Triethylammonium 2

In the reaction of Q,/3-unsaturated ketones and esters, sometimes simple Michael-type addition (insertion and hydrogenolysis, or hydroarylation, and hydroalkenylation) of alkenes is observed[53,54]. For example, a simple addition product 56 to methyl vinyl ketone was obtained by the reaction of the heteroaromatic iodide 55[S5]. The corresponding bromide affords the usual insertion-elimination product. Saturated ketones are obtained cleanly by hydroarylation of o,/3l-unsaturated ketones with aryl halides in the presence of sodium formate, which hydrogenolyses the R—Pd—I intermediate to R— Pd—H[56]. Intramolecular hydroarylation is a useful reaction. The diiodide 57 reacts smoothly with sodium formate to give a model compound for the afla-toxin 58. (see Section 1.1.6)[57]. Use of triethylammonium formate and BU4NCI gives better results. 

Formate is an excellent hydride source for the hydrogenolysis of aryl halides[682]. Ammonium or triethylammonium formate[683] and sodium formate are mostly used[684,685]. Dechlorination of the chloroarene 806 is carried out with ammonium formate using Pd charcoal as a catalyst[686]. By the treatment of 2,4,6-trichloroamline with formate, the chlorine atom at the /iiara-position is preferentially removed[687]. The dehalogenation of 2,4-diha-loestrogene is achieved with formic acid, KI, and ascorbic acid[688]. 

A method for protecting ketones and aldehydes is the formation of oximes, but sometimes further protection of the oximes is required. For this purpose, the oximes can be protected as allyl ethers. The oxime ethers ean be eleaved with triethylammonium formate in boiling dioxane[444]. The allyl ether of oximes is eleaved under mild conditions without attaeking the aeetal group in 677. 

The reaction of isoprcnc with Et NH in the presence of triethylammonium iodide (10 mol%) gives the 1 1 adducts 51 and 52 with high selectivity(53]. The reaction of isoprene with ammonia or diethylamine affords the tail-to-tail dimer 53 when Pdfacac) and (BuO)jP are used as the catalyst. The head-to-head dimer 54 is obtained with Pd(acac)2, BF,. and tricyclohexylphosphine(54]. 

Stereoselective and chemoselective semihydrogenation of the internal alkyne 208 to the ew-alkene 210 is achieved by the Pd-catalyzed reaction of some hydride sources. Tetramethyldihydrosiloxane (TMDHS) (209) i.s used in the presence of AcOH[116]. (EtO)3SiH in aqueous THF is also effective for the reduction of alkynes to di-alkenes[l 17], Semihydrogenation to the d.v-alkene 211 is possible also with triethylammonium formate with Pd on carbon[118]. Good yields and high cis selectivity are obtained by catalysis with Pd2fdba)3-Bu3P[119],... 

Triethylammonium formate is another reducing agent for q, /3-unsaturated carbonyl compounds. Pd on carbon is better catalyst than Pd-phosphine complex, and citral (49) is reduced to citronellal (50) smoothly[55]. However, the trisubstituted butenolide 60 is reduced to the saturated lactone with potassium formate using Pd(OAc)2. Triethylammonium formate is not effective. Enones are also reduced with potassium formate[56]. Sodium hypophosphite (61) is used for the reduction of double bonds catalyzed by Pd on charcoal[57]. 

Formic acid is a good reducing agent in the presence of Pd on carbon as a catalyst. Aromatic nitro compounds are reduced to aniline with formic acid[100]. Selective reduction of one nitro group in 2,4-dinitrotoluene (112) with triethylammonium formate is possible[101]. o-Nitroacetophenone (113) is first reduced to o-aminoacetophenone, then to o-ethylaniline when an excess of formate is used[102]. Ammonium and potassium formate are also used for the reduction of aliphatic and aromatic nitro compounds. Pd on carbon is a good catalyst[103,104]. NaBH4 is also used for the Pd-catalyzed reduction of nitro compounds 105]. However, the ,/)-unsaturated nitroalkene 114 is partially reduced to the oxime 115 with ammonium formate[106]... 

In this experiment students analyze an artificial RNA digest consisting of cytidine, uridine, thymidine, guanosine, and adenosine using a Cjg column and a mobile phase of 0.4% v/v triethylammonium acetate, 5% v/v methanol, and 94.6% v/v water. The chromatogram is recorded using a UV detector at a wavelength of 254 nm. 

Corrosion inhibitors are used to protect both the container and the metal substrate being stripped. Acid activated removers use inhibitors to block corrosion on active metals. Typical inhibitors are propylene oxide [75-56-9], butylene oxide [9106-88-7], triethylammonium phosphates, and sodium ben2oate [532-32-1] (see Corrosion and corrosion control). 

Triethylammonium hydroiodide [4636-73-1 j M 229.1, m 181 . Purified as for triethylammonium bromide, except the soln for pptn was precooled acetone at -10 and the ppte was twice recrystd from a cooled acetone/hexane mixture at -10°. 

Triethylammonium trichloroacetate [4113-06-8] M 263.6. Equimolar solns of triethylamine and trichloroacetic acid in -hexane were mixed at 10°. The solid so obtained was recrystd from CHCl3/ benzene. 

Triethylammonium trifluoroacetate [454-49-9J M 196.2. Purified as for the corresponding trichloroacetate. The salt was a colourless liquid at ambient temperature. 

Adenosine 5"-[P-thio]diphosphate tri-lithium salt [73536-95-5] M 461.1. Purified by ion-exchange chromatography on DEAE-Sephadex A-25 using gradient elution with 0.1-0.5M triethylammonium bicarbonate. [Biochem Biophys Acta 276 155 7972.]... 

Chloromethoxy-1,2,2 2-tetrafluoroethane is converted by triethylammonium fluoride or piperidine hydrogen fluoride to fluoromethoxy 1 2,2,2-tetra-fluoroethane in greater than 60% yield Piperidine hydrogen fluoride or butyl-ammonium fluoride can convert methoxy-l-chloro-2,2,2-trifluoroethane to methoxy-1,2,2,2-tetrafluoroethane in 80% yield [79]... 

This easily prepared lipophilic 5 -phosphate protective group is cleaved by NCS oxidation (dioxane, triethylammonium hydrogen carbonate, 2 h, rt) followed by ammonia-induced j3-elimination. ... 

BIs-triethylammonium pyrophosphate Adenosine triphosphate Bis(trimethylsilyl) acetamide Cefaclor Cefroxadine Ceftizoxime... 

Fig. 2-5. Examples showing the eomplementary separations on glyeopeptide CSPs. (A) Separation of N-CBZ-norvaline on vaneomyein (left) and teieoplanin (right). The mobile phase was methanol 1 % triethylammonium aeetate (20/80 v/v) pH 4.1. (B) Separation of warfarin on teieoplanin (left) and vaneomyein (right) CSPs. The mobile phase was aeetonitrile 1 % triethylammonium aeetate (10/90 v/v) pH 4.1. (C) Separation of naproxen on teieoplanin (left) and ristoeetin A (right). The mobile phase was methanol 0.1 % triethylammonium aeetate (30/70 v/v) pH 4.1. All eolumns were 250 x 4.6 mm i.d. The flow rate for all the separations was 1 mL min at ambient temperature (23 °C).

Fig. 2-8. Chromatograms of ketoprofen in reversed phase on vaneomyein (A), teieoplanin (B), risto-eetin A (C), vaneomyein + teieoplanin (D), ristoeetin A + teieoplanin (E), and ristoeetin A + vaneomyein + teieoplanin (F). All eolumns were 100 x 4.6 mm. The numbers by the peaks refer to the retention time in minutes. The mobile phase was methanol 0.1 % triethylammonium aeetate (25/75 v/v) pH 6.0. The flow rate was 1.0 mL min at ambient temperature (23 °C).

Scheme 5.1-52 The reaction between benzene and ethene in a triethylammonium ionic liquid.

These reagents exhibit a high selectivity for the attack of aldehydic over ketonic oxo groups26. The triethylammonium salt of 2-(bromomethyl)acrylic acid and base-sensitive aldehydes, under these conditions, can be used for the synthesis of lactones27. 

Workup (a) The product is isolated by passage through an ion exchange column (Dowcx AG1-X8, HCOf 100 mL) and consecutive elution with 200 mM triethylammonium bicarbonate solution. After ion exchange... 

CONVERSION OF PRIMARY ALCOHOLS TO URETHANES via THE INNER SALT OF METHYL (CARBOXYSULFAMOYL)TRIETHYLAMMONIUM HYDROXIDE METHYL n-HEXYLCARBAMATE... 

The above procedure describes the only known preparation of the inner salt of methyl (carboxysulfamoyl)triethylammonium hydroxide and illustrates the use of this reagent to convert a primary alcohol to the corresponding urethane.2 Hydrolysis of the urethane would then provide the primary amine. The method is limited to primary alcohols secondary and tertiary alcohols are dehydrated to olefins under these conditions, often in synthetically useful yields.2... 

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