Reagents reactions

The Reformatsky Reaction consists of the interaction of an ester of an a-halogeno-acid with an aldehyde, a ketone or another ester in the presence of zinc. For example, if a mixture of ethyl bromoacetate and benzaldehyde is heated with zinc, the latter undoubtedly first combines with the ethyl bromoacetate to form a Grignard-like reagent (reaction A), which then adds on to the benzaldehyde Just as a Grignard reagent would do (reaction B). The complex so formed, on acidification gives ethyl p-phenyl-p-hydroxy-propionate (reaction C). Note that reaction A could not satisfactorily be carried out using... 

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

The alcohol intermediate happens to be the exact kind of intermediate that was produced by the Grignard reagent reaction with propanal to produce isosafrole back-a-ways in the big chapter. So what the chemist does is apply the 1g of KHSO4 to that crude alcohol intermediate and process it just as was done before to give isosafrole, or propenylbenzene or 3,4-methylenedioxyphenyl -1-butene or phenylbutene (yield=91% ). This is a great little procedure. 

Because of the increased importance of inductive electron withdrawal, nucleophilic attack on uncharged azole rings generally occurs under milder conditions than those required for analogous reactions with pyridines or pyridones. Azolium rings are very easily attacked by nucleophilic reagents reactions similar to those of pyridinium and pyrylium compounds are known azolium rings open particularly readily. 

Aniline — Diphenylamine — Phosphoric Acid Reagent Reaction (according to [16])... 

Entiy Oxidizing Reagent Reaction Conditions Yield (%) of ... 

On treatment with a strong base such as sodium hydride or sodium amide, dimethyl sulfoxide yields a proton to form the methylsulfinyl carbanion (dimsyl ion), a strongly basic reagent. Reaction of dimsyl ion with triphenylalkylphosphonium halides provides a convenient route to ylides (see Chapter 11, Section III), and with triphenylmethane the reagent affords a high concentration of triphenylmethyl carbanion. Of immediate interest, however, is the nucleophilic reaction of dimsyl ion with aldehydes, ketones, and particularly esters (//). The reaction of dimsyl ion with nonenolizable ketones and... 

Vilstneier reagent, reaction with ketones to form 0-chloro-a,/3- unsaturated aldehydes, 46,19... 

Fortum s Reagent, reaction of organic substrates with 96... 

As 29 had been recognized as the most accessible starting-material for the synthesis of racemic carba-sugars, its resolution was successfully achieved with optically active a-methylbenzylamine as chiral reagent. Reaction of 29 with (-l-)-a-methylbenzylamine gave a mixture of two diastereoisomeric salts [(+)-amine, (—)-29 and (+)-amine, (-l-)-29], which were well separated, and the former salt was converted into (—)-29, [a] -111.8° (ethanol). Analogously, (+)-29, [a] +110.7° (ethanol), was obtained. ... 

Yield based on the limiting reagent Reactions carried out in inert atmosphere The corresponding anions were not mentioned... 

An entirely analogous study using Hg(OAc)2 showed that for this reagent reaction ceases at the organometallic compound unless the temperature is increased to 135 °C k ec = 8.6X 10 sec ). 

Aldehyde Reagent Reaction temperature (°C) Product Yield (%)... 

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