γ- And δ-lycorane

Kotera, K.

doi:10.1016/0040-4020(61)80041-0

Cited by 39 publications

(18 citation statements)

References 12 publications

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“…All of the ring junctures in γ‐lycorane are cis 20 and total syntheses of racemic γ‐lycorane have been reported by several groups 8. A number of efforts9 geared towards asymmetric syntheses of optically active (+)‐γ‐lycorane have also been reported, but with only one example involving the asymmetric catalytic construction of the stereogenic centers (with 46 % ee 9a) a concise asymmetric catalytic total synthesis of optically pure (+)‐γ‐lycorane is of great importance.…”

Section: Resultsmentioning

confidence: 89%

“…The cis , cis ‐ 15a was subjected to Raney nickel‐catalyzed hydrogenation under 80 atmosphere of hydrogen at 55 °C, which directly formed lactam 16a in 95 % yield. A modified Pictet–Spengler ring closure21 of 16a with paraformaldehyde and trifluoroacetic acid afforded 17a in 88 % yield, and reduction of 17a with lithium aluminum hydride gave (+)‐γ‐lycorane in 98 % yield with an optical rotation consistent with that of the natural product 20. The overall yield of this concise total synthesis of optically pure (+)‐γ‐lycorane from the reaction between 1a and 3,4‐methylenedioxyphenylboronic acid is 38 %, and was improved to 52 % when the synthesis commenced with the reaction between 1a and 3,4‐methylenedioxyphenylzinc chloride.…”

Section: Resultsmentioning

confidence: 90%

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Rhodium‐Catalyzed Asymmetric Nitroallylation of Arylmetallics with Cyclic Nitroallyl Acetates and Applications in Organic Synthesis

et al. 2006

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Highly enantioselective rhodium-catalyzed nitroallylations of arylboronic acids and arylzinc chlorides with cyclic nitroallyl acetates are described. Catalyst screening indicated that the rhodium complex of [Rh(OH)(COD)] 2 and optically pure binap is the optimal catalyst for the nitroallylation of arylboronic acids with 2-nitrocyclohex-2-enyl esters, providing good yields and high enantioselectivities of up to 99 % ee. The rhodium complex prepared from Rh(acac)(C 2 H 4 ) 2 and (R)-binap efficiently catalyzed the nitroallylation of arylzinc chlorides with 2-nitrocyclohex-2-enyl acetate at 0°C in high

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 90%

Rhodium‐Catalyzed Asymmetric Nitroallylation of Arylmetallics with Cyclic Nitroallyl Acetates and Applications in Organic Synthesis

et al. 2006

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“…To address this challenge, we investigated the hydrogenation of cycloketones with an α‐alkoxycarbonylalkyl group and an α′‐aryl group. We expected that the enantioselective hydrogenation of these racemic α,α′‐disubstituted ketones through DKR would produce chiral cycloalkanols with three contiguous stereocenters and that these cycloalkanols could serve as chiral intermediates for the synthesis of natural alkaloids such as lycorane5 and hexahydroapoerysopine 6. Herein, we report the highly enantioselective hydrogenation of this type of cycloketones through DKR to chiral diols with three contiguous stereocenters and the use of the reaction for the asymmetric total synthesis of (+)‐γ‐lycorane.…”

Section: Methodsmentioning

confidence: 99%

“…To demonstrate the synthetic utility of this highly efficient strategy for producing chiral diols with three contiguous stereocenters in one step, we carried out an asymmetric total synthesis of (+)‐γ‐lycorane, which is a degradation product of the amaryllidaceae alkaloid lycorine 5. Although this type of deoxygenated amaryllidaceae alkaloid skeleton has received much attention in recent years, a highly efficient catalytic asymmetric total synthesis of optically pure (+)‐γ‐lycorane is desirable 10.…”

Section: Methodsmentioning

confidence: 99%

P128: Ultrasonographic findings of endometrial polyp

Kwon

Ji²,

Hong³

et al. 2003

Ultrasound Obstet Gynecol

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Objective: The aim of this study was to evaluate the accuracy of transvaginal ultrasound scanning (TVS) in the detection of endometrial polyps. Materials and methods: During a period of two years all women with history of abnormal bleeding were examined by B-mode transvaginal ultrasound. Women with endometrial polyps identified on the scan and those with abnormally thick endometrium not suitable for outpatient biopsy, were referred for hysteroscopy. Results: 192 patients were included. Ultrasound correctly identified 101 of 126 endometrial polyps, diagnosed at hysteroscopy. 35 women had a false positive diagnosis of endometrial polyp on ultrasound scan, with normal uterine cavity or submucous fibroids detected at hysteroscopy. 31 women with uniformly thickened endometrium on the scan had the diagnosis confirmed at hysteroscopy. The sensitivity of transvaginal ultrasound to detect endometrial polyps was 80.2%, with a specificity of 47.0%. The positive predictive value was 74.4%, negative predictive value was 55.4%. Conclusion:Transvaginal sonography is a sensitive tool for detection of endometrial polyps. However, the false positive rate is high and therefore the diagnosis should be confirmed by saline infusion sonohysterography, before an operative hysteroscopy is scheduled. P126Comparison of saline infusion sonography with diagnostic hysteroscopy for the evaluation of the uterine cavity in patients with abnormal uterine bleeding M Kamel EgyptObjective: To evaluate the diagnostic accuracy of saline infusion sonography in the evaluation of the endometrium and uterine cavity in patients with abnormal uterine bleeding. Study design: The endometrium and uterine cavity of 100 patients complaining of abnormal uterine bleeding were evaluated by saline infusion sonography and findings were compared to office hysteroscopic evaluation of the same patients. Findings of endometrial hyperplasia, submucous myoma, endometrial polyps and atrophic endometrium were recorded independently and evaluation of the sensitivity and specificity and diagnostic significance for each of these findings was done. Dilatation and curettage was done in all cases to exclude or confirm endometrial hyperplasia and/or atypia. Results: Both procedures were done in 100 patients. Findings of endometrial hyperplasia, endometrial polyps, submucous myoma, and atrophic endometrium were recorded. As regards endometrial hyperplasia, sensitivity was 94.74%, specificity was 93.6%, PPV was 90%, NPV was 96.5% and diagnostic accuracy 0.94. As regards endometrial polyp, sensitivity was 82.4, specificity was 95.2%, PPV was 77.8%, NPV was 96.4% and diagnostic accuracy 0.81. As regards submucous myoma, sensitivity was 94.3%, specificity was 97.6%, PPV was 88.3%, NPV was 98.8% and diagnostic accuracy 0.97. For all findings combined, sensitivity was 89.8%, specificity was 76.2%, PPV was 86.9%, NPV was 79.5% and diagnostic accuracy was 0.88. Conclusion: Saline infusion sonography is an accurate method to evaluate the endometrium and endometrial cavity in cases of abnorm...

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“…We here report our further studies on the synthesis of '-lycorane and its related compound. -Lycorane [4] (18), derived from Amaryllidaceae alkaloids, was synthesized by SAKAN and his do-workers [5] as shown in Scheme 1; a similar approach involving this key reaction has also been reported by IIDA and his co-workers [6] as illustrated in Scheme 2. Both syntheses [7], however, required the Birch reduction of aromatic ring to prepare the starting materials, and the introduction of A-aromatic moiety to the resulting amines was achieved in later stages with some little difficulty to obtain the desired compound as a sole product.…”

Section: Introductionmentioning

confidence: 90%