Thionyl chloride complexes from

Dodecylbenzenesulfonyl chlorides have been prepared from the corresponding acids using chlorosulfonic acid,4 phosphorus oxychloride,2 and thionyl chloride.5 The use of catalytic amounts of DMF in conjunction with thionyl chloride is based on the work of H. Bosshard, et al. The insolubility of the DMF/thionyl chloride complex in the reaction solvent permits easy removal at the end of reaction. Extraction with dilute base removes the last trace of acids and the solution is pure enough for the next step. 

Also surprising is the conversion of nicotinic acid chloride hydrochloride into 5-bromonicotinic acid in 87 per cent yield, by heating with bromine at 150-170°. Direct chlorination was much less successfuP . This may be a direct electrophilic substitution, but the nicotinic acid chloride hydrochloride was prepared from nicotinic acid and thionyl chloride (see p. 322), and it is just possible that the reaction is related to the substitutions into pyridine-thionyl chloride complexes discussed below (p. 228). It might even be that nicotinic acid chloride hydrochloride is not a simple salt but possesses a structure like the pyridine-thionyl chloride complex. 

Direct halogenation of sucrose has also been achieved using a combination of DMF—methanesulfonyl chloride (88), sulfuryl chloride—pyridine (89), carbon tetrachloride—triphenylphosphine—pyridine (90), and thionyl chloride—pyridine—1,1,2-trichloroethane (91). Treatment of sucrose with carbon tetrachloride—triphenylphosphine—pyridine at 70°C for 2 h gave 6,6 -dichloro-6,6 -dideoxysucrose in 92% yield. The greater reactivity of the 6 and 6 primary hydroxyl groups has been associated with a bulky halogenating complex formed from triphenylphosphine dihaUde ((CgH )2P=CX2) and pyridine (90). 

Introduction of the C2 sulfonamide is accomplished via sulfonylation with chlorosulfonic acid, conversion to the sulfonyl chloride using thionyl chloride, and amidation using concentrated ammonium hydroxide in tetrahydrofuran. Reduction of the 4-acetamido compound using borane-tetrahydrofuran complex provides the 4-ethylamino derivative. The 45,65-frans diastereomer is selectively crystallized as its maleate salt from acetone in the presence of the unwanted 4R,6S-cis diastereomer. Neutralization of the maleate salt and extraction of the free base in ethyl acetate, followed by formation of the hydrochloride salt, yields crude dorzolamide hydrochloride. 

The incorporation of complex side chains at the 7 position based on alkyloximes of 2-amino-thiazole-5-gyloxylamides has provided drugs with very wide antibacterial activity that extend to hitherto resistant species such as pseudomonas. The preparation of one of the simpler side chains involves, first, the formation of the methyl ether from the oxime obtained by the nitrosation of methyl acetoacetate. Chlorination of the product, for example with sulfuryl chloride, gives the intermediate (21-1). The aminothiazole ring is then formed by reaction of that with thiourea to give (21-2). The free acid (21-3) is obtained by saponification of the product. The protected acid chloride (21-5) is obtained by sequential acylation of the amino group with chloroacetyl chloride and then reaction with thionyl chloride. 

When nicotinic acid is heated for 8 hours at 180° with thionyl chloride, a low yield of 5-chloronicotiriic acid is obtained.182 The orientation observed in this case suggests an electrophilic attack, perhaps on a complexed nicotinic acid chloride molecule (which would thus behave somewhat like a pyridine A-oxide). If the reaction is carried out at 150° and the reaction time lengthened to 50 hours, a 30% yield of 5,6-dichloronicotinic acid is obtained.182 Both mechanistic pathways may be involved here. Isonicotinic acid reacts with thionyl chloride at 180-220°, presumably by, way of an electrophilic attack since 3-chloro-and 3,5-dichloroisonicotinic acid are formed.182 Nicotinoyl chloride (from nicotinic acid and thionyl chloride—probably in the complexed form) gives an 87% yield of 5-bromonicotinic acid on reaction with bromine for 10 hours at 150-1700.185... 

SO, S2O, and S2O2 are stabilized as ligands in metal complexes. The coordination chemistry of SO and S2O has been developed by preparations that involve formation of the ligand from suitable precmsor complexes. The most common method involves oxidation of a coordinated S ligand. The first example of an S2O complex was reported by Schmidt and Ritter and subsequently refined by Rauchfuss " (Figure 20), and extended to the corresponding S2O2 complex. A dinuclear complex of S2O has been isolated. SO complexes may also be obtained by the reaction of thionyl chloride, irawx-stilbene episulfoxide, or thiirane. S -oxide with metal complexes. 

Treatment of 2,2,4,4-tetramethyl-3-thietanone with diiron nonacarbonyl gives the binuclear iron complex 381. 2,2-Dimethyl-3-thietanone undergoes oxidative dimerization to 382 on treatment with potassium ferricyanide. Methylene-3-thietanones such as 359 add chlorine from thionyl chloride to the carbon-carbon double bond. 2,2,4,4-tetramethyl-3-thietanone is converted to the 3-thione in 14% yield by treatment with hydrogen sulfide-hydrogen chloride. Electrochemical reduction of the thione produces radical anions. 

Analogous, but less common, syntheses have employed the mercury(II)complexes 82 which provide cyclopropenethiones 78 (Z = S). The replacement of the thioalkyl substituent of compound 83 occurs upon treatment with a secondary amine and a limited range of aminothiocyclopropenthiones are available in excellent yields. Moreover, these same compounds result from reaction of the corresponding thiolate (84) with, for example, benzoyl or thionyl chloride (equation 32). Such compounds have possible application in medicine, as dyes and as agrochemicals. 

Anhydrous lanthanide trihalides, particularly the trichlorides, are important reactants for the formation of a variety of lanthanide complexes, including organometallics. Routes for the syntheses of anhydrous lanthanide trihalides generally involve high temperature procedures or dehydration of the hydrated halides.The former are inconvenient and complex for small scale laboratory syntheses, while dehydration methods may also be complex and have limitations, for example, use of thionyl chloride. - Moreover, the products from these routes may require purification by vacuum sublimation at elevated temperatures. Redox transmetalation between lanthanide metals and mercury(II) halides was initially carried out at high temperatures. However, this reaction can be carried out in tetrahydrofuran (THF, solvent) to give complexes of lanthanide trihalides with the solvent. These products are equally as suitable as reactants for synthetic purposes as the uncomplexed... 

Thionyl chloride is a versatile reagent for transforming secondary amides - and lactams to imidoyl chlorides, e.g. (207 Scheme 28) because only gaseous byinxxlucts are formed. Thionyl chloride can be used in excess. Even from the Ni complexes of N-benzoylthioureas and SCXTb imide chlorides (208) could be prepared. ... 

Aminoethoxy)ethanol, acetic anhydride (99+%), thionyl chloride (99+%), benzylamine (99%), 1,2-bis(2-iodoethoxy)ethane (98%), anhydrous sodium iodide (99+%) and borane-tetrahydrofuran complex (1.0 M solution in tetrahydrofuran) were purchased from Aldrich Chemical Company, Inc. and were used without further purification. 

---