排序方式: 共有45条查询结果,搜索用时 171 毫秒
41.
Tetsuya Tsujihara Moriho Tomeba Shigeaki Ohkubo-Sato Kyoko Iwabuchi Rino Koie Natsumi Tada Satoru Tamura Tsunayoshi Takehara Takeyuki Suzuki Tomikazu Kawano 《Tetrahedron letters》2019,60(42):151148
The one-pot reactions of catalytically generated bicyclic zinc enolate with various electrophiles are reported. The zinc enolate as a key intermediate is efficiently delivered from Ni-catalyzed reductive cyclization of alkynyl cyclohexadienone. Employing aldehydes, imine, nitroalkene, and α,β-unsaturated carbonyl compounds as electrophiles, this new class of one-pot reactions gave multi-functionalized cis-hydrobenzofurans and octahydro-4,7-ethanobenzofuran-9-one derivatives in moderate to good yields. 相似文献
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43.
Kazuo Yamaura Kohsei Hirata Satoko Tamura Shuji Matsuzawa 《Journal of Polymer Science.Polymer Physics》1985,23(8):1703-1712
The dilute-solution behavior of poly(vinyl alcohol) (PVAVTFA), derived from vinyl trifluoroacetate, in water-dimethylsulfoxide (DMSO) mixtures was investigated. With solvent mixtures ranging from 10 to 20 vol % DMSO, the relation between the reduced viscosity ηsp/C and the polymer concentration C was linear for polymer concentrations above 0.2 g/dL, whereas in solutions in mixed solvents of other compositions the dependence was linear for polymer concentrations above 0.1 g/dL. The relation between the intrinsic viscosity [η] obtained for aqueous solutions of PVAVTFA and the molecular weight M estimated from viscosity measurements in solutions of poly(vinyl acetate) (PVAVTFA), obtained by acetylation of PVAVTFA, was given by [η] = 7.34 × 10?4 M0.63. The value of [η] was greatest for the solvent mixture with 10 vol % DMSO and smallest for about 50 vol % DMSO, and Huggins constants k were smallest and greatest for these two cases, respectively. The turbidity of the solutions of low-molecular-weight PVAVTFA, was higher than that of high-molecular-weight PVAVTFA up to 30 vol % DMSO, and the reverse relation held for 40-70 vol % DMSO. 相似文献
44.
K Ozeki T Ichikawa H Takehara K Tanimura M Sato H Yaginuma 《Chemical & pharmaceutical bulletin》1989,37(7):1780-1787
A series of 2-anilino-1,6-dihydro-6-oxo-5-pyrimidinecarboxylic acids with various substituents was synthesized and evaluated in the rat passive cutaneous anaphylaxis test for antiallergic activity. High activity by intraperitoneal and oral administrations was observed for the 3-trifluoromethyl and 2-alkoxyanilino derivatives (64, 79, 81, 82 and 85). Structure-activity relationships are discussed. 相似文献
45.
Imaoka I Sugimura K Masui T Takehara Y Ichijo K Naito M 《Magnetic resonance imaging》1999,17(10):653-1455
The objective of the study was to assess the usefulness of magnetic resonance (MR) imaging in distinguishing malignant from benign conditions in patients with an abnormal uterine cavity. Fifty-four patients that were suspected of having abnormal uterine cavities were retrospectively evaluated by using MR imaging. The diagnosis of an abnormal uterine cavity included a thickened endometrium, and/or a endometrial mass, and/or a submucosal mass. Threshold values to classify the uterine cavity as abnormal on sagittal T2-weighted images were >10 mm for premenopausal women and >5 mm for postmenopausal women. Malignancy was diagnosed when lesions invaded the myometrial/junctional zone, and/or lesion enhancement was lower than that of the adjacent myometrium. The results found that histology confirmed 18 malignant and 37 benign lesions. Twelve of 15 endometrial carcinomas and 3 malignant mixed mesodermal tumors (MMMT) were correctly characterized as malignant on enhanced T1-weighted images; whereas 6 of 15 endometrial carcinomas and 3 MMMT were correctly characterized on T2-weighted images. Thirty-four of 37 benign cases were correctly characterized as not malignant on enhanced T1-weighted images. One of 14 submucosal leiomyomas, one endometrial stromal metaplasia, and one of ten pathologically normal endometria were misdiagnosed on enhanced T1-weighted images but were correctly diagnosed on T2-weighted images. The overall sensitivity, specificity, and accuracy for distinguishing malignant from benign central uterine masses were 83%, 92%, and 89% for enhanced T1-weighted image, and 50%, 97%, and 82% for T2-weighted image, respectively. We came to the conclusion that in diagnosing patients with abnormal uterine cavity, MR imaging may help differentiate malignant from benign disorders. 相似文献