Thallium!I ethoxide

A mild and effective method for obtaining N- acyl- and N- alkyl-pyrroles and -indoles is to carry out these reactions under phase-transfer conditions (80JOC3172). For example, A-benzenesulfonylpyrrole is best prepared from pyrrole under phase-transfer conditions rather than by intermediate generation of the potassium salt (81TL4901). In this case the softer nature of the tetraalkylammonium cation facilitates reaction on nitrogen. The thallium salts of indoles prepared by reaction with thallium(I) ethoxide, a benzene-soluble liquid. 

When the reaction is run with potassium fert-butoxide in THF at -5°C, one obtains (after hydrolysis) the normal Knoevenagel product (32), except that the isocyano group has been hydrated (16-65). With the same base but with DME as solvent the product is the nitrile (33). When the ketone is treated with 31 and thallium(I) ethoxide in a 4 1 mixture of absolute ethanol and DME at room temperature, the product is a 4-ethoxy-2-oxazoline (34). Since 33 can be hydrolyzed to a carboxylic acid and 34 to an a-hydroxy aldehyde, this versatile reaction provides a means for achieving the conversion of RCOR to RCHR COOH, RCHR CN, or RCR (OH)CHO. The conversions to RCHR COOH and to RCHR CN have also been carried out with certain aldehydes (R = H). 

The present procedure offers a convenient alternative to the Prevost reaction and the Woodward modification of the Prevost reaction in which silver carboxylates are used instead of thal-lium(I) carboxylates. Thallium(I) salts have the advantages of being generally stable crystalline solids that can be readily prepared in high yield by neutralization of the appropriate carboxylic acid with thallium(I) ethoxide. Silver salts, on the other hand, are frequently unstable and difficult to dry. Thallium and its compounds are, however, extremely toxic, and great care must therefore be taken in the use and disposal of thallium salts. ... 

Thallium(I) ethoxide has been known for many years, and a series of related alkoxides can be prepared by methods which include Tl + ROH, TIOH + ROH and T120 + ROH.295 The ethoxide,296 and a number of other TIOR compounds,297 are tetrameric in solution, and an X-ray crystallographic study of (T10Me)4 shows that the structure is based on that of cubane,298 with no T1—T1 bonding interactions. The bonding in such molecules has been discussed.299 Phenoxide, and substituted phenoxides, can be prepared from PhOH + TlOH, while reaction... 

Halide complexes of this group react with carbanions to form stable alkylmetalloporphyrins.27 The thallium atom is significantly displaced (0.98 A) from the N4 plane with a large T1—N,, distance (2.29 A) in Tl(TPP)Me, formed by the reaction of H2TPP and MeTl(OCOMe)2 (Scheme 5). Monovalent thallium porphyrin complexes are also known.17 They can be prepared by treating a porphyrin with thallium(I) ethoxide in THF.29 Unlike the other Group IIIB metalloporphyrins, [Tl i Por) is easily hydrolyzed. 

A. Thallium T) 2-methylpropane-2-thiolate. A 500-mL, round-bottomed flask equipped with a magnetic stirring bar and a pressure-equalizing dropping funnel to which a nitrogen inlet adapter is attached is charged with 47.2 g (0.189 mol) of thallium(I) ethoxide (Note 1) and 200 mL of anhydrous benzene (Note 2). Over a period of 15 min 19.2 g (24 mL, 0.213 mol) of 2-methylpropane-2-thiol (Note 1) is added. The... 

Thallium(I) ethoxide Ethanol, thallium (1 +) salt (8, 9) (20398-06-5) 2-Methylpropane-2-thiol 2-Propanethiol, 2-methyl- (8, 9) (75-66-1) S-ferf-Butyl cyclohexylmethanethioate Cyclohexanecarbothioic acid, S-(1,1 -dimethylethyl) ester (9) (54829-37-7)... 

Thallium(I) ethoxide and 2-methylpropane-2-thiol were purchased from Aldrich Chemical Company, Inc. 

Ethanol (4 ml.) is added to 4.4 g. (0.02 mol) of thallium (I) hydroxide in a 50-ml. beaker, and the mixture is stirred until nearly all the yellow solid disappears. To dissolve the thallium (I) ethoxide selectively, 20 ml. of benzene is added. After decanting, the extraction is repeated to increase the yield of ethoxide. The clear, filtered solution of ethoxide is added to a solution of 3.24 g. (0.02 mol) benzoylacetone (l-phenyl-l,3-butanedione) in 20 ml. of benzene. The impure thallium (I) benzoylacetonate is collected by evaporating the solvent under reduced pressure. Purification is accomplished by dissolving the impure product in 25 ml. of benzene and reprecipitating with an equal volume of petroleum ether (b.p. 90 to 110°). (The checkers report that it was necessary to scratch the flask to induce crystallization.)... 

The case of p-hydroxy-y-alkenyl selenides merits further comments. The rearrangement efficiently takes place using the thallium(I) ethoxide method and the presence of an additional double bond in the reactant does not introduce a serious problem associated with unwanted reaction with the dichlorocarbene intermediate. This is not the case when silver tetrafluoroborate is used. 

Thallium(I) acetate Acetic acid, thallium salt (8, 9) (15843-14-8) Acetic acid, thallium (H-) salt (8,9) (563-68-8) 1,2-Cyclohexanediol diacetate, trans- (8,9) (1759-71-3) Thallium(I) ethoxide Ethyl alcohol, thallium (1+) salt (8) Ethanol, thallium (1+) salt (9) (20398-06-5)... 

Reaction of acyl or aroyl halides with thallium(I) phenyl selenide, prepared by the reaction of either thallium(I) ethoxide or thdlium(I) phenoxide with benzeneselenol, gave the corresponding phenyl sele-nol esters in yields over 97% (equation 3). ... 

Nitrosolysis of camphor ethyl acetal with ethanolic ethyl nitrite in sulphur dioxide yields the orthoester oxime (205) which is rapidly dehydrated by excess acetal to the orthoester nitrile which then reacts with sulphur dioxide to form the ester nitrile and diethyl sulphite.Further papers in this section include the full paper on ozonolysis of silyl ethers (Vol. 5, p. 33), another synthesis of camphor-enol trimethylsilyl ether (cf. Vol. 6, p. 41)/°° the conversion of camphor oxime with Grignard reagents into the corresponding imine with no aziridine formation/° the preparation of (206) by treating bornylene with trichloroacetyl isocyanate/ the oxidation of thiocam-phor to the 5-oxide and alkylation in the presence of thallium(i) ethoxide to a/S-unsaturated sulphoxides/ and the free-radical C-3 alkylation of camphor with alkenes. " ... 

ETHERS m-Chloroperbenzoic acid. Thallium(I) ethoxide. Triethylsilane-Boron trifluoride. 

The treatment of the readily available model cyclopenteno coumarin (d)55) with silver (I) oxide/sodium hydroxide, of thallium (I) ethoxide/hydrogen peroxide, gave fair to good yields of the desired Q, analog (115). [Exhaustive hydrogenolysis of (115), prepared by either method, proceeded by absorption of three equivalents of... 

Alkylation of cyclic 1,3-diketones. The reaction of cyclic 1,3-diketones with thallium(I) ethoxide, thallium(l) carbonate, or thallium(l) cyclopentadienide gives colorless, crystalline thallium(l) salts (2,408). These salts can be alkylated in nonpolar solvents (benzene, DME) to give products of O-alkylation in high yield, as illustrated... 

Michael addition has been applied to the formation of cyclopropanic systems. Thus, the addition of phosphonate carbanions generated by LDA in THF, by NaH in THF, by thallium(I) ethoxide in refluxing THF, or by electrochemical technique to oc,P-unsaturated esters provides a preparation of substituted 2-(alkoxycarbonyl)cyclopropylphosphonates in moderate to good yields via a tandem Michael addition-cyclization sequence (Scheme 8.47). The cyclopropanation has also been achieved via oxidation with iodine in the presence of KF-AI2O3. Nitrile ylides prepared from acyl chlorides and diethyl isocyanomethylphosphonate in the presence of Et3N react with methyl acrylates by a 1,3-dipolar cycloaddition to give phosphoryl pyrrolines or pyrroles. ... 

A route to alkynylarenes and enynes from 1-alkynes involves formation of alkynylboronic esters [lithioalkynes -I- (/-PrOl B] and Suzuki coupling in situ. Suzuki cross-coupling using thallium(I) ethoxide as promoter is superior to TlOH because of its stability, commercial availability, and ease of use. A convenient method for assembling conjugated polyenes is assured. 

N-Alkyl-N-triflylarylsulfonimides. N-Alkylarylsulfonamides (1) react with thallium(I) ethoxide in benzene at 25° (N2) to form the stable thalhum(I) compounds (2) in high yield. Treatment of (2) with triflic anhydride leads to (3). 

ETHERS Antimony(V) fluoride. Hexamethylphosphorus triamide. Tetra-n-butyl hydrogen sulfate. Thallium(I) ethoxide. Triphenylphosphine-Diethyl azodicarboxylate. ETHYL KETONES Sodium tetracarbonylferratefll). 

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