Synthesis of new aldehyde derivatives from β-lapachone and nor-β-lapachone

Abstract

Derivatives 6a and 6b, have been obtained in a chemoselective manner by a two step synthesis from β-lapachone (3a) and nor-β-lapachone (3b), respectively, using CH 2 N 2 in ether, which provided the lapachone-epoxide derivatives, 5a and 5b, followed by treatment with BF 3 .Et 2 O/CH 2 Cl 2 . Basic work-up of the reaction mixture of 5a or 5b with BF 3 .Et 2 O/CH 2 Cl 2 led instead to isolation of the rearranged derivatives 7a and 7b, respectively. An ab initio theoretical study [B3LYP/6-311+G(d)] on 3a indicated that the carbon atom, C6, carries a higher positive charge than that at C5 and hence predicts a greater reactivity towards nucleophiles at C6. Another important factor controlling the chemoselectivity in the reaction of 3a with CH 2 N 2 is the steric hindrance of the CH 2 groups of the pyran ring.

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“…The available literature confirmed that there is a strong correlation between nutrients, photosynthesis and secondary metabolite production. Plants such as Alstonia extracts obtained from these plants were used to treat many ailments such as fever, malaria [33], tumors [34], asthma [35], antidiabetic [36] and antioxidant [37]; antitumor activity, antimetastatic activity anti-microbial and antifungal activity [38,39], antiviral activity [40], anti-inflammatory [41], antiparasitic activity [42], leishmanicidal activity [43]and molluscicidal activity [44];…”

Antioxidant Activity and Phytochemical Screening of Crude Endophytes Extracts of <i>Tabebuia argentea</i> Bur. & K. Sch.

“…The antitumor activity of lapachol may be due to its interaction with nucleic acids and the interaction of the naphthoquinone moiety between base pairs of the DNA helix occurs with subsequent inhibition of DNA replication and RNA synthesis [4]. Other biological activities of lapachol are antimetastatic activity [5], antimicrobial and antifungal activity [6], antiviral activity [7], anti-inflammatory [8], antiparasitic activity [4], leishmanicidal activity [9] and molluscicidal activity [10].…”