, and 70 % hydrogen fluoride/pyridine, a-fluorohydrins or their acetates, a-chloro-fl-fluoroalkanes or a,/ -difluoroal-kanes, e.g. 14. are obtained.146 Reaction of styrene and ( >l-phenylpropene with Id in dich-loromethane/acetic acid gives l-acetoxy-2-fluoro-l-phenylethane and -propane, in 92 and 99 % yield, respectively, the latter product in a ratio (erythrojthreo) 1 l.146... 

Essentially the same substituents as listed above may be present in the alkene being substituted, with the possible exception of chloro, alkoxy and acetoxy groups on vinyl or allyl carbons. These groups, especially chloro, may be lost or partially lost with palladium when the final elimination step occurs. For example, vinyl acetate, iodobenzene and triethylamine with a palladium acetate-triphenylphosphine catalyst at 100 C form mainly (E)-stilbene, presumably via phenylation of styrene formed in the first arylation step (equation 21 ).6 ... 

Trimethylsilyl groups also may be lost from vinylic or allylic positions in the arylation reaction.70 Halide ion facilitates die desilylation as well as the loss of alkoxy and acetoxy groups. Inclusion of soluble silver salts in reactions where trimethylsilyl groups are lost prevents this reaction.70 The reaction in the absence of silver ion is useful for preparing styrene derivatives. However, they also may be prepared directly from aryl halides and ethylene in fair to good yields.71... 

An eco-friendly oxidation of alcohols under an oxygen atmosphere using catalytic amounts of [bis(acetoxy)iodo]benzene-TEMPO-KN02 has been reported. The use of a catalytic amount of poly[4-(bis(acetoxy)iodo)]styrene allowed the successful recycling of this catalytic component. The protocol can be used to promote the oxidation of different kinds of alcohols in the presence of other functional groups and also in the oxidation of primary benzylic alcohols in the presence of secondary and aliphatic ones. Primary alcohols can be oxidized to the corresponding aldehydes without any noticeable overoxidation to the carboxylic acids.269... 

An analogous reaction of 2-acetoxy-1,4-naphthoquinone with 1-morpholinopropene gives the dihydronaphthofuran 27 (equation 18)37 similarly, enamines add to styrene oxide and 2-chlorotropone to yield the hydrogenated furans 2838 and 2939, respectively (equation 19). 

Amphiphilic triblock copolymers were prepared from polyethylene glycol) (PEG) [35], Starting from PEG segments of different lengths (Mw = 200,400, MO, 1000 and 1500) and with different end-groups (e,g, hydroxy, acetoxy, benzoyl, oleoyl, phenylurethane), telechelic macroazoinitiators are first prepared. By polymerization of styrene, a wide range of original copolymers are produced ... 

The relationship between structure and photoinitiation activity has been examined for polymeric systems bearing side-chain 1-substituted cyclohexyl-phenyl ketone moieties in the UV curing of the HDDA/BA equimolar mixture [19,20]. Indeed, the activity of poly[(l-acryloxycyclohexyl)phenyl ketone] [poly (APK)] and styrene/4-chloromethyl-styrene/l-(4-styrylmethyloxy)cyclohexyl phenyl ketone copolymers (PABOK) has been compared with that of the corresponding low-molecular-weight structural models such as 1-hydroxy-cyclohexyl phenyl ketone (HPK), 1-acetoxy-cyclohexyl phenyl ketone (ACPK) and l-(4-isopropyl-benzyloxy) cyclohexyl phenyl ketone (PIBOK). 

Starting Molecule 2-Nitro-vanrllin Reagents Nitromethane, acetic anhydride Product 8 2-Dinitro-4-acetoxy-5-methoxy-styrene Reference (Partington 1948)... 

Infrared spectra are valuable in the examination of small molecular-weight intermediates, such as blocked and activated derivatives of amino acids. The stretching frequency for the urethane carbonyl (around 1700 cm" ) is distinguishable from that of the activated carbonyl group in anhydrides (over 1800 cm or in active esters (around 1800 cm ). Also, changes in ir spectra were used for monitoring transformations in polymeric supports. For instance, conversion of chloromethylated copoly-styrene-divinylbenzene to the acetoxy... 

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