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1.
A. S. R. Anjaneyulu A. Madhusudhana Rao V. Kameswara Rao L. Ramachandra Row 《Tetrahedron letters》1975,16(52):4697-4700
A new lignan from is shown to be 1, 2a-dihydroxy-2e-piperonyl-6e-(6″-bromopiperonyl)-3, 7-dioxabicyclo-[3,3,0]-octane, the first example of a bromine containing lignan. 相似文献
2.
Koppaka V. Rao 《Journal of heterocyclic chemistry》1997,34(2):675-680
Paclitaxel, an antitumor drug effective on ovarian and breast carcinomas, is currently being produced both by direct isolation from the bark of Taxus brevifolia and by semi-synthesis from a natural precursor, 10-deacetyl baccatin III. Although other potential precursors such as 10-deacetyl paclitaxel-7-xyloside were known since 1984, their conversion to paclitaxel could not be achieved because of the lack of suitable methodology for hydrolyzing the xylose residue, compatible with the stability of the compound. A method is described here using periodate, followed by phenylhydrazine, to effect deglycosidation of 10-deacetyl paclitaxel-7-xyloside to form 10-deacetyl paclitaxel. In addition, by including an intermediate acetylation step before the reaction with phenylhydrazine, “direct” conversion of this xyloside to paclitaxel itself, is described. Because 10-deacetyl paclitaxel-7-xyloside occurs at >0.1% in the bark of Taxus brevifolia, its successful hydrolytic conversion to paclitaxel represents an extremely important reaction for the enhanced availability of this drug. 相似文献
3.
Dmitrenok A. S. Radhika P. Anjaneyulu V. Subrahmanyam C. Subba Rao P. V. Dmitrenok P. S. Boguslavsky V. M. 《Russian Chemical Bulletin》2003,52(8):1868-1872
Sphingolipids and glycolipids including previously unknown (2S,3S,4R)-1,3,4-trihydroxy-2-(2-(R)-hydroxyoctadecanoylamino)octadec-8E-ene, (2S,3R)-1,3-dihydroxy-2-octadecanoylamino-4E,8E-hexadecadiene, and (2-hydroxy-3-hexadecyloxypropyl)--L-fucopyranoside were isolated from soft corals collected on the shelf near the Andaman Islands (Indian Ocean). The structures of all compounds were established by spectroscopic methods and chemical analyses. The lipids possessed antibacterial activity against Bacillus subtilis, Bacillus pumilus, Escherichia coli, and Pseudomonas aeruginosa and antifungal activity against Aspergillus niger, Rhizopus oryzae, and Candida albicans. 相似文献
4.
Three related compounds of aripiprazole were identified during the synthesis. These related compounds were synthesized and characterized by their respective spectral data. 相似文献
5.
Abstract 10-Hydroxycamptothecin is prepared by chemoselective catalytic hydrogenation of the B-ring of camptothecin over PtO2 with sulfur moderators followed by oxidation using iodobenzenediacetate. New moderators (viz. thioanisole, dimethyl sulfide, diphenyl sulfide, 2-mercapto ethanol), which moderate the hydrogenation of the B- ring of camptothecin, are being explored.
ACKNOWLEDGMENTS
The authors thank the management of Dr. Reddy's Laboratories Ltd. for supporting this work, and support from analytical colleagues is highly appreciated. 相似文献6.
The synthesis of streptonigrin or its tricyclic (ABC) analogues by the Friedlander condensation requires a 2-nitrobenzaldehyde with all the necessary functionalities. A number of alternative syntheses are examined. It is shown that oxidation of 8-amino-5,6-dimethoxy-2,2-pyridylquinoline leads to 8-amino-2,2-pyridylqunoline-5,6-dione instead of 6-methoxy-2,2-pyridylquinoline-5,8-dione. The synthesis of two useful precursors: 4-bromo-3-hydroxy-5,6-dimethoxy-2-nitrobenzaldehyde and 4-bromo-3-hydroxy-5-methoxy-2-nitrobenzaldehyde is described. 相似文献
7.
Abstract A simple, efficient, and alternative synthetic route for docetaxel with better control on the protection–deprotection sequence has been developed. The process is easily scalable and commercially viable, and critical impurities can be controlled efficiently. For the first time, absolute configuration of docetaxel was determined unambiguously by single-crystal x-ray diffraction. 相似文献
8.
9.
The synthesis of the cis and trans forms of the cyclic dipeptide of O-diazoacetyl-DL-serine is described. 相似文献
10.
Critical current measurements on a cold rolled Pb60In40 foil show two pinning maxima, one close to Hc2 in the neighborhood of h = 0.95, and the other at low fields around h = 0.15. The high field pinning force maximum shifts to lower fields, and the low field maximum shifts to higher fields with increasing pinning strength. The data is explained in terms of Kramer's pinning force model incorporating Brandt's expression for C>66. 相似文献