124236-83-5Relevant academic research and scientific papers
The Structure and Function of Estrogens. XI. Synthesis of (+/-)-7(8->11α)abeo-Estradiol and its 9,11-Didehydro Derivative
Collins, David J.,Fallon, Gary D.,Skene, Colin E.
, p. 71 - 97 (2007/10/02)
Two approaches to the synthesis of (+/-)-7(8->11α)abeo-estra-1,3,5(10)triene-3,17β-diol (2a) from (+/-)-1β-t-butoxy-7aβ-methyl-2,3,3aα,6,7,7a-hexahydro-1H-inden-5(4H)-one (11) were studied.A pathway involving 6-alkylation of (11) with 2-(3'-methoxyphenyl)ethyl halides or sulfonate esters was unsuccessful, but conjugate addition of 3-methoxybenzyl nucleophiles with (+/-)-1β-t-butoxy-7aβ-methyl-6-methylene-2,3,3aα,6,7,7a-hexahydro-1H-inden-5(4H)-one (18), prepared from (11), led to (+/-)-1β-t-butoxy-6α--7aβ-methyl-2,3,3aα,6,7,7a-hexahydro-1H-inden-5(4H)-one (10a).Acid-catalyzed cyclization of (10a) afforded (+/-)-17β-t-butoxy-3-methoxy-7(8->11)abeo-estra-1,3,5(10),9(11)-tetraene (29) which upon lithium/ammonia reduction in the presence of diphenylmethane gave (+/-)-17β-t-butoxy-3-methoxy-7(8->11α)abeo-estra-1,3,5(10)-triene (31).Deprotection of (31) and (29) afforded (+/-)-7(8->11α)abeo-estra-1,3,5(10)-triene-3,17β-diol (2a) and (+/-)-7(8->11)abeo-estra-1,3,5(10),9(11)-tetraene-3,17β-diol (32), respectively. Alternatively, reaction of (+/-)-1β-t-butoxy-7aβ-methyl-6-methylene-2,3,3aα,6,7,7a-hexahydro-1H-inden-5(4H)-one (18) with 3-methoxybenzyl phenyl sulfoxide (23a) gave (1RS,3'SR,2RS,3a'SR,7a'SR)-3'-t-butoxy-2-(3''-methoxyphenyl)-3a'-methyl-2',3',3a',4',7',7a'-hexahydrospiroinden>-6'(1'H)-one (26), reductive cleavage of which with lithium/ammonia afforded (10a). The relative stereochemistries of (31) and of the spiro cyclopropyl ketone intermediate (26) were established unambiguously by X-ray crystallography.
The Ei Reaction of Substituted threo- and erythro- 1-Phenylethyl Phenyl Sulfoxides
Yoshimura, Toshiaki,Tsukurimichi, Eiichi,Iizuka, Yukihiko,Mizuno, Hironobu,Isaji, Hiroshi,Shimasaki, Choichiro
, p. 1891 - 1899 (2007/10/02)
Substituted (RS,SR)-1-phenylethyl phenyl sulfoxides (threo) (XC6H4S(O)CH(CH3)C6H4Y) and some substituted (RR,SS)-sulfoxides (erythro) were prepared and kinetic investigation for the thermal decomposition was carried out at 80.0, 90.0, and 100.0 deg C in dioxane.Hammett plots for threo-XXC6H4S(O)CH(CH3)C6H5 gave positive ρ-values (ρx=0.60-0.64 at three temoeratures), while those for threo- and erythro-C6H5S(O)CH(CH3)C6H4Y showed V-shape lines with bottoms at the m-OCH3 substituent though the effects of the substituents were small.Meanwhile, large kinetic isotope effects for threo- and erythro-C6H5S(O)CH(O)CH(CH3)C6H4Y (Y=H, p-OMe, m-Cl) (kH/kD=4-6) were observed at all temperatures.The activation energies were in the range of 104-121 kJ mol-1 for all sulfoxides, while the activation entropies were relatively large (7-37 JK-1mol-1) and were correlated with Hammett ?-values to give small negative trend.Reactions of all erythro-isomers examined were 2-3 times faster than those of corresponding threo-isomers.From these results, it is suggested that the pyrolysis of 1-arylethyl aryl sulfoxides proceeds via a concerted mechanism in which the transition state is variable from an Ei'1-like to a conjugated one.In the latter transition state, conjugation of the phenyl group bearing the electron-withdrawing substituent with developing ?-bond electron acidifies the β-proton.
