Chlorine thiol group reaction

In one synthesis of this drug, L-proline (11-2) is acylated with the acid chloride (11-1) obtained from the addition of hydrogen chloride to the double bond in methacrylic acid followed by reaction with thionyl chloride to give amide (11-3) as a mixture of diastereomers. The pure 2S isomer is then isolated from the mixture by fractionation as the dicyclohexylamine salt. Treatment of that compound with ammonium hydrosulfide leads to the displacement of chlorine by a thiol group and the formation of captopril (11-4) [13]. 

Reductive oxidation of />-nitrotoluene to -aminobenzaldehyde, 31, 6 Reformatsky reaction, 37, 38 Reissert s compound, 38, 58 Reissert reaction, 38, 58 Replacement, benzenesulfonate groups by bromine atoms, 31, 82 bromine, by a thiol group, 30, 35 by fluorine, 36, 40 chlorine, by an amino group, 31,45 by a thiol group, 32, 101 by iodine, 30, 11 by methoxyl, 32, 79 by nitrile, 36, 50 in an imido-chloride group by an anilino group, 31, 48 chlorine and nitro by ethoxyl radicals, 32,68... 

Sulfur-containing pyrimidines are frequent intermediates in substitution reactions. Several methods exist for exchange of the thiol group with hydrogen, either by hydrogenolysis, especially by the use of Raney Nickel, or by oxidative desulfurization which involves a sulfinic acid intermediate. Oxidation may also lead to a sulfonic acid. The 2- and 4-/6-thiones are considerably more stable to air oxidation than 5-thiol derivatives. Disulfides are conveniently formed by oxidation with bromine. Oxidation with chlorine at low temperature can be used to prepare sulfonyl chlorides. These reactions have been summarized [Pg.187]

Another remarkable reaction is the nucleophilic substitution of the chlorine by alkoxy or sulfido groups using the alcohol or the thiol and the weak base Na2C03 in situ. For example, in the case of ethanol, the reaction proceeds in 12 h at reflux Eq. (23), Table 3. 

Perfluorophenylsulfonyl chloride and its 4-substituted derivatives 5 are prepared from reaction of the thiols 4 with chlorine in acetic containing the amount of water calculated for formation of the sulfonyl group.287 The initially formed precipitate of disulfide is slowly dissolved, Surprisingly, in the case of the 4-acetamido derivative, the oxidation is accompanied with desulfuration. The use of hydrogen peroxide does not have a substantial influence on the desulfuration process.287... 

For example, polymers having hydroxyl end groups can be prepared by reaction of polymer lithium with epoxides, aldehydes, and ketones III-113). Carboxylated polymers result when living polymers are treated with carbon dioxide (///) or anhydrides (114). When sulfur (115, 116), cyclic sulfides (117), or disulfides (118) are added to lithium macromolecules, thiol-substituted polymers are produced. Chlorine-terminus polymers have reportedly been prepared from polymer lithium and chlorine (1/9). Although lithium polymers react with primary and secondary amines to produce unsubstituted polymers (120), tertiary amines can be introduced by use of p-(dimethylamino)benzaldehyde (121). 

The 5-position in 1,2,4-thiadiazoles is most reactive in nucleophilic substitution reactions. Chlorine, for example, may be displaced by nucleophiles (Nu) such as fluoride, hydroxide, thiol, amino, hydrazino, sulfite and azido groups (Scheme 11). Active methylene compounds such as malonic, acetoacetic and cyanoactic esters as their sodio derivatives also displace the 5-halo substituent (65AHC(5)ll9). The reaction follows second-order kinetics, the rate determining step being addition of the nucleophile at C-5 followed by rapid elimination of X. 

The mechanism works well if we attack the chlorine position ortho to the nitro group with the anion of the thiol nucleophile as the negative charge can then be pushed into the nitro group. Satisfy yourself that you cannot do this if you attack the other chlorine position. This is a very practical reaction and is used in the manufacture of a tranquillizing drug. 

Animals. Rapidly and completely metabolized, primarily by oxidative dealkylation of the amino groups and by reaction of chlorine atom with endogenous thiols. Diaminochlorotriazine is the main primary metabolite, which readily conjugates with glutathione. More than 50% of the dose is eliminated in the urine and around 33% in feces within 24 hr... 

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