68394-39-8Relevant academic research and scientific papers
Synthesis of l-threitol-based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions
Rapi, Zsolt,Nemcsok, Tamás,Pálv?lgyi, ádám,Keglevich, Gy?rgy,Grün, Alajos,Bakó, Péter
, p. 257 - 272 (2017/05/29)
A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with β-nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers.
Structure-based design, synthesis and preliminary evaluation of selective inhibitors of dihydrofolate reductase from Mycobacterium tuberculosis
El-Hamamsy, Mervat H.R.I.,Smith, Anthony W.,Thompson, Andrew S.,Threadgill, Michael D.
, p. 4552 - 4576 (2008/03/12)
Tuberculosis is an increasing threat, owing to the spread of AIDS and to the development of resistance of the causative organism, Mycobacterium tuberculosis, to the currently available drugs. Dihydrofolate reductase (DHFR) is an important enzyme of the folate cycle; inhibition of DHFR inhibits growth and causes cell death. The crystal structure of M. tuberculosis DHFR revealed a glycerol tightly bound close to the binding site for the substrate dihydrofolate; this glycerol-binding motif is absent from the human enzyme. A series of pyrimidine-2,4-diamines was designed with a two-carbon tether between a glycerol-mimicking triol and the 6-position of the heterocycle; these compounds also carried aryl substituents at the 5-position. These, their diastereoisomers, analogues lacking two hydroxy groups and analogues lacking the two-carbon spacing linker were synthesised by acylation of the anions derived from phenylacetonitriles with ethyl (4S,5R)-4-benzyloxymethyl-2,2-dimethyl-1,3-dioxolane-4-propanoate, ethyl (4S,5S)-4-benzyloxymethyl-2,2-dimethyl-1,3-dioxolane-4-propanoate, tetrahydrooxepin-2-one and 2,3-O-isopropylidene-d-erythronolactone, respectively, to give the corresponding α-acylphenylacetonitriles. Formation of the methyl enol ethers, condensation with guanidine and deprotection gave the pyrimidine-2,4-diamines. Preliminary assay of the abilities of these compounds to inhibit the growth of TB5 Saccharomyces cerevisiae carrying the DHFR genes from M. tuberculosis, human and yeast indicated that 5-phenyl-6-((3R,4S)-3,4,5-trihydroxypentyl)pyrimidine-2,4-diamine selectively inhibited M. tuberculosis DHFR and had little effect on the human or yeast enzymes.
Synthesis and conformational and configurational studies of diastereoisomeric O-protected 4-(arylsulfonimidoyl)butane-1,2,3-triols
Kwong, Joey S.W.,Mahon, Mary F.,Lloyd, Matthew D.,Threadgill, Michael D.
, p. 12601 - 12607 (2008/03/14)
Chiral sulfoximines have applications as transition-state mimicking enzyme inhibitors, as peptide isosteres and as chiral auxiliaries in synthesis. To access the required O-protected 4-(arylsulfonimidoyl)butane-1,2,3-triols, 4S,5S-di(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane (prepared from diethyl R,R-tartrate) was converted into its monobenzyl ether. Mitsunobu-like coupling with thiophenols gave 4S,5R-4-(benzyloxymethyl)-2,2-dimethyl-5-(arylthiomethyl)-1,3-dioxolanes. Sulfoxidation and S-imination (trifluoroacetamide, iodosobenzene diacetate, rhodium acetate) proceeded without stereoselectivity, giving inseparable diastereomeric mixtures of 4S,5R,S(±)-4-(benzyloxymethyl)-2,2-dimethyl-5-(N-(trifluoroacetyl)arylsulfonimidoylmethyl)-1,3-dioxolanes. Removal of the trifluoroacetyl protection allowed chromatographic separation of the diastereomeric 4S,5R,S(±)-4-(benzyloxymethyl)-2,2-dimethyl-5-(arylsulfonimidoylmethyl)-1,3-dioxolanes. The configurations at sulfur were determined by X-ray crystallography and some analysis of the solution and solid-state conformations was carried out. The resulting O-protected 4-(arylsulfonimidoyl)butane-1,2,3-triols are of use in developing enzyme inhibitors.
New supramolecular host systems, 11. The stereoisomeric diaminobutanediol and dioxadiazadecalin systems: Synthesis, structure, stereoelectronics, and conformation - Theory vs. experiment
Star, Alexander,Goldberg, Israel,Lemcoff, N. Gabriel,Fuchs, Benzion
, p. 2033 - 2043 (2007/10/03)
We present new approaches to the (C2) chiral and meso 1,4-diamino-2,3- butanediol (1) and 2,3-diamino-1,4-butanediol (2) and derivatives. Reactions of these compounds with aldehydes to form the novel 1,5-dioxa-3,7- diazadecalin (DODAD) and 1,5-diaza-3,7-dioxadecalin (DADOD) classes of compounds (7, 9, 11-15) are also reported. These reactions are diastereospecific, i e, erythro (meso) or threo starting compounds lead to trans or cis products, respectively. The structural, conformational, and stereoelectronic aspects of these systems were probed experimentally and computationally and provided excellent insight into their properties and behaviour. Good agreement was observed between X-ray, NMR, and calculated results of the N,N'-dibenzyl derivatives of trans-DODAD (14) and trans-DADOD (15).
Highly selective Silver(I) oxide mediated monoprotection of symmetrical diols
Bouzide, Abderrahim,Sauve, Gilles
, p. 5945 - 5948 (2007/10/03)
Treatment of symmetrical diol with Ag2O and alkyl halide gave the monoprotected derivative in good to excellent yield.
Comparative Study of Mono- and Di-substituted 14-Crown-4 Derivatives as Lithium Ionophores
Kataky, Ritu,Nicholson, Patrick E. Patrick,Parker, David
, p. 321 - 327 (2007/10/02)
14-Crown-4 derivatives bearing either one or two methoxy, methoxycarbonylmethyl or carbamoylalkyl substituents have been prepared in an attempt to obtain selective ionophores for lithium ions.Complexation with lithium has been fabricated and evaluated using the fixed interference method.The highest selectivity for lithium with respect to sodium is observed for a diamide derivative (630:1).
Enanthioselective Phase-Transfer Catalysis by Optically Active Crown Ethers
Dehmlow, Eckehard V.,Sauerbier, Christiane
, p. 181 - 186 (2007/10/02)
1,2-Bis(hydroxymethyl)-15-crown-5 (1a), its dibenzyl ether (1b), and a series of esters with substituted benzoic acid (3) were probed as enanthioselective phase-transfer catalysts.Optical yields were observed in epoxidations of unsaturated ketones by hypochlorite and in cyanide additions to such compounds.The maximum ee value was 45percent.Polar side groups of the optically active crown ethers proved to be vital for enanthiomeric excesses.
