Triethylamine Triphenylphosphine oxide

Indoxyls are normally prepared from anthranilic acids via alkylation with a haloacetic acid followed by a cyclising condensation with loss of carbon dioxide. " Indoxyl itself is best prepared by Friedel-Crafts type ring closure of iV-phenylglycine activated with triphenylphosphine oxide/triflic anhydride in the presence of triethylamine at room temperature. " ... 

Azetidines. Reaction of 7-amino alcohols with triphenylphosphine dibromide and then with triethylamine first at 0° and then at 25° results in formation of triphenylphosphine oxide and N-substituted azetidines. This method had been used previously to prepare aziridines from 3-amino alcohols (3, 322). 

The cychzation to the desired benzofurans of the thus formed phosphonium bromide with a variety of acid chlorides was performed under microwave irradiation at 110°C for two cycles of 30 min in toluene (Scheme 8.27) using triethylamine as the base. The solid-bound triphenylphosphine oxide was easily removed from the product by simple filtration of the resin. 

Dehydration of (3-nitro alcohols using DCC gives a mixture of E/Z nitroalkenes 48 The pure (E)-isomers are obtained on treatment with catalytic amounts of triethylamine or polymer-bound triphenylphosphine (TPP) (Eq. 3.28).51 When (Z) nitroalkenes are desired, the addition of PhSeNa to the E/Z mixture and protonation at -78 °C followed by oxidation with H202 gives (Z)-nitroalkenes (Eq. 3.29).52... 

The /V -hydroxylamino compounds (404) and (405), obtained from the reaction of tert-butyl acetate with 3,4-dihydroisoquinoline-A-oxide or 5,5-dimethyl-pyrroline-/V-oxide, when boiled in methylene chloride in the presence of triphenylphosphine, carbon tetrachloride and triethylamine, are transformed to (1,2,3,4- tetrahydroisoquinolin-l-ilidene) acetate (406) or (pyrrolidin-2-ilidene) acetate (407) (Scheme 2.181) (645). 

There are several methods reported in the literature for transforming vicinal diols into ct-diketones while avoiding the risk of C-C bond cleavage.26 Examples include the standard Swem conditions (dimethyl sulfoxide and oxalyl chloride followed by triethylamine), or the use of DMSO activated by acetic anhydride, pyridine-sulfur trioxide complex, or dicyclohexylcarbodiimide (Mq/J-att oxidation). Diones are also obtained by treatment with benzalacetone as a hydride acceptor in the presence of catalytic amounts of tris(triphenylphosphine)ruthenium dichlonde [(PPh RuCFl.27 Recent developments include the use of w-iodoxyben/.oic acid28 or the oxoammonium salt of 4-acctamidoletramethylpipcridine-1-oxyl and y -toluencNulfonic acid.29... 

Fascinating chemistry has been developed by Nakayama and Ishii on the first dithiiranes, which were prepared by oxidation of dithietanes and subsequent rearrangement. It was recently reviewed [82, 83]. Monodesulfurisa-tion of dithiiranes was achieved with triphenylphosphine or triethylamine to yield the corresponding thioketones [84-86]. 

Amino-5-chloromethyl-3-cyanopyrazine 1-oxide with triphenylphosphine in dimethylformamide at 80-90° gave 2-amino-3-cyano-5-(triphenylphosphonio)-methylpyrazine 1-oxide chloride (97) (520) and the 5-bromomethyl analogue reacted similarly with triphenylphosphine in propan-2-ol (542). Compound (97) on hydrolysis with 30% aqueous ethanol containing a small amount of triethylamine gave 2-amino-3-cyano-5-methylpyrazine 1-oxide and thus enabled removal of the chloro substituent from the chloromethylpyrazine (529) compound (97) with triethylamine and acetaldehyde (and other aldehydes) in chloroform at room temperature gave 2-amino-3-cyano-5-(prop-l -enyl)pyrazine 1-oxide (and other alkenyl analogues) (529). 

Fischer-type reaction of enhydrazine 74a with cyclohexanone in the presence of p-toluenesultonic acid afforded octahydrocarbazole 75 (R = Me), which can be oxidized with chloranil to tetrahydrocarbazole 76 (R = Me) (70CB1767). The carbazole 76 (R = H, Et) were obtained from the enamines 77 (R = H, Et) by photolysis in dioxane-acetonitrile containing triethylamine or by treatment with triphenylphosphine-palladium acetate complex (2 1) in DMF in the presence of NaHCCb... 

Oxazoles are prepared from tryptophan loaded Wang resin 53 (Scheme 9.7) The deprotected N-terminal was condensed with carboxylic acids 54 or carboxylic acid anhydrides 55 to give Af-acetyltryptophans 56. The key step involved oxidation of 56 with 2 equiv of DDQ (dichlorodicyanoquinone) in THF H20 (9 1) at room temperature for 15 min, producing the key intermediate 57. Compound 57 underwent cyclocondensation in the presence of triethylamine, CCLj, and triphenylphosphine in acetonitrile at room temperature for 2h to afford the oxazole 58. After cleavage from the resin with 20% TFA in DCM, esterification was carried out using TMS diazomethane to give the final product 59. 

The synthesis of ureas by reaction of ammonia or aliphatic primary and secondary amines with carbon monoxide at atmospheric pressure under selenium catalysis is noted. The intermediate salt can be oxidized to the sym-urea, or an exchange can be effected with a second amine, leading to unsym-ureas, as shown in Scheme 34. Ureas are readily dehydrated to carbodi-imides by the triphenylphosphine-carbon tetrachloride-triethylamine combination... 

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