Efficient synthesis of 17-acetyl-13-(p-bromophenyl)-3-methoxy-11,11-bis(methoxycarbonyl)gona-1,3,5(10)-trienes

We described an efficient synthesis of (8β,9β,14β)-17β-acetyl-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-3-methoxygona-1,3,5(10)-triene, (8β,9α,14β)-17β-acetyl-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-3-methoxygona-1,3,5(10)-triene, (8β,9β,14β)-13 β-p-bromophenyl-11,11-di(methoxycarbonyl)-17β-(2-hydroxyethyl)-3-methoxygona-1,3,5(10)-triene, and (8β,9β,14β)-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-17β-(2-oxoxyethyl)-3-methoxygona-1,3,5(10)-triene in five or six steps from 1-iodo-4-methoxybenzocyclobutene and readily available materials.     

Conjugate hydrocyanation of 17-acetyl-11-carbomethoxygona-1,3,5(10),13(17)-tetraenes

The conjugate hydrocyanation of 17-acetylgona-11-carbomethoxy-1,3,5(10),13(17)-tetraenes using diethylaluminum cyanide (Nagata reaction) is reported. This methodology has allowed the introduction of an angular cyano group at the C-13 position of the steroid skeleton. Subsequent reduction of the nitrile group yielded various functionalized steroids. One of them, 22 bears the natural trans/anti/trans stereochemistry and possesses an hydroxyl and aminomethyl functionalities in the positions 11beta and 13beta, respectively. The characteristic (1)H and (13)C NMR spectroscopic features of the synthesized steroids are reported.     

First synthesis of thia steroids from cholic acid

Heterosteroids remain interesting due to their potential biological activities. This prompted us to synthesize novel thia steroids possessing the heteroatom in the A-ring. We set out to describe a new and versatile method for preparing 3-thia steroids from cholic acid via a selective oxidation of one hydroxyl group, a Baeyer-Villiger oxidation and a photolysis as the key steps. The characteristic ¹H and ¹³C NMR spectroscopic features of the synthesized compounds are reported.     

Efficient synthesis of C-11 functionalized steroids

An efficient synthesis from readily available materials of numerous steroids functionalized at C-11 position, interesting from a biological point of view, is described using our general approach. The characteristic (1)H and (13)C NMR spectroscopic features of the synthesized steroids are reported.     

First synthesis of (+/-)-robinlin

The first synthesis of (+/-)-robinlin (1), a novel homo-monoterpene with strong bioactivity in the brine shrimp lethality test, was achieved by starting from 3-isobutyloxy-2,6,6-trimethyl-2-cyclohexen-1-one (2).     

Total synthesis of heterocyclic steroids, part I, synthesis of (+/-)-A-nor-3-thiaestra-1,5(10)-dien-17 beta-ol.

Total synthesis of (±)-A-nor-3-thiaestra-1,5(10)-dien-17β-ol was achieved starting from 4-o xo-4,5,6,7-tetrahydrobenzothiophene.     

Cytotoxic steroids with antiestrogenic activity of the 11alpha-acyloxyestra-1,3,5(10)-triene series

Esterification of 3-hydroxyl group in 11-acyloxyestra-1,3,5(10)-trienes with p-[bis(2-chloroethyl)amino]phenylacetic acid led to antitumor steroids displaying antiestrogenic and cytotoxic activities. Our substances exhibit their activities on the model of murine mammary adenocarcinoma Ca-755, with inhibition of the tumor growth being 94-99%. A new approach was used for the 11alpha-hydroxylation of estra-1,3,5(10)-trienes.     

alpha,beta-Dibenzyl-gamma-butyrolactone lignan alcohols: total synthesis of (+/-)-7'-hydroxyenterolactone, (+/-)-7'-hydroxymatairesinol and (+/-)-8-hydroxyenterolactone

Two trans-alpha,beta-dibenzyl-gamma-butyrolactone lignans carrying a hydroxyl group at the beta-benzylic carbon atom and a alpha-hydroxy alpha,beta-dibenzyl-gamma-butyrolactone lignan were synthesized in racemic form using the tandem conjugate addition reaction to construct the basic lignan skeleton. Subsequent reaction steps involved either a catalytic reduction of the regenerated keto group to the alcohol, or a hydrogenolysis to benzylic methylene followed by lactone enolate formation and oxidation to give the alpha-hydroxybutyrolactones. These procedures were applied for the synthesis of 7'-hydroxyenterolactones and 7'-hydroxymatairesinols, and 8-hydroxyenterolactones, respectively. The diastereomeric mixtures of these compounds were separated either by HPLC techniques or column chromatography and the structures were elucidated using NMR spectroscopy.     

Some unreported by-products from the reaction of 1,4-dien-3-one steroids with 2-(methylammo)benzethiol/BF3

In a previous report, it was demonstrated that the 3-carbonyl of androsta-1,4-dien-3,17-dione (ADD) can be selectively protected with 2-(methylamino)benzethiol in the presence of BF3 in good yield. We explored the applicability of this method for other 1,4-dien-3-one steroids and got the desired protective products in different yield. Other than the usual protected products, we also got some unexpected by-products, including benzathiazol[4,3-b]-estra steroids. Their structures were determined by spectral analysis.     

Total synthesis of heterocyclic steroids, Part III. Synthesis of (+/-)-3,17-dithia-A-nor-14 beta-estra-1,5(10),6,8-tetraene-17-dioxide

With 4-oxo-4,5,6,7-tetrahydrobenzothiophene and 2-methyl-3-oxothiophane-1-dioxide (III) as AB and D ring precursors respectively, (+/-)-3,17-dithia-A-nor-14 beta-estra-1,5(10),6,8-tetraene-17-dioxide (I) was synthesised following the modified Torgov method.     

The synthesis and nicotinic binding activity of (+/-)-epiquinamide and (+/-)-C(1)-epiepiquinamide

The synthesis of (+/-)-epiquinamide 1 and (+/-)-C(1)-epiepiquinamide 2 based on the use of a Curtius rearrangement to introduce the C(1) amino residue is reported. In a competition binding assay for [(3)H]epibatidine binding to rat brain membranes neither (+/-)-1 nor (+/-)-2 showed any significant level of nicotinic activity.     

First total synthesis of (5Z,9Z)-(+/-)-2-methoxy-5,9-octadecadienoic acid, a marine derived methoxylated analog of taxoleic acid

The first total synthesis for the sponge derived (5Z,9Z)-(+/-)-2-methoxy-5,9-octadecadienoic acid, an analog of taxoleic acid, was accomplished in seven steps and in a 10% overall yield. It was again corroborated that the best strategy to prepare these cis,cis dimethylene interrupted double bonds is the double-alkyne bromide coupling reaction of 1,5-hexadiyne, which provides the advantage of achieving a 100% cis stereochemical purity for both double bonds after hydrogenation under Lindlar conditions. The alpha-methoxy functionality was best prepared via the Mukaiyama reaction of (4Z,8Z)-heptadecadienal with trimethylsilyl cyanide and triethylamine followed by acid hydrolysis. Selective methylation of the hydroxyl group of (5Z,9Z)-(+/-)-2-hydroxy-5,9-octadecadienoic acid was achieved with sodium hydride/methyl iodide when tetrahydrofuran was used as solvent. Complete spectral data is presented, for the first time, for this unusual marine alpha-methoxylated fatty acid.     

17Beta-hydroxy-11alpha-(3'-sulfanylpropyl)oxy-estra-1,3,5(10)- trien-3-yl sulfamate--a novel hapten structure: toward the development of a specific enzyme immunoassay (EIA) for estra-1,3,5(10)-triene-3-yl sulfamates.

The title compound 17 has been synthesized for the use as hapten in the development of a competitive enzyme immunoassay for estrogen sulfamates. The synthesis started from estradiol diacetate 2. Oxyfunctionalization at C-11 to give 11alpha-hydroxy steroid 8 was accomplished by hydroboration/alkaline hydrogen peroxide oxidation of the 9(11)-dehydro derivative 7, which was obtained from compound 2 via 9-hydroxylation with dimethyldioxirane. After transformation of compound 8 into the allyl ether 9, the side chain was thio-functionalized at the omega-position affording the thioate 11 in two steps. Selective silylether deprotection at position 3 followed by sulfamoylation gave the sulfamate 19, which in turn was demasked at position 17 and treated with sodium borohydride/aluminum chloride to liberate the side chain thiol. Alternatively, title compound 17 was synthesized via the disulfides 13-16. For the preparation of the immunogen the title compound 17 was coupled to bovine gamma globulin in a two-step procedure using an amine and thiol specific bifunctional crosslinker. The immunization of rabbits resulted in the formation of antibodies which clearly discriminated the sulfamoylated estrogens from the non-esterified estrogens. The use of a biotinylated hapten derivative as a tracer in combination with a streptavidin-peroxidase-tetramethylbenzidine based detection system allowed the measurement of estradiol 3-sulfamate (1) in the range of about 1 to 1000 pg/well.     

Total synthesis of heterocyclic steroids,part VI. synthesis of (±)-3-methoxy-6-aza-12-thia-12-dioxo-B-nor-14β-estra-1,3, 5(10),8-tetraen-17α-OL

With 7-hydroxy-7a-methyl-4-oxo-cyclopenta(b)tetrahydrothiopyran-1-dioxide (III) as the CD part, the synthesis of the title compound (II) was achieved by the Fischer indole synthesis.     

Prostaglandins V (1). Synthesis and pharmacology of (+/-)-11-deoxy-10-hydroxyprostaglandin E1 methyl ester

(+/-)-Deoxy-10-hydroxy-PGE1 methyl ester (Va) has been synthesised via conjugate addition of the cuprate (III) to the 5-tetrahydropyranyloxycyclopentenone (IId). Va was found to be 0.1 times as active as PGE1 as a uterine stimulant in the anaesthetized pregnant rat, 0.25 times as active as PGE1 in causing vasodepression in the anaesthetized cat, and approximately equiactive to PGE1 in inducing bronchoconstriction.     

Heterocyclic steroids-Part-IV. Studies on the total synthesis of 3-methoxy-7beta-phenyl-6-oxaestra-1,3,5(10)-trien-17beta-ol.

7-Methoxyflavanone(I) has been converted, into dl-3-methoxy-7β-phenyl-6-oxaestra-1,3,5 (10)-trien-17β-ol (IX) in fairly good yield.     

Reaction of (13S)-13-iodo-6beta-methoxy-3alpha,5-cyclo-13,14-seco-5alpha-androstane-14,17-dione with hydroxylamine and its application to the synthesis of new 13,14-seco steroids

The synthesis of 13,14-seco steroids starting from easily available (13S)-13-iodo-6beta-methoxy-3alpha,5-cyclo-13,14-seco-5alpha-androsta-14,17-dione is described. The C-17 ketone was converted regioselectively into its oxime with simultaneous stereoselective deiodination at C-13. The remaining C-14 carbonyl group was then reduced stereoselectively with Ca(BH4)2. The configurations at the relevant stereocenters of the thus obtained hydroxy oxime were determined by X-ray analysis. Successful regeneration of the C-17 carbonyl group was achieved by treatment of the corresponding oxime acetate with TiCl3.