Triethylamine compound, with

Formation of a vinyl-substituted pyrrolizidine derivative is also observed in case of an allylstan-nane cyclization94. Since the allylstannane moiety is acid sensitive, the iV-acyliminium ion is generated by exposure of the hydroxylactam to methanesulfonyl chloride and triethylamine in dichloromethane. The very rapid cyclization produces the endo-vinyl compound with very high stereoselectivity. 

An example of a completely stereoselective cyclization of an allylsilane, leading to a seven-mem-bered ring in excellent yield, is known158. Treatment of the hydroxy compound with methanesulfonyl chloride and triethylamine in acetonitrile gives a single isomer of the bicyclic compound via cyclization of the (T )-iminium ion. 

A general method for nitrone formation is based on the interaction of nitro compounds with carbanions. Interaction between nitroso compounds (175) and anions of aliphatic nitro compounds (178) leads to nitrones (179). The source of anions are metal salts of nitro compounds, triethylamines, and trimethylsilylni-tronates (Scheme 2.63) (334, 335). 

When 5-phenyl-l,2,4-triazole-3-thiol 437 reacts with bis-hydrazonoyl chloride, in ethanol in the presence of sodium ethoxide (or in refluxing choloroform in the presence of triethylamine), compound 47 is obtained (Equation 95) <2002MI7>. 

Reacting this with thiourea in the classic scheme of thiazole synthesis by reacting of a-halogencarbonyl compounds with thioamides forms the ethyl ester of (Z)-2-(2-aminoth-iazole-4-yl)-2-hydroxyminoacetic acid (32.1.2.74). The amino group in this molecule is protected by a reaction with triphenylchloromethane in dimethylformamide in the presence of triethylamine, which gives the ethyl ester of (Z)-2-(2-tritylaminothiazole-4-yl)-... 

The conclusion of the unsupervised PCA analysis was that there was enough selectivity to distinguish between compounds based on functional groups. However, it was unclear whether the se array could distinguish between compounds with the same chemical functionaltty. SIMCA models for 2 of the 10 compounds, triethylamine (TEA) and methylethylketone (MEK), are constructed and validated against the entire data set containing all 10 classes of compounds. 

The nucleus of the one-time widely prescribed prescribed COX-2 inhibitor, rofecoxib, better known by its trade name Vioxx , actually comprises a butenolide rather than a classical heterocycle. The drug was withdrawn from the market at full flood due to an unexpectedly high incidence of adverse cardiovascular side effects. The compound is included at this point to emphasize the breadth of the SAR for COX-2 anti-inflammatory agents. Reaction of phenylacetic acid (35-1) with ethyl bro-moacetate in the presence of triethylamine leads to the formation of the ester (35-2). Treatment of that intermediate with a strong base generates a carbanion at the benzyhc position in an intramolecular reaction, this attacks the terminal ester carbonyl to yield the butenolide (35-3). Reaction of that compound with triflic anhydride converts the... 

Dichloro-5-fluoropyrimidine (238) reacts with 3-aminopropanol in the presence of triethylamine to give the intermediate hydroxypropylamino substituted pyrimidine (239). Reaction of this compound with thionyl chloride results in the desired ring closure to the product (240), which is isolated as the hydrochloride salt (65USP3320256). 

Dehydrohalogenations at two adjacent carbon atoms lead to compounds with C = CorCsC bonds and arc an important route to fluorinated alkencs and alkynes. Some dehydrohalogenations occur spontaneously, others require elevated temperatures, and the majority occur in a basic medium which takes up the eliminated hydrogen halide.1 4 In addition to aqueous or alcoholic alkalis, organic bases such as triethylamine are often used for this purpose. 

A facile method for the preparation of a variety of stabilized arsonium ylides in good yield has been developed by the action of active methylene compounds with tertiary arsine oxide or tertiary arsine dihalide. Thus triphenyl-arsine dihalides react with a number of active methylene compounds in the presence of a tertiary amine to afford arsonium ylides (6) (40). The reaction of triphenylarsine oxide with active methylene compounds in the presence of either acetic anhydride or triethylamine-phos-phorus pentoxide gave rise to arsonium ylides (6) (32, 36. 65, 67). 

The ring closure of amino alcohols with C02 to yield cyclic carbamates, was achieved under mild conditions (atmospheric pressure of C02, room temperature), in acetonitrile as solvent and in the presence of triethylamine as the base, using more easily available reactants, such as P(III)-derivatives (Ph3P, (PhO)3P, n-Bu3P, (MeO)3P) and haloalkanes (CC14, CC13CC13) [76]. According to the proposed mechanism, the active species is a phosphonium adduct of the used P(III)-compound with the haloalkane, which activates the intermediate carbamate formed from amino alcohol and C02 at the carbamic moiety to produce a transient species which cyclizes to the final product (Scheme 6.12). 

Silyl enol ethers, Reaction of carbonyl compounds with in situ generated BrSi(CH3)3 and triethylamine results mainly in the thermodynamic silyl ether, usually the (Z)-isomer. 

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