Phosphorus acid chloride

Rearrangements.— Both propargyl alcohol and propargyl mercaptan give the corresponding allenylphosphonates (90) and (91) on reaction with tervalent phosphorus acid chlorides. In the case of a similar reaction with the acetylenic diol (92) a double rearrangement occurs to give the diphosphonate (93),... 

Finally, phosphorus acid chlorides or bromides containing organic groups can be used for replacing the OH of carboxylic acids by Cl or Br. Carboxylic acids or their anhydrides afford the acid chlorides or bromides when heated for 30-60 minutes at 100° with 2,2,2-trichloro-1127 or 2,2,2-tribromo-l,3,2-benzodioxaphosph(v)ole (pyrocatechylphosphorus trihalides),1022,1128 yields being good. This method has the advantages that these trihalides have... 

We surmised that our previous failures were caused by the rapid hydrolysis of the phosphorus acid chloride mainly from the following two observations. First, phosphorus acid chlorides are rapidly hydrolyzed in the presence of water. Second, classical interfacial reactions employing fully charged Lewis Bases such as R-0 and RCO are found to occur within the... 

Table 2. Results as a Function of Phosphorus Acid Chloride Employing Ditriethylamine Terephthalic Acid... 

We have synthesized a number of phosphorus-containing polymers utilizing the condensation of phosphorus acid chlorides amd the diisocyanate with a variety of Lewis bases utilizing the interfacial condensation technique. ... 

Here again the simple formulation [Sb ] is used to represent all the cationic species present.) The hydrolysis is reversible and the precipitate dissolves in hydrochloric acid and the trichloride is reformed. This reaction is in sharp contrast to the reactions of phosphorus(III) chloride. 

One of the general methods for the preparation of acid chlorides is the action of phosphorus pentachloride on the corresponding carboxylic acid ... 

One disadvantage of this method is that it is sometimes difficult to separate the acid chloride sharply from the phosphorus oxychloride by fractional dis tillation, and unless the boiling oints of these two substances are fairly wide apart, traces of the oxychloride will occasionally pass over in the vapour of the acid chloride. If, however, thionyl chloride is used instead of phosphorus... 

Required 3,5-Dinitrobcnzoic acid, 15 g. phosphorus penta-chloride, 17 g. 

Very pure acid chlorides may be obtained by reaction between the anhydrous sodium salt of the acid and phosphorus oxychloride, for example ... 

Ethyl a-bromopropionate. This preparation illustrates the facile bromination of an acid chloride (propionyl chloride) in the presence of red phosphorus, and the subsequent conversion of the bromoacid chloride into the ethyl ester by direct interaction with ethanol. 

The Y-phenylbutyric acid is cyclised to a-tetralone by converting it into the acid chloride with thionyl chloride or phosphorus pentachloride and then an intramolecular Friedel and Crafts reaction is carried out ... 

The liquid phosphorus oxychloride, b.p. 107°, is a by-product and is removed by fractional distillation under normal pressure. Unless the b.p. of the acid chloride differs very considerably (say, <] 100°) from that of the phosphorus oxychloride, the acyl halide is liable to contain traces of the latter. In such circumstances it is preferable to use thionyl chloride for the preparation of the acid chloride. 

Formation of the acid chloride, e.g., with thionyl chloride or with phosphorus pentachloridc ... 

Decane-1 10-dicarboxylic acid from sebacic acid. Convert sebacic acid into the acid chloride by treatment with phosphorus penta-chloride (2 mols) and purify by distillation b.p. 146-143°/2 mm. the yield is almost quantitative. Dissolve the resulting sebacoyl chloride in anhydrous ether and add the solution slowly to an ethereal solution of excess of diazomethane (prepared from 50 g. of nitrosomethylurea) allow the mixture to stand overnight. Remove the ether and excess of diazomethane under reduced pressure the residual crystalline 1 8-bis-diazoacetyloctane weighs 19 -3 g. and melts at 91° after crystaUisation from benzene. 

Hydroxyalkylthiazoles are also obtained by cyclization or from alkoxyalkyl-thiazoles by hydrolysis (36, 44, 45, 52, 55-57) and by lithium aluminium hydride reduction of the esters of thiazolecarboxylic acids (58-60) or of the thiazoleacetic adds. The Cannizzaro reaction of 4-thiazolealdehyde gives 4-(hydroxymethyl)-thiazole (53). The main reactions of hydroxyalkyl thiazoles are the synthesis of halogenated derivatives by the action of hydrobroraic acid (55, 61-63), thionyl chloride (44, 45, 63-66), phosphoryl chloride (52, 62, 67), phosphorus penta-chloride (58), tribromide (38, 68), esterification (58, 68-71), and elimination that leads to the alkenylthiazoles (49, 72). 

Pyridazinecarboxamides are prepared from the corresponding esters or acid chlorides with ammonia or amines or by partial hydrolysis of cyanopyridazines. Pyridazinecarboxamides with a variety of substituents are easily dehydrated to nitriles with phosphorus oxychloride and are converted into the corresponding acids by acid or alkaline hydrolysis. They undergo Hofmann degradation to give the corresponding amines, while in the case of two ortho carboxamide groups pyrimidopyridazines are formed. 

Chlorophenylacetic acid has been prepared from mandeloni-trile and hydrochloric acid in a sealed tube, from mandelic acid and hydrochloric acid in a sealed tube/ from a-nitrostyrene and hydrochloric acid in a sealed tube, from phenylglycine, hydrochloric acid, and sodium nitrite, from mandelic acid and phosphorus pentachloride (to give the acid chloride which is then hydrolyzed), and, in poor yield, from mandelic acid and thionyl chloride. In the method described, ethyl mandelate is prepared according to Fischer and Speier. The conversion to the chloroester and the acid hydrolysis step are modifications of a preparation described by McKenzie and Barrow. ... 

Tetrahydroharman, m.p. 179-80°, has been prepared by a number of workers by a modification of this reaction, viz., by the interaction of tryptamine (3-)5-aminoethylindole) with acetaldehyde or paraldehyde and Hahn et al. have obtained a series of derivatives of tetrahydronorharman by the use of other aldehydes and a-ketonic acids under biological conditions of pH and temperature, while Asahina and Osada, by the action of aromatic acid chlorides on the same amine, have prepared a series of amides from which the corresponding substituted dihydronorharmans have been made by effecting ring closure with phosphorus pentoxide in xylene solution. 

The hydriodic acid is then decomposed by chloiine, and ICl regenerated. Phosphorus acts by for.ming the chloride of phosphorus from which the acid chloride is produced, which is more readily attacked by chlorine than the acid. Sulphur behaves in a similar fashion, sulphur chloride converting the... 

A thioamide of isonicotinic acid has also shown tuberculostatic activity in the clinic. The additional substitution on the pyridine ring precludes its preparation from simple starting materials. Reaction of ethyl methyl ketone with ethyl oxalate leads to the ester-diketone, 12 (shown as its enol). Condensation of this with cyanoacetamide gives the substituted pyridone, 13, which contains both the ethyl and carboxyl groups in the desired position. The nitrile group is then excised by means of decarboxylative hydrolysis. Treatment of the pyridone (14) with phosphorus oxychloride converts that compound (after exposure to ethanol to take the acid chloride to the ester) to the chloro-pyridine, 15. The halogen is then removed by catalytic reduction (16). The ester at the 4 position is converted to the desired functionality by successive conversion to the amide (17), dehydration to the nitrile (18), and finally addition of hydrogen sulfide. There is thus obtained ethionamide (19)... 

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