Giving Halides

Pi peridinobenzimidazole also serves as starting material for the antipsychotic agent halopemide (69). In the absence of a specific reference, one may speculate that the first step involves alkylation with bromochloro-ethane to give halide The chlorine may then be converted to the primary amine by any of several methods such as reaction with phthalimide anion followed by hydrazinolysis. Acylation with j -fluorobenzoyl chloride then gives the desired product. 

Therefore the attack by I ion breaks O-CHg bond to form CH 3I. Phenols do not react further to give halides because the sjf hybridised carbon of phenol cannot undergo nucleophlfic substitution reaction needed for conversion to the halide. 

The procedure described here is general for the oxidation of primary and secondary alcohols to carbonyl compounds,3 but not for allylic and dibenzylic alcohols, which give halides in high yields.4 The yields of carbonyl compounds are usually high, and the... 

Ketene Insertions. Ketenes insert into strongly polarized or polarizable single bonds, such as reactive carbon-halogen bonds, giving acid halides (7) and into active acid halides giving halides of P-ketoacids (8) (46). Phosgene [77 14-5] (47) and thiophosgene [463-71-8] (48) also react with ketenes. 

Phosphorylated ketenes add halogens to give halides of phosphorylated halogenoacetic acids. 

Halogens attack phosphine vigorously giving halides of hydrogen and usually of phosphorus as well. These reactions were early investigated by Thomson, Balard and Hofmann.9-10-11 The action of sulphur was also investigated by Davy 12 and Dalton.18- 14-1B... 

Cobalt(II) compounds react with an alkyl halide to give an organocobalt(III) compound, as shown in equation (32), where Y is an axial ligand. It takes place by three separate mechanisms, depending on the nature of the Co compound and the alkyl halide. The best known pathway involves the atom-transfer reactions shown in equations (33) and (34). The second mechanism involves electron transfer from the Co compound to the alkyl halide, which decomposes to give halide and organic radicals, which react with the Co compound. The third mechanism has been observed for the alkylation of vitamin B jr by alkyl iodides. 

Internal metallation is easier for X = I > Br > Cl and for tertiary phosphines than arsines ". The Pd analogs give halide-bridged dimeric compounds . 

More recently it was found that methyl sulfide-iV-chlorosuccin-imide in toluene at 0°C gives good yields of ketones by the oxidation of primary and secondary alcohols. However, allylic and dibenzylic alcohols give halides. The latter alcohols can be oxidized to ketones with a dimethyl sulfoxide-chlorine reagent. 

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