The Structure and Function of Estrogens. IX. Synthesis of the trans Isomer of 5,5,10b-Trimethyl-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol

1988 ◽  
Vol 41 (5) ◽  
pp. 735 ◽  
Author(s):  
DJ Collins ◽  
JD Cullen
Keyword(s):  
Trans Isomer ◽  
Methanesulfonic Acid ◽  
Structure And Function ◽  
Clemmensen Reduction ◽  
And Function ◽  
Zinc Iodide ◽  
Cis Isomer

Alkylation of ketene methyl trimethylsilyl acetal (10) with 1ξ-acetoxy- 6-methoxy-2-(p- methoxyphenyl )-2-methyl-1,2,3,4-tetrahydronaphthalene (9) in the presence of zinc iodide gave 84% of methyl (1′RS,2′RS)-2- [6′-methoxy-2′-(p-methoxyphenyl )-2?-methyl-1′,2′,3′,4′- tetrahydronaphthalen-1′-yl] ethanoate (11a). Cyclization of the derived acid (11b) with methanesulfonic acid gave 89% of 2,8-dimethoxy-10b-methyl-cis-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (12a), Clemmensen reduction of which afforded 52% of 2,8-dimethoxy-4b-methyl-cis- 4b,5,6,10b,11,12-hexahydrochrysene (12b). Oxidation of (12b) with dichlorodicyanobenzoquinone gave 70% of the conjugated enone (4), which upon hydrogenation over 10% palladium/charcoal gave a 5:1 ratio of 2,8-dimethoxy-10b-methyl-trans-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (14) and the cis isomer (12a). Exhaustive methylation of the trans ketone (14) yielded 49% of 2,8-dimethoxy-5,5,10b-trimethyl-trans-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (16), which upon Clemmensen reduction followed by O- demethylation afforded 5,5,10b-trimethyl-trans-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol(2).

The structure and function of oestrogens. VIII. Synthesis of 5,5, 10b-Trimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol from 6-Methoxy-3,4-dihydronaphthalen-1(2H)-one

1984 ◽  
Vol 37 (11) ◽  
pp. 2279 ◽  
Author(s):  
DJ Collins ◽  
JD Cullen ◽  
GD Fallon ◽  
BM Gatehouse
Keyword(s):  
Methanesulfonic Acid ◽  
Enol Ether ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydride Reduction ◽  
Lithium Aluminium ◽  
Ring Junction ◽  
Clemmensen Reduction ◽  
And Function ◽  
Zinc Iodide

Treatment of 2-hydroxymethylene-6-methoxy-3,4-dihydronaphthalen-1(2H)-one (13a) with p-meth-oxyphenyllead triacetate afforded 93% of 2-formyl-6-methoxy-2-(p-methoxyphenyl)-3,4-dihydro- naphthalen-1(2H)-one (14a) which upon deformylation and methylation gave 60% of 6-methoxy- 2-(p-methoxyphenyl)-2-methyl-3,4-dihydronaphthalen-1(2H)-one (17). An alternative route to the α α'-disubstituted ketone (17) by way of 6-methoxy-2-methyl-3,4-dihydronaphthalen-1(2H)-one (15) and 2-chloro-6-methoxy-2-methyl-3,4-dihydronaphthalen-1(2H)-one (16) was less efficient. Lithium aluminium hydride reduction of the ketone (17) followed by acetylation yielded 80% of 1 ξ acetoxy- 6-methoxy-2-(p-methoxyphenyl)-2-methyl-1,2,3,4-tetrahydronaphthalene (23), treatment of which with the trimethylsilyl enol ether of ethyl 2-methylpropanoate in the presence of zinc iodide afforded 71% of ethyl (1SR,2RS)-2-methyl-2-[6'-methoxy-2'-(p-methoxyphenyl)-2'-methyl-1',2 ',3',4'-tetrahydronaphthalen-yl'ξ-yl]propanoate (26a). Treatment of the ester (26a) or the corresponding acid (26b) with methanesulfonic acid yielded 68 or 82% respectively, of 2*-dimethoxy-5,5,10b-trimethyl- cis-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (27a); Clemmensen reduction of this followed by demethylation with hydrobromicacidin aceticacid gave 49% of cis-5,5,10b-trimethyl-4b,5,6,10b,11,12- hexahydrochrysene-2,8-diol (7a). The sterochemistry of the ring junction in compound (7a) was established by X-ray crystallography of the corresponding dimethyl ether (27b).

The Structure and Function of Estrogens .10. Synthesis of 5,5-Dimethyl-Cis-4b,5,6,10b,11,12-Hexahydrochrysene-2,8-Diol - the Estrogenic Activity of This and of Related C-Methylated Hydrochrysenediols

1988 ◽  
Vol 41 (5) ◽  
pp. 745 ◽  
Author(s):  
DJ Collins ◽  
JD Cullen ◽  
GM Stone
Keyword(s):  
Titanium Tetrachloride ◽  
Estrogenic Activity ◽  
Methanesulfonic Acid ◽  
Structure And Function ◽  
And Function ◽  
Zinc Iodide

Reaction of 6-methoxy-2-(p- methoxyphenyl )-3,4-dihydronaphthalen-1(2H)- one (9) with dimethylketene ethyl trimethylsilyl acetal (10) in the presence of titanium tetrachloride gave ethyl 2-methyl-2-[6?-methoxy- 2?-(p- methoxyphenyl )-3?,4?-dihydronaphthalen-1?-yl] propanoate (11) which upon treatment with methanesulfonic acid afforded the lactone (13). Reduction of (11) with lithium/ammonia yielded mainly 6-methoxy- 2-(p- methoxyphenyl )-1,2,3,4-tetrahydronaphthalene (16), but hydrogenation of (11) over palladium/charcoal gave 61% of ethyl (1?RS,2?RS)-2-methyl-2-[6?-methoxy-2?-(p- methoxyphenyl )-1?,2?,3?,4?- (tetrahydronaphthalen-1?-yl] propanoate (21a). Alternatively, the ester (21a) was prepared in three steps from the ketone (9) by reaction of the derived 1ξ-acetoxy-6-methoxy-2ξ-(p- methoxyphenyl )-1,2,3,4- tetrahydronaphthalene (20b) with the ketene silyl acetal (10) in the presence of zinc iodide. Treatment of the ester (21a) with methanesulfonic acid afforded 72% of 2,8-dimethoxy-5,5-dimethyl-cis-4b, 10b,11,12-tetrahydrochrysen-6(5H)-one (22) which was converted into 2,8-dimethoxy-5,5-dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene (23) in 63% yield via the dithiolan (24). Demethylation of (23) gave 5,5- dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol (3a). ��� Assays of the oestrogenic activity of compound (3a), and of related hydrochrysenediols are reported.

Synthesis of 3-(4′-Methoxyphenyl)-2,2,4,4-Tetramethylpentane and Some Cyclic Analogs

1986 ◽  
Vol 39 (12) ◽  
pp. 2095 ◽  
Author(s):  
DJ Collins ◽  
HA Jacobs
Keyword(s):  
Methanesulfonic Acid ◽  
Similar Reaction ◽  
Reaction Sequence ◽  
Quinone Methides ◽  
Hydride Reduction ◽  
Lithium Aluminium ◽  
Clemmensen Reduction ◽  
Analogous Manner ◽  
Hydrolysis Of ◽  
Zinc Iodide

Reaction of 1-methoxy-2-methyl-1-trimethylsilyloxyprop-1-ene (8) with 1-acetoxy-1-(4′-methoxyphenyl)-2,2-dimethylpropane (7b) in the presence of zinc iodide gave 84% of methyl 3-(4′methoxyphenyl)-2,2,4,4- tetramethylpentanoate (9a), which was reduced with lithium aluminium hydride to 3-(4′-methoxyphenyl)-2,2,4,4-tetramethylpentan-1-ol(12a). Hydride reduction of the derived tosylate (12b) afforded 3-(4′-methoxyphenyl )-2,2,4,4-tetramethylpentane (5b) which upon demethylation yielded the corresponding phenol (10a). In an analogous manner, 1-acetoxy-1-(4′-methoxyphenyl)-2-methylpropane (7d) was converted into 3- (4′-hydroxyphenyl)-2,2,4-trimethylpentane (10b). By a similar reaction sequence, 6-methoxy-2,2-dimethyl-3,4- dihydronaphthalen-1(2H)-one (14) was transformed into 6-hydroxy-2,2- dimethyl-1-(1′,1′-dimethylethyl)-1,2,3,4-tetrahydronaphthalene (16b). Hydrolysis of the ester (9a) and cyclization of the resulting carboxylic acid (19) by treatment with methanesulfonic acid at 20° for 18 h afforded 3-(1′, 1′-dimethylethyl)-6-methoxy-2,2-dimethyl-2,3-dihydro-1H-inden-1-one (20). Clemmensen reduction of this followed by demethylation yielded 1-(1′,1′-dimethylethyl)-2,2-dimethyl-2,3-dihydro-1H-inden-5-ol (21b). Attempts to oxidize the phenols (10a), (10b), (16b) and (21b) to the corresponding quinone methides by conventional methods failed.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Use of human autoantibodies and immunoelectron microscopy to study structure and function of the nucleolus and nuclear bodies

1992 ◽  
Vol 50 (1) ◽  
pp. 506-507
Author(s):  
Robert L. Ochs
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Nuclear Bodies ◽  
Nuclear Interior ◽  
Coiled Bodies ◽  
Interchromatin Granules ◽  
And Function ◽  
Conventional Electron Microscopy ◽  
Perichromatin Granules ◽  
Perichromatin Fibrils

By conventional electron microscopy, the formed elements of the nuclear interior include the nucleolus, chromatin, interchromatin granules, perichromatin granules, perichromatin fibrils, and various types of nuclear bodies (Figs. 1a-c). Of these structures, all have been reasonably well characterized structurally and functionally except for nuclear bodies. The most common types of nuclear bodies are simple nuclear bodies and coiled bodies (Figs. 1a,c). Since nuclear bodies are small in size (0.2-1.0 μm in diameter) and infrequent in number, they are often overlooked or simply not observed in any random thin section. The rat liver hepatocyte in Fig. 1b is a case in point. Historically, nuclear bodies are more prominent in hyperactive cells, they often occur in proximity to nucleoli (Fig. 1c), and sometimes they are observed to “bud off” from the nucleolar surface.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

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