Ureas sentence example
- Mez (ibid., 1901, 35, p. 242) on substituted ureas, illustrate this point.
- 3, p. 319.) Ammonia finds a wide application in organic chemistry as a synthetic reagent; it reacts with alkyl iodides to form amines, with esters to form acid amides, with halogen fatty acids to form amino-acids; while it also combines with isocyanic esters to form alkyl ureas and with the mustard oils to form alkyl thioureas.
- They are readily hydrolysed by water, and combine with bases to form alkyl ureas, and with alcohols to form carbamic esters.
- Alkyl ureas are formed by the action of primary or secondary amines on isocyanic acid or its esters: [[Conh+Nh2r= R Nhc0nh]] 2 i [[Conr+Nhr 2 =Nr 2 Co Nhr]]; by the action of carbonyl chloride on amines: COC12+2NHR2=C0(NR2)2+2HC1; and in the hydrolysis of many ureides.
- The symmetrically substituted ureas are generally tasteless, while the asymmetrical derivatives are sweet.Advertisement
- Investigation of the cyanic ethers (1848) yielded a class of substances which opened out a new field in organic chemistry, for, by treating those ethers with caustic potash, he obtained methylamine, the simplest organic derivative of ammonia (1849), and later (1851) the compound ureas.