NATURAL WAXES 310 



There are a number of substances with which the alcohols react to form 

 stable crystalline compounds readily identifiable by their melting points. 

 The most common derivative is the urethan which is formed by a reaction 

 of the alcohol and isocyanate. The formation of the phenylurethan of 

 myristyl alcohol (1-tetradecanol) is illustrated here. In addition to phenyl- 



H yp 



CsH5N = C=0 + H0CH2(CHg),2CH3 ► C6H5N-C-0CH2(CH2),2CH3 



Phenyl iso- Myristyl Phenylurethan 



cyanate alcohol of myristyl alcohol 



urethan, the a-naphthylurethans,^^-^^ the p-nitrophenylurethans/"" and 

 the SjS-dinitrophenylurethans^"' give satisfactory derivatives for identifica- 

 tion. A number of other substituted urethans, including the o-, m-, and 

 p-nitrophenyl derivatives, are crystalline. The higher alcohols form car- 

 bamates on heating with carbamic acid. 



Esters with characteristic melting points result when the higher alcohols 

 react with 3,5-dinitrobenzoic acid.^"^ p-Nitrobenzoates have likewise been 

 prepared. ^"^ 



b. Sterols. The sterols comprise one of the most interesting groups 

 of lipids. These products are alcohols which possess a cyclic structure 

 containing the cyclopentenophenanthrene ring. In nature they occur 

 free, as well as combined with fatty acids in an ester linkage. In the 

 latter case the products are considered to be waxes. 



Although the sterols are a most important group in themselves, they are 

 merely a class of a larger division to which Callow and Youngi*** have given 

 the names ''steroids." The term "steride" is sometimes employed in the 

 same connection. These compounds containing a steroid nucleus are 

 widely distributed in nature. They are of especial interest because they 

 possess very specific and potent physiological effects. In this category 

 are included the sex hormones, the adrenocorticohormones, the bile acids, a 

 number of provitamins D, as well as those saponins which comprise the 

 glucosides of the digitalis group, and the so-called sapogenins. 



Few fields in organic chemistry have been as fruitful during the last 

 several decades as has that of steroid chemistry. During this time not 

 only has the structure of a large group of sterols been elucidated, but also 

 the chemistry of the much larger number of hormones and related steroids 

 has been disclosed. The subject of steroids has been exhaustively dis- 

 ss C. Neuberg and E. Kanskv, Biochem. Z., SO, 445-449 (1909). 



99 V. T. Bickel and H. E. French. J. Am. Chem. Soc, 48, 747-751 (1926). 



«» R. L. Shriner and R. F. B. Cox, /. Am. Chem. Soc, 53, 1601-1605 (1931). 



•»i F. Hoeke, Rec. trav. chim., 64, 505-517 (1935). 



>»2 C. B. Malone and E. E. Reid, /. Am. Chem. Soc, 51, 3424-3427 (1929). 



1" H. Henstofk, J. Chem. Soc, 1933, 216. 



»"^ H. K. ("allow and F. G. Young, Proc Royal Soc. London, A157, 194-212 (1936). 



