Thallous ethoxide

The preparatively useful and simple N-alkylation procedure that utilizes a combination of carboxylic acid and sodium borohydride has been applied to carbazole giving an efficient 9-ethylation. Also of preparative importance is the use of thallous ethoxide as base in dimethylformamide-ether 9-methyl-, 9-ethyl-, n-propyl-, n-butyl-, benzyl-, and n-allylcarbazoles were efficiently produced, as well as 9,9 -dicarbazolylalkanes using C3, C4, and Cg dihalides. 2-Acetyl- and 2-vinylcarbazole were also efficiently 9-ethylated by this route. Another more recent approach to N-alkylation of carbazole utilizes potassium terf-butoxide in the presence of a catalytic quantity of 18-crown-6 9-methylcarbazole was prepared in high yield. ... 

There is no evidence for the existence of thallic hydroxide addition of hydroxide to an aqueous solution of a T1(III) salt gives TLO, instead. Thallous hydroxide can be isolated as yellow needles by the hydrolysis of thallous ethoxide [20398-06-5], which is conveniendy prepared as a heavy oil by the oxygen oxidation of thallium metal in ethanol vapor. Thallous hydroxide darkens at room temperature and decomposes to T O and H20 on warming. 

Hydroxydithiocinnamic acids (1) can be converted into the monosalt by treatment with tetra-n-butylammonium hydrogen sulfate and NaOCHj, which on alkylation gives the dithioesters (2) in high yield. Mercaptals (3) can be prepared in 70-88% yield by treatment of (2) with thallous ethoxide (2, 407 411) and an alkyl halide. 

Alkylation of N-heteroeycKc compoumb. Pyrrole can be N-alkylated sali ractorily by conversion to pyrrylthallium(I) by reaction with thallous ethoxide. This is a relatively stable solid the structure is uncertain. Reaction of this salt with an excess of an alkyl halide (or an alkyl tosylate) for 1-32 hr. at 20-60° gives N-alkylpyrroles in good yield. Alkylation of pyrrylmagnesium bromide gives isomeric 2- and 3-alkylpyrroles as the major products. 

Carbazole (I). phenothiazine (2), and (to a lesser extent) dibenz[6. /jazepine (3) can be N-alkylated in high yields under mild conditions in the following way. The heterocycle and a slight excess of thallous ethoxide dissolved in DMF ether are stirred at... 

N-Methylation of 2,3-dihydro-l,5-bcnzoxazcpin-4(5/f)-one (4) was achieved by treatment with thallous ethoxide followed by addition of methyl iodide.- However, in... 

To avoid using thallium, sodium 2-(dimethylamino)ethoxide may be used, although yields may be lower. The catalyst, thallous 2-(dimethylamino)ethoxide, is prepared by mixing thallous ethoxide (0.75 g, 3.0 mmol) with DMF (42 mL), DMAE (21 mL), and benzene (8mL), and distilling at 50°C under water aspirator vacuum until 10 mL distillate is obtained. This operation removes EtOH, which wUl yield stable ethyl esters if it is allowed to remain. Use an appropriate aliquot of this soln to catalyze the transesterification. To avoid using toxic thalhum, prepare the sodium salt in a similar fashion from sodium ethoxide (204 mg, 3.0 mmol).W... 

The reaction involving dichlorocarbene also provides a wide range of epoxides, " including terminal. a.a- and a,p-dialkyl-substituted and tiialkyl-substituted compounds, from a large variety of 3-hy-drcxyalkyl methyl and phenyl selenides (Scheme 162, d). The thallous ethoxide reaction, although it takes place more slowly (especially with phenylseleno derivatives) than under phase transfer catalysis condirions, " has to be in several instances preferred since it avoids the concomitant formation of... 

DABCO). 1,5-Diazabicy do [5,4,0 ] undec-ene-5 (DBU). Diethylamine. Ethylene-diamine. Lithio propylidene-f-buty limine. Lithium bis(trimethylsilyl)amide. Lithium f-butoxide. Lithium diethylamide. Lithium diisopropylamide. Lithium N-isopro-pylcyclohexylamide. Lithium orthophosphate. Lithium 2,2,6,6-tetramethylpiper-ide. Lithium triethylcarboxide. 1,2,2,6,6-Pentamethylpiperidine. Piperazine. Potassium f-butoxide. Potassium hexamethyldi-silaznae. Potassium hydride. Potassium hydroxide. Pyridine. 4-Pyrrolidopyridine. Quinuclidine. Sodium ethoxide. Sodium methoxide. Sodium thioethoxide. Tetra-methylguanidine. Thallous ethoxide. Tri-ethylamine. 

Krief et al. have shown that selenium ylides behave as their sulfur analogues and convert a variety of carbonyl compounds to oxiranes <89H(28)1203>. The latter compounds can be directly obtained by using R2Se=CHR /i-hydroxyalkylselenides (available from carbonyl compounds by addition of RSeCH2Li) may serve as suitable precursors as well, either in a two-step protocol, via the selenonium salt by alkylation with magic methyl (MeS03F), or directly by treatment with thallous ethoxide in chloroform. Oxidation of the /t-hydroxyalkylselenides with peracid, followed by treatment of the resulting selenone with base, results in oxirane formation (Scheme 60). 

Uses. Thallous ethoxide is soluble in most organic solvents, including heptane, and thus possesses the considerable advantage over sodium ethoxide of effecting homogeneous base-catalyzed reactions in nonpolar solvents. Thallous ethoxide converts most /3-dicarbonyl compounds into stable, crystalline, light-insensitive, colorless, 1 1 salts (2) which may be subsequently mono-C-alky lated in almost quantitative yield by heating with alkyl iodides.3 The salts are readily prepared by addition... 

Bases Alumina, see p-Toluenesulfonylhydrazine. Dehydroabietylamine. 1,5-Diazabicyclo [4.3.0]nonene-5. 1,4-Diazabicyclo[2.2.2]octane. l,S-Diazabicyclot5.4.0]undecene-5. 2,6-Di-/-butylpyridine. N,N,-Diethylglycine ethyl ester, see /-Amyl chloroformate. 2,6-Dimethyl-piperidine. Ethanolamine. Lithium diisopropylamide, see Diphenylsulfonium isopropylide. Lithium nitride. Magnesium methoxide. N-Methylmorpholine. Piperidine. Potassium amide. Potassium hydroxide. Potassium triethylmethoxide. Pyridine. Pyrrolidine. Sodium methoxide. Sodium 2-methyl-2-butoxide. Sodium thiophenoxide. Thallous ethoxide. Triethyla-mine. Triphenylphosphine, see l-Methyl-2-pyrrolidone. 

Carbene generation Alumina—Potassium hydroxide. Bis(tribromomethyl)mercury. Bis (trimethylsilyldichloromethyl)mercury. Bromotrifluoromethane. n-Butyllithium. Copper (II) acetylacetonate. Diazoacetaldehyde. Di-n-chloro-x-allyldipalladium. Dichloromethyl 2-chloroethyl ether. Dicyanodiazomethane. sym-Difluorotetrachloroacetone. Ethylene oxide. Methyl dichlorofluoroacetate. Methyllithium. Phenyl (trichloromethyl)mercury. Sodium chlorodifluoroacetate. Sodium trichloroacetate. Thallous ethoxide. / -Toluene-sulfonyl-hydrazine. 

Thallium triacetate, 406 Thallous carboxylates, 410 Thallous ethoxide, 407-411 Thebaine, 330, 331 Thiacyclohexane, 358 Thiazolidine-4-carboxylic acid, 27 Thiele reaction, 7-9, 12, 13 Thiepin-1,1-dioxide, 392 Thioanisole, 99, 311, 324 Thiocarbonates, 105, 106 N,N -Thiocarbonyldiimidazole, 411-412 Thiocyanogen, 105, 440 Thionyl chloride, 176, 395, 410, 412 Thiophenols, 173, 174 Thiophosgene, 412 Thiourea, 157, 412-413 Thymidine, 297, 298 Thymidine 5 -phosphate, 298 Thymine, 370 Tigonin, 136 Tin, 414... 

The 500-ml. boiling flask is charged with 350 ml. of ethanol and the reflux condenser is fitted with a drying tube filled with Ascarite (or soda lime) to exclude carbon dioxide, which reacts rapidly with thallous ethoxide. The ethanol is... 

The same workers have shown that a wide variety of acidic substrates form thallous salts by treatment with thallous ethoxide, and that these salts offer unique advantages either in yields, specificity of reactions, or convenience or simplicity in handling over alkali or other heavy-metal salts.4 Thallous salts of phenols, for example, are readily prepared in quantitative yield by the addition of thallous ethoxide to a solution of the phenol in benzene or ethanol. These salts are crystalline, sharp-melting, colorless... 

Thallous salts of carboxylic acids are also readily prepared in quantitative yield by addition of thallous ethoxide to a solution of the acid in ether or ethanol.5 Treatment of these crystalline, light-insensitive, sharp-melting stable salts with a stoichiometric amount of an acyl or aroyl chloride, followed by removal of thallous chloride by filtration and evaporation of solvent, affords crystalline carboxylic anhydrides in quantitative yield. This procedure, which employs stoichiometric amounts of both reactants and proceeds quantitatively at room temperature or below, appears to... 

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