Chlorination by sulfuryl chloride

Catalyst, alumina, 34, 79 35, 73 ammonium acetate, 31, 25, 27 copper chromite, 31, 32 36, 12 cuprous oxide-silver oxide, 36, 36, 37 ferric nitrate, hydrated, 31, 53 piperidine, 31, 35 piperidine acetate, 31, 57 Raney nickel, 36, 21 sulfuric acid, 34, 26 Catechol, 33, 74 Cetylmalonic acid, 34, 16 Cetylmalonic ester, 34,13 Chlorination, by sulfuryl chloride, 33, 45 ... 

Indole, like benzothiophene, reacts with electrophiles to give preferentially -substituted products. Bromination241-243 in dioxane or pyridine, nitration by ethyl nitrate,244 chlorination by sulfuryl chloride,245 iodination in aqueous solution,246, 247 Vilsmeier and Reimer-Tiemann formylations,248-261 diazo coupling,252 thio-cyanation,263 and nitrosation254 all give the 3-substituted indoles, practically free from other isomers. 

Chlorination by sulfuryl chloride occurs at position 3 for l-oxa-6,6aA4-dithiapentalenes (71AHC(13)161, p. 181). Bromination of l,6-dioxa-6aA4-thiapentalene occurs readily and leads to the 3,4-dibromo derivative. With the same compound, iodine and silver acetate give the 3-iodo and the 3,4-diiodo derivatives (72CC1283). 

Ionic chlorination of alkanes.6 Alkanes are readily chlorinated by sulfuryl chloride in sulfolane (I, 1144-1145 2, 402-403). Thus adamantane (1) is converted almost exclusively into 1-chloroadamantane (2). Norbomane is converted under these conditions exclusively into 2-cxo-chloronorbornanc. -Hexane is converted into 1-chloro-hexane (20%), 2-chlorohexane (56%), and 3-chlorohexane (24%). The chlorination proceeds by an ionic mechanism. 

The only acid-resistant protective group for carbonyl functions is the dicyanomethy-lene group formed by Knoevenagel condensation with malononitrile. Friedel-Crafts acylation conditions, treatment with hot mineral acids, and chlorination with sulfuryl chloride do not affect this group. They have, however, to be cleaved by rather drastic treatment with concentrated alkaline solutions (J.B. Basttis, 1963 H. Fischer, 1932 R.B. Woodward, 1960, 1961). 

Dichlorophenols. Among all the dichlorophenols, C H Cl O, it is 2,4-dichlorophenol that is produced in greatest quantity. 2,4-Dichlorophenol is used in manufacturing 2,4-dichlorophenoxyacetic acid [94-75-7] (2,4-D) and 2-(2,4-dichlorophenoxy)propionic acid [720-36-5] (2,4-DP). Industrially, 2,4-dichlorophenol can be obtained by chlorinating phenol, -chlorophenol, o-chlorophenol, or a mixture of these compounds in cast-iron reactors. The chlorinating agent may be chlorine or sulfuryl chloride in combination with a Lewis acid. For example ... 

Sufficient activation was present in 5-ethylamino-2-oxoimidazolo [4,5-6]pyrazine (173) for it to be halogenated in the 6-position by chlorine and bromine in acetic acid or by sulfuryl chloride (69FRP1578366 71BRP1248146). The 2-oxo group could be replaced by chlorine (75KFZ10 76KFZ35). 

Kojic acid was brominated at position 6 with bromine water4 the 2-(chloromethyl) derivative of kojic acid was brominated with N-bromo-succinimide,87 and chlorinated with sulfuryl chloride and aluminum chloride,88 in both cases probably at C6. The C-benzoylation89 and C-acetylation90 of kojic acid, likewise at C6, was accomplished by Woods using a modification of the Friedel-Crafts reaction. The 2-carboxyethyl side chain was introduced at C6 in a reaction with 2-bromopropionic acid.91... 

Similarly, when the selective O-pivaloylation of trehalose was investigated by Richardson, Hough, and Cortes-Garcia, a number of useful derivatives were also obtained in quantities adequate to be of preparative value. Thus when 12 equivalents of pivaloyl chloride were employed for this esterification at — 20 °C, and the reactants were thereafter stored at room temperature for three days, a 61% yield of the 2,2 3,3, 4, 6,6 -heptapivalate was obtained, and following invertive chlorination with sulfuryl chloride, a displacement with different nucleophiles gave access to C-4-modified trehaloses, one example of which is shown in Scheme 17. 

Alkylsulfenyl chlorides.2 Sulfenyl chlorides are usually prepared by reaction of thiols with chlorine or sulfuryl chloride. NCS can also be used. NBS can be used to obtain sulfenyl bromides, but these substances are extremely sensitive to heat. 

Explain why the product distribution in the chlorination of propane by sulfuryl chloride is expected to differ according to whether the hydrogen-abstraction step is accomplished by Cl- or -S02CI. 

Taft reported the conversion of chloropyrazine into 2,6-dichloro-pyrazine by chlorination with sulfuryl chloride or liquid chlorine.274 This reaction is conveniently carried out in the laboratory by heating 2-chloropyrazine and sulfuryl chloride in a sealed tube at 120° for 3 hours. More recently 2,6-dichloropyrazine has been prepared in 90% yield from chloropyrazine by reaction with chlorine in dimethyl-formamide at 70°-75° 2,3-dichloropyrazine is obtained in 84% yield... 

Addition of Ph SeCl to terminal olefins, followed by chlorination with sulfuryl chloride and hydrolysis, leads to 2-chloro-l-alkenes (equation 143)952. 

The chlorination of alkyl aromatics by sulfuryl chloride promoted by free-radical initiators, which was originally discovered by Kharasch and Brown990, can be modified by incorporation of transition metal complexes. Matsumoto and coworkers have observed that, upon addition of Pd(PPh3)4, in place of a radical initiator, the side-chain monochlorination of toluene is substantially more selective991. Davis and his colleagues992 have extended this study and report that Pt(0) and Pd(0) are effective initiators for side-chain chlorination of toluene by sulfuryl chloride and dichlorine. Mn, Re, Mo and Fe complexes, on the other hand, behave more like Friedel-Crafts catalysts. Gas-phase chlorination of olefins to allyl chlorides is catalyzed by PdCl2 or by PtCl2993. 

Of all the methods described for the synthesis of thiazole compounds, the most efficient involves the condensation of equimolar quantities of thiourea and a-halo ketones or aldehydes to yield the corresponding 2-aminothiazoles (Scheme 167) (l888LA(249)3l). The reaction occurs more readily than that of thioamides and can be carried out in aqueous or alcoholic solution, even in a distinctly acid medium, an advantage not shared by thioamides which are often unstable in acids. The yields are usually excellent. A derived method condenses the thiourea (2 mol) with the non-halogenated methylene ketone (1 mol) in the presence of iodine (1 mol) or another oxidizing agent (chlorine, bromine, sulfuryl chloride, chlorosulfonic acid or sulfur monochloride) (Scheme 168) (45JA2242). 

Further studies of electrophilic substitution using the 2,3-dihydrothiazolo analogue (320) show that regioselective bromination can be effected in the 7-position (347) at low temperature. Chlorination with sulfuryl chloride, however, occurs exclusively in the 5-position. The 5-chloro derivative (348) can be further nitrated in the 7-position. By analogy, bromination of quinoline analogues (349) occurs in the azine ring, in the 5-position. The [3,2-a]pyrimidine analogue (350 R=H) similarly yields the 7-bromide. The activation by... 

A number of halogen compounds are capable of oxidizing sulfoxides to sulfones, although synthetically useful procedures are rather limited. Chlorine and sulfuryl chloride oxidize sulfoxides to sulfones in aqueous solvents, but the oxidation is often accompanied by many side reactions as shown in equations... 

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