A convenient method to recover the solvent from halogen-CCl4 mixtures

Sabol, Joseph E.; Kurtz, David W.

doi:10.1021/ed067p532

Cited by 4 publications

(3 citation statements)

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“…We observed that compounds 4a − e undergo decomposition in the presence of tributyltin hydride if the mixture is allowed to stay at room temperature; the longer the contact time, the lower the yields obtained. Formation of the tributyltin hydride was avoided by treating the crude product with an aqueous solution of sodium thiosulfate. 17j, In this case, the excess iodine and compounds 9a − e were reduced completely while the tributyltin iodide remains intact, which by treatment with potassium fluoride was transformed into the tributyltin fluoride that is insoluble and was retained on top of the column chromatography.…”

Section: Resultsmentioning

confidence: 99%

Hydrozirconation of Stannylacetylenes. Synthesis and Reactions of Ketene Stannyl(Telluro) Acetals

Dabdoub

Baroni

1999

J. Org. Chem.

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Stannylacetylenes 7a-e react with Cp(2)Zr(H)Cl in THF at room temperature to give the alpha-zirconated vinylstannane intermediates 8a-e, which subsequently react with butyltellurenyl bromide (2.0 equiv) to give exclusively ketene stannyl(telluro) acetals 6a-e of E configuration. Similar reactions were performed using phenylselenenyl bromide (2.0 equiv) as the electrophile, but a mixture of products was formed including the expected ketene stannyl(seleno) acetals 12. Otherwise, the use of 1.4 equiv of Cp(2)Zr(H)Cl and 1.0 equiv of PhSeBr results in the exclusive formation of 12, in good yields. Treatment of ketene stannyl(telluro) acetals with iodine or NBS followed by reductive dehalogenation results in the formation of 1-iodo-1-telluroalkenes 4a-e and 1-bromo-1-telluroalkenes 5a-e, respectively, with total retention of the configuration.

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Section: Resultsmentioning

confidence: 99%

Hydrozirconation of Stannylacetylenes. Synthesis and Reactions of Ketene Stannyl(Telluro) Acetals

Dabdoub

Baroni

1999

J. Org. Chem.

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“…For 5f , the minor steric hindrance permits the formation of 9a as the major product (45% yield, Table , entry 8). However, when the organics were washed with aqueous sodium borohydride to remove excess iodine, yields of 7 were very good in most cases (entries 1−4 and 6; Table ), since very efficient transformation of 9 to 7 was also promoted (Figure ). After treatment with NaBH 4 , the crude reaction products were routinely analyzed by 1 H NMR and CG/MS.…”

Section: Resultsmentioning

confidence: 99%

Iodocyclization of (Z)-1-(Butyltelluro)-1,4-diorganylbut-1-en-3-ynes. Synthesis and Reactions of 3-Iodotellurophenes

Dabdoub

Pereira

et al. 1996

J. Org. Chem.

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The iodocyclization of (Z)-tellurobutenynes 5a − g by reaction with I2/petroleum ether was studied in detail. 3-Iodotellurophenes 7a − f were formed, and optimum conditions to obtain these compounds in high yields were established. The reaction involves attack of iodide at the initially formed intermediate of type 10 followed by ring closure that is favored by the strong aromatic character of the resulting products. Two possible and alternative pathways for the ring closure are proposed to explain our observations: (a) transformation of 10 to 11 that undergoes further cyclization to give 7a − f (pathway a) or (b) direct cyclization of 10 to give tellurophene diiodide 9 (pathway b). The products and side products obtained are in agreement with the proposed mechanisms. Formation of 7a from ditelluride 14 and iodine provides additional evidence of the intermediacy of 11 (in pathway a). Structures of 7a and 5g were elucidated by X-ray crystallography. In the case of compound 5e, where a terminal triple bond was present, the resulting intermediate of type 10 also underwent the attack of iodide directly at the terminal carbon to give compound 12 together with 7e. Ring-opening of 3-iodotellurophene 7a occurs by reaction with n-butyllithium to form acyclic ditelluride 14 or monotelluride 16 depending on the alkyllithium amounts employed. Plausible mechanisms for these novel reactions are proposed and supported. Conversion of 7a to 3-(butyltelluro)-2,5-diphenyltellurophene (22) was carried out readily by an unusual “aromatic nucleophilic substitution” using the butyl tellurolate anion.

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“…Concern about the volume of halogenated solvent generated in this experiment recently led Sabol and Kurtz (6) to describe a method of recovering these solvents. At Purdue we have taken a different approach to reducing the threat to the safety of both individual students and the environment from exposure to the halogenated solvents used in this experiment.…”

Section: Safetymentioning

confidence: 99%

An alternative to halogenated solvents for halogen/halide extractions

Petrovic¹,

Bodner²

1991

J. Chem. Educ.

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A convenient method to recover the solvent from halogen-CCl4 mixtures

Abstract: An alternative to disposal and distillation which is easy to perform, allowing the solvent to be recovered and stored within one hour after the completion of the experiment is presented here.

Cited by 4 publications

References 0 publications

Hydrozirconation of Stannylacetylenes. Synthesis and Reactions of Ketene Stannyl(Telluro) Acetals

Hydrozirconation of Stannylacetylenes. Synthesis and Reactions of Ketene Stannyl(Telluro) Acetals

Iodocyclization of (Z)-1-(Butyltelluro)-1,4-diorganylbut-1-en-3-ynes. Synthesis and Reactions of 3-Iodotellurophenes

An alternative to halogenated solvents for halogen/halide extractions

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