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排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
G. Kumaraswamy A. Pitchaiah G. Ramakrishna D.S. Ramakrishna K. Sadaiah 《Tetrahedron letters》2006,47(12):2013-2015
An efficient protocol for the benzylation or allylation of amides using the corresponding benzyl or allyl chlorides as electrophiles under basic conditions with commercially available 5 mol % of [Cu(OH)TMEDA]2Cl2 as catalyst was developed. Under these conditions, unprotected amino acids were benzylated without any racemization. 相似文献
2.
Kumaraswamy S Kommana P Kumar NS Swamy KC 《Chemical communications (Cambridge, England)》2002,(1):40-41
New modes of 1,3-dipolar cycloaddition are uncovered by the isolation of [CH2(6-t-Bu-4-Me-C6H2O)2]P(C(CO2Me)C(CO2Me)N[NP(N3)(OC6H2-6-t-Bu-4-Me)2CH2]N) (3) and [CH2(6-t-Bu-4-Me-C6H2O)2]P(C(CO2Me)C(CO2Me)C(O)N) (4) on treating [CH2(6-t-Bu-4-Me-C6H2O)2]P-X [X = N3 (1) and NCO (2)] with the dipolarophile MeO2CC identical to CCO2Me; compound 4 undergoes an unprecedented ring expansion upon addition of 2-(methylamino)ethanol to afford the spirocycle [CH2(6-t-Bu-4-Me-C6H2O)2]P(OCH2CH2N(Me)CH(CO2Me)CH(CO2Me)C(O)N) (5). 相似文献
3.
Miscibility and phase separation in SAN/PMMA blends have been investigated using DSC, IR spectroscopy and positron lifetime spectroscopy (PLS). Single broad glass transition observed throughout the blend compositions, may be due to overlap of two glass transitions. IR measurements clearly indicate the absence of strong interactions. This supports miscibility is due to intramolecular repulsive forces in the SAN component. On the other hand, free volume data show negative deviation from linear additivity indicating the blends are miscible. The interchain interaction parameter β exhibits a complex behavior and the extent of miscibility is not revealed. Following Wolf’s treatment, we have evaluated the geometry factor γ and hydrodynamic interaction parameter α and found α is a suitable parameter in predicting the miscibility window. The cloud points in SAN/PMMA blends increase with decreasing PMMA content. The change in free volume size correlates well with the observed change in cloud point. 相似文献
4.
Gullapalli Kumaraswamy Kadivendi Sadaiah Nimmakayala Raghu 《Tetrahedron: Asymmetry》2012,23(8):587-593
An efficient enantioselective synthesis of the potent anticancer agent (+)-duryne was achieved by the use of a one-pot organocatalyzed hydroxylation/Ohira–Bestmann and Grubbs cross-metathesis/selective cis-Wittig reaction. This new approach is envisioned to facilitate the synthesis of every representative member of the family. 相似文献
5.
K. C. Kumaraswamy S. S. Krishnamurthy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):241-244
Abstract The different mechanistic features involved in the replacement of chlorine and fluorine atoms from N3P3 (NPPh3)X5[X [dbnd] Cl(I) or F(II)] by methoxide have been identified. An oxophosphazadiene derivative is also isolated. 相似文献
6.
B. P. Nandeshwarappa D. B. Aruna Kumar M. N. Kumaraswamy Y. S. Ravi Kumar H. S. Bhojya Naik K. M. Mahadevan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1545-1556
A series of novel substituted thiopyrano[2,3-b]quinolines 4a–e , 5a–e , and 6a–e were prepared from substituted 3-formyl-2-mercapto quinolines 2a–e , on reaction with ethyl acetoacetate, diethyl malonate, and ethyl cyanoacetate 3a–c by microwave irradiation in the presence of piperidine. Synthesized compounds were evaluated for antimicrobial activities. Among the compounds tested, 7-chloro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6d and 7-nitro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6e were highly active against S. aureus and M. roseus. 相似文献
7.
A stereoselective total synthesis of oplopandiol, oploxyne A, and (−)-oploxyne B is described. The key reactions include Sharpless asymmetric epoxidation, d-proline catalyzed aminoxylation, Cadiot–Chodkiewicz cross-coupling reaction, m-CPBA induced substrate-controlled stereoselective epoxidation, and Lewis acid catalyzed stereo- and regioselective ring-opening of epoxide. 相似文献
8.
9.
S. Kumaraswamy E. Sankarasubramanian 《The Journal of the Operational Research Society》1981,32(11):997-1001
A stochastic model for an inventory system in which depletion of stock takes place due to random demand as well as random failure of items is studied under the assumption that the intervals between successive unit demands, as well as those between successive unit failures, are independently and identically distributed random variables having negative exponential distribution with different parameters. The transient and steady state probability distributions of the stock level are derived and the optimum decision rules in the long run given. 相似文献
10.