... as catalyst. 15 In these conditions, we obtained the β-O-galactoside 7, which, in the crude product of the reaction, was not accompanied by any detectable quantity of the corresponding α-anomer or ortho-ester. On the contrary ...
ABSTRACT The paper describes a mild, selective, and rapid replacement of an N-methyl group of tertiary amines with other alkyl groups via a simple one-pot procedure. This transformation is easily achieved by preparation of the appropriate...
moreABSTRACT The paper describes a mild, selective, and rapid replacement of an N-methyl group of tertiary amines with other alkyl groups via a simple one-pot procedure. This transformation is easily achieved by preparation of the appropriate quaternary ammonium salt in sulfolane and in situ treatment with sodium sulfide or potassium thioacetate. The protocol is successfully applied to the transformation of dihydrolysergol, dextromethorphan and laudanosine (as models of ergot and opium N-methyl alkaloids) into various N-alkyl congeners.
ABSTRACT The paper describes a mild, selective, and rapid replacement of an N-methyl group of tertiary amines with other alkyl groups via a simple one-pot procedure. This transformation is easily achieved by preparation of the appropriate...
moreABSTRACT The paper describes a mild, selective, and rapid replacement of an N-methyl group of tertiary amines with other alkyl groups via a simple one-pot procedure. This transformation is easily achieved by preparation of the appropriate quaternary ammonium salt in sulfolane and in situ treatment with sodium sulfide or potassium thioacetate. The protocol is successfully applied to the transformation of dihydrolysergol, dextromethorphan and laudanosine (as models of ergot and opium N-methyl alkaloids) into various A-alkyl congeners.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select...
moreABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ABSTRACT Cited By (since 1996): 13, Export Date: 3 April 2013, Source: Scopus
ABSTRACT A four step synthesis of (2S,5R)- and (2S,5S)-5-hydroxylysine using Williams' glycine template methodology for controlling the stereogenicity at the α-position is reported. This route offers the possibility for the...
moreABSTRACT A four step synthesis of (2S,5R)- and (2S,5S)-5-hydroxylysine using Williams' glycine template methodology for controlling the stereogenicity at the α-position is reported. This route offers the possibility for the synthesis of all possible isomers of 5-hydroxylysine and of an important α-amino acidic iodohydrin required for the construction of the hydroxylated side chain of the collagen cross-link pyridinoline.
The paper reports the first enantioselective synthesis of all the possible collagen reduced cross links as described: (2S,2′S,5R)- and (2S,2′S,5S)-5-hydroxylysinonorleucine 3a and 3b, (2S,2′S,5R,5′R)-5,5′-dihydroxylysinonorleucine 4a,...
moreThe paper reports the first enantioselective synthesis of all the possible collagen reduced cross links as described: (2S,2′S,5R)- and (2S,2′S,5S)-5-hydroxylysinonorleucine 3a and 3b, (2S,2′S,5R,5′R)-5,5′-dihydroxylysinonorleucine 4a, (2S,2′S,5R,5′S)-5,5′-dihydroxylysinonorleucine 4b and (2S,2′S,5S,5′S)-5,5′-dihydroxylysinonorleucine 4c. The Williams’ glycine template methodology was used both for the introduction of a stereogenic at the α-position and for an easy protection of the amino acidic functionalities during the synthesis
... as catalyst. 15 In these conditions, we obtained the β-O-galactoside 7, which, in the crude product of the reaction, was not accompanied by any detectable quantity of the corresponding α-anomer or ortho-ester. On the contrary ...
The paper reports some successful results on the first fully stereoselective total synthesis of the collagen cross-link pyridinolines. All stereogenic centers are stereoselectively introduced using Williams glycine template methodology,...
moreThe paper reports some successful results on the first fully stereoselective total synthesis of the collagen cross-link pyridinolines. All stereogenic centers are stereoselectively introduced using Williams glycine template methodology, and oxazinones are used as a source of chirality and as easily removable protecting groups of the amino acidic functionalities during the assembly of the pyridinoline nucleus.
Low density lipoprotein (LDL) cholesterol is known to be oxidized both in vitro and in vivo giving rise to oxygenated sterols. Conflicting results, however, have been reported concerning both the nature and the relative concentrations of...
moreLow density lipoprotein (LDL) cholesterol is known to be oxidized both in vitro and in vivo giving rise to oxygenated sterols. Conflicting results, however, have been reported concerning both the nature and the relative concentrations of these compounds in oxidized human LDL. We examined the extracts obtained from Cu(2+)-oxidized LDL. Thin layer chromatography analysis showed that the sterol mixture became more complex with reaction time. Analysis of the components by thin layer chromatography and mass spectrometry allowed to establish that 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 alpha OOH and beta OOH) are largely prevalent among the oxysterols at early times of oxidation. These hydroperoxy derivatives have not been previously identified in oxidized LDL. The concentration of 7-hydroperoxycholest-5-en-3 beta-ol decreased with oxidation time with a concomitant increase of cholest-5-en-3 beta, 7 alpha-diol (7 alpha OH), cholest-5-en-3 beta, 7 beta-diol (7 beta OH), cholesta-3,5-dien-7-one (CD) and cholest-5-en-3 beta-ol-7-one (7CO). After 24 h of oxidation a minor component of the LDL sterols was cholestan-3 beta-ol-5,6-oxide (EP).
... Enzymatic Resolution of (R)- and (S)-(E)-4-Hydroxyalk-2-enals Related to Lipid Peroxidation Pietro Allevi,' Mario Anastasia, Francesco Cajone? Pierangela Ciuffreda, and Anna M. Sanvito ... 1987, 28, 2091. (11) Fitzpatrick, PA;...
more... Enzymatic Resolution of (R)- and (S)-(E)-4-Hydroxyalk-2-enals Related to Lipid Peroxidation Pietro Allevi,' Mario Anastasia, Francesco Cajone? Pierangela Ciuffreda, and Anna M. Sanvito ... 1987, 28, 2091. (11) Fitzpatrick, PA; Klibanov, A. M. J. Am. Chem. SOC. lSSl,113, 3166. ...
... 3265 Mario Anastasia,* Pietro Allevi, Albert0 Fiecchi, and Antonio Scala Istituto di Chimica Facoltd di Medicina e Chirurgia, 20133 Milano, Italy Received February 17, 1981 ... 1978,251, 1745. (2) Schroepfer, G. J.; Parish, EJ; Chen,...
more... 3265 Mario Anastasia,* Pietro Allevi, Albert0 Fiecchi, and Antonio Scala Istituto di Chimica Facoltd di Medicina e Chirurgia, 20133 Milano, Italy Received February 17, 1981 ... 1978,251, 1745. (2) Schroepfer, G. J.; Parish, EJ; Chen, H. W.; Kandutsch, AA Fed. Proc., Fed. Am. SOC. ...
... Albert0 Fiecchi,' Giovanni Galli,* Pierluigi Gariboldi,s and Antonio Scala? ... (3) Bhacca, NW; Williams, D. H. 'Applications of NMR Spectros-copy in Organic Chemistry"; Holden-Day: San...
more... Albert0 Fiecchi,' Giovanni Galli,* Pierluigi Gariboldi,s and Antonio Scala? ... (3) Bhacca, NW; Williams, D. H. 'Applications of NMR Spectros-copy in Organic Chemistry"; Holden-Day: San Francisco, CA, 1964; Chapters 2 and 6. (4) Tsuda, M.; Parish, E. J.; Schroepfer, GJJ Org. ...
Starting from l-lysine as the only chiral building block, pyridinoline and deoxypyridinoline are efficiently synthesised, thus mimicking the postranscriptional formation of these collagen...
moreStarting from l-lysine as the only chiral building block, pyridinoline and deoxypyridinoline are efficiently synthesised, thus mimicking the postranscriptional formation of these collagen cross-links.Graphic(2S,5R)-2-Benzyloxycarbonylamino-5-bromomethyl-δ-valerolactoneC14H16BrNO4[α]D25=+5.4 (c 1, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 2S,5R(2S,5S)-2-Benzyloxycarbonylamino-5-bromomethyl-δ-valerolactoneC14H16BrNO4[α]D25=+58.2 (c 1, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 2S,5SAllyl (2S,5R)-2-benzyloxycarbonylamino-4-(2-oxiranyl)butanoateC17H21NO5[α]D25=+10.8 (c 1, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 2S,5RAllyl (2S,5R)-2-benzyloxycarbonylamino-5-hydroxy-6-iodohexanoateC17H22INO5[α]D25=+6.9 (c 1, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 2S,5RMethyl (2S,5S)-2-benzyloxycarbonylamino-6-bromo-5-hydroxyhexanoateC15H20BrNO5[α]D25=+7.6 (c 1, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 2S,5S4-[(S)-2-Benzyloxycarbonylamino-2-(tert-butyloxycarbonyl)ethyl]-5-[(S)-3-benzyloxy carbonylamino-3-(tert-butyloxycarbonyl)propyl]-1-[(2R,5S)-5-benzyloxycarbonylamino-5-(allyloxycarbonyl)-2-hydroxypentyl]-3-pyridiniumolateC53H66N4O14[α]D25=−2.3 (c 0.6, CHCl3)Source of chirality: natural l-lysineAbsolute configuration: 4(2)S,5(3)S,1(2)R,1(5)S
ABSTRACT A stereoselective synthesis of crinosterol, (22E,24S)-ergosta-5,22-dien-3β-ol, was developed from (20S)-6β-acetoxy-3α,5-cycle-5α-pregnane-20-carbaldehyde using the Claisen rearrangement of an appropriate precursor of established...
moreABSTRACT A stereoselective synthesis of crinosterol, (22E,24S)-ergosta-5,22-dien-3β-ol, was developed from (20S)-6β-acetoxy-3α,5-cycle-5α-pregnane-20-carbaldehyde using the Claisen rearrangement of an appropriate precursor of established absolute configuration.
ABSTRACT The evaluation of the uptake of 24-epibrassinolide (BR) in growing maize root segments by means of multiple-selected ion monitoring showed that BR is accumulated into the fresh tissue independently of energy supply, while the...
moreABSTRACT The evaluation of the uptake of 24-epibrassinolide (BR) in growing maize root segments by means of multiple-selected ion monitoring showed that BR is accumulated into the fresh tissue independently of energy supply, while the experiments performed with frozen-thawed roots show a large adsorption to cell structures. The adsorption is freely reversible in frozen-thawed roots, whereas 30% of BR taken up in fresh roots is irreversibly bound.
Low density lipoprotein (LDL) cholesterol is known to be oxidized both in vitro and in vivo giving rise to oxygenated sterols. Conflicting results, however, have been reported concerning both the nature and the relative concentrations of...
moreLow density lipoprotein (LDL) cholesterol is known to be oxidized both in vitro and in vivo giving rise to oxygenated sterols. Conflicting results, however, have been reported concerning both the nature and the relative concentrations of these compounds in oxidized human LDL. We examined the extracts obtained from Cu(2+)-oxidized LDL. Thin layer chromatography analysis showed that the sterol mixture became more complex with reaction time. Analysis of the components by thin layer chromatography and mass spectrometry allowed to establish that 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 alpha OOH and beta OOH) are largely prevalent among the oxysterols at early times of oxidation. These hydroperoxy derivatives have not been previously identified in oxidized LDL. The concentration of 7-hydroperoxycholest-5-en-3 beta-ol decreased with oxidation time with a concomitant increase of cholest-5-en-3 beta, 7 alpha-diol (7 alpha OH), cholest-5-en-3 beta, 7 beta-diol (7 beta OH), cholesta-3,5-dien-7-one (CD) and cholest-5-en-3 beta-ol-7-one (7CO). After 24 h of oxidation a minor component of the LDL sterols was cholestan-3 beta-ol-5,6-oxide (EP).
ABSTRACT Beckmann rearrangement of Δ4-6-hydroxyimino steroids gave solely the products of vinyl migration. Compounds having a 3-hydroxy or 3-acetoxy group suffer elimination of the substituent during the reaction.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select...
moreABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
The first synthesis of the four possible isomers of (E)-4, 5-dihydroxydec-2-enal, a cytotoxic product of microsomal lipid peroxidation, is accomplished starting with D-and L-arabinose, D-ribose and D-lyxose by an identical reaction...
moreThe first synthesis of the four possible isomers of (E)-4, 5-dihydroxydec-2-enal, a cytotoxic product of microsomal lipid peroxidation, is accomplished starting with D-and L-arabinose, D-ribose and D-lyxose by an identical reaction sequence. Each pentose was diacetonised ...
ABSTRACT (2R,3S,22R,23R)- and (2R,3S,22S,23S)-2,3,22,23-tetrahydroxy-B-homo-7a-oxa-5α-ergostan-7-ones (4a and 4b) were synthesized starting from the 5α-ergosta-2,7,22-triene (7). Osmilation of the 2,7,22 double bonds of 7 afforded the two...
moreABSTRACT (2R,3S,22R,23R)- and (2R,3S,22S,23S)-2,3,22,23-tetrahydroxy-B-homo-7a-oxa-5α-ergostan-7-ones (4a and 4b) were synthesized starting from the 5α-ergosta-2,7,22-triene (7). Osmilation of the 2,7,22 double bonds of 7 afforded the two hexols 6 which were rearranged by acidic treatment to (2R,3S,22R,23R)- and (2R,3S,22S,23S)-2,3,22,23-tetrahydroxy-5α-ergostan-7-ones (5a and 5b) whose structures were determined by chemical methods. Baeyer-Villiger oxidation of the 7-oxo group of 5a and 5b afforded 4a and 4b, respectively. The triene 7 was obtained in pure form by dehydrotosylation of the 3β-hydroxy-3′,5′-dioxo-4′-phenyl-5,8[1′,2′]- 1′,2′,4′-triazolidino-5α,8α-ergosta-6,22-diene 3-p-toluenesulfonate (8) and subsequent reduction with lithium dissolved in liquid ammonia of the obtained 3′,5′-dioxo-4′-phenyl-5,8[1′,2′]-1′,2′ ,4′-triazolidino-5α,8α-ergosta-2,6,22-triene (9).
ABSTRACT the antitumor agent etoposide has been synthesized for the first time from unprotected 4′-demethylepipodophyllotoxin.
ABSTRACT The chemical synthesis of some (S)- and (R)-(E)-4-hydroxyalk-2-enals, important products of lipid peroxidation (LPO), has been carried out via enantiomerically pure 2-benzoyloxyaldehydes, chiral key intermediates obtained from...
moreABSTRACT The chemical synthesis of some (S)- and (R)-(E)-4-hydroxyalk-2-enals, important products of lipid peroxidation (LPO), has been carried out via enantiomerically pure 2-benzoyloxyaldehydes, chiral key intermediates obtained from two diastereomeric diepoxides deriving from D-mannitol. These aldehydes were transformed into the final compounds by Wittig condensation with (formylmethylene)triphenylphosphorane and regeneration of the hydroxy group.
Previous studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new...
morePrevious studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new treatments for ischemic diseases. Herein, the synthesis of several dephosphonated CMP-Neu5Ac congeners and their anti-GM3-synthase activity is reported. Biological activity testes revealed that some inhibitors almost completely blocked the GM3-synthase activity in vitro and reduced the GM3 content in living embryonic kidney 293A cells, eventually activating the epidermal growth factor receptor (EGFR) signaling cascade.