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Pyrazolidinones, bicyclic

Boyd DB. Application of the hypersurface iterative projection method to bicyclic pyrazolidinone antibacterial agents. J Med Chem 1993 36 1443-9. [Pg.47]

Combinatorial solution-phase cycloadditions of (1Z,4R, 5R )-4-benzoylamino-5-phenylpyrazolidin-3-on-l-azomethine imines 320 to 3-keto esters afforded a library of 26 highly pure bicyclic pyrazolidinones 713 in 6-89% yields and in 14-100% de. Most of the products were isolated as mixtures of the major (13, 23, 3/ , 5/ , 6/ )-epimers 713 and the minor (1R, 2A, 3R, 5R, 6R )-epimers 714 (Scheme 113). Epimerization of these cycloadducts at the anomeric position in solution was confirmed by H NMR spectroscopy <2007MI717>. [Pg.471]

J. M. Indelicato, C. E. Pasini, The Acylating Potential of y-Lactam Antibacterials Base Hydrolysis of Bicyclic Pyrazolidinones , J. Med. Chem. 1988, 31, 1227-1230. [Pg.247]

J. Rabiczko and M. Chmielewski, New route to bicyclic pyrazolidinones and hydroxypyrrolidinones from a,/i-unsaturated sugar lactones, J. Org. Chem., 64 (1999) 1347-1351. [Pg.116]

See, e.g, D. B. Boyd,. Med. Chem., 36, 1443 (1993). Application of the Hypersurface Iterative Projection Method to Bicyclic Pyrazolidinone Antibacterial Agents. [Pg.378]

Similar methodology as used for the 5-5 fused pyrazolidinones (see Section 8.31.12.1.2) based on an acid-induced cyclization of exocyclic hydrazonium intermediates is also useful for the synthesis of similar 5-6 bicycles as is shown in Scheme 87 <94RTC145>. [Pg.812]

In principle, binding a copper catalyst to a surface requires that during the catalytic cycle the copper ions will not be released into the solvent. Recently, it was shown that this is even the case for Cu(0H)a Al203 which contains ca. 10% water as a catalyst for the catalytic synthesis of A7, A -bicyclic pyrazolidinone in organic solvents, a process which involves Cu(I) as the reactive intermediate 171). [Pg.255]

A first approach towards bicyclic pyrazolidinones [108, 109] used 1,3-dipolar cycloaddition of pyrazolidinium ylides to acetylenic compounds as a key step. The reaction of ylide 211 [110] with allyl acetylenedicarboxylate yielded 212 from which the diacid 213 was readily obtained (Scheme 60). This compound exhibits weak in vitro antimicrobial activity against S. aureus. [Pg.765]

The Strategy above suffered from a lack of regiocontrol in the cycloaddition step. A modification [113] used vinyl sulphones 222 which reacted regio-selectively with pyrazolidinium ylide 218 to give the cycloadducts 223 (Scheme 64). Base-catalysed elimination of benzene sulphinic acid led to the desired bicyclic pyrazolidinones 220a to d. These compounds could also be prepared without racemisation from the optically pure pyrazolidinone 216, derived from L-serine [114]. [Pg.767]

The required bifunctional intermediates 226 were prepared via selective functionalisation of N-1 and N-2 of the chiral synthon 216. The chiral bicyclic pyrazolidinone 221d is as active against E. coll as ceftazidime (MIC = 0.25 pg/ml). Compound 221e is even more active (MIC = 0.125 pg/ml). In this case, the biological activity correlates well with chemical reactivity [109] (Scheme 66). [Pg.768]

Sommer et al. found that Cu(I)-exchanged zeolites (Cu(l)-USY) could be utilized as heterogeneous catalysts for [3 + 2] cycloaddition of azomethine imines with terminal alkynes (Scheme 4.20). This method provides an efficient, versatile, and highly regi-oselective approach to Af,Af-bicyclic pyrazolidinone derivatives, which might exhibit useful bioactivities. The catalysts were readily available, convenient to remove, and reusable (Keller et al., 2009). [Pg.108]

Dipolar cycloaddition reactions with stable and easily prepared azomethine imines, for the synthesis of a diverse array of heterocycles, have attracted considerable attention [125]. The complex RhjldS-MPPlM) (47) catalyzes the highly diastereoselective [3-l-2-l-l]-cycloaddition reaction between a diazo ketone and azomethine imines [126]. The final products are multi-functionalized bicyclic pyrazolidinone derivatives isolated in moderate to high yields (Scheme 9.12). [Pg.296]

Kobayashi and co-workers successfully achieved the asymmetric 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by CuHMDS and DIP-BINAP ligand to provide N,N-bicyclic pyrazolidinone derivatives in high yields with exclusive regioselectivity and excellent enantioselectivity (Scheme 26) [46]. Mechanistic studies elucidated a stepwise reaction pathway and revealed that the steric character of the ligand determines the regioselectivity. Arai and co-workers applied chiral bis(imidazolidine)pyridine-CuOAc complex to the [3+2]cycloaddition of azomethine imines with propiolates for the construction of bicyclic pyrazolo[l,2-a]pyrazolone derivatives with up to 74% ee [47]. [Pg.195]

Projection Method to Bicyclic Pyrazolidinone Antibacterial Agent. [Pg.448]

Asymmetric 1,3-dipolar cycloadditions of azomethine imines with terminal alkynes have been catalysed by 11 chiral ligand (8) coordinated metal amides to form N,N-bicyclic pyrazolidinone derivatives. Mechanistic studies have established the factors that determine the regioselectivity of the stepwise reaction. Novel phosphoramidite ligands (9) coordinated with palladium have been used to effect enantioselective synthesis of pyrrolidines by 3-P 2-cycloaddition of trimethylenemethane (from 2-trimethylsilylmethyl allyl acetate) to a wide range of imine acceptors (Scheme 11). ... [Pg.11]

Azomethine imines react with propiolates under copper catalysis to form N,N-bicyclic pyrazolidinone. Different catalysts have been used in this reaction Cul in the presence of A/ -methyldicyclohexylamine [103] copper(l)-exchanged zeolites [102,104] copper hydroxide catalyst, Cu(0H) /Al203 (Cu 1.5 mol%) [105] orthe efficient copper(I) acetate [106]. [Pg.90]


See other pages where Pyrazolidinones, bicyclic is mentioned: [Pg.289]    [Pg.537]    [Pg.12]    [Pg.295]    [Pg.831]    [Pg.768]    [Pg.509]    [Pg.331]    [Pg.331]    [Pg.331]    [Pg.331]    [Pg.442]    [Pg.90]   
See also in sourсe #XX -- [ Pg.509 ]




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Pyrazolidinone

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