- Salamanca, Castilla y Leon, Spain
David Diez
University of Salamanca, Quimica Orgánica, Faculty Member
Sclareol has been employed as starting material for the synthesis of several advanced intermediates towards the synthesis of highly ring B oxygenated labdanes. Dinorlabdanes 6,7,8,9-tetraoxygenated with 6,7-dioxygenated functionalities... more
Sclareol has been employed as starting material for the synthesis of several advanced intermediates towards the synthesis of highly ring B oxygenated labdanes. Dinorlabdanes 6,7,8,9-tetraoxygenated with 6,7-dioxygenated functionalities with α- cis or β- cis dispositions, have been prepared and can be used for forskolin or analogues synthesis.
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The title compound, C22H25NO5, was prepared by CAN [cerium(IV) ammonium nitrate] oxidation of the corresponding β-lactam. The dihedral angle between the benzene rings is 13.3 (4)° and the C-N-C(=O)-C torsion angle is 176.1 (6)°. In the... more
The title compound, C22H25NO5, was prepared by CAN [cerium(IV) ammonium nitrate] oxidation of the corresponding β-lactam. The dihedral angle between the benzene rings is 13.3 (4)° and the C-N-C(=O)-C torsion angle is 176.1 (6)°. In the crystal, amide-C(4) N-H⋯O and reinforcing C-H⋯O hydrogen bonds link the mol-ecules into infinite [010] chains. Further C-H⋯O hydrogen bonds cross-link the chains in the c-axis direction.
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Carvone is one of the most versatile synthons in organic synthesis. It has been used as starting material for a huge number of organic syntheses of natural products with interesting biological activities. This manuscript communicates the... more
Carvone is one of the most versatile synthons in organic synthesis. It has been used as starting material for a huge number of organic syntheses of natural products with interesting biological activities. This manuscript communicates the antioxidant activity against superoxide of carvone and several derivatives.
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Salamanca, Spain; E-mails: ddm@usal.es, mgn@usal.es, rfm@usal.es, nmg@usal.es, ismarcos@usal.es, pbb@usal.es, jgu@usal.es ... * Author to whom correspondence should be addressed; E-mail: ddm@usal.es ... Received: 12 November 2006; in... more
Salamanca, Spain; E-mails: ddm@usal.es, mgn@usal.es, rfm@usal.es, nmg@usal.es, ismarcos@usal.es, pbb@usal.es, jgu@usal.es ... * Author to whom correspondence should be addressed; E-mail: ddm@usal.es ... Received: 12 November 2006; in revised form: 12 ...
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A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of... more
A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potential photoprotective chiral 1,3-cyclohexadienals and extra extended conjugation compounds in a simple manner.
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A new family of molecular hybrids, between cyclolignans related to podophyllic aldehyde and several diterpenylnaphthohydroquinones (DNHQ), was prepared and its biological activity evaluated in several human solid tumor cell lines, which... more
A new family of molecular hybrids, between cyclolignans related to podophyllic aldehyde and several diterpenylnaphthohydroquinones (DNHQ), was prepared and its biological activity evaluated in several human solid tumor cell lines, which are representative of the most prevalent solid tumors in the Western world. Both cyclolignan and quinone fragments were linked through aliphatic or aromatic spacers. The new hybrid family was evaluated for its cytotoxicity, and it was found that the hybrids were several times more potent against the osteosarcoma cell line MG-63 than against MCF-7 and HT-29 cell lines. The presence of an aromatic ring in the linker gave the most potent and selective agent, improving the cytotoxicity of the parent compounds. Cell cycle studies demonstrated that this hybrid induces a strong and rapid apoptotic effect and arrests cells at the G2/M phase of the cell cycle, in the same way that the parent compound podophyllic aldehyde does.
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The title compound, C12H15NO3S, was prepared by 1,3-dipolar cyclo-addition of 3,4-di-hydro-2H-pyrrole 1-oxide and phenyl vinyl sulfone. In the mol-ecule, both fused five-membered rings display a twisted conformation. In the crystal, C-H⋯O... more
The title compound, C12H15NO3S, was prepared by 1,3-dipolar cyclo-addition of 3,4-di-hydro-2H-pyrrole 1-oxide and phenyl vinyl sulfone. In the mol-ecule, both fused five-membered rings display a twisted conformation. In the crystal, C-H⋯O hydrogen bonds link neighbouring mol-ecules, forming chains running parallel to the b axis.
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Natural sesterterpenolides, luffarin I and luffarin A, from Luffariella geometrica have been synthesized, and this is the first reported synthesis of luffarin A. The Yamaguchi esterification of the nor-diterpenic fragment, obtained from... more
Natural sesterterpenolides, luffarin I and luffarin A, from Luffariella geometrica have been synthesized, and this is the first reported synthesis of luffarin A. The Yamaguchi esterification of the nor-diterpenic fragment, obtained from 2.8-15 [Formula: see text]M, with the appropriate furane alcohols yielded the necessary diene intermediates for the synthesis of the target molecules. The key strategic step in this synthesis was the ring-closing metathesis (RCM) reaction of the diene intermediates. This strategy allowed for the synthesis of 16-epi-luffarin I and analogues for structure-activity relationship (SAR) studies. The most active compound exhibited antiproliferative activity against a panel of six human solid tumour cell lines with [Formula: see text] values in the range 2.8-15 M.
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The first synthesis of luffarin L (1) and 16-epi-luffarin L (2) by a silicon-tethered ring closing metathesis as a key step has been achieved. The stereochemistry and absolute configuration of the natural sesterterpenolide luffarin L (1)... more
The first synthesis of luffarin L (1) and 16-epi-luffarin L (2) by a silicon-tethered ring closing metathesis as a key step has been achieved. The stereochemistry and absolute configuration of the natural sesterterpenolide luffarin L (1) and a new route for the stereoselective synthesis of sesterterpenolides with a luffarane skeleton have been established.
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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... more
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 a “Full Text” option. The original article is trackable via the “References” option.
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The first organocatalytic synthesis of cis-decalins using sulfonyl Nazarov reagents is reported. The Jørgensen's catalyst directs this highly enantioselective synthesis using different cyclohexenal derivatives.
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Sesterterpenes with salmahyrtisane skeleton have been synthesized for the first time. (-)-Sclareol has been selected as precursor for the synthesis of two novel natural products: salmahyrtisol A (1) and hippospongide A (2). Our results... more
Sesterterpenes with salmahyrtisane skeleton have been synthesized for the first time. (-)-Sclareol has been selected as precursor for the synthesis of two novel natural products: salmahyrtisol A (1) and hippospongide A (2). Our results represent a biomimetic approach to obtaining salmahyrtisanes from hyrtiosanes. Salmahyrtisol A has shown an activity comparable to the standard anticancer drugs in the cell lines A549, HBL-100, HeLa and SW1573.
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ABSTRACT Diphenylsilylprolinol is demonstrated to be an efficient catalyst for sulfonyl analogue Nazarov reagents (I) to afford chiral cyclohexa-1,3-dienes in a Diels—Alder reaction manner.
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The asymmetric Aza-Michael addition of homochiral lithium benzylamides to α,β-unsaturated esters represents an extended protocol to obtain enantioenriched β-amino esters. An exhaustive mechanistic revision of the originally proposed... more
The asymmetric Aza-Michael addition of homochiral lithium benzylamides to α,β-unsaturated esters represents an extended protocol to obtain enantioenriched β-amino esters. An exhaustive mechanistic revision of the originally proposed mechanism is reported, developing a quantum mechanics/molecular mechanics protocol for the asymmetric Aza-Michael reaction of homochiral lithium benzylamides. Explicit and implicit solvent schemes were considered, together with a proper account of long-range dispersion forces, evaluated through a density functional theory benchmark of different functionals. Theoretical results showed that the diastereoselectivity is mainly controlled by the N-α-methylbenzyl moiety placing, deriving a Si/Re 99:1 diastereoselective ratio, in good agreement with reported experimental results. The main transition state geometries are two transition state conformers in a "V-stacked" orientation of the amide's phenyl rings, differing in the tetrahydrofuran molecu...
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The pyrans are prepared from 3,3-dialkyl-substituted α,β-unsaturated aldehydes, including natural products, and β-oxosulfones.
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ABSTRACT
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One of the chemotypes of Halimium viscosumLa Fregenedaprovided a new natural product with a rearranged skeleton. The new bicyclic diol possesses an aromatic ring B and its structure has been determined on the basis of 1H, 13C and 2D NMR... more
One of the chemotypes of Halimium viscosumLa Fregenedaprovided a new natural product with a rearranged skeleton. The new bicyclic diol possesses an aromatic ring B and its structure has been determined on the basis of 1H, 13C and 2D NMR (1H 13C ...
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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... more
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 a “Full Text” option. The original article is trackable via the “References” option.
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ABSTRACT
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The authors gratefully acknowledge the help of A. Lithgow (NMR) and C. Raposo (MS) of Universidad de Salamanca; FSE, MICINN CTQ2009-11172BQU, Junta de Castilla and Leon for financial support. MFF is grateful to the JCyL for her fellowship.
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... Narciso M. Garrido a , Corresponding Author Contact Information , E-mail The Corresponding Author , Magda Blanco a , Imanol F. Cascón a ... Furthermore, the Michael adduct intermediate (1S,2R,αR)-14 could be used towards the synthesis... more
... Narciso M. Garrido a , Corresponding Author Contact Information , E-mail The Corresponding Author , Magda Blanco a , Imanol F. Cascón a ... Furthermore, the Michael adduct intermediate (1S,2R,αR)-14 could be used towards the synthesis of the natural product tashiromine. ...
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Recently, we have been involved in the synthesis of chiral pyrroles 14 and organocatalysts. 8 With the aim of obtaining more versatile organocatalysts that could be easily tuneable, we decided to obtain catalyst 15 (Scheme 1). The diol... more
Recently, we have been involved in the synthesis of chiral pyrroles 14 and organocatalysts. 8 With the aim of obtaining more versatile organocatalysts that could be easily tuneable, we decided to obtain catalyst 15 (Scheme 1). The diol intermediate 13 can be manipulated into ...
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... The synthesis of a new chiral pyrrolidine and its application as an organocatalyst in the Michael addition of cyclohexanone into nitrostyrenes are described. Graphical abstract. ... Typical procedure for Michael addition reaction... more
... The synthesis of a new chiral pyrrolidine and its application as an organocatalyst in the Michael addition of cyclohexanone into nitrostyrenes are described. Graphical abstract. ... Typical procedure for Michael addition reaction Acknowledgements References. 1. Introduction. ...
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... and in 42% overall yield was achieved. The highly stereoselective domino reaction initiated by the Michael addition of chiral (S)-9 provide the required (R)-configuration in the final product. With the cyclohexane adduct (1S,2S ...
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The addition of the lithium anion of 7 to acetone has previously been used by us, for the synthesis of a variety of tetrahydropyran and tetrahydrofuran derivatives. 12 Hence we decided to study the addition of this anion under different... more
The addition of the lithium anion of 7 to acetone has previously been used by us, for the synthesis of a variety of tetrahydropyran and tetrahydrofuran derivatives. 12 Hence we decided to study the addition of this anion under different conditions 13 to imine 3 (Scheme 1).
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... 94 S7.00+0.00 00404039(94)E06188 Diastereoselective RingOpening of 12Acetoxy9a and 9p(ll)Epoxy7Drimene: Homochiral Semisynthesis of Poligodial and Warburganal Julio G. Urones*,Isidro S. Marcos, Belen ... b) Van Rheenen, V., Kelly, RC... more
... 94 S7.00+0.00 00404039(94)E06188 Diastereoselective RingOpening of 12Acetoxy9a and 9p(ll)Epoxy7Drimene: Homochiral Semisynthesis of Poligodial and Warburganal Julio G. Urones*,Isidro S. Marcos, Belen ... b) Van Rheenen, V., Kelly, RC and Cha, DY Tetrahedron Lett. ...