Molluscicidal activity of 2-hydroxy-[1,4]naphthoquinone and derivatives

Abstract

The toxic profile of lawsone (2-hydroxy-[1,4]naphthoquinone) and a series of [1,4]naphthoquinone derivatives was evaluated against the brine shrimp Artemia salina and against the mollusk Biomphalaria glabrata, the main transmitting vector of schistosomiasis in Brazil. Of the seventeen compounds tested nine fell below the threshold of 100 µg/mL set for potential molluscicidal activity by the World Health Organization. As a general rule derivatives with non-polar substituents presented the highest molluscicidal activities. These substances showed significant toxicity in A. salina lethality bioassay.

Synthesis of New 2-N,N' ­ dialkylamino-1,4-naphthoquinone Derivatives: Concerning the Reactivity of Lapachol with Secondary Amines

“…[9][10][11][12][13] In our group, we have been found facile acess to lapachol (1) by extraction from Brazilian Tabebuia sp (ipê) heartwood, 14 allowed us to observe that (1) reacts with neat primary amines to yield phenazines 15 (2) (Scheme 1), in the so called Strecker degradation oxidation. 16 This behavior contrasts with other previously direct substitution procedure explored by our group 12,17,18 which the 2-methoxy derivative of (1a) or synthetic nor-lapachol (5) smoothly afford the formation of 2-aminoalkyl derivatives and some other interesting unexpected cyclization products (Scheme 1).…”

“…17, 18 The change in reactivity profile is attributed to the etho l s i pro ed leaving group character in compound (1a) compared to the hydroxyl group in lapachol. In this paper our interest was to synthesize a series of 2-dialkylamino derivatives obtained by direct displacement of 2-methoxylapachol (1a), 2-methoxy-nor-lapachol (5a) and 2-methoxy-lawsone (6a) with suitable secondary amines from an inexpensive source.…”

“…In this paper our interest was to synthesize a series of 2-dialkylamino derivatives obtained by direct displacement of 2-methoxylapachol (1a), 2-methoxy-nor-lapachol (5a) and 2-methoxy-lawsone (6a) with suitable secondary amines from an inexpensive source. 12,17,18 The compounds were synthesized in a straightforward procedure using suitable cyclic and acyclic secondary amines (Scheme 2) and the series obtained had their structure confirmed by usual spectroscopy techniques. In this work we also compared the NMR spectroscopic data of synthesized compounds with data previously reported in the literature, discussing some observed disagreements in previously reported data.…”

Structural and reactivity analyses of 2-benzylamino-1,4-naphthoquinone by X-ray characterization, electrochemical measurements, and dft single-molecule calculations

“…[8][9][10][11][12][13] Among these chemical compounds, a particular bioactive derivative is the 2-benzylamino-1,4-naphthoquinone 1, since this compound is a useful intermediate in the synthesis of densely substituted nitrogen heterocycles. 2,14,15 Despite 1 has been described many years ago, new developments in its preparations have been reported, 16,17 and considering its synthetic and biological applications, no structural study of such compound seems to be described in the literature. In this way, in our ongoing investigation on the chemistry of enaminones, [18][19][20][21][22] we describe herein our results concerning the structural and reactivity analyses through X-ray solid state characterization, electrochemical measurements, and employing density functional theory calculations for this substance.…”

Obtenção e avaliação da atividade de compostos isolados de Piper em modelos biológicos para o controle da esquistossomose mansônica.

“…Estratégias que envolvam seu controle são prioritárias para a redução da transmissão da esquistossomose mansonica, pois além de ser o organismo mais vulnerável no ciclo de transmissão, sua eliminação previne a infecção de pessoas em contato com águas em áreas de risco (CAMARA et al, 2008;LARDANS;DISSOUS, 1998;WHO, 1984).…”