- Regioselective 2-alkylation of indoles with α-bromo esters catalyzed by Pd/P,P=O system
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A palladium-catalyzed 2-alkylation of indoles with α-bromo esters is developed by employing a P,P=O ligand. The method features excellent regioselectivities, mild reaction conditions, and good functional group compatibility. The employment of the P,P=O ligand as well as 4? molecular sieves were crucial for the success of the transformation. Mechanistic studies indicate the reaction proceed through a radical pathway.
- Tian, Wei,Li, Bowen,Tian, Duanshuai,Tang, Wenjun
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supporting information
p. 197 - 200
(2021/08/13)
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- PROTECTED ORGANOBORONIC ACIDS WITH TUNABLE REACTIVITY, AND METHODS OF USE THEREOF
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Disclosed are a range of protected organoboronic acid reagents useful in the modular assembly of complex organic compounds. The reactivities of the protected organoboronic acid reagents may be varied predictably by changes to the number and identities of their substituents. Also disclosed are methods of using the protected organoboronic acid reagents in the synthesis of organic compounds.
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Page/Page column 51
(2017/03/08)
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- Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
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The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
- Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
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supporting information
p. 17662 - 17668
(2015/02/02)
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- Novel ibuprofen prodrugs with improved pharmacokinetics and non-ulcerogenic potential
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In the present study, we evaluated the anti-inflammatory activity with pharmacokinetic, ulcerogenic properties of various synthesized prodrugs of ibuprofen in experimental animals. Prodrugs 2, 6, 9, 10, 12, and 14 were found to possess significant anti-inflammatory activity with almost non-ulcerogenic potential than standard drug ibuprofen 1a in both normal and inflammation-induced rats. Metabolic stability of prodrugs 2, 6, 9, 10, 12, and 14 were also studied in rat liver microsomes and oral bioavailability was determined by estimating area under curve (AUC) and plasma concentration of these prodrugs at various time intervals. The experimental findings elicited higher AUC and plasma concentration at 1 and 2 h indicating improved oral bioavailability as compared to parent ibuprofen. These prodrugs are found to have least gastric ulceration with retain anti-inflammatory activity observed in experimental animals. Therefore, present experimental findings demonstrated significant improvement of various pharmacokinetic properties with least ulcerogenic potential of ester prodrugs of ibuprofen an anti-inflammatory agent
- Dhakane, Valmik D.,Chavan, Hemant V.,Thakare, Vishnu N.,Adsul, Laxman K.,Shringare, Sadanand N.,Bandgar, Babasaheb P.
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p. 503 - 517
(2014/03/21)
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- Synthesis and antifolate properties of 9-alkyl-10-deazaminopterins
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Reformatski condensation of benzyl 2-bromopropionate with 4-carbomethoxybenzaldehyde, followed by dehydration afforded benzyl 2-methyl-p-carbomethoxycinnamate (4a). Hydrogenation over a Pd catalyst gave the hydrocinnamic acid 5a. Conversion to the chloromethyl (6a) and azidomethyl ketone (7a) was followed by hydrogenation to the aminomethyl ketone (8a). Direct N-alkylation by 2,4-diamino-5-nitro-6-chloropyrimidine followed by reductive ring closure in Zn-HOAc and subsequent saponification of the benzoate ester yielded 4-amino-4-deoxy-9-methyl-10-deazapteroic acid (11a). Coupling with diethyl L-glutamate and saponification afforded 9-methyl-10-deazaminopterin (13a). The 9-ethyl analogue (13b) was similarly prepared from benzyl 2-bromobutyrate. The 9-methyl analogue (13a) was 21 times more potent than MTX as an inhibitor of cell growth in L1210 cells. The reason for this enhanced cytotoxicity in L1210 is unclear, since enzyme inhibition and transport parameters were similar to those of MTX. In human Manca leukemia cells growth inhibition was not dramatic and paralleled MTX.
- DeGraw,Christie,Kisliuk,Gaumont,Sirotnak
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p. 212 - 215
(2007/10/02)
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