330 VII. ACIDS, AMIDES, ALDEHYDES AND HYDROCARBONS 



verted to phenols in man/^" and in rabbits. ^^^ In the case of the dog, 

 Schmiedeberg'^2 noted that an excretion of 1.884 g. as phenol and 0.445 

 g. as dihydroxyphenols occurred after 21 g. of benzene had been ad- 

 ministered. This amounts to a total excretion of only 8.5% of the ad- 

 ministered benzene in the form of phenols. 



c'. Oxidation of Benzene to Di- and Trihydroxyphenols : In addition 

 to the formation of the monohydroxy derivative, at least two dihydroxy- 

 phenols and one trihydroxyphenol are now recognized as oxidation prod- 

 ucts of benzene. Catechol, o-dihydroxybenzene, 



and hydroquinone, p-dihydroxybenzene. 



were isolated by Brieger^^^ from 40 liters of urine obtained from hospital 

 patients treated with phenol, but no reference is made to the quantities iso- 

 lated, or to the amount of phenol administered. Nencki and Giacosa^^'* 

 isolated catechol in the crystalline state from the urine of both dogs and 

 men after relatively large doses of benzene (5 to 6 g. per day) had been 

 given. 



Hydroquinone was isolated, many years ago, from dog urine by Baumann 

 and Preusse,^^^'^^ after phenol had been given. Nencki and Giacosa^^^ 

 did not detect quinol in dog urine, but they did demonstrate its presence 

 qualitatively in human urine. However, Baernstein,^^^ using newer 

 methods for the determination of the several separate phenols, was able 

 to prove that catechol, phenol, and hydroquinone occur in the urine of 



>8o H. Boruttau and E. Stadelmann, Biochem. Z., 61, 372-386 (1914). 



'" A. E. Braunstein, A. N. Parschin, and O. D. Chalisowa, Biochem. Z., 235, 311-327 

 (1931). 



^^^ O. Schmiedeberg, Naunyn-Schmiedeberg's Arch, expil. Pathol. Pharmakol., 14, 288- 

 312(1881). 



183 L. Brieger, Arch. Anat. Physiol. SuppL, 1879, 61-68. 



'8^ M. Nencki and P. Giacosa, Z. physiol. Chem., 4, 325-338, 339-344 (1880). 



'85 E. Baumann and C. Preusse, Arch. Anat. Physiol., Physiol. Abt., 1879, 245-249. 



i8« E. Baumann and C. Preusse, Z. physiol. Chem., 3, 156-160 (1879). 



18^ H. D. Baernstein, /. Biol. Chem., 161, 685-692 (1945). 



