Acid chlorides, purification

These are often commercially available or can be easily prepared by reaction of glycerol with an appropriate acid chloride. Purification can be effected by crystallization or by TLC. 

Additional phosphonic acid is derived from by-product streams. In the manufacture of acid chlorides from carboxyUc acids and PCl, phosphonic acid or pyrophosphonic acid is produced, frequentiy with copious quantities of yellow polymeric LOOP. Such mixtures slowly evolve phosphine, particularly on heating, and formerly were a disposal problem. However, purification of this cmde mixture affords commercial phosphonic acid. By-product acid is also derived from the precipitate of calcium salts in the manufacture of phosphinic acid. As a consequence of the treatments of the salt with sulfuric acid, carbonate is Hberated as CO2 and phosphonic acid goes into solution. 

The phenylbenzamide is prepared from the acid chloride in the presence of Et3N (86% yield) and can be cleaved with 3% Na(Hg) (MeOH, 25°, 4 h, 81% yield). Most amides react only slowly with Na(Hg). Phenylbenzamides are generally crystalline compounds, an aid in their purification. ... 

Lmine(s)—cont d primary. 916 properties of, 920 purification of. 923-924 pyramidal inversion in, 919-920 reaction with acid anhydrides, 807 reaction with acid chlorides, 803-804... 

PC15 (60 g, 290 mmol) was added in small portions to a stirred solution of a oxobenzotriazepinecarboxylic acid 8 (35 mmol) in benzene (400 mL) at such a rate that the temperature did not exceed 25 C. Stirring was continued for 3 16h and the resulting crude yellow acid chloride 10 (yield ca. 95%) was filtered off and used without purification. 

A mixture of 2.0 mmol of a 1.6 N solution of butyllithium in hexane and 0.47 g (2.0 mmol) of(-)-spartcinc in 10 mL of diethyl ether is stirred for 15 min at — 78 rC then 0.26 g (2.0 mmol) of 1-methyl-l//-indene in 2 mL of diethyl ether are added. Stirring is continued for 30 inin at 20 °C, the mixture is cooled to — 70 CC and 2.5 mmol of the acid chloride in 2 mL of diethyl ether are added. After stirring for 4h the usual aqueous workup was accomplished by addition of 10 mL of diethyl ether and successive washing with 10 mL of 2 N aq HC1. water and sat. aq NtiCl, respectively, followed by chromatographic purification on silica gel with diethyl cthcr/pentane. 

In most of the studies discussed above, except for the meta-linked diamines, when the aromatic content (dianhydride and diamine chain extender), of the copolymers were increased above a certain level, the materials became insoluble and infusible 153, i79, lsi) solution to this problem with minimum sacrifice in the thermal properties of the products has been the synthesis of siloxane-amide-imides183). In this approach pyromellitic acid chloride has been utilized instead of PMDA or BTDA and the copolymers were synthesized in two steps. The first step, which involved the formation of (siloxane-amide-amic acid) intermediate was conducted at low temperatures (0-25 °C) in THF/DMAC solution. After purification of this intermediate thin films were cast on stainless steel or glass plates and imidization was obtained in high temperature ovens between 100 and 300 °C following a similar procedure that was discussed for siloxane-imide copolymers. Copolymers obtained showed good solubility in various polar solvents. DSC studies indicated the formation of two-phase morphologies. Thermogravimetric analysis showed that the thermal stability of these siloxane-amide-imide systems were comparable to those of siloxane-imide copolymers 183>. 

Materials. The starting PPO was purchased from Aldrich Chemical Co. Two reprecipitations from chloroform into methanol served to purify the polymer. The bromine, chlorosulfonic acid, sulfonyl chlorides, acid chlorides as well as all other reagents and solvents were purchased from Aldrich Chemical Co. and were used without further purification. 

Suberyl dichloride purchased from Frinton Laboratories was used without further purification. The purity of the acid chloride was checked by gas chromatography by first converting it to the diethyl ester. 

The acid chloride or the acid may be purchased from Aldrich Chemical Company, Inc. The acid chloride must be pure (99% minimum by gas chromatography analysis) whether purchased or prepared. Purification was effected by recrystallization from Skellysolve B. 

Anhydrides. The corresponding acids, resulting from hydrolysis, are the most likely impurities. Distillation from phosphorus pentoxide, followed by fractional distillation, is usually satisfactory. With high boiling or solid anhydrides, another method involves refluxing for 0.5-1 hour with acetic anhydride, followed by fractional distillation. Acetic acid distils first, then acetic anhydride and finally the desired anhydride. Where the anhydride is a solid, removal of acetic acid and acetic anhydride at atmospheric pressure is followed by heating under vacuum. The solid anhydride is then either crystallised as for acid chlorides or (in some cases) sublimed in a vacuum. A preliminary purification when large quantities of acid are present in a solid anhydride (such as phthalic anhydride) can sometimes be... 

Acetylene, purification, 39, 58 Acetylene, diphenyl-, 34, 42 y-hydroxypropyl, 33, 68 Acetylenedicarboxyuc acid, dimethyl ESTER, 32, SS Acetylenic glycols, 39, 57 2- -Acetylphenylhydroquinone, 34,1 S-Acetyl- -valeric acid, 31, 3 Acid chlorides, 39, 19 synthesis of, 37, 69... 

Methyl -propyl ketone, 340 Methyl pyridines, purification of, 177-179 N-Methylpyrrole, 837, 838 Methyl red, 621, 625 sodium salt of, 626 Methyl salicylate, 780,782 Methyl sulphite, 304 2-Methylthiophene, 836 Methyl p-toluenesulphonate, 825 Methylurea, 968, 969 Methylene bromide, 300 Methylene chloride, purification of, 176 3 4-Methylenedioxycinnamic acid, 711, 719... 

S-(0-Methyl)mandelic acid chloride was prepared (14-h reflux in 5 mL of benzene) from the S-(0-methyl)mandelic acid (0.33 g, 2.0 mmol) and oxalyl chloride (0.34 mL, 4.0 mmol). The chloride was added to a solution of 3 (0.56 g, 2.0 mmol) and dry pyridine (0.33 mL, 4.0 mmol) in dry toluene (20 mL) at — 10°C. The mixture was then allowed to attain 0°C. After 14 h, toluene was added, and the mixture was washed with water (20 mL). Toluene solution was dried (MgS04) and concentrated to dryness to yield 4 (0.84, 98%), which was used in the next step without purification. 

A soln of 4-benzoylbenzoic acid (7 4.37 g, 19.3 mmol) in CH2Q2 (120 mL) was treated with (COCl)2 (3.37 mL, 38.6 mmol) under N2 at rt for 2h. The solvent was removed under vacuum. The residue was redissolved in CH2C12 (50 mL) and the soln was evaporated to dryness, yielding the crude acid chloride 84, which was used in the next step without further purification. 

A mixture of 4-(chloromethyl)benzoic acid (50 g, 0.29 mol) and (COCl)2 (100 g, 0.79 mol) in anhyd benzene (100 mL) (CAUTION carcinogen ) was stirred at 25 °C and then refluxed for 2h. Unreacted (COQ)2 and benzene were removed by distillation. Traces of the remaining reagents were removed under reduced pressure to give 92 as a colorless liquid. The acid chloride was used in the next step without further purification. 

Scheme 44 summarizes an addition reaction by the Barton method. Thiohydroxamate esters (32) are readily prepared and isolated, but, more typically, they are generated in situ. Experimental procedures have been described in detail148151 and often entail the slow addition of an acid chloride to a refluxing chlorobenzene solution of the readily available sodium salt (31), dimethylaminopyridine (DMAP, to catalyze the esterification), and excess alkene. The products are usually isolated by standard aqueous work-up and chromatographic purification. 

The traditional methods utilize sulfur or phosphorous halides to convert the acid to die acid chloride. Of these methods, thionyl chloride [often with a catalytic amount of dimethyl formamide (DMF)] is the most useful since the by-products of die reaction are gases (SO2, HC1) which can be easily purged from the reaction mixture with a stream of nitrogen. The acid chloride product can then be purified on a small scale by bulb-to-bulb distillation or crystallization. Because an excess of thionyl chloride is usually used, there must be a purification step to remove the excess reagent. 

Treatment of 1-phenyl-2,4-hexadien-l-ol with the acid chloride of fumaric acid monomethyl ester in ether/triethylamine gave a quantitative yield of the crude ester as an oil. Attempted purification by Kugelrohr distillation at 180-190°C under high vacuum gave the bicyclic lactone 1 in 45% yield. It was subsequently found that the fumarate esters of the isomeric alcohols 1-phenyl-l,4-hexadien-3-ol and l-phenyl-l,3-hexadien-5-ol also gave compound 1 in 43 and 35% yield respectively when distilled in a Kugelrohr apparatus. 

Treatment of p-acetoxybenzoic acid with thionyl chloride generated the acid chloride, which was used without purification to acylate diethyl L-glutamate. Deacetylation of the resulting triester (36) gave (37) [51] (Scheme 3.6). 

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