Indoles, antimicrobial activity

The results of investigation revealed that the introduction of phenylazo group in the third position in pyrrole ring of benzopynoloindole gives the key cycle, lH,10H-benzo[e]pyrrolo[3,2-g]indole, antimicrobial activity towards different pathogenic bacteria and opportunistic pathogenic bacteria. 

Condensation of 165 with ethoxymethylenemalononitrile gave 171, and with ethyl ethoxymethylenecyanoacetate or methyl bis(methylmercapto)-methylene cyanoacetate it yielded 172 (80AP108). The reaction of 172 with urea, thiourea, and benzyl nitrile afforded 173 (91PHA98). Treatment of hydrazino derivatives 165 with alkyl, aryl, or aralkyl isothiocyanates yielded (86JHC1731) 3-(/V-substituted-thiocarbamoyl)-hydrazino[l,2,4]triazino[5,6-b]indoles which have been evaluated for in vitro antimicrobial activity (Scheme 36). 

Sterically controlled legiospecific heterocyclization of aldehydo sugars (5-methyl-13,4-triazino[5,6-h]indol-3-yl)hydrazones 116 to 3-(alditol-l-yl)-10-methyl[13>4]triazolo-[4, 3 23][l,2,4]triazino[5,6-b]indoles 117 has been carried out and the antimicrobial activity of some representative memberes tested <99PHA580>. 

A series of tricyclic indole alkaloids (physostigmine alkaloids) has been obtained from the cheilostome bryozoan Flustrafoliacea (90). In addition, flustramide B (83) and flustrarine B (84) were isolated from this bryozoan (91). Flustrarine B (84) was prepared from previously known fiustramine B (85) (92) via oxidation with hydrogen peroxide. Five fiustramine derivatives, dihydroflustramine C (86) and its N-oxide (87), fiustramine D (88) and its N-oxide (89), and isoflustramine D (90), were isolated from the methylene chloride fraction of the aqueous methanol extract of a Canadian F. foliacea, and these alkaloids were found to be responsible for the antimicrobial activity of the extract (93). Oxidation of dihydroflustramine C (86) and fiustramine D (88) with m-chloroperbenzoic acid afforded the corresponding A-oxides (87 and 88, respectively). 

Aromatic and phenolic compounds can mediate UV-protecting activities, which might be favorable for plants living in UV-rich environments, such as high altitudes [1[. Alkaloids (such as isoquinoline, quinoline, and indole alkaloids) that derive from aromatic amino acids, such as phenylalanine, tyrosine, and tryptophan, may have UV-absorbing properties, besides antiherbivoral and antimicrobial activities. 

Methyl-lf/-indol-l-yl)butanoic acid 135 easily prepared from 3-methylindole and dihydro-2(3//)-furanone, was used in the synthesis of natural 12//-pyrido[l,2- 7 3,4-/ ]diindoles which have antimicrobial activity and are cytotoxic against L-1210 mouse leukemia (Equation 25) <1996TL5207>. 

Yang Y, Zuo WJ, Zhao YX, Dong WH, Mei WL, Dai HF. Indole alkaloids from Kopsia hainanensis and evaluation of their antimicrobial activity. Planta Med 2012 78(17) 1881. ... 

Some indole derivatives also show promising antimicrobial activity. Five out of 24 bisindo-lyhnethane Schtff base derivatives S3mthesized were found to specifically inhibit Salmonella tjfphi, S. paratyphi A and S. paratyphi B, even if the inhibition was moderate at best, when nitro or halogen substituents were introduced [43]. 

Epoxidation of 3-aroylmethylene-indole-2-ones (173) with 30% aqueous hydrogen peroxide using cetyltrimethyl ammonium bromide (CTAB) as a phase-transfer catalyst under ultrasound irradiation afforded spiro[indole-3,2-oxiranes] derivatives (174) in 90%-97% yields (Scheme 8.55). The lead compounds showed potent antimicrobial activity and antioxidant properties (Dandia et al. 2011a). 

Deeni Y, Hussain H (1991) Screening for antimicrobial activity and for alkaloids of Nauclea latifolia. J Ethnopharmacol 35 91-96. doi 10.1016/0378-8741(91)90137-3 Cardoso CL, Castro-Gamboa I, Silva DHS, Furlan M, Epifanio RA, Pinto AC, Rezende CM, Lima JA, Bolzani VS (2004) Indole glucoalkaloids from Chimarrhis turbinata and their evaluation as antioxidant agents and acetylcholinesterase inhibitors. J Nat Prod 67 1882-1885. doi 10.1021/np049863m... 

Tetrabromo-l /7-indole showed antimicrobial activity and, at a level of 100 mcM per 12.7-mm disk, produced inhibition zones of 16 and 14 mm for... 

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