14 
ties of urobilin are not sufficiently characteristie for the purpose 
of identification. It was therefore necessary to seek for more exact 
means of characterising the reduction product in question as well 
as haemopyrroline, obtained from haemoglobin or chlorophyll deri- 
vatives. The search for such means proved successful; one of us 
(L. M.) described’) with J. Hetper and H. Goldmann combination 
produets of haemopyrroline with diazonium compounds with suffi- 
eiently characteristie properties. It remained now to investigate the 
behaviour of the synthetical produet. mentioned above towards dia- 
zonium compounds. The present communication contains an account 
of our results in this respect. 
The methyl-n-propyl-maleie anhydride from which as stated we 
started, was obtained according to Michael and Tissots method. The 
crude reaction product containing methyl-n-propvl-malie acid was 
distilled and divided by fractionation into the following fractions: 
1., 117—1400; 2. 140—171°; 3, 171—1900, 4, 190—230°, 4. 
230—245. 
The four first fractions were united and the heavier portion se- 
parated from the lighter one in a dividing funel and distilled again. 
The following fractions were obtained: 1.. up to 210°, 2., 210—2350, 
3, 235—2450 This third fraction was united with the fifth frac- 
tion of the first series of distillations and distilled again; the major 
part distilled now at 239— 245°, and after distilling it twice using 
a Zincke thermometer a product was finally obtained distilling con- 
stantly at 242—243° under 734 mm pressure. Küster and Haas?) 
found the boiling point of methyl-n-propyl-maleie anhydride at 
241— 242°. The refraction of. this anhydride we found at 259 — 
1'46913, and its density d£ — 108995, from which data the fol- 
lowing molecular refraction is derived: 
MR, = M =: : — 39:33 
whereas theoretically the following value is obtained using the ato- 
mic refractions as ascertained by Brühl: 
20-008 + 10-510 + 4574 4 1:683 — 1:707 — 38-482. 
1) This Bull. p. 279. 1905. 
?) Ber. 1904, p. 2471. 
