The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Gary A Molander - One of the best experts on this subject based on the ideXlab platform.
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late stage c h alkylation of heterocycles and 1 4 quinones via oxidative homolysis of 1 4 dihydropyridines
Journal of the American Chemical Society, 2017Co-Authors: Alvaro Gutierrezbonet, Camille Remeur, Jennifer K Matsui, Gary A MolanderAbstract:Under oxidative conditions, 1,4-dihydropyridines (DHPs) undergo a homolytic cleavage, forming exclusively a Csp3-centered radical that can engage in the C–H alkylation of heterocyclic bases and 1,4-quinones. DHPs are readily prepared from aldehydes, and considering that aldehydes normally require harsh reaction conditions to take part in such transformations, with mixtures of alkylated and acylated products often being obtained, this net decarbonylative alkylation approach becomes particularly useful. The present method takes place under mild reaction conditions and requires only persulfate as a stoichiometric oxidant, making the procedure suitable for the late-stage C–H alkylation of complex molecules. Notably, structurally complex pharmaceutical agents could be functionalized or prepared with this protocol, such as the antimalarial Atovaquone and antitheilerial Parvaquone, thus evidencing its applicability. Mechanistic studies revealed a likely radical chain process via the formation of a dearomatized i...
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Late-Stage C–H Alkylation of Heterocycles and 1,4-Quinones via Oxidative Homolysis of 1,4-Dihydropyridines
2017Co-Authors: Álvaro Gutiérrez-bonet, Camille Remeur, Jennifer K Matsui, Gary A MolanderAbstract:Under oxidative conditions, 1,4-dihydropyridines (DHPs) undergo a homolytic cleavage, forming exclusively a Csp3-centered radical that can engage in the C–H alkylation of heterocyclic bases and 1,4-quinones. DHPs are readily prepared from aldehydes, and considering that aldehydes normally require harsh reaction conditions to take part in such transformations, with mixtures of alkylated and acylated products often being obtained, this net decarbonylative alkylation approach becomes particularly useful. The present method takes place under mild reaction conditions and requires only persulfate as a stoichiometric oxidant, making the procedure suitable for the late-stage C–H alkylation of complex molecules. Notably, structurally complex pharmaceutical agents could be functionalized or prepared with this protocol, such as the antimalarial Atovaquone and antitheilerial Parvaquone, thus evidencing its applicability. Mechanistic studies revealed a likely radical chain process via the formation of a dearomatized intermediate, providing a deeper understanding of the factors governing the reactivity of these radical forebears
R. Hashemi-fesharki - One of the best experts on this subject based on the ideXlab platform.
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Chemotherapeutic value of Parvaquone and buParvaquone against Theileria annulata infection of cattle.
Research in veterinary science, 1991Co-Authors: R. Hashemi-fesharkiAbstract:Abstract Parvaquone (BW993C), 2-cyclohexyl-3-hydroxy-1,4-naphthoquinone, and buParvaquone (BW720C) 2-(trans-4-t-butylcyclohexyl-methyl)-3-hydroxy-1,4-naphthoquinone, were evaluated to determine their therapeutic efficacy in the treatment of theileriosis caused by Theileria annulata infection in cattle in Iran. One hundred and fifty-nine pure and crossbred Bos taurus cattle, experimentally or naturally infected with T annulata, were treated. Parvaquone was injected into 86 animals with up to three doses of 20 mg kg−1 or 10 mg kg−1 at intervals of 48 hours between doses. BuParvaquone was injected into 73 animals. Up to three doses of 2·5-mg kg−1 were injected with an interval of 48 hours between doses. The recovery rate of animals treated with Parvaquone was 60 · 7 per cent and with buParvaquone it was 88 · 7 per cent. No significant side effects or relapse of disease were observed following the use of either compound. It is concluded that buParvaquone at a dose of 2 · 5 mg kg−1 has a satisfactory therapeutic index and is a more effective treatment of T annulata infection than Parvaquone. The prophylactic use of schizont tissue culture vaccine and chemotherapy with buParvaquone could be the most promising means of controlling theileriosis in Iran.
N. Mchardy - One of the best experts on this subject based on the ideXlab platform.
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Treatment of East Coast Fever of Cattle with a Combination of Parvaquone and Frusemide
Tropical Animal Health and Production, 2004Co-Authors: R. Azuba Musoke, R. Tweyongyere, E. Bizimenyera, S. Biryomumaisho, Antony Mugisha, Charles Waiswa, N. MchardyAbstract:Pulmonary oedema is a common sign of East Coast fever (ECF, Theileria parva infection) of cattle. A trial was conducted on farms in Uganda to compare a product containing both the antitheilerial compound Parvaquone and the diuretic compound frusemide with one containing only Parvaquone, in the treatment of ECF. The trial involved 40 clinical cases of ECF, some of them complicated by other infections, in cattle of all ages and on several farms. Confirmed cases were treated with either Parvaquone + frusemide (P+F) or Parvaquone alone (P). Survival after treatment with P+F was 77% compared with 71% with P. Five of the 10 fatalities were complicated cases. The cure rate for severe but uncomplicated ECF was 89% with P+F and 40% with P. Pulmonary signs were resolved within 24–48 h after treatment with P+F and clinical recovery was noticeably more rapid than with P. The antiparasitic effect of the two treatments was similar. P+F could be particularly useful when reporting, diagnosis or laboratory confirmation of ECF is delayed, because advanced cases are more likely to be encountered under these circumstances.
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treatment of east coast fever a comparison of Parvaquone and buParvaquone
Veterinary Parasitology, 1999Co-Authors: G R Muraguri, Henry K Kiara, N. MchardyAbstract:Two trials were conducted to compare the efficacy of Parvaquone and buParvaquone for the treatment of naturally acquired East Coast fever (ECF, Theileria parva infection) which, if untreated, is almost invariably fatal in European breeds of cattle. In the first trial 28 naive cattle were exposed in a paddock infested with ticks carrying a virulent form of the disease. Twelve were treated with each drug when they developed clinical ECF. All 24 cattle were cured. In the second study, 100 cases of ECF occurring naturally on farms in Kenya were treated, 50 with each drug. Parvaquone cured 44 (88%) buParvaquone cured 45 (90%). Intercurrent infections, predominantly anaplasmosis and bacterial pneumonia or scour, were treated specifically. It is concluded that Parvaquone and buParvaquone are similarly effective in curing ECF and cure rates are maximised by accurate diagnosis and prompt treatment of both ECF and intercurrent infections.
H A Mbwambo - One of the best experts on this subject based on the ideXlab platform.
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evaluation of buParvaquone buta kel kela belgium as a treatment of east coast fever in cattle in the peri urban of dar es salaam city tanzania
Veterinary Parasitology, 2006Co-Authors: H A Mbwambo, H B Magwisha, J M MfinangaAbstract:Abstract Evaluation trials of the efficacy of buParvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), as a treatment of field cases of Theileria parva infection (East Coast fever – ECF) were carried out on 63 cattle in the peri-urban of Dar Es Salaam city, Tanzania, during the period November 2004 to August 2005. Thirty-two cattle (56%) received single-dose treatment (2.5 mg buParvaquone per kg body weight), while two and three-dose treatment with interval(s) of 48 h was given to 33% and 11% of total treated cattle, respectively; 38 cattle (60.3%) were treated at an early stage of the disease, while 25 cattle (39.7%) were treated at an advanced stage of the disease. The rectal body temperature of 90.5% of buParvaquone-treated cattle dropped to normal values (37.5–39.5 °C) by day 7 of treatment, and by day 15 of treatment 96.8% of treated cattle showed normal values. Pulmonary signs were observed in 8/68 (11.8%) of total ECF diagnosed cattle and were successfully treated, albeit with Parvaquone plus frusemide (Fruvexon); were not included in final evaluation of the efficacy of BUTA-kel. The present evaluation trials record a recovery rate of 95.2%. BuParvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), therefore, records another efficacious and valuable alternative treatment against East Coast fever in Tanzania.
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comparative studies of the efficacy of Parvaquone and Parvaquone plus frusemide in the treatment of theileria parva infection east coast fever in cattle
Veterinary Parasitology, 2002Co-Authors: H A Mbwambo, J M Mfinanga, P. A. Mkonyi, F F Sudi, E S Mella, C J NgoviAbstract:Comparative studies of the efficacy of Parvaquone (Parvexon®) and Parvaquone-plus-frusemide (Fruvexon®) Bimeda Chemicals, Ireland, were done on 60 naturally infected cases of East Coast fever (ECF; Theileria parva infection in cattle). Small-scale dairy farmers in the peri-urban of Dar Es salaam city reported ECF-suspected cases from March to mid-October 2001 and were treated with the two drugs alternately, as were diagnosed positive for ECF. Four sub-groups of 15 cattle each (early stage, 15; advanced stage, 15) were treated with Parvaquone and Parvaquone-plus-frusemide. Twenty-eight out of 30 (93.3%) cattle treated with Parvaquone-plus-frusemide were cured, so do 24 out of 30 (80.0%) cattle treated with Parvaquone without frusemide. Early diagnosis and prompt management of pulmonary signs, which accounted for 30.0% of total ECF cases is advised in order to improve cure rates. Unlike Parvaquone without frusemide (Parvexon), Parvaquone-plus-frusemide (Fruvexon) proved useful in the management of pulmonary signs, hence, a drug of choice in the treatment of ECF cases that are accompanied by or are likely to manifest pulmonary signs.
J M Mfinanga - One of the best experts on this subject based on the ideXlab platform.
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evaluation of buParvaquone buta kel kela belgium as a treatment of east coast fever in cattle in the peri urban of dar es salaam city tanzania
Veterinary Parasitology, 2006Co-Authors: H A Mbwambo, H B Magwisha, J M MfinangaAbstract:Abstract Evaluation trials of the efficacy of buParvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), as a treatment of field cases of Theileria parva infection (East Coast fever – ECF) were carried out on 63 cattle in the peri-urban of Dar Es Salaam city, Tanzania, during the period November 2004 to August 2005. Thirty-two cattle (56%) received single-dose treatment (2.5 mg buParvaquone per kg body weight), while two and three-dose treatment with interval(s) of 48 h was given to 33% and 11% of total treated cattle, respectively; 38 cattle (60.3%) were treated at an early stage of the disease, while 25 cattle (39.7%) were treated at an advanced stage of the disease. The rectal body temperature of 90.5% of buParvaquone-treated cattle dropped to normal values (37.5–39.5 °C) by day 7 of treatment, and by day 15 of treatment 96.8% of treated cattle showed normal values. Pulmonary signs were observed in 8/68 (11.8%) of total ECF diagnosed cattle and were successfully treated, albeit with Parvaquone plus frusemide (Fruvexon); were not included in final evaluation of the efficacy of BUTA-kel. The present evaluation trials record a recovery rate of 95.2%. BuParvaquone (BUTA-kel™ KELA Laboratoria, N.V. Belgium), therefore, records another efficacious and valuable alternative treatment against East Coast fever in Tanzania.
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comparative studies of the efficacy of Parvaquone and Parvaquone plus frusemide in the treatment of theileria parva infection east coast fever in cattle
Veterinary Parasitology, 2002Co-Authors: H A Mbwambo, J M Mfinanga, P. A. Mkonyi, F F Sudi, E S Mella, C J NgoviAbstract:Comparative studies of the efficacy of Parvaquone (Parvexon®) and Parvaquone-plus-frusemide (Fruvexon®) Bimeda Chemicals, Ireland, were done on 60 naturally infected cases of East Coast fever (ECF; Theileria parva infection in cattle). Small-scale dairy farmers in the peri-urban of Dar Es salaam city reported ECF-suspected cases from March to mid-October 2001 and were treated with the two drugs alternately, as were diagnosed positive for ECF. Four sub-groups of 15 cattle each (early stage, 15; advanced stage, 15) were treated with Parvaquone and Parvaquone-plus-frusemide. Twenty-eight out of 30 (93.3%) cattle treated with Parvaquone-plus-frusemide were cured, so do 24 out of 30 (80.0%) cattle treated with Parvaquone without frusemide. Early diagnosis and prompt management of pulmonary signs, which accounted for 30.0% of total ECF cases is advised in order to improve cure rates. Unlike Parvaquone without frusemide (Parvexon), Parvaquone-plus-frusemide (Fruvexon) proved useful in the management of pulmonary signs, hence, a drug of choice in the treatment of ECF cases that are accompanied by or are likely to manifest pulmonary signs.