Alcohols Ritter reaction

Sulfuric acid Amines from alcohols Ritter reaction... 

CH3)2CH0H + CH2=C=0 CH3C00CH(CH3)2 and the Ritter reaction to prepare A/-isopropylacrylamide [2210-25-5] from acrylonitrile [107-13-1] and isopropyl alcohol ... 

In contrast to the normal Ritter reaction, the reaction shown in equation 47 gives good results starting from primary and secondary alcohols Other advantages are the mild reaction conditions and easy workup [96]... 

Other sequences that transform primary alcohols to primary amines include (a) conversion of the alcohol to a cyanate, rearrangement to an isocyanate, and hydrolysis,3 and (b) conversion of the alcohol to an -V alkylformamide via the Ritter reaction, followed by hydrolysis.4... 

Ritter reaction org chem A procedure for the preparation of amides by reacting alkenes or tertiary alcohols with nitriles in an acidic medium. rid-ar re,ak-sh3n ) Ritz s combination principie spect The empirical rule that sums and differences of the frequencies of spectral lines often equal other observed frequencies. Also known as combination principle. rit-soz, kam-b3 na-sh3n. prin-sa-pal )... 

Reformatsky reaction, 1, 1 22, 4 Reimer-Tiemann reaction, 13, 2 28, 1 Reissert reaction, 70, 1 Resolution of alcohols, 2, 9 Retro-Diels-Alder reaction, 52, 1 53, 2 Ritter reaction, 17, 3... 

Reactions with secondary or tertiary alcohols in strongly acidic media yield amides (Ritter reaction) ... 

Dorzolamide contains two chiral centers, and is therefore capable of existing in four diastereomers. The stereochemistry at the C-6 position of the starting material is preserved during the various chemical reactions which take place during the synthesis. The stereochemistry at the C-4 position (absolute configuration being 5) results from the Ritter substitution reaction (Scheme 1, Steps I-II) used to transform the alcohol to an acetamide. The Ritter reaction yields mostly the rra j-diastereomer, and the c/s-diastereomers are easily separated as their maleate salts. The potential sulfonamide positional isomer (3-sulfonamide) has not been observed at levels greater than 0.1% in HPLC analyses. 

Enantiomerically pure epoxides and diols, readily available through the asymmetric epoxidation and asymmetric dihydroxylation reactions, are ideal precursors to prepare cis-amino alcohols via the Ritter reaction. " " A Merck group has shown that indene oxide 175a can be converted effectively to c/i-l-amino-2-indanol, a key fragment of the HlV-protease inhibitor Indinavir via the cis-... 

However, these cations are stabilized by an arenechromium tricarbonyl group in the a-position. Thus benzyl alcohol complexed with chromium tricarbonyl undergoes Ritter reactions rapidly and in high yield (equation I). On the other hand, the... 

A preliminary experiment indicates the usefulness of similar complexation for Ritter reactions with a propargyl alcohol (equation II). 

Exercise 15-24 It is possible to prepare amides from tertiary alcohols and alkane-nitriles, RCN, in concentrated sulfuric acid as the catalyst (Ritter reaction), as illustrated in the equation for the synthesis of W-fe/f-butylethanamide ... 

Keywords alcohol, nitrile, montmorillonite KSF, Ritter reaction, microwave irradiation, amide... 

In addition to Ritter-type transformations already discussed in previous sections, there are additional examples of the Ritter reaction—that is, the transformation of alkenes or alcohols with nitriles to give carboxamides carried out under superacidic conditions. 

Nafion-H has also been shown to be active in the Ritter reaction. Treatment of alcohols, such as benzyl alcohols, 1-adamantanol [Eq. (5.346)], and 2-norborneols with acetonitrile or benzonitrile in the presence of Nafion-H under forcing conditions (140-145°C, 18—48h), affords the corresponding carboxamides in moderate to excellent yields (40-99%).652 Nafion-H can be reused after a simple activation (washing with deionized water and acetone followed by drying at 105°C). 

Tertiary hydroxyls can undergo several reactions under acidic conditions to form artifacts in degradation experiments. In acidic acetonitrile/ water solutions, primary, secondary and tertiary alcohols can undergo a Ritter reaction to form amides (Fig. 83). 

Figure 83 Ritter reaction of tertiary alcohols to form amides under acidic conditions in acetonitrile.

The Ritter reaction (42,42A) is a general method for converting alcohols to amines by reaction with a nitrile and a strong acid (Reaction XXVI). In this reaction only tertiary,... 

Abb. 7.16. Ritter reaction part I (cf. Fig. 7.17) SN1 reaction between a tertiary alcohol and a nucleophile containing C=N, with hydrogen cyanide acting as the nucleophile. Under reaction conditions the C=N group is tert-alkylated at the N atom and hydrated at the nitrile nitrogen leading to the formation of an W-tert-alkyl-formamide (B). 

Abb. 7.17. Ritter reaction part II (cf. Fig. 7.16) SN2 reaction between a secondary alcohol and a nucleophile containing C=N with acrylic nitrite acting as the nucleophile. 

Various modifications of the reaction of an alcohol with ammonia provide the most common commercial routes to alkylamines. Some others routes that are used to make certain individual amines include aldehyde/amine additions, nitrile reduction, the Ritter reaction, amination of isobutylene, and hydrogenation of anilines. Capacities of many plants depend on the product mix of mono/di/tri products as well as the variety of amines (ethyl, propyl and butyl). One must know the product mix that the capacity is based upon and the actual scheduled output of produces) to determine what amounts can actually be manufactured. Capacities are often in excess of anticipated demand to satisfy seasonal demands for pesticide uses116. 

Ritter reaction. The original version for this conversion of a tertiary alcohol to an amide involved a reaction with nitriles in a strongly acidic medium.1 In a new version, the alcohol is converted into a triflate, which need not be isolated, but is treated with a nitrile (2 equiv.) in CH2C12 and then with aqueous NaHC03. Overall yields are 50-98%. The advantage of this version is that it is applicable to primary and secondary alcohols as well as tertiary ones.2... 

Another collection of related intermediates occurs in the Ritter reaction and the Beckmann fragmentation. The Ritter reaction involves the combination of a tertiary alcohol and a nitrile in acid solution and the proposed mechanism involves a series of intermediates. 

In the Ritter reaction a rather different kind of evidence for the cation is the fact that families of isomeric alcohols all give the same product. In all these cases, rearrangements of the first formed carbocation (Chapter 37) can easily account for the products. Another example in the decalin series is this Ritter reaction with KCN as the nitrile in acidic solution so that HCN is the reagent. The starting material is a spirocyclic tertiary alcohol but the product is a frans-decalin formed by... 

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