Dimethylcarbamoyl chloride

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Dimethylcarbamoyl chloride
Dimethylcarbamoylchlorid Strukturformel.svg
Names
Preferred IUPAC name
Dimethylcarbamoyl chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.001.099 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C3H6ClNO/c1-5(2)3(4)6/h1-2H3
    Key: YIIMEMSDCNDGTB-UHFFFAOYSA-N
  • CN(C)C(=O)Cl
Properties
C3H6ClNO
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Dimethylcarbamoyl chloride (DMCC) is a reagent for transferring a dimethylcarbamoyl group to alcoholic or phenolic hydroxyl groups forming dimethyl carbamates, usually having pharmacological or pesticidal activities. Because of its high toxicity and its carcinogenic properties shown in animal experiments and presumably also in humans, [1] dimethylcarbamoyl chloride can only be used under stringent safety precautions.

Contents

Production and occurrence

The production of dimethylcarbamoyl chloride from phosgene and dimethylamine was reported as early as 1879 (reported as "Dimethylharnstoffchlorid" – dimethylurea chloride). [2]

Synthesis of dimethylcarbamoyl chloride with dimethylamine DMCC mit Dimethylamin.svg
Synthesis of dimethylcarbamoyl chloride with dimethylamine

DMCC can be produced in high yields (90%) at 275 °C by reacting phosgene with gaseous dimethylamine in a flow reactor. [3] To suppress the formation of ureas, excess phosgene is used (in a 3:1 ratio).

The reaction can also be carried out at the laboratory scale with diphosgene or triphosgene and an aqueous dimethylamine solution in the two-phase system of benzenexylene and water in a stirred reactor with sodium hydroxide as an acid scavenger. However, considerably lower yields (56%) are achieved due to the hydrolysis sensitivity of DMCC. [4]

Dimethylcarbamoyl chloride is also formed (together with methyl chloride) when reacting phosgene with trimethylamine. [5]

Synthesis of dimethylcarbamoyl chloride with trimethylamine DMCC mit Trimethylamin.svg
Synthesis of dimethylcarbamoyl chloride with trimethylamine

A more recent process is based on chlorodimethylamine, which is converted practically quantitatively to dimethylcarbamoyl chloride on a palladium catalyst under pressure with carbon monoxide at room temperature. [6]

Synthesis of dimethylcarbamoyl chloride from chloramine DMCC aus Chloramin.svg
Synthesis of dimethylcarbamoyl chloride from chloramine

DMCC can also be formed in small amounts (up to 20 ppm) from dimethylformamide (DMF) in the Vilsmeier–Haack reaction [7] or when DMF is used as a catalyst in the reaction of carboxylic acids with thionyl chloride to the corresponding acyl chloride. [8]

Synthesis of dimethylcarbamoyl chloride with dimethylformamide DMCC mit Dimethylformamid.svg
Synthesis of dimethylcarbamoyl chloride with dimethylformamide

The tendency towards DMCC formation depends on the chlorination reagent (thionyl chloride > oxalyl chloride > phosphorus oxychloride) and is higher in the presence of a base. However, dicarbamoyl chloride hydrolyses very quickly to dimethylamine, hydrochloric acid and carbon dioxide (with a half-life of about 6 minutes at 0 °C) so that less than 3 ppm of dicarbamoyl chloride is found in the Vilsmeier product after aqueous workup. [9]

Properties

Dimethylcarbamoyl chloride is a clear, colorless, corrosive and flammable liquid with a pungent odor and a tear-penetrating effect, which decomposes rapidly in water. [10] Because of its unpleasant, toxic, mutagenic and carcinogenic properties, [11] [12] it has to be used under extreme precautions.

DMCC behaves like an acyl chloride whose chlorine atom can be exchanged for other nucleophiles. Therefore, it reacts with alcohols, phenols and oximes to the corresponding N,N-dimethylcarbamates, with thiols to thiolourethanes, with amines and hydroxylamines to substituted ureas, and with imidazoles and triazoles to carbamoylazoles. [10]

Reactions of dimethylcarbamoyl chloride with nucleophiles DMCC-Reaktion mit Nukleophilen.svg
Reactions of dimethylcarbamoyl chloride with nucleophiles

DMCC is less reactive and less selective to substrates with multiple nucleophilic centers than conventional acyl chlorides.

Unsaturated conjugated aldehydes such as crotonaldehyde (trans-but-2-enal) react with DMCC forming dienyl carbamates, which can be used as dienes in Diels–Alder reactions. [13]

Synthesis of dienyl carbamates with dimethylcarbamoyl chloride Synthese von Dienylcarbamaten mit DMCC.svg
Synthesis of dienyl carbamates with dimethylcarbamoyl chloride

Alkali metal carboxylates react with DMCC forming the corresponding dimethylamides. DMCC reacts with anhydrous sodium carbonate [14] or with excess dimethylamine to form tetramethylurea. [15]

The reaction of DMCC with DMF forms tetramethylformamidinium chloride, [16] which is a major intermediate in the preparation of tris(dimethylamino)methane, a reagent for the introduction of enamine functions in conjunction with activated methylene groups [17] and the preparation of amidines. [18]

Synthesis of tris(dimethylamino)methane with dimethylcarbamoyl chloride Synthese von Tris(dimethylamino)methan.svg
Synthesis of tris(dimethylamino)methane with dimethylcarbamoyl chloride

DMCC is a starting material for the insecticide class of the dimethyl carbamates which act as inhibitors of acetylcholinesterase, including dimetilane, [19] and the related compounds isolane, pirimicarb and triazamate.

Synthesis of dimetilane with dimethylcarbamoyl chloride Synthese von Dimetilan.svg
Synthesis of dimetilane with dimethylcarbamoyl chloride

The quaternary ammonium compounds neostigmine [20] finds pharmaceutical applications as acetylcholinesterase inhibitors. It is obtained from 3-(dimethylamino)phenol and DMCC and subsequent quaternization with methyl bromide or dimethyl sulfate [21]

Synthesis of neostigmine with dimethylcarbamoyl chloride Synthese von Neostigmin.svg
Synthesis of neostigmine with dimethylcarbamoyl chloride

and pyridostigmine, which is obtainable from 3-hydroxypyridine and DMCC and subsequent reaction with methyl bromide. [22]

Synthesis of pyridostigmine with dimethylcarbamoyl chloride Synthese von Pyridostigmin.svg
Synthesis of pyridostigmine with dimethylcarbamoyl chloride

DMCC is also used in the synthesis of the benzodiazepine camazepam. [23]

Synthesis of camazepam with dimethylcarbamoyl chloride Synthese von Camazepam.svg
Synthesis of camazepam with dimethylcarbamoyl chloride

See also

Related Research Articles

<span class="mw-page-title-main">Protecting group</span> Group of atoms introduced into a compound to prevent subsequent reactions

A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis.

<span class="mw-page-title-main">Fischer–Speier esterification</span>

Fischer esterification or Fischer–Speier esterification is a special type of esterification by refluxing a carboxylic acid and an alcohol in the presence of an acid catalyst. The reaction was first described by Emil Fischer and Arthur Speier in 1895. Most carboxylic acids are suitable for the reaction, but the alcohol should generally be primary or secondary. Tertiary alcohols are prone to elimination. Contrary to common misconception found in organic chemistry textbooks, phenols can also be esterified to give good to near quantitative yield of products. Commonly used catalysts for a Fischer esterification include sulfuric acid, p-toluenesulfonic acid, and Lewis acids such as scandium(III) triflate. For more valuable or sensitive substrates other, milder procedures such as Steglich esterification are used. The reaction is often carried out without a solvent or in a non-polar solvent to facilitate the Dean-Stark method. Typical reaction times vary from 1–10 hours at temperatures of 60-110 °C.

In organic chemistry, an acyl chloride is an organic compound with the functional group −C(=O)Cl. Their formula is usually written R−COCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CH3COCl. Acyl chlorides are the most important subset of acyl halides.

<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

<span class="mw-page-title-main">Triphosgene</span> Chemical compound

Triphosgene (bis(trichloromethyl) carbonate (BTC) is a chemical compound with the formula OC(OCCl3)2. It is used as a solid substitute for phosgene, which is a gas and diphosgene, which is a liquid. Triphosgene is stable up to 200 °C. Triphosgene is used in a variety of halogenation reactions.

Dimethylformamide is an organic compound with the formula (CH3)2N−C(=O)H. Commonly abbreviated as DMF, this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions. Dimethylformamide is odorless, but technical-grade or degraded samples often have a fishy smell due to impurity of dimethylamine. Dimethylamine degradation impurities can be removed by sparging samples with an inert gas such as argon or by sonicating the samples under reduced pressure. As its name indicates, it is structurally related to formamide, having two methyl groups in the place of the two hydrogens. DMF is a polar (hydrophilic) aprotic solvent with a high boiling point. It facilitates reactions that follow polar mechanisms, such as SN2 reactions.

<span class="mw-page-title-main">Oxalyl chloride</span> Chemical compound

Oxalyl chloride is an organic chemical compound with the formula Cl−C(=O)−C(=O)−Cl. This colorless, sharp-smelling liquid, the diacyl chloride of oxalic acid, is a useful reagent in organic synthesis.

<span class="mw-page-title-main">Phosphorus pentachloride</span> Chemical compound

Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides/oxychlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.

<i>N</i>-Bromosuccinimide Molecule

N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br, the bromine radical.

<span class="mw-page-title-main">Claisen rearrangement</span> Chemical reaction

The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation.

<span class="mw-page-title-main">Curtius rearrangement</span> Chemical reaction

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.

<span class="mw-page-title-main">Carbonyldiimidazole</span> Chemical compound

1,1'-Carbonyldiimidazole (CDI) is an organic compound with the molecular formula (C3H3N2)2CO. It is a white crystalline solid. It is often used for the coupling of amino acids for peptide synthesis and as a reagent in organic synthesis.

Di-<i>tert</i>-butyl dicarbonate Chemical compound

Di-tert-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a tert-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give N-tert-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids. Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group.

The Bergmann degradation is a series of chemical reactions designed to remove a single amino acid from the carboxylic acid (C-terminal) end of a peptide. First demonstrated by Max Bergmann in 1934, it is a rarely used method for sequencing peptides. The later developed Edman degradation is an improvement upon the Bergmann degradation, instead cleaving the N-terminal amino acid of peptides to produce a hydantoin containing the desired amino acid.

<span class="mw-page-title-main">Tetramethylurea</span> Chemical compound

Tetramethylurea is the organic compound with the formula (Me2N)2CO. It is a substituted urea. This colorless liquid is used as an aprotic-polar solvent, especially for aromatic compounds and is used e. g. for Grignard reagents.

<i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-Tetramethylformamidinium chloride Chemical compound

N,N,N′,N′-Tetramethylformamidinium chloride is the simplest representative of quaternary formamidinium cations of the general formula [R2N−CH=NR2]+ with a chloride as a counterion in which all hydrogen atoms of the protonated formamidine [HC(=NH2)NH2]+ are replaced by methyl groups.

<span class="mw-page-title-main">Tris(dimethylamino)methane</span> Chemical compound

Tris(dimethylamino)methane (TDAM) is the simplest representative of the tris(dialkylamino)methanes of the general formula (R2N)3CH in which three of the four of methane's hydrogen atoms are replaced by dimethylamino groups (−N(CH3)2). Tris(dimethylamino)methane can be regarded as both an amine and an orthoamide.

<span class="mw-page-title-main">3-Dimethylaminoacrolein</span> Chemical compound

3-Dimethylaminoacrolein is an organic compound with the formula Me2NC(H)=CHCHO. It is a pale yellow water-soluble liquid. The compound has a number of useful and unusual properties, e.g. it "causes a reversal of the hypnotic effect of morphine in mice" and has a "stimulating effect in humans".

<span class="mw-page-title-main">Bis(dimethylamino)methane</span> Chemical compound

Bis(dimethylamino)methane is the organic compound with the formula [(CH3)2N]2CH2. It is classified as an aminal as well as a ditertiary amine, in fact the simplest. It is a colorless liquid that is widely available. It is prepared by the reaction of dimethylamine and formaldehyde:

<i>tert</i>-Butoxybis(dimethylamino)methane Chemical compound

tert-Butoxybis(dimethylamino)methane is an organic compound with the formula (CH3)3COCH(N(CH3)2)2. The compound is classified as an aminal ester, i.e. the tert-butyl alcohol derivative of the aminal bis(dimethylamino)methane. It is a colorless liquid with a amine odor.

References

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