HILL AND CORNELISON. — CROTONOLACTONES. 37 



viscous solution, in which some metallic zinc was still suspended, was 

 warmed, filtered, and the clear filtrate diluted with water. As the oil 

 which was then precipitated showed no tendency to crystallize when 

 cooled and scratched, the whole was extracted with ether, the ethereal 

 solution washed with a dilute solution of sodic carbonate, dried with 

 calcic chloride, and the ether removed by distillation. The liquid 

 residue left by the ether was then distilled under diminished pressure. 

 After two distillations the greater part of the product was collected 

 between 128° and 130°, under a pressure of 22 mm., and on cooling 

 this fraction to 10° the larger portion of it solidified. The solid was 

 drained on the pump in a Gooch crucible, and carefully pressed with 

 filter paper. This perfectly dry material was then melted, cooled, and 

 the crystalline solid again pressed, and these operations repeated for 

 a second time without raising perceptibly the melting point. An 

 analysis showed that the body was a chlorcrotonolactoue. 



0.3071 grm. substance gave 0.3720 grm. AgCl. 



Calculated for C 4 H 3 C10 2 . Found. 



CI 29.95 29.95 



The /3-chlorcrotonolactone is very readily soluble in alcohol, ether, 

 chloroform, or benzol; less soluble in carbonic disulphide, and spar- 

 ingly soluble in ligroin. It may be crystallized most conveniently by 

 strongly cooling the ethereal solution after the addition of ligroin. It 

 crystallizes in well-formed flat prisms, which melt at 25-26°. The 

 boiling point of the pure substance was found to be 124-125° under 

 a pressure of 18 mm. It is quite freely soluble in hot water, and 

 distils slowly with steam. Toward the alkaline hydrates and aniline 

 it behaves like the /3-bromcrotonolactone. We have not yet studied 

 its behavior toward bromine or oxidizing agents. Although the 

 /35-dichlorpyromucic acid is an extremely expensive substance on 

 account of the difficulties which lie in the way of its preparation, and 

 the small yield which can be obtained, its conversion into this same 

 /3-chlorcrotonolactone by heating with acids seemed to us of sufficient 

 importance to warrant an experiment in this direction. "We therefore 

 heated to boiling 0.7 grm. of the acid with 7 grm. of sulphuric acid of 

 sp. gr. 1.43. Carbonic dioxide was slowly evolved, and the sulphuric 

 acid became strongly colored. After boiling for several hours the 

 solution was cooled, diluted, and extracted with ether. The ethereal 

 extract was then washed with a dilute solution of sodic carbonate, 

 which took up a small amount of the unaltered dichlorpyromucic 

 acid, and dried with calcic chloride. The greater part of the ether 



