Pyridines reaction with thionyl chloride

The dichlorides of aliphatic glycols are obtained by reaction with thionyl chloride in the presence of a small quantity of pyridine, for example ... 

Because tertiary alcohols are so readily converted to chlorides with hydrogen chloride, thionyl chloride is used mainly to prepare primary and secondary alkyl chlorides. Reactions with thionyl chloride are nonrrally carried out in the presence of potassium carbonate or the weak organic base pyridine. 

PLLA-fr-PCL) multiblock copolymers were prepared from the coupling reaction between the bischloroformates of carboxylated PLLA with diol-terminated PCL in the presence of pyridine [140]. LLA was polymerized with SnOCt2 and 1,6-hexanediol followed by the reaction with succinic anhydride to provide the dicarboxylated PLLA. The carboxyl end groups were subsequently transformed to acid chloride groups by the reaction with thionyl chloride (Scheme 65). As expected, the molecular weight distributions were broad for all samples (1.84 < Mw/Mn < 3.17). 

The existence of a substituted pyridine molecule such as III was considered as a probable intermediate for the oxidation of pyridine to l-(4-pyridyl) pyridinium ion by thionyl chloride (10). The authors believe the mechanism of the reaction with thionyl chloride to be similar to that proposed here, but further discussion of... 

In the event, iodolactonization of the carboxylate salt derived from the ester 458 afforded 459, and subsequent warming of the iodo lactone 459 with aqueous alkali generated an intermediate epoxy acid salt, which suffered sequential nucleophilic opening of the epoxide moiety followed by relactonization on treatment with methanol and boron trifluoride to deliver the methoxy lactone 460. Saponification of the lactone function in 460 followed by esterification of the resulting carboxylate salt with p-bromophenacylbromide in DMF and subsequent mesylation with methanesulfonyl chloride in pyridine provided 461. The diazoketone 462 was prepared from 461 by careful saponification of the ester moiety using powdered potassium hydroxide in THF followed by reaction with thionyl chloride and then excess diazomethane. Completion of the D ring by cyclization of 462 to the keto lactam 463 occurred spontaneously on treatment of 462 with dry hydrogen chloride. 

Very useful is 4-pyridylpyridinium chloride-hydrochloride (65), which is obtained by reaction of pyridine 64 with thionyl chloride as described in Section IV,B. 4-Pyridylpyridinium chloride-hydrochloride (65), which can be readily prepared in large quantities, reacts on heating in DMFas solvent and reactant (cf. Section 1II,B and especially IV,B reactions 105-108) to form the important nucleophilic catalyst DMAP (228) on a technical scale in —60-70% yield. Similarly, N-formy I pyrrolidine affords PPY (184) in 60% yield (77USP4I40853). 

Pyridine-4-sulfonic acid. The formation of an arylsulfonic acid by reaction with thionyl chloride is a special reaction of pyridine derivatives a possible sequence of events is indicated in the formulation. ... 

I he 11/3-hydroxyl group to produce a 9,11-double bond (7), whereas on reaction with thionyl chloride-pyridine both the 11/8- and the 17a-hydroxyl groups were eliminated, giving (8). Thus SOCIj-Py is the more powerful reagent, but POCla-Py hits an advantage where selectivity is desired. 

Ticolubant (310) is a leukotriene receptor antagonist that exhibits anti-inflammatory activities. The Wittig reaction with 3-hydroxy-6-methylpicolinaldehyde followed by a Mitsunobu reaction with 2-phenylethanol gave phenyl ether 308. Oxidation with wCPBA converted the pyridine ring into the corresponding A-oxide, which then underwent the Boekelheide reaction with TFAA to afford the methyl alcohol 309. Reaction with thionyl chloride and then 2,5-dichlorothiophenol followed by saponification gave 310. ° ... 

Preparation.—From Alcohols or other Halides. Factors affecting the formation of isomerically and optically pure alkyl halides from saturated aliphatic alcohols have been discussed by Hudson and co-workers. - Reactions with thionyl chloride give reduced amounts of rearrangement products if pyridine hydrochloride is added, and isomerically pure chlorides RCl from almost all alcohols ROH if HMPT or DMF is the solvent. In the latter medium (58) is a presumed intermediate, as is the case in the reaction of alcohols with Vilsmeier reagents (59, X = Cl or Br). Such species produce halides via inversion of configuration from secondary alcohols, presumably according to Scheme 24. In the related reaction of PCI3 with unhindered primary alcohols in DMF to produce alkyl... 

These reactions can be cataly2ed by bases, eg, pyridine, or by Lewis acids, eg, 2inc chloride. In the case of asymmetric alcohols, steric control, ie, inversion, racemi2ation, or retention of configuration at the reaction site, can be achieved by the choice of reaction conditions (173,174). Some alcohols dehydrate to olefins when treated with thionyl chloride and pyridine. 

Diorgano Sulfites. Symmetrical or mixed dialkyl sulfites ate prepared by the stepwise reaction of thionyl chloride either with two molecules of an alcohol or with stoichiometric quantities of two alcohols in pyridine (105). 

The reaction of propiophenone with thionyl chloride in pyridine provides 3,4-diben-zoylthiophene (79H(l2)46i). The boron trifluoride catalyzed reaction of benzophenone with f-butyl isocyanide gives an indole derivative (Scheme 84b) (67TL3881). Another... 

ITitrabenzoyI Chloride (Coll. Vol. i, 387) Pyridine is used (in considerable quantity) to catalyze the reaction of the add, suspended in ether, with thionyl chloride. Carr Libermann, Compt. rend, igg, 1422 (1934). 

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