The synthesis of 2- and 3-substituted indoles

One of the main groups of organic compounds containing nitrogen in both cyclic systems and straight chains is the alkaloids. Indole is perhaps the single most common heterocycle in all of chemistry and it is embodied in a myriad of natural products, pharmaceutical agents and a growing list of polymers. This dissertation presents method for the synthesis of substituted indoles bearing aryl substituents onto the 2- and 3- position as well as 2,3-fused indoles. The route for the synthesis of the aryl substituted indoles starts from the indole nucleus which was protected using the phenylsulfonyl group because it was found that the group is easy to remove and does not require harsh conditions. After successful protection of the indole nucleus NH as Nphenylsulfonyl, bromine was introduced at the 3-position of the indole nucleus while iodine was introduced at the 2-position of the indole nucleus. The bromination of the indole nucleus was not easily achieved because the reaction of molecular bromine with indole resulted in the formation of 2,3-dibromoindole while activated 5-methoxyindole gave an insoluble 2,3,4-tribromoindole. However, this problem was solved by refluxing indole with molecular bromine in the presence of sodium methoxide while activated 5-methoxyindole was refluxed with N-bromosuccinimide in the presence of catalytic benzoyl peroxide. 2-Iodoindoles were synthesized using directed ortho metallation, where isopropyl magnesium chloride was used in the presence of catalytic amount of diisopropylamine. Using standard aqueous Suzuki-Miyaura cross-coupling in the presence of sodium carbonate as a base, 2-aryl, 3-aryl as well as 2,3-diaryl substituted indoles were synthesized in good to excellent yields. The synthesis of 2,3-fused indoles was achieved in poor yields starting from 1-(phenylsulfonyl)indole which was alkylated using allyl bromide at the 2- position and formylated at the 3-position of the indole nucleus to the cyclization of the alcohols using mercury acetate

Further studies on South African plants : acaricidal activity of organic plant extracts against Rhipicephalus (Boophilus) microplus (Acari : Ixodidae)

The goal of our research is to develop a lower cost eco-friendly tick control method because acaricides that are commonly used to control ticks are often toxic, harmful to the environment or too expensive for resource-limited farmers. Acetone and ethanol extracts were prepared and their acaricidal activities determined against the southern cattle tick, Rhipicephalus (Boophilus) microplus. A 1% solution of each of the plant extracts was prepared for efficacy testing using the adapted Shaw Larval Immersion Test (SLIT). The acetone stem extract from Cissus quadrangularis (Vitaceae) and the ethanol leaf and flower extract from Calpurnia aurea (Fabaceae) had potent activity like that ofthe commercial acaricide, chlorfenvinphos [corrected mortality (CM) = 100.0%]. The ethanol extracts ofthe stem of C. quadrangularis (CM = 98.9%) and that of the roots, leaves and fruit of Senna italica subsp arachoides (CM = 96.7%) also had good acaricidal activity. There is potential for the development of botanicals as natural acaricides against R. (B.) microplus that can be used commercially to protect animals against tick infestation. Further studies to isolate the acaricidal active compounds and to determine the environmental fate, species toxicity and skin toxicity of these plants species are, however, required before they can be considered as a treatment against ticks.The Technology Innovation Agency (TIA) of South Africahttp://www.elsevier.com/locate/vetpar2018-01-31hb2017Paraclinical Science

Anthelmintic activity of acetone extracts from South African plants used on egg hatching of Haemonchus contortus

The nematode, Haemonchus contortus, is responsible for major economic losses in the livestock industry. The management of parasites such as H. contortus has been through the use of synthetic parasiticides. This has resulted in the presence of residues in meat and milk, which affects food safety. The development of resistance to available anthelmintics coupled with their high cost has further complicated matters. This has led to the investigation of alternative methods to manage nematodes, including the use of plants and plant extracts as a potential source of novel anthelmintics. Acetone extracts were prepared from 15 South African plant species and their anthelmintic activity determined using the egg hatch assay (EHA). The leaf extract of Cleome gynandra had the best inhibitory activity (68% ± 3%) at a concentration of 2.5 mg/mL, followed by the stem extract of Maerua angolensis (65% ± 5%). The extracts had a relatively low toxicity on Vero cells determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) cellular assay.The Technology Innovation Agency (TIA) of South AfricaAcetone extractsam2016Paraclinical Science

Investigation of the acaricidal activity of the acetone and ethanol extracts of 12 South African plants against the adult ticks of Rhipicephalus turanicus

The acaricidal activity of acetone and ethanol extracts of 12 plant species was evaluated using the contact method on Rhipicephalus turanicus (Acari: Ixodidae) ticks at an initial concentration of 20% (200 mg/mL). Eight of the 12 plants had mortality greater than 50% and the acetone extracts had better acaricidal activity than the ethanol extracts. The acetone extract of Calpurnia aurea (leaves and flowers) had the highest corrected mortality (CM) of 92.2% followed by Schkuhria pinnata (whole plant) with a CM of 88.9%, Ficus sycomorus (bark and stems) 86.7% and Senna italica subsp. arachoides (roots, leaves and fruits) 83.3%. Selected extracts were tested at five different concentrations using the adult immersion test. From dose–response assays, EC50 values of 61.82 mg/mL, 115.21 mg/mL and 161.02 mg/mL were obtained for the acetone extracts of S. pinnata (whole plant), S. italica subsp. arachoides (roots, leaves and fruits) and C. aurea (leaves and flowers) respectively. The ethanol extract of Monsonia angustifolia (whole plant) had the highest CM of 97.8% followed by S. pinnata (whole plant) with a CM of 86.7%, C. aurea (leaves and flowers) 81.1% and Cleome gynandra (leaves) 77.8%. There is potential for the development of environmentally benign botanicals as natural acaricides against R. turanicus.The authors thank the Technology Innovation Agency (TIA) of South Africa for financial support.http://www.ojvr.orgam2018Paraclinical Science

Acaricidal activity of the organic extracts of thirteen South African plants against Rhipicephalus (Boophilus) decoloratus (Acari : Ixodidae)

The African blue tick, Rhipicephalus (Boophilus) decoloratus, is a common tick species found in South Africa and affects cattle production as well as vectoring pathogens in regions of Africa and Asia. In an attempt to develop a non-toxic, lower cost and environmentally friendly tick control method, twenty-six plant extracts were prepared from thirteen plant species using 99.5% acetone and 99% ethanol. The adapted Shaw Larval Immersion Test (SLIT) was used to test the efficacy of the extracts. A 1% solution of each of the plant extracts was prepared for efficacy testing and the ethanol extracts were found to have better acaricidal activity than the acetone extracts. The ethanol extract from the leaves and flowers of Calpurnia aurea had the best activity [Corrected Mortality (CM) = 82.9%] which was followed by the stem extract of Cissus quadrangularis (CM = 80.4%). The plant species were screened against Vero cells and were found to have low toxicity. From this study it is apparent that there is potential for the development of botanicals as natural acaricides against R. (B.) decoloratus.Technology Innovation Agency (TIA) of South Africa.http://www.elsevier.com/locate/vetpar2017-07-31hb2016Paraclinical Science

The effect of work conditions and general health on employees performance in mining industry in Limpopo Province

MCom (Human Resource Management)Department of Human Resources Management and Labour RelationsSee the attached abstract belo

Novel syntheses of 5- and 7- azaindole derivatives

This thesis describes the application of the Sonogashira coupling reaction to access a variety of 5-and 7-azaindoles derivatives. The background chapter paints a picture about the importance of indole-containing compounds and azaindole-containing compounds. In this first chapter, discovery, synthesis, properties and reactivity of indole and azaindoles were explained

Benzylated Sulfamethoxazole Derivatives with Improved Safety Profile as Potential Anti-Mycobacterium tuberculosis and Antibacterial Agents

This study focussed on the synthesis of sulfamethoxazole derivatives and their biological evaluation. The sulfamethoxazole derivatives were successfully biologically evaluated against Mycobacterium tuberculosis, Staphylococcus aureus, and Chinese Hamster Ovarian (CHO) cells. The biological evaluation revealed compounds with improved antitubercular activity and antibacterial activity against S. aureus as well as safety profile when compared to the starting material, sulfamethoxazole. The most active compounds against Mycobacterium tuberculosis were3q with 92% inhibition followed by 3s (90%), 3k (88%), 3t (85%), and 3o (84%)

Acaricidal activity of the aqueous and hydroethanolic extracts of 15 South African plants against Rhipicephalus turanicus and their toxicity on human liver and kidney cells

Hot water and hydroethanolic (70:30) extracts were prepared from 15 plant species, which were investigated to discover eco-friendly and less expensive tick control methods as an alternative to synthetic acaricides. A contact bioassay was used to determine the acaricidal activity of these extracts against the cattle tick, Rhipicephalus turanicus (Acari: Ixodidae) at a concentration of 20% (200 mg/mL). The hydroethanolic extracts had better activity than the hot water extracts against R. turanicus. The hydroethanolic extract from Tabernaemontana elegans (leaves) had the best mortality (87.0%). This was followed by Calpurnia aurea (stems) with a mortality of 75.0%, Schkuhria pinnata (whole plant) with a mortality of 67.0% and Aloe rupestris (leaves) with a mortality of 66.6%. The toxicity of the plant extracts was also investigated and it was found that most of the hydroethanolic and hot water extracts were either safe or very safe on human Vero kidney and liver HepG2 cells. From this study, it was evident that botanicals have the potential to be developed as environmentally benign natural acaricides against R. turanicus.The Technology Innovation Agency (TIA) of South Africahttp://www.ojvr.orgam2020ChemistryParaclinical Science

Investigation of the acaricidal activity of the acetone and ethanol extracts of 12 South African plants against the adult ticks of <i>Rhipicephalus turanicus</i>

The acaricidal activity of acetone and ethanol extracts of 12 plant species was evaluated using the contact method on Rhipicephalus turanicus (Acari: Ixodidae) ticks at an initial concentration of 20% (200 mg/mL). Eight of the 12 plants had mortality greater than 50% and the acetone extracts had better acaricidal activity than the ethanol extracts. The acetone extract of Calpurnia aurea (leaves and flowers) had the highest corrected mortality (CM) of 92.2% followed by Schkuhria pinnata (whole plant) with a CM of 88.9%, Ficus sycomorus (bark and stems) 86.7% and Senna italica subsp. arachoides (roots, leaves and fruits) 83.3%. Selected extracts were tested at five different concentrations using the adult immersion test. From dose–response assays, EC50 values of 61.82 mg/mL, 115.21 mg/mL and 161.02 mg/mL were obtained for the acetone extracts of S. pinnata (whole plant), S. italica subsp. arachoides (roots, leaves and fruits) and C. aurea (leaves and flowers) respectively. The ethanol extract of Monsonia angustifolia (whole plant) had the highest CM of 97.8% followed by S. pinnata (whole plant) with a CM of 86.7%, C. aurea (leaves and flowers) 81.1% and Cleome gynandra (leaves) 77.8%. There is potential for the development of environmentally benign botanicals as natural acaricides against R. turanicus