Cyanamides oxazoles, 2-amino

Cyanamide in methanolic ammonia converts 21-hydroxypregnan-20-ones (463) into 17j8-(2-amino-oxazol-4-yl)androstanes (464). The reaction proceeds equally well in the presence of a 17a-hydroxy-group. ... 

Oxazole itself has been prepared from its 4,5-diester, by hydrolysis then decarboxylation though this formally falls into the same category of synthesis, it is probable that the ring oxygen derives from the 2-hydroxy-ketone, and not from the formamide the reaction of acyloins with formamide can be looked on as a general approach to oxazoles. " The use of cyanamide gives 2-amino-oxazoles. ... 

Condensation with the appropriate components is widely represented in literature approach to fluoroaUcyl derivatives of oxazole. Fluoroalkyloxazoles are of interest due to their application as surface modifiers of hydrophilic polymers, polymeric films for second-order non-linear optics, effective herbicides, body-membrane penetration enhancers, and intermediates for the synthesis of unnatural a-amino acids [12]. Thus, the syntheses of the trifiuoromethylated 2-aminooxazoles 8 and 9 were performed by reacting commercially available trifiuorobromoacetone with five equivalents of urea or cyanamide in refluxing fe/t-butanol to afford the corresponding 4- and 5-trifluoro-methyl-2-aminooxazoles in 70 % and 14 % yields, respectively [13,14]. 

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See also in sourсe #XX -- [ , ]

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