Preparation of Organomercury Compounds

[100-56-1] C6H5ClHg (MW 313.15)





InChI = 1S/C6H5.ClH.Hg/c1-2-4-6-5-3-1;;/h1-5H;1H;/q;;+1/p-1



InChIKey = AWGTVRDHKJQFAX-UHFFFAOYSA-M



(phenylating agent for allylic halides3 and alkenes;4-8 converts primary and secondary allylic alcohols into 3-phenyl alcohols and 3-phenyl aldehydes;9 reacts with carbon monoxide to give ketone10-13)



Physical Data: mp 250–252 °C. 1H NMR:16, 17 δ (DMSO, ppm) Ho 7.46 (3JHo–Hg = +203 Hz); Hm 7.37 (4JHm–Hg = +49 Hz); Hp 7.46. 13C NMR:18, 19 δ (DMF + (CD3)2CO (20%) at 340 K (ppm)) Cα 150.5, (1JHg–C = 2530 Hz), Cβ 136.4 (2JHg–C = 117 Hz); Cγ 128.0 (3JHg–C = 205 Hz); Cδ 127.9 (4JHg–C = 35 Hz). 199Hg NMR:18 (CH2Cl2) −1192, ((CD3)2SO) −1182 ppm. MS:20 mass of ions observed: C6H5HgCl+, C6H5Hg+, HgCl+. IR: ν(Hg–Cl) 331–332 cm−1.15



Solubility: sparingly sol H2O; sol C6H6, ether, pyridine; slightly sol hot ethanol.2



Form Supplied in: white satiny leaflets; stable in air; widely available.



Preparative Method: by mercuration of benzene21 with Mercury(II) Chloride (eq 1) or red Mercury(II) Oxide. 

(1)



Copper or Copper(I) Chloride22 promotes facile displacement of nitrogen from double salts of Benzenediazonium Chloride and mercury(II) chloride in good yield (eq 2). 

(2)



Phenylmercury(II) chloride can also be prepared by the Peters reaction23 involving mercury(II) chloride and sulfinic acid (eq 3), by the decomposition of the phenyl–tin bond in PhSn(alkyl)3 with mercury(II) chloride (eq 4),24 by mixing equimolar mercury(II) chloride and Diphenylmercury (eq 5),25 or by photolysis of diphenylmercury in CCl4 (eq 6).26

(3)

(4)

(5)

(6)



In PhHgCl the PhHg bond is less polar than the HgCl bond. The PhHg bond is weak and undergoes homolytic cleavage.



Handling, Storage, and Precautions: highly toxic irritant; LD50 orally in rats 60 mg kg−1. Use in a fume hood.

Phenylmercury(II) Chloride

1.

The reaction of acetaldehyde, acetone, methylethyl ketone and butyrone hydrazones with mercuric acetate p rovides a method of preparation of some new types of organomercury compounds.




2.

This reaction is of the “conjugated addition” type with the medium taking part. In water, α,α′-dimercurated or α,α′,ββ′-tetramercurated ethers are formed, in methanol-α-mercurated or α,β-dimercurated alkylmethyl ethers, and finally in absolute benzene — a-mercurated or α,β-dimercurated alkyl acetates.




3.

The chemical properties of the organomercury compounds obtained have been studied and it was shown that: a) the dimercurated compounds of types (IV–VI) decompose on heating with concentrated hydrochloric acid with liberation of mercurous chloride and formation of the corresponding carbonyl compound; b) bromination of dimercurated compounds of types (IV–VI) with bromine and saturated aqueous potassium bromide solution in the cold leads to the formation of the corresponding α-bromoketone in addition to the ketone; c) the monomercurated compounds of types (I-III) decompose in concentrated alkali in the cold with liberation of metallic mercury and formation of the corresponding carbonyl compound.

Synthesis of organomercury compounds from hydrazones Communication 1. Reaction of hydrazones of aliphatic aldehydes and ketones with mercuric acetate

1.

The stereochemistry of the reactions of symmetrical, α-mercurated L-menthyl phenylacetate and mercuribis-α,α′-camphor with mercuric bromide in acetone solution has been studied. Both reactions are examples of electrophilic substitution at a saturated carbon atom.




2.

It is shown that the first reaction proceeds with retention of configuration at the carbon atom in question. The racemization observed at 56° is a secondary process.




3.

It is not possible to elucidate the stereochemistry of the reaction between mercuribis-αα′-camphor and mercuric acetate because the 3-bromomercuricamphor formed racemizes even in the cold by the action of mercuric acetate under the experimental conditions.




4.

By a study of the reaction of the symmetrical, α-mercurated L-menthyl ester with an equimolar quantity of hydrogen bromide the conclusion, drawn previously [1], that the symmetrization of organomercury salts proceeds with retention of the configuration at the saturated carbon atom was confirmed.

A. N. Nesmeianov

Papers

Synthesis of organomercury compounds from hydrazones Communication 1. Reaction of hydrazones of aliphatic aldehydes and ketones with mercuric acetate

The problem of the stereochemistry of the reaction of symmetrical organomercury compounds with mercuric halides