Abstract:The stereoselective synthesis of methyl 3,11 -dimethyl-10,11 -cí'í-epoxy-7-ethyl-2-fra«s,6-/razzí-tridecadienoate (1), the C-18 juvenile hormone of Hyalophora cecropia, by two alternative routes is described. The first method proceeds via a Claisen condensation of trimethylorthoacetate with methyl 6-hydroxy-3-methyl-7-methylene-2-/ra«j-nonenoate (9) and a second method utilized the versatile bifunctional intermediate 25.he isolation and identification3 of the juvenile hormones 1 and 2 of Hyalophora cecropia pr… Show more
“…Synthesis. Most synthetic methods (Figure 1) are modifications of published procedures and are illustrated in the supplementary material (Mechoulam and Sondheimer, 1958; Hauser et al, 1963;Seyferth and Fogel, 1966;Henrick et al, 1972;Kamimura et al, 1972;Sharpless and Michaelson, 1973; Hammock et al, 1974;Mori et al, 1975;Hangartner et al, 1976;Henrick et al, 1978). All chemicals and radiochemicals were handled according to recommended procedures of laboratory safety (Steere, 1967;Green and Turk, 1978).…”
Table III, C). This increased persistence of [14C]paraoxon due to anethole could, therefore, be related to the increased toxicity of paraoxon.In summary, four major results should be mentioned. (1) Topically applied anethole and anisaldehyde increased the toxicity of several classes of topically applied synthetic insecticides to houseflies (Table I). ( 2) The presence of anethole in the housefly diet increased the toxicity of topically applied parathion or paraoxon to houseflies. (3) The presence of anethole in the diet resulted in an increased penetration of [14C]paraoxon derived radiocarbon into the housefly body (Table II). ( 4) The presence of anethole in the housefly diet reduced the degradation of [14C]paraoxon by a cell-free supernatant prepared from houseflies fed anethole for 3 days (Table III). It appears, therefore, that the increased mortalities of houseflies fed anethole in their diet for 3 days prior to topical application of paraoxon was due to an increased penetration of paraoxon into the insect body and an increased stability of paraoxon due to a reduction in the degradation of paraoxon to nontoxic, water-soluble metabolites. Both of these effects would increase the amount of toxic paraoxon within the houseflies and hence increase mortalities.
“…Synthesis. Most synthetic methods (Figure 1) are modifications of published procedures and are illustrated in the supplementary material (Mechoulam and Sondheimer, 1958; Hauser et al, 1963;Seyferth and Fogel, 1966;Henrick et al, 1972;Kamimura et al, 1972;Sharpless and Michaelson, 1973; Hammock et al, 1974;Mori et al, 1975;Hangartner et al, 1976;Henrick et al, 1978). All chemicals and radiochemicals were handled according to recommended procedures of laboratory safety (Steere, 1967;Green and Turk, 1978).…”
Table III, C). This increased persistence of [14C]paraoxon due to anethole could, therefore, be related to the increased toxicity of paraoxon.In summary, four major results should be mentioned. (1) Topically applied anethole and anisaldehyde increased the toxicity of several classes of topically applied synthetic insecticides to houseflies (Table I). ( 2) The presence of anethole in the housefly diet increased the toxicity of topically applied parathion or paraoxon to houseflies. (3) The presence of anethole in the diet resulted in an increased penetration of [14C]paraoxon derived radiocarbon into the housefly body (Table II). ( 4) The presence of anethole in the housefly diet reduced the degradation of [14C]paraoxon by a cell-free supernatant prepared from houseflies fed anethole for 3 days (Table III). It appears, therefore, that the increased mortalities of houseflies fed anethole in their diet for 3 days prior to topical application of paraoxon was due to an increased penetration of paraoxon into the insect body and an increased stability of paraoxon due to a reduction in the degradation of paraoxon to nontoxic, water-soluble metabolites. Both of these effects would increase the amount of toxic paraoxon within the houseflies and hence increase mortalities.
“…This ester was prepared in the same manner as described for VIa in 70 % yield from Vb, bp 133°C Methyl 3,7, This was prepared in the same manner as described for VIb in 64.5 % yield from Vb using lithium di-npropylcuprate, bp 139~ 140°C (0.80 mmHg), n~= 1.4811, IRlimaxcm-1: 17251.4811, IRlimaxcm-1: ,16501.4811, IRlimaxcm-1: ,12251.4811, IRlimaxcm-1: ,1150 3,7, This was prepared in the same manner as described for VIb in 50 % yield from Vb, but the solution of lithium di-n-butylcuprate in ether was prepared at -25°C. This ester (VId) 3,7, A solution of methyl 3,7, 11-trimethyltrideca-2,6-trans, 10-trans-trienoate(500 mg) and potassium cyanide (395 mg) in ethanol (20 ml) was heated under reflux for 19 hr. After removal of the solvent, the residue was diluted with water and extracted with ether.…”
Section: Methodsmentioning
confidence: 99%
“…This reaction is known to give only lO-trans compound. 3 ) Epoxidation with m-chloroperbenzoic acid followed by TLC purification afforded four homo logs (Ila~d) of dl-CwJH (IV).…”
Section: Synthesis and Biological Activity Of Jh Analogs With Carbomementioning
“…As the absolute configuration of tonantzitlolone 1 was unknown and no precedence of a structurally related diterperne was known, we had to arbitrarily choose one target enantiomer as depicted in Scheme . Thus, aldehyde 5 was prepared from methyl geranate 4 as described in the literature and was subjected to the Kiyooka aldol protocol using ketene acetal 6 , which yielded the diester 3 in good yield and stereoselectivity (91% ee; determined by 1 H NMR spectroscopy in the presence of Eu(hfc) 3 (Scheme ). 2 …”
[structure: see text] The first enantioselective total synthesis of tonantzitlolone, a novel 15-membered macrocyclic diterpene, utilized a Julia olefination, a highly selective, potassium enolate-based anti-Felkin aldol reaction, and an E-selective ring-closing metathesis as key C-C bond-forming steps. The absolute configuration of tonantzitlolone is established.
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