4-Dimethylaminopyridine

Description

4-(Dimethylamino)pyridine (DMAP) is a toxic, corrosive solid that is widely used as a nucleophilic catalyst in esterification, hydrosilylation, Bayliss–Hillman reactions, and many more. In 2001, G. C. Fu and co-workers showed that chiral derivatives of DMAP can be used for stereoselective catalysis. More recently,?D. Seidel and co-workers used DMAP and other inexpensive reagents in acylation reactions?to give products that can be enantiomerically resolved. DMAP is also a nucleophilic catalyst and can be used in a variety of different reactions.DMAP is used as a very efficient acyl transfer agent. Studies have shown that esterification of hindered alcohols via anhydrides can be increased by a factor of 10,000 using 4-aminopyridines such as DMAP.

Chemical properties

White solid

The Uses of 4-Dimethylaminopyridine

4-Dimethylaminopyridine is a versatile hypernucleophilic acylation catalyst, it is used to improve the yield, reduce the reaction time, improving relaxation process conditions, for a variety of reactions such as esterifications with anhydrides, the Baylis-Hillman reaction, hydrosilylations, tritylation, the Steglich rearrangement. DMAP is widely used in perfumes, dyes, pigments, pesticides, pharmaceuticals and polymer compounds and other fields.

What are the applications of Application

4-Dimethylaminopyridine is a highly efficient catalyst for acylation reactions

Definition

ChEBI: 4-Dimethylaminopyridine is a dialkylarylamine and a tertiary amino compound.

General Description

Valacyclovir Related Compound G, also called as 4-(Dimethylamino)pyridine (DMAP) is an excellent catalyst for acylation of hindered alcohols and in chemical transformations. It is highly nucleophilic in nature.

Hazard

4-Dimethylaminopyridine (4-DMAP) is readily absorbed through the skin and is highly toxic by skin absorption. It also causes skin and eye burns. All skin and eye contact and inhalation should be avoided. Appropriate OSHA/ MSHA-approved respirator, chemical-resistant gloves and impervious or disposable protective clothing should be worn. Work should be carried out in a chemical fume hood.

Hazard

4-Dimethylaminopyridine is a strong skin and eye irritant; toxic if ingested; highly toxic if absorbed through the skin.

Solubility in organics

4-Dimethylaminopyridine can be soluble in methanol, benzene, ethyl acetate, chloroform, methylene chloride, acetone, and acetic acid. Less soluble in ether, diisopropyl ether, cyclohexane, hexane, and water.

Synthesis

N-[4-Pyridyl] pyridinium chloride hydrochloride (641.0 gm, 94.99% assay, 2.657 mole) and N,N-dimethyl formamide (421 gm, 99% assay, 5.709 mole) were charged in a 2 liter round bottom flask fitted with a stirrer, thermometer pocket and double surface condenser. The reaction mass was slowly heated to reflux temperature (150 to 155° C.), and refluxing continued for 2 to 3 hours. After the completion of the reaction, pyridine was distilled off. The aqueous mother liquor obtained after alkaline hydrolysis and filtration was extracted with chloroform (2940 g×1 and 1470 g×3). A lot of emulsion was observed after extraction, which creates problem in layer separation. After extraction with chloroform, the organic phase was separated out and treated with charcoal for removing off-color impurities. Light yellow mother liquor was taken for chloroform recovery. After chloroform recovery, 700.0 gm ethyl acetate was added for the crystallization of crude 4-DMAP. After cooling to 0° C. followed by filtration, 180 g 4-DMAP, with 98.97% assay by G.C, and 54.88% yield were recovered. This clearly indicates that in spite of additional steps involved, yield and assay of the 4-DMAP is reduced compared to the process of the present invention.

Purification Methods

Recrystallise DMAP from toluene [Sadownik et al. J Am Chem Soc 108 7789 1986]. [Beilstein 22 V 112.] § A polystyrene supported version (PS-DMAP) is commercially available.