| Ritter reaction | |
|---|---|
| Named after | John J. Ritter |
| Reaction type | Addition reaction |
| Identifiers | |
| Organic Chemistry Portal | ritter-reaction |
| RSC ontology ID | RXNO:0000058 |
The Ritter reaction is a chemical reaction that transforms a nitrile into an N-alkyl amide using various electrophilic alkylating reagents. The original reaction formed the alkylating agent using an alkene in the presence of a strong acid. [1] [2] [3] [4]
The Ritter reaction proceeds by the electrophilic addition of either a carbenium ion or covalent species [5] [6] to the nitrile. The resulting nitrilium ion is hydrolyzed to the desired amide.
Primary, [7] secondary, [4] tertiary, [8] and benzylic [9] alcohols, [1] as well as tert-butyl acetate, [10] also successfully react with nitriles in the presence of strong acids to form amides via the Ritter reaction. A wide range of nitriles can be used. In particular, formonitrile (hydrogen cyanide) can be used to prepare formamides, which are useful precursors to isocyanides.
The large scale application of the Ritter reaction is in the synthesis of tert-octylamine. An estimated 10,000 tons/y (year: 2000) of this and related lipophilic amines are prepared in this way. [11] Otherwise, the Ritter reaction is most useful in the formation of amines and amides of pharmaceutical interest. Real world applications include Merck's industrial-scale synthesis of anti-HIV drug Crixivan (indinavir); [12] the production of the falcipain-2 inhibitor PK-11195; the synthesis of the alkaloid aristotelone; [13] and synthesis of Amantadine, an antiviral and antiparkinsonian drug. [14] Other applications of the Ritter reaction include synthesis of dopamine receptor ligands [13] and production of racemic amphetamine from allylbenzene and methyl cyanide. [1] [15]
The Ritter reaction is inferior to most amination methods because it cogenerates substantial amounts of salts. Illustrative is the conversion of isobutylene to tert-butylamine using HCN and sulfuric acid followed by base neutralization. The weight of the salt byproduct is greater than the weight of the amine. [11]
In the laboratory, the Ritter reaction suffers from the necessity of an extremely strong acid catalyst. Other methods have been proposed in order to promote carbocation formation, including photocatalytic electron transfer [16] or direct photolysis. [17]
The reaction is named after John J. Ritter, who supervised the Ph.D. thesis work of P. Paul Minieri.
In chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines, trimethylamine, and aniline. Inorganic derivatives of ammonia are also called amines, such as monochloramine.
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−OH) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, C
6H
5OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule.
The Pinner reaction refers to the acid catalysed reaction of a nitrile with an alcohol to form an imino ester salt ; this is sometimes referred to as a Pinner salt. The reaction is named after Adolf Pinner, who first described it in 1877. Pinner salts are themselves reactive and undergo additional nucleophilic additions to give various useful products:
The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring. Friedel–Crafts reactions are of two main types: alkylation reactions and acylation reactions. Both proceed by electrophilic aromatic substitution.
Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene. Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents.
In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.
In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.
In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups. The nitro group is one of the most common explosophores used globally. The nitro group is also strongly electron-withdrawing. Because of this property, C−H bonds alpha (adjacent) to the nitro group can be acidic. For similar reasons, the presence of nitro groups in aromatic compounds retards electrophilic aromatic substitution but facilitates nucleophilic aromatic substitution. Nitro groups are rarely found in nature. They are almost invariably produced by nitration reactions starting with nitric acid.
The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one less carbon atom. The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate. The reaction can form a wide range of products, including alkyl and aryl amines.
The Gabriel synthesis is a chemical reaction that transforms primary alkyl halides into primary amines. Traditionally, the reaction uses potassium phthalimide. The reaction is named after the German chemist Siegmund Gabriel.
N,N′-Dicyclohexylcarbodiimide (DCC or DCCD) is an organic compound with the chemical formula (C6H11N)2C. It is a waxy white solid with a sweet odor. Its primary use is to couple amino acids during artificial peptide synthesis. The low melting point of this material allows it to be melted for easy handling. It is highly soluble in dichloromethane, tetrahydrofuran, acetonitrile and dimethylformamide, but insoluble in water.
Xanthate usually refers to a salt of xanthic acid. The formula of the salt of xanthic acid is [R−O−CS2]−M+ ,. Xanthate also refers to the anion [R−O−CS2]−. Xanthate also may refer to an ester of xanthic acid. The formula of xanthic acid is R−O−C(=S)−S−H, while the formula of the esters of xanthic acid is R−O−C(=S)−S−R', where R and R' are organyl groups. The salts of xanthates are also called O-organyl dithioates. The esters of xanthic acid are also called O,S-diorganyl esters of dithiocarbonic acid. The name xanthate is derived from Ancient Greek ξανθός xanthos, meaning “yellowish, golden”, and indeed most xanthate salts are yellow. They were discovered and named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and for extraction of certain sulphide bearing ores. They are also versatile intermediates in organic synthesis.
The Curtius rearrangement, first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a variety of nucleophiles such as water, alcohols and amines, to yield a primary amine, carbamate or urea derivative respectively. Several reviews have been published.
The Knorr pyrrole synthesis is a widely used chemical reaction that synthesizes substituted pyrroles (3). The method involves the reaction of an α-amino-ketone (1) and a compound containing an electron-withdrawing group α to a carbonyl group (2).
The Strecker amino acid synthesis, also known simply as the Strecker synthesis, is a method for the synthesis of amino acids by the reaction of an aldehyde with ammonia in the presence of potassium cyanide. The condensation reaction yields an α-aminonitrile, which is subsequently hydrolyzed to give the desired amino acid. The method is used commercially for the production of racemic methionine from methional.
The tert-butyloxycarbonyl protecting group or tert-butoxycarbonyl protecting group is a protecting group used in organic synthesis.
In electrochemistry, electrosynthesis is the synthesis of chemical compounds in an electrochemical cell. Compared to ordinary redox reactions, electrosynthesis sometimes offers improved selectivity and yields. Electrosynthesis is actively studied as a science and also has industrial applications. Electrooxidation has potential for wastewater treatment as well.
Oxazoline is a five-membered heterocyclic organic compound with the formula C3H5NO. It is the parent of a family of compounds called oxazolines, which contain non-hydrogenic substituents on carbon and/or nitrogen. Oxazolines are the unsaturated analogues of oxazolidines, and they are isomeric with isoxazolines, where the N and O are directly bonded. Two isomers of oxazoline are known, depending on the location of the double bond.
In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.
Trichloroacetonitrile is an organic compound with the formula CCl3CN. It is a colourless liquid, although commercial samples often are brownish. It is used commercially as a precursor to the fungicide etridiazole. It is prepared by dehydration of trichloroacetamide. As a bifunctional compound, trichloroacetonitrile can react at both the trichloromethyl and the nitrile group. The electron-withdrawing effect of the trichloromethyl group activates the nitrile group for nucleophilic additions. The high reactivity makes trichloroacetonitrile a versatile reagent, but also causes its susceptibility towards hydrolysis.