Phosphorus pentachloride reaction with alcohols

The reaction with thionyl chloride affords a chlorosulfite, the decomposition of which may generate an alkyl chloride by the S i (substitution, nucleophilic, internal) mechanism (Scheme 2.16). This reaction, w hich may proceed by an ion pair, can lead to the retention of configuration of an asymmetric secondary alcohol in the conversion to the alkyl chloride. This is in contrast to the inversion of configuration found with the reaction with phosphorus pentachloride and with the nucleophilic displacement of a leaving group. 

Method 2. Mix 1 0 g. of 3 5-dinitrobenzoic acid with 1 5 g. of phosphorus pentachloride in a small, dry test-tube. Warm the mixture gently over a small smoky fiame to start the reaction when the reaction has subsided (but not before), boil for 1-2 minutes or until the solid matter has dissolved. Pour the mixture while still liquid on a dry watch glass (CAUTION the fumes are irritating to the eyes). When the product has solidified, remove the liquid by-product (phosphorus oxychloride) by transferring the pasty mixture to a pad of several thicknesses of filter paper or to a small piece of porous tile. Spread the material until the liquid has been absorbed and the residual solid is dry. Transfer the 3 5 dinitrobenzoyl chloride to a test-tube, add 0-5-1 ml. of the alcohol, and continue as in Method 1. 

Constitution. Pelletierine behaves as a secondary amine and the oxygen atom of the alkaloid is present in the form of an aldehyde group, since the base yields an oxime, convertible by the action of phosphorus pentachloride into a nitrile, b.p. 104-6°/13 mm., which is hydrolysed by caustic potash in alcohol to an acid, the ethyl ester of which is Loffler and Kaim s ethyl -2-piperidylpropionate. Pelletierine is not directly oxidisable to this acid. It also yields a liquid hydrazone, b.p. 130°/20 ram., which with sodium in alcohol at 136-70° reduces to dZ-eoniine. These reactions are explained by the following formulas, in which pelletierine is represented as -2-piperidylpropionaldehyde. 

The traditional method for transforming carboxylic acids into reactive acylating agents capable of converting alcohols to esters or amines to amides is by formation of the acyl chloride. Molecules devoid of acid-sensitive functional groups can be converted to acyl chlorides with thionyl chloride or phosphorus pentachloride. When milder conditions are necessary, the reaction of the acid or its sodium salt with oxalyl chloride provides the acyl chloride. When a salt is used, the reaction solution remains essentially neutral. 

Reactions. Saligenin [90-01-7] undergoes the typical reactions of phenols and benzyl alcohol. When heated above 100°C, it transforms into a pale yellow resinous material. Amorphous condensation products are obtained when saligenin reacts with acetic anhydride, phosphorus pentachloride, or mineral acids. Upon boiling with dilute acids, saligenin is converted into a resinous body, saliretin, a condensed form of saligenin. Condensation reactions of saligenin with itself in the absence of any catalysts and in the presence of bases have also been studied. 

Benzoyl chloride, [98-88-4], C6HbCOC1, mp, — 1°C bp, 197.2°C at 101.3 kPa df, 1.2070 n], 1.55369. Benzoyl chloride is a colorless liquid that fumes upon exposure to the atmosphere, has a sharp odor, and in vapor form is a strong lachrimator. It is decomposed by water and alcohol, and is miscible with ether, benzene, carbon disulfide, and oils. Benzoyl chloride may be prepared in several ways, including the partial hydrolysis of benzotrichloride, the chlorination of benzaldehyde, and from benzoic acid and phosphorus pentachloride. The most common method is the reaction of benzoic acid and benzotrichloride [98-07-7]. Since benzoic acid may be easily obtained from benzotrichloride, the latter is used as the sole raw material for large-scale production of benzoyl chloride. 

VI, obtained from stereospecific reactions of the corresponding optically active alcohol (11) with thionyl chloride, phosphorus pentachloride, etc., was not racemized under any of the reaction conditions. Monitoring the carbonyl absorption frequencies in the IR during these decarbonylations showed that the transformations II — III — IV took place during the conversion of V to racemic VI. Thus rearrangement or decomposition or both could be responsible for the racemization. 

Oxalvl Chloride. This diacid chloride is produced by the reaction of anhydrous oxalic acid and phosphorus pentachloride. The compound vigorously reacts with water, alcohols, and amines, and is employed for tile synthesis of agrochemicals, pharmaceuticals, and fine chemicals. 

Separation of o- and p-Toluenesulpbonic Acids.—The mixture prepared above is treated gradually with an equal weight of finely pulverised phosphorus pentachloride. When the reaction is complete, cold water is added, the whole being surrounded by a freezing mixture. The p-sulphonyl chloride separates as a solid (M.P. 69°) recrystallisable from alcohol. The o-sulphonyl chloride is an oily liquid (M.P. 10°), and is separated from the filtrate by means of a funnel. 

D) Ethyl 2-Chloro-6-(n)-Propyl-Isonicotinate The 40 grams of the acid just obtained are treated with 80 grams of phosphorus oxychloride and 95 grams of phosphorus pentachloride. The phosphorus oxychloride is distilled and the reaction mixture is treated with 400 grams of absolute alcohol. 40 grams of chlorinated ester, having a BP of 115°-116°C/2 mm, are obtained. 

Sulfinic esters, aromatic, by oxidation of disulfides in alcohols, 46, 64 Sulfonation of D,L-camphor to d,l-10-camphorsulfonic acid, 46,12 Sulfoxides, table of examples of preparation from sulfides with sodium metaperiodate, 46,79 Sulfur dioxide, reaction with styrene phosphorus pentachloride to give styrylphosphonic dichloride, 46,... 

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