The phytochemistry of the genus Piper (Piperaceae) has been widely studied due to the biological properties of amides from these plants. In this work, we have synthesized and evaluated the toxic effect of 11 amides against the fall armyworm Spodoptera frugiperda larvae. The naturally occurring piperine was also evaluated. The most active amide was N-[3-(3Ј,4Ј-methylenedioxyphenyl)-2-(E)-propenoyl]piperidine with a LD 50 of 1.07 µg mg Ð1 larvae. This amide was also evaluated by ingestion.

The fall armyworm Spodoptera frugiperda is a polyphagous pest that causes important damage in different regions of America and mainly affects corn crops in both tropical and subtropical areas. Currently, control relies on both transgenic plants and/or chemical pesticides. In this work we describe the preparation of an indexed combinatorial library of amides and its toxic effect by contact against S. frugiperda . (E)-1-(1-Piperidinyl)-3-[4-(trifluoromethoxy)phenyl]-2-propen-1-one was the most active compound with an LD(50) = 0.793 μg mg(-1) of larva. This amide was also evaluated by ingestion and at the lowest concentration (1 mg kg(-1)) achieved 83.3% mortality.

1 Nine synthetic amides similar to natural N-piperidine-3-(4,5-methylenedioxyphenyl)-2-(E)-propenamide and N-pyrrolidine-3-(4,5-methylenedyoxiphenyl)-2-(E)-propenamide were synthesized and identified by their spectroscopic data. 2 The toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leucoagaricus gongylophorus, the symbiotic fungus of the leaf-cutting ants, were determined. 3 Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N-pyrrolidine-3-(3 0 ,4 0 -methylenedioxyphenyl)-2-(E)-propenamide and N-benzyl-3-(3 0 ,4 0 -methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mg/mL. 4 The completely inhibition (100%) of the fungal growth was observed with Npiperidine-3-(3 0 ,4 0 -methylenedioxyphenyl)-2-(E)-propenamide and N,N-diethyl-3-(3 0 ,4 0 -methylenedioxyphenyl)-2-(E)-propenamide at concentrations of 50 and 100 mg/mL and N-pirrolidine-3-(3 0 ,4 0 -methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mg/mL. 5 The possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.

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In the kinetically-controlled enzymatic synthesis of amoxicillin catalyzed by penicillin G acylase (PGA, E.C.3.5.1.11) p-hydroxyphenylglycine (PHPG) is a by-product continuously formed in the reaction. Also, methyl ester is the standard substrate used in the production of amoxicillin generating methanol as a byproduct. Thus, we assessed the recovery and reuse of PHPG as reactant for the synthesis of p-hydroxyphenylglycine ethyl ester substrate (PHPGEE) and the integration to the process through the recycle of PHPGEE for the reactor of enzymatic synthesis of amoxicillin generating ethanol as a by-product. Recovery of the byproduct of the enzymatic synthesis of amoxicillin was effective reaching a purity of 99% for the PHPG. Purified PHPG was successfully employed in the production of PHPGEE with a conversion of 93%. The enzymatic synthesis of amoxicillin employing the previously synthesized PHPGEE was feasible following the characteristic profile that is expected for these reactions.