Aromatic (alpha)-hydroxy-amides used as insect repellants - are prepd. e.g. from mandelic acid

摘要

Aromatic alpha-hydroxyamides of formula (I) are new In (I) R1 is CO, opt. branched 1-10C alkylene, 2-12C alkenylene, 1-10C alkanylylidene, 2-12C oxoalkylene, 3-13C oxoalkenylene or 2-12C oxoalkanyl-ylidene opt. substd. with 1-10C alkyl methylene, 2-10C alkenyl, 1-10C alkoxy, OH, 1-10C hydroxyalkyl, 2-10C hydroxyalkenyl or 1-10C hydroxy: alkoxy; R2-3 are each H, 1-10C alkyl, 2-10C alkenyl, or together form a 5-10C (pref. 5-6) membered ring opt. contg. another heteroatom and opt. substd. with lower alkyl and/or lower alkenyl; R4 is OH, 1-10C alkyl or 1-10 C alkoxy. R5 is H, 1-10C alkyl, 1-10C alkoxy or Ph; a is 0 or 1, b is 0 if R1 is alkanyl-ylidene or 1 if R1 is any other gp.; and m and n are 0-3; including the D-, L- and DL- forms if b is 1). (I) are hydrophilic and lipophilic, are tolerated on the skin and mucous membranes, are colourless and practically odourless. (I) because of their low vapour pressure are effective over long periods and in low concns. e.g. N,N-diethyl-D,L-mandelic acid amide at a concn. of 3.1 wt. % repelo mosquitos for 8 hrs., and at a concn. of 1.6 wt. % repels mosquitos for 6 hrs. (I) are comparatively stable and are not readily hydrolysed, e.g. by perspiration.