6537-44-6

Upstream product

• 4707-32-8 2,2-dimethyl-3,4-dihydro-2H-benzo[h]chromene-5,6-dione 
• 95-54-5 1,2-diamino-benzene 
• 39145-59-0 o-phenylenediamine hydrochloride 

Relevant academic research and scientific papers

Preparation and NMR characterization of new substituted benzo[a]phenazines

Benzo[a]phenazines were prepared by condensation of β-lapachone with 1,2-phenylenediamme and 4-chloro-1,2-phenylenediamine. The latter diamine gave two regioisomers that could be separated and unambiguously identified by means of their 1H and 13C NMR spectra with the aid of 2D NMR experiments, mainly HETCOR and COLOC.

Reaction of β-lapachone with 1,2-diamines: Facile synthesis of novel tetracyclic pyrazines

The reactions of β-lapachone (1) with 1,2-diaminoethane (2) and 1,2-diaminopropane (4) gave the tetracyclic pyrazine derivatives (3) and mixtures of (5) and (6), respectively, while reaction with o-phenylene diamine (7) gave the quinoxaline derivative (8). The structure of pyrazine derivative (3) is confirmed by single-crystal X-ray diffraction study. Copyright Taylor & Francis Group, LLC.

Antimalarial activity of phenazines from lapachol, β-lapachone and its derivatives against Plasmodium falciparum in vitro and Plasmodium berghei in vivo

The antimalarial activity of benzo[a]phenazines synthesized from 1,2-naphthoquinone, lapachol, β-lapachone and several derivatives have been tested against Plasmodium falciparum in vitro using isolates of parasites with various susceptibilities to chloroquine and/or mefloquine. Parasite growth in the presence of the test drugs was measured by incorporation of [ 3H]-hipoxanthine in comparison to controls with no drugs, always testing in parallel chloroquine, a standard antimalarial. Among seven benzophenazines tested, four had significant in vitro activities; important, the parasites resistant to chloroquine were more susceptible to the active phenazines in vitro. The doses of phenazines causing 50% inhibition of parasite growth varied from 1.67 to 9.44 μM. The two most active ones were also tested in vivo against Plasmodium berghei in mice, in parallel with lapachol and β-lapachone. The 3-sulfonic acid-β-lapachone-derived phenazine was the most active causing up to 98% inhibition of parasitaemia in long term treatment (7 doses) subcutaneouly, whereas the phenazine from 3-bromo-β-lapachone was inactive. Thus, these simple phenazines, containing polar (-Br,-I) and ionizable (-SO3H, -OH) groups, easily synthesized from cheap, natural or synthetic precursors (lapachol and β-lapachone), at rather low cost, provide prototypes for development of new antimalarials aiming the chloroquine resistant parasites.

Chemistry of lapachol - Syntheses of some new biogenetically related naphthoquinones, naphthoquinone dimers, naphthaquinoxaline and naphtha-azaquinoxaline derivatives from lapachol

The present short review focus on chemical transformations of lapachol to a large number of biogenetically related lapachol conegeners, dimers and heterocyclic analogues that have been achieved in our laboratory during more than two decades. Conversion of lapachol to stenocarpoquinone-B, rhinacanthin-A, β-(l-hydroxyisopropanyl)-dihydrofurano-1,2-naphthoquinone, stenocarpoquinone-A, dehydro-α-lapachone and dehydro-β-lapachone by the reaction with m-chloroperbenzoic acid; dehydroiso-α-lapachone, dehydroiso-β-lapachone, dehydro-α-lapachone, α-lapachone and β-lapachone by the reaction with aqueous NaNO2 and glacial AcOH; adenophyllone, quadrllone and dehydro-α-lapachone by the reaction with boiling pyridine; naphthaquinoxaline and naphtha-azaquinoxaline derivatives by the reaction with 1,2-diamines and dialkyltin dilapacholates by the reaction with dialkyltin diisopropoxides have been accomplished. Notably the syntheses of rhinacanthin-A, β-(1-hydroxyisopropanyl)-dihydrofurano-1,2-naphthoquinone, dehydroiso-α-lapachone, dehydroiso-β-lapachone, adenophyllone and quadrllone have been reported for the first time from our group starting from lapachol. The synthesis of novel naphthaquinoxaline and azaquinoxaline derivatives from lapachol has been additional interesting results of this investigation.

A macrolactone from benzo[a]phenazine with potent activity against Mycobacterium tuberculosis

We report here an alternative to the MCPBA or ozonolysis-based oxidation methods of quinoxaline-featuring compounds prepared from beta-lapachones. The use of peracetic acid allowed a simple preparation of the corresponding macrolactones by cleavage of the ring system. These lactones were evaluated for their antimycobacterial potential and compound 4 turned out to have an MIC of 0.62 μg per mL on Mycocabteriumtuberculosis H37Rv. These results justify further research into its value as a potential lead for an original treatment of tuberculosis.

Studies on novel polycyclic heterocycles: Synthesis of new naphthaquinoxaline and naphthazaquinoxaline derivatives from naturally occurring quinones

A facile synthesis of novel polycyclic heterocycles namely naphthaquinoxaline and naphthazaquinoxaline derivatives is carried out by the reaction of lapachol and β-lapachone, naturally occurring naphthoquinones with o-phenylene diamine and 2,3-diaminopyridine. Regioselectivity in the reaction of β-lapachone with 2,3-diaminopyridine is confirmed by single crystal X-ray diffraction of a representative compound 6,7-dihydro-8,8-dimethyl- 8//-pyrano[3',2':4]-naphtha[2,l-e]pyrido[2,3-b]pyrazine; C20H 17N3O, crystallizes as orthorhombic in the space group Pbca with cell parameters a =9.793(3)A, b=17.514(6)A, c=18.334(6)A, V=3144.5(17) A3, Z=8,1.332 mg/m 3, R1=0.3076, WR2=0.3595.