Trichloroacetyl chloride, reaction with

In the reaction with enamino ketones derived from dimedone (e.g., 49) p-toluenesulfonyl chloride gives the chloroiminium cation (138) isolated as the perchlorate. This indicates that initial O sulfonation is followed by addition of chloride ion and subsequent expulsion of tosylate (42) in a manner similar to the trichloroacetyl chloride reaction with 49 (Section IV.A). 

Thiocarbonyl tetrachloride, i6, 21 Thionyl chloride, 45, 16, 98 Thiophosgene, 45, 21 Thiophosphoryl chloride, reaction with methylmagnesium bromide to yield tetramethylbiphosphine disulfide, 45,102 Toluenesulfonybromide, 46, 88 Trichloroacetyl fluoride, 46, 6 1,1,3-Trichloiio- -nonane, 46,104 Tricyclo[2.2.1.0 ]heptan-3-ol, 45,... 

Chloroacetyl chloride is manufactured by reaction of chloroacetic acid with chlorinating agents such as phosphoms oxychloride, phosphoms trichloride, sulfuryl chloride, or phosgene (42—44). Various catalysts have been used to promote the reaction. Chloroacetyl chloride is also produced by chlorination of acetyl chloride (45—47), the oxidation of 1,1-dichloroethene (48,49), and the addition of chlorine to ketene (50,51). Dichloroacetyl and trichloroacetyl chloride are produced by oxidation of trichloroethylene or tetrachloroethylene, respectively. 

It is of interest to note that 2,4,6-trinitrochlorobenzene reacts similarly with 49 to give the cation of 138 isolated as the perchlorate. In the reaction of the enamino ketone (50) with trichloroacetyl chloride (77) the chloro-... 

Symmetrical piperazines 364 have been obtained from the corresponding 4,5-dihydrazinofurazano[3,4- ]pyraz ne 363 in good yield on reaction with acetic anhydride in the presence of a Lewis acid (Equation 98) <1999CHE499>. When formaldehyde was used, the yield was slightly reduced at 76%. Acid chlorides can also be used in this reaction although the yield drops to 23% when trichloroacetyl chloride is used. 

A. Pyrrol-2-yl trichloromethyl ketone. In a 3-1. three-necked round-bottomed flask equipped with a sealed mechanical stirrer, a dropping funnel, and an efficient reflux condenser with a calcium chloride drying tube are placed 225 g. (1.23 moles) of trichloroacetyl chloride and 200 ml. of anhydrous ether. The solution is stirred while 77 g. (1.15 moles) of freshly distilled pyrrole in 640 ml. of anhydrous ether is added over 3 hours (Note 1). The heat of reaction causes the mixture to reflux during the addition. Following the addition, the mixture is stirred for 1 hour, and then 100 g. (0.72 mole) of potassium... 

In this experiment, no carbon tetrachloride was detected but, on the basis of the mechanism proposed, carbon tetrachloride would have been an important reaction product, arising by the combination of chlorine atoms and trichloj-omethyl radicals. Further, the production of octachloropropane by the secondary photolysis of octachlorobutanone would involve the formation of decachlorobutane. In the presence of chlorine, only carbon tetrachloride was formed, whereas by interaction of the postulated CCI3CO- radical with chlorine, substantial amounts of trichloroacetyl chloride should have been observed. In the presence of oxygen, only carbon dioxide and phosgene were found and the yield of the latter was far too small to account for the loss of the radical products. 

Some acyl halides are reactive enough to effect Friedel-Crafts acylation on the neutral heterocycles without a catalyst. For pyrrole such reactions are known, for example, with trifluoroacetyl chloride and trichloroacetyl chloride. Indole reacts smoothly in cold ether with oxalyl chloride and on heating with acetic anhydride. Some examples of these types of acylation are collected in Table 10. 

Cycloaddition to alkynes. Dichlorokelene, generated from trichloroacetyl chloride by zinc (8,156), adds to alkynes to give cyclobutenones. The reaction occurs preferentially with the triple bond of enynes. 

A variety of cydopropanecarbonitriles have been prepared by dehydration of cyclopropanecarboxamides. The reactions were with phosphorus pentoxide and triethylamine, ° phosphoryl chloride, thionyl chloride/ and trichloroacetyl chloride and triethylamine. The yields ranged from mediocre to very good, an example is dehydration of carboxamide 1 to carbonitrile 2. ... 

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