Triethylamine, in synthesis

Triethylaluminum, apparatus and procedures for handling, 52, 90, 96, 100 Triethylamine, in synthesis of diazoketones, 50, 77 Triflates, vinyl-, 54, 82... 

To illustrate the specific operations involved, the scheme below shows the first steps and the final detachment reaction of a peptide synthesis starting from the carboxyl terminal. N-Boc-glycine is attached to chloromethylated styrene-divinylbenzene copolymer resin. This polymer swells in organic solvents but is completely insoluble. ) Treatment with HCl in acetic acid removes the fert-butoxycarbonyl (Boc) group as isobutene and carbon dioxide. The resulting amine hydrochloride is neutralized with triethylamine in DMF. 

Phosphorothioates. All three synthetic approaches appHcable to unmodified oligonucleotides can be adapted for synthesis of phosphorothioates (11) (33,46). If all of the phosphodiester linkages in an oligonucleotide are to be replaced with phosphorothioates, the ff-phosphonate method for coupling, followed by oxidation with Sg in carbon disulfide and triethylamine in the final step, is the most straightforward method. 

During the course of an elegant synthesis of the multifunctional FR-900482 molecule [( )-43, Scheme 9], the Danishefsky group accomplished the assembly of tetracycle 42 using an intramolecular Heck arylation as a key step.24 In the crucial C-C bond forming reaction, exposure of aryl iodide 41 to a catalytic amount of tetra-kis(triphenylphosphine)palladium(o) and triethylamine in acetonitrile at 80 °C effects the desired Heck arylation, affording 42 in an excellent yield of 93 %. The impressive success of this cyclization reaction is noteworthy in view of the potentially sensitive functionality contained within 41. 

The synthesis of 2,3-diphenylthiirene l-oxide 519 has been accomplished by treatment of ( )-a, a -dibromobenzyl sulphoxide 516 with a slight excess of triethylamine in boiling CH2C1246 (equation 318). ... 

Tejedor and coworkers have utilized a combination of two domino processes for a microwave-promoted synthesis of tetrasubstituted pyrroles [344]. The protocol combines two coupled domino processes the triethylamine-catalyzed synthesis of enol-protected propargylic alcohols and their sequential transformation into pyrroles through a spontaneous rearrangement from 1,3-oxazolidines (Scheme 6.183). Overall, these two linked and coupled domino processes build up two carbon-carbon bonds, two carbon-nitrogen bonds, and an aromatic ring in a regioselective and efficient manner. The tetrasubstituted pyrroles could be directly synthesized from the enol-protected propargylic alcohols and the primary amines by microwave irradia-... 

Tridecanedione, 47, 95 Triethylamine, 46,18 dehydrobromination of a-bromo-y-butyrolactone, 46, 23 dehydrobromination of o.a -dibromo-dibenzyl ketone, 47, 62 dehydrochlorination of cyclohexane-carbonyl chloride, 47, 34 in synthesis of nicotinic anhydride with phosgene, 47, 90 Triethylenetetramine, see Hexamethylenetetramine... 

The synthesis of ethyl ester derivatives of imidazo[5,l-4][l,2,4]triazole-3-carboxylic acid 64 has been reported (Scheme 25) <1999CHE1349>. Starting from the known substituted 5-diazoimidazoles 276, their coupling with malonic acid derivatives afforded the azo compounds 277, which on treatment with triethylamine in DMF, upon prolonged heating time, gave products 64 in moderate yield. 

We therefore needed a ready synthesis of the 1,6-epithio epoxide 119. Normally, for such syntheses, the sulftir atom is introduced at an early stage [64]. However, it appeared to us that a suitable doubly-activated sugar such as 120 should be capable of direct conversion to the 1,6-epithio sugar 121 by treatment with some type of sulfur reagent. Indeed, the o-glucosyl bromide 122 was easily prepared and, upon treatment with either hydrogen sulfide and triethylamine in DMF or benzyltriethylammonium tetrathiomolybdate in chloroform, gave the... 

During a peptide synthesis study, Slebioda (5) apparently independently observed the formation of miinchnone (12) from A -benzoylphenylalanine and DCC. He was able to isolate and fully characterize this crystalline miinchnone along with oxazolone 13. The tautomerization of 13 to 12 as a function of base and solvent is best effected with triethylamine in DMF (68% yield). 

The manner in which a carbene was generated was found to be critical to the product distribution in a synthesis of 4(5//)-thiooxazolones (Scheme 6.9). Treatment of diethyl bromomalonate with excess triethylamine in the presence of benzoyl isothiocyanate afforded a mixture of the 4(5//)-thiooxazolone 25 (44%) and the 1,3-oxathiole 26 (minor). However, if the carbene was generated via copper-catalyzed decomposition of diethyl diazomalonate, then 26 was isolated as the major product, albeit in low yield (22%). 

In 1998, Evans published an improved synthesis of bu-box 3 starting from the same amino acid. The updated synthesis began with sodium borohydride-iodine reduction to afford amino alcohol 23 followed again by treatment with dimethyl-malonyl dichloride 24 to afford 25 in 88% yield (from 23). Cyclization was achieved by treatment of 25 with toluenesulfonyl chloride and triethylamine in the presence of a catalytic amount of dimethylaminopyridine to afford bu-box 3 in 82% yield (Fig. 9.6). 

Chakrabarti and coworkers at Eli Lilly in the United Kingdom have reported the initial discovery and synthesis of olanzapine (Schemes 5 and,6). The thiophene 22 was synthesized by adding a DMF solution of malononitrile to a mixture of sulfur, propionaldehyde and triethylamine in DMF. The anion of amino thiophene 22 underwent a nucleophilic aromatic substitution with 2-fluoronitrobenzene to provide 23. The nitro group was reduced with stannous chloride and the resulting anihne cyclized with the cyano group to form amidine 24. Finally, a mixture of N-methylpiperazine and 24 were refluxed in DMSO/toluene to afford olanzapine (2). 

A very short and elegant synthesis of the 16-rtiembered dilactone ( )-pyrenophorin (515) has been accomplished by the dipolar cycloaddition reaction of a trialkylsilyl nitronate (81TL735). Nitromethane was added to 3-buten-2-one and the carbonyl group of the product reduced with sodium borohydride. The nitro alcohol (511) was converted to the acrylate (512) which was then subjected to a dimerization-cyclization reaction by treatment with chlorotrimethylsilane and triethylamine in dry benzene. Hydrogenation of the mixture of isoxazoline products (513) over palladium on charcoal followed by double dehydration of the intermediate bis-/3-hydroxyketone (514) led to ( )- and meso-pyrenophorin (Scheme... 

In solution-phase peptide synthesis, acylation of amino acids or peptides with N-protected azetidine-2-carboxylic acid is performed via the active esters, e.g. A-hydroxysuccin-imide 100 111-112 or pentachlorophenyl ester, m 117 as well as by the mixed anhydride 101114 or carbodiimide 118 methods. An attempt to prepare the A-carbonic acid anhydride by cycli-zation of A-(chloroformyl)azetidine-2-carboxylic acid with silver oxide in acetone or by addition of triethylamine in situ failed, presumably due to steric hindrance. 111 In SPPS, activation of the Fmoc-protected imino acid by HBTU 119,120 is reported. In solution-phase peptide synthesis, coupling of N-protected amino acids or peptides to C-protected azetidine-2-carboxylic acid or related peptides may be performed by active esters, 100 118 121 mixed anhydrides, 95 or similar methods. It may be worth mentioning that the probability of pip-erazine-2,5-dione formation from azetidine-2-carboxylic acid dipeptides is significantly reduced compared to proline dipeptides. 111 ... 

Warkentin and Zoghbi [87] have demonstrated the synthesis of novel spiro-(S-lactam oxadiazolines 57 (Scheme 15) by the reaction of differently substituted acid chloride 55 and 2-amino-A3-l,3,4 oxadiazolines 56 using triethylamine in dichloromethane. 

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