496 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



Haematoporphyrin Hydrochloride. 



5 gm. of haemin are added in small portions with continual shaking to 75 

 c.c. of glacial acetic acid saturated with hydrobromic acid at 10. The liquid 

 is allowed to stand at room temperature for 3 or 4 days with occasional 

 shaking. The haemin slowly dissolves and a purple-red solution of haemato- 

 porphyrin is obtained. The acid solution is poured into water and filtered ; 

 haematoporphyrin, which is insoluble in acetic acid, together with iron oxide, 

 is precipitated on neutralisation of the hydrobromic acid with sodium hydroxide. 



The precipitate is washed by dccantation with water until the washings 

 no longer react with silver nitrate. The moist precipitate is treated with 

 dilute sodium hydroxide on a water-bath. The haematoporphyrin dissolves 

 and is filtered from ferric oxide. By neutralising the filtrate with acetic acid 

 the haematoporphyrin is thrown down, filtered off and washed. It is made 

 into a paste with water and carefully treated with dilute hydrochloric acid so 

 as to dissolve the pigment. The solution is filtered from resinous matter and 

 treated with more hydrochloric acid ; if resin be again precipitated, it is removed 

 by filtration and the solution is evaporated in vacua over sulphuric acid. 

 Haematoporphyrin hydrochloride crystallises out. The crystals are filtered 

 off and washed with 10 per cent, hydrochloric acid. They are recrystallised 

 in the same way. 



Haematoporphyrin hydrochloride forms needles arranged in rosettes of 

 the formula C^HagOgN.^ . 2HC1 and of a purple-red colour. It dissolves 

 easily in dilute hydrochloric acid, not so easily in more concentrated acid. 



Crystalline Haematoporphyrin (Willstatter). 



Willstatter has found that haemin dissolves readily in glacial acetic acid 

 saturated with hydrobiomic acid only if its specific gravity is 1*41 at o. 

 He puts 36 gm. of haemin in 700-900 c.c. of the reagent and shakes for 

 15 minutes; in about 7 hours it is completely in solution. The solution 

 is poured into 5 litres of water and filtered from coarse particles through talc. 

 On standing for 3 hours the addition product is hydrolysed. The haemato- 

 porphyrin and ferric oxide, precipitated by adding sodium acetate, are filtered 

 off, washed with water and dried at the ordinary temperature ; the yield is 

 34 gm. The precipitate is dissolved in sodium hydroxide, the solution filtered 

 from ferric hydroxide and the filtrate acidified with acetic acid. The haemato- 

 porphyrin is filtered off and washed. 



The moist material from 10 gm. of haemin is dissolved in i litre of alcohol 

 and poured into 25 litres of ether in 7 separating funnels. The alcohol is 

 washed away by running tap water through the ether for 20 minutes. Some 

 flocculent calcium salt which separates is collected and converted into haemato- 

 porphyrin. The ethereal solution is dried with sodium sulphate and concen- 

 trated to a volume of i litre. Haematoporphyrin separates out an<3 crystallises 

 on standing. It is filtered off, washed with ether and dried in a desiccator; 

 4-5 gm. are obtained. 



The crystals have a violet colour, red-brown in transmitted light. They 

 are soluble wiih difficulty in ether, methyl alcohol and 96 per cent, ethyl 

 alcohol, more easily in absolute alcohol and easily soluble in acetone and glacial 

 acetic acid. They are slightly soluble in -03 per cent. HC1, completely in -4 

 per cent. HC1. In vacua at 105 they lose i mol. of water. It is a stable 

 compound of the formula C 3 3H 38 O 6 N^ 



