( 516 ) 



Acetothienon ' was prepared from thiophen according to the method of Friedel 

 and Crafts, and a very good yield was obtained. The thiophen was prepared hy 

 ourselves by distillation of sodium succinate with P 2 S 3 . 1 1 .5 grams of ketone and 

 12 grams of sodium hydroxide were introduced into a litre of water, and to this 

 was added slowly, at the ordinary temperature, a solution of 42 grams of potas- 

 sium permanganate dissolved in a litre of water. After each addition the pink 

 colour was allowed to change to green before addition of a fresh portion. 



After all the permanganate had been added the liquid was allowed to remain 

 overnight; the solution was heated gently on the waterbath until the green colour 

 had disappeared, then filtered off from the manganese dioxide, and concentrated to 

 250 cc. Without isolation of the thienylglyoxylic acid, beforehand the liquid, after being 

 nearly neutralised with hydrochloric acid, is mixed with '.) grams of 30% hy- 

 drogen peroxide previously diluted with its own volume of water. The whole is 

 set aside for a few hours, and afterwards heated for a few moments on a water- 

 bath. On acidification the liquid the greater part of the a-thiophenic acid formed is 

 precipitated in a pure condition; a further small quantity may be recovered from 

 the mother-liquor by extraction with ether. By recrystallisation from water and 

 distillation in vacuo, the acid may he obtained pure and quite free from thienyl- 

 glyoxylic acid. The yield amounts to about 9 grams. 



The solution of a-thiopbenic acid saturated at 24°.9 contains 0.75 °/ . 



Preparation of $-thiophenic acid. V. Meter has effected this by 

 oxidising with potassium permanganate in very dilute, cold solution. 

 The yield of fJ-aeid was however very poor, in fact only about 

 5 — 8°/ of the thiotolene employed. After trying various modifications 

 of this direct oxidation process without arriving at a better result 

 we decided to follow an indirect way by firs! chlorinating- the sid<- 

 chain, then preparing the aldehyde from the thienalchloride and 

 finally oxidising the former to the acid: 



C 4 H 8 S . CH 8 -> C 4 H :( S . CHC1, -* C 4 H 8 S . CHO -* C 4 H„S . COOH. 



Bearing in mind van der Laan's research 1 ) on the bromination 

 of toluene where it was shown that in presence of PC1 5 the sub- 

 stitution in the side chain is accelerated, this substance was added 

 in the chlorination of ,i-thiotolene. The above mentioned processes 

 all proceeded very smoothly, but unfortunately an acid rich in 

 chlorine was finally obtained as, apparently, the chlorination had 

 also extended to the nucleus. This certainly could be freed from 

 chlorine by treatment with sodium-amalgam but a large proportion 

 of the ^-thiophenic acid was lost thereby so that the yield did, finally, 

 not exceed 10% of the thiotolene employed. 



We add a few particulars as to the modus operandi followed. 



/J-thiotolene was prepared by ourselves by distilling sodium pyrotartrate with 

 phosphorus trisulphide. The chlorination took place indirect sunlight in the presence 

 of 10"/ of PG1 5 . The reaction product is boiled in a reflux apparatus with water 

 and calcium carbonate. The aldehyde is distilled in steam and purified over the 



i) These Proc. Oct. 1905). 



