The Experts below are selected from a list of 393 Experts worldwide ranked by ideXlab platform
Miquel A Pericas - One of the best experts on this subject based on the ideXlab platform.
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highly enantioselective cross aldol reactions of acetaldehyde mediated by a dual catalytic system operating under site isolation
ChemInform, 2015Co-Authors: Xinyuan Fan, Carles Rodriguezescrich, Shoulei Wang, Sonia Sayalero, Miquel A PericasAbstract:Two polymer supported materials are used as recyclable catalyst mixture for the aldol condensation of Paraldehyde (I) with aromatic aldehyde.
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highly enantioselective cross aldol reactions of acetaldehyde mediated by a dual catalytic system operating under site isolation
Chemistry: A European Journal, 2014Co-Authors: Xinyuan Fan, Carles Rodriguezescrich, Shoulei Wang, Sonia Sayalero, Miquel A PericasAbstract:Polystyrene-supported (PS) diarylprolinol catalysts 1 a (Ar=phenyl) and 1 b (Ar=3,5-bis(trifluoromethyl)phenyl) have been developed. Operating under site-isolation conditions, PS-1 a/1 b worked compatibly with PS-bound sulfonic acid catalyst 2 to promote deoligomerization of Paraldehyde and subsequent cross-aldol reactions of the resulting acetaldehyde in one pot, affording aldol products in high yields with excellent enantioselectivities. The effect of water on the performance of the catalytic system has been studied and its optimal amount (0.5 equiv) has been determined. The dual catalytic system (1/2) allows repeated recycling and reuse (10 cycles). The potential of this methodology is demonstrated by a two-step synthesis of a phenoperidine analogue (68 % overall yield; 98 % ee) and by the preparation of highly enantioenriched 1,3-diols 4 and 3-methylamino-1-arylpropanols 5, key intermediates in the synthesis of a variety of druglike structures.
Jinpei Cheng - One of the best experts on this subject based on the ideXlab platform.
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chiral primary amine catalyzed asymmetric direct cross aldol reaction of acetaldehyde
ChemInform, 2011Co-Authors: Long Zhang, Sanzhong Luo, Jinpei ChengAbstract:Aqueous acetaldehyde solution and Paraldehyde can be conveniently applied in this reaction.
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chiral primary amine catalyzed asymmetric direct cross aldol reaction of acetaldehyde
European Journal of Organic Chemistry, 2011Co-Authors: Long Zhang, Sanzhong Luo, Jinpei ChengAbstract:The first primary aminocatalytic direct cross-aldol reaction of acetaldehyde is presented. Among the various vicinal diamines screened, the L-tert-leucine derivative 1c in conjunction with (H4SiW12O40)0.25 was identified as the optimal catalyst; good catalytic activity (up to 99 % yield in 4 h), and high enantioselectivities (up to 92 % ee) were achieved for a range of donors, including aromatic aldehydes and isatin derivatives. Aqueous acetaldehyde solution and Paraldehyde can be conveniently applied in this system.
Gürsel Ergen - One of the best experts on this subject based on the ideXlab platform.
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Histological Investigations on the Neurosecretory Cells in Thoracic and Abdominal Ganglia of Melanogryllus desertus (PALLAS, 1771) (Orthoptera; Gryllidae)
Turkish Journal of Zoology, 2001Co-Authors: Esen M. Aydemir, Gürsel ErgenAbstract:In this study, three kinds of neurosecretory cells, which are called A, B and C-types, have been described in the thoracic and abdominal ganglia of adult Melanogryllus desertus (PALLAS, 1771), (Orthoptera; Gryllidae) by using Paraldehyde fuchsine and azan staining methods at the light microscope level.
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Melanogryllus desertus (PALLAS, 1771) (Orthoptera, Gryllidae)'un torasik ve abdominal ganglion nörosekresyon hücrelerinin histolojik araştırılması
2001Co-Authors: Esen Aydemir, Gürsel ErgenAbstract:Bu çalışmada ergin Melanogryllus desertus (PALLAS, 1771), (Orthoptera; Gryllidae)un torasik ve abdominal ganglionlarında paraldehit fuksin ve azan boya metodları kullanılarak; ışık mikroskobu düzeyinde A, B ve C- tipleri olarak adlandırılan üç çeşit nörosekresyon hücresi tesbit edilmiştir.In this study, three kinds of neurosecretory cells, which are called A, B and C-types, have been described in the thoracic and abdominal ganglia of adult Melanogryllus desertus (PALLAS, 1771), (Orthoptera; Gryllidae) by using Paraldehyde fuchsine and azan staining methods at the light microscope level
Michael Emmett - One of the best experts on this subject based on the ideXlab platform.
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increased anion gap metabolic acidosis as a result of 5 oxoproline pyroglutamic acid a role for acetaminophen
Clinical Journal of The American Society of Nephrology, 2006Co-Authors: Andrew Z. Fenves, Haskell M Kirkpatrick, Viralkumar Patel, Lawrence Sweetman, Michael EmmettAbstract:The endogenous organic acid metabolic acidoses that occur commonly in adults include lactic acidosis; ketoacidosis; acidosis that results from the ingestion of toxic substances such as methanol, ethylene glycol, or Paraldehyde; and a component of the acidosis of kidney failure. Another rare but underdiagnosed cause of severe, high anion gap metabolic acidosis in adults is that due to accumulation of 5-oxoproline (pyroglutamic acid). Reported are four patients with this syndrome, and reviewed are 18 adult patients who were reported previously in the literature. Twenty-one patients had major exposure to acetaminophen (one only acute exposure). Eighteen (82%) of the 22 patients were women. Most of the patients were malnourished as a result of multiple medical comorbidities, and most had some degree of kidney dysfunction or overt failure. The chronic ingestion of acetaminophen, especially by malnourished women, may generate high anion gap metabolic acidosis. This undoubtedly is an underdiagnosed condition because measurements of serum and/or urinary 5-oxoproline levels are not readily available.
Xinyuan Fan - One of the best experts on this subject based on the ideXlab platform.
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highly enantioselective cross aldol reactions of acetaldehyde mediated by a dual catalytic system operating under site isolation
ChemInform, 2015Co-Authors: Xinyuan Fan, Carles Rodriguezescrich, Shoulei Wang, Sonia Sayalero, Miquel A PericasAbstract:Two polymer supported materials are used as recyclable catalyst mixture for the aldol condensation of Paraldehyde (I) with aromatic aldehyde.
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highly enantioselective cross aldol reactions of acetaldehyde mediated by a dual catalytic system operating under site isolation
Chemistry: A European Journal, 2014Co-Authors: Xinyuan Fan, Carles Rodriguezescrich, Shoulei Wang, Sonia Sayalero, Miquel A PericasAbstract:Polystyrene-supported (PS) diarylprolinol catalysts 1 a (Ar=phenyl) and 1 b (Ar=3,5-bis(trifluoromethyl)phenyl) have been developed. Operating under site-isolation conditions, PS-1 a/1 b worked compatibly with PS-bound sulfonic acid catalyst 2 to promote deoligomerization of Paraldehyde and subsequent cross-aldol reactions of the resulting acetaldehyde in one pot, affording aldol products in high yields with excellent enantioselectivities. The effect of water on the performance of the catalytic system has been studied and its optimal amount (0.5 equiv) has been determined. The dual catalytic system (1/2) allows repeated recycling and reuse (10 cycles). The potential of this methodology is demonstrated by a two-step synthesis of a phenoperidine analogue (68 % overall yield; 98 % ee) and by the preparation of highly enantioenriched 1,3-diols 4 and 3-methylamino-1-arylpropanols 5, key intermediates in the synthesis of a variety of druglike structures.
