Showing papers on "Oxazolidine published in 2009"
TL;DR: New dynamic combinatorial libraries (DCLs) were generated using the reversible aminothiol exchange reaction of thiazolidines and aromatic aldehydes to generate thermodynamically controlled mixtures of heterocycles.
46 citations
TL;DR: Three novel dinuclear Zn(II) complexes of phenol-based compartmental macrocyclic ligands have been synthesized and characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis, and all of them exhibit an inhibitory effect on the cell proliferation of human stomach cancer cell line AGS.
Abstract: Three novel dinuclear ZnII complexes of phenol-based compartmental macrocyclic ligands have been synthesized and characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis. The dinuclear macrocyclic complexes 1, 2, and 3 were obtained through a 1:2 condensation reaction of 2,6-diformyl-4-methylphenol and N-(hydroxyalkyl) ethylenediamine (L1, L2, and L3, respectively) in the presence of zinc(II) acetate, followed by the addition of thiocyanate anion [L1 = N-(2-hydroxyethyl)ethylenediamine, L2 = N-(3-hydroxypropyl)ethylenediamine, and L3 = N-(2-hydroxypropyl)ethylenediamine]. The synthesized 18-membered macrocycles are noted to be structurally unique, and their formation proceeds with the generation of two oxazolidine side rings in complexes 1 and 3 and two oxazine side rings in 2, along with the creation of four new chiral centers in each case. Complexes 1 and 2 are characterized by a butterfly-like arrangement with the SCN ligands situated on the same side wi...
40 citations
TL;DR: A new rhodium-catalyzed hydroformylation reaction of N-allyl oxazolidines, carried out under a CO/H(2) atmosphere, followed by a diastereoselective deformylative cyclization affords hexahydropyrrolo[2,1-b]oxazoles in good yields.
Abstract: Fleetingly formyl: A new rhodium-catalyzed hydroformylation reaction of N-allyl oxazolidines, carried out under a CO/H(2) atmosphere, followed by a diastereoselective deformylative cyclization affords hexahydropyrrolo[2,1-b]oxazoles in good yields. The reaction proceeds by a unique hydroformylation-deformylation sequence in which the formyl group virtually substitutes for the {CH(2)-O} fragment of the oxazolidine heterocycle.
34 citations
TL;DR: A practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2-subStituted 6-oxocyclohexenepropionates 2 with (R)-phenylglycinol.
Abstract: A practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2-substituted 6-oxocyclohexenepropionates 2 with (R)-phenylglycinol, the stereoselective hydrogenation of the resulting unsaturated tricyclic lactams, and the stereoselective reductive cleavage of the oxazolidine ring.
24 citations
TL;DR: In this paper, a facile one-pot synthesis of oxazolidine, hexahydropyrrolooxazole and tetrahydro-2 H -oxazolothiazole grafted macrocycles through intramolecular 1,3-dipolar cycloaddition reaction was reported.
24 citations
TL;DR: In this paper, a method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products, which comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone.
Abstract: A method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products. The approach comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone. Oxazolidine derivative of p-synephrine was subjected to analysis by nuclear magnetic resonance (1H and 13C NMR), GC-FID and GC-MS. The GC method was validated and was found to be linear in the range of 125–500 mg%. Intra-day and inter-day precisions were 3.60 and 3.59%, respectively. Mean recovery from extract of C. aurantium was 78.1 ± 3.64%. The selectivity of the method was further improved by confirmation of oxazolidine derivative of p-synephrine by GC-MS.
23 citations
Patent•
10 Dec 2009TL;DR: In this article, a reactive hot melt adhesives using an oxazolidine functional prepolymer and a polyfunctional isocyanate was used to obtain a solvent-free, moisture-curable reactive hot-melt adhesive.
Abstract: Solvent free, moisture curable reactive hot melt adhesives are prepared using an oxazolidine functional prepolymer and a polyfunctional isocyanate.
20 citations
TL;DR: In this article, the 3-Spiropseudonucleosides, in which the heterocyclic base is a five-membered (oxazolidine, imidazolidines, thiohydantoin) or six-mesbered (perhydrooxazine) heterocycle, have been prepared starting from a hexofuranos-3-ulose.
18 citations
Patent•
30 Sep 2009
TL;DR: In this paper, the oxazolidine derivatives of the formula (I) wherein A, B, and R 1 are as described in the description, to salts, especially pharmaceutically acceptable salts, of such compounds and to their use as medicaments, especially as orexin receptor antagonists.
Abstract: The invention relates to oxazolidine derivatives of the formula (I) wherein A, B, and R 1 are as described in the description, to salts, especially pharmaceutically acceptable salts, of such compounds and to their use as medicaments, especially as orexin receptor antagonists.
14 citations
TL;DR: The use of achiral N-acetyloxazolidine-2-thiones in the C-glycosylation of lactol acetates has allowed to prepare with high diastereoselectivity the expected trans 2,5-disubstituted tetrahydrofurans as discussed by the authors.
13 citations
TL;DR: In this article, the effect of oxazolidine and zirconium oxalate on the thermal, enzymatic and mechanical stability of type I rat tail tendon (RTT) collagen was studied.
TL;DR: It was found that the carbonyl group of the bicyclic alpha-chlorocyclobutanones was highly electrophilic and readily reacted with a hydroxy group to give, for example, cyclized compound 4.
TL;DR: In this article, a trifluoromethylated oxazolidine (Fox) chiral auxiliary was removed from amide enolates derived from triflooromethodo-methane (TME) and showed good yields with a moderate anti diastereoselectivity (Li and Na enolate) to a high syn diasterenolate (boron enolate).
TL;DR: In this article, an efficient catalytic system was developed for the enantioselective reaction of alkynoates with aromatic aldehydes for the synthesis of optically active γ-hydroxy-α,β-acetylenic esters.
Abstract: An efficient catalytic system has been developed for the enantioselective reaction of alkynoates with aromatic aldehydes for the synthesis of optically active γ-hydroxy-α,β-acetylenic esters (with up to 81 % isolated yield and up to 84% enantioselectivity).
Patent•
14 Jan 2009
TL;DR: In this paper, the oxazolidine and thiazolidine derivatives were used as subtype selective alpha 2 adrenergic agonists for treating a wide variety of disorders associated with selective subtype modulation of alpha2 adrenergic receptors.
Abstract: The invention provides oxazolidine and thiazolidine derivatives that are useful as subtype selective alpha 2 adren-ergic agonists. As such, the compounds described herein are useful in treating a wide variety of disorders associated with selective subtype modulation of alpha 2 adrenergic receptors.
Patent•
27 Mar 2009
TL;DR: In this paper, the oxazolidine derivative and its salt is represented by general formula (2) (wherein R 1 and R 2 are each aryl which may be substituted; R 3 is alkyl or aryls; R 4 is a hydrogen atom or alkyls; X is an organic acid to form a salt with an ox-acid derivative skeleton).
Abstract: PROBLEM TO BE SOLVED: To provide a new oxazolidine derivative and its salt and a method for producing an optically active compound using the oxazolidine derivative salt useful as an asymmetric organic molecular catalyst SOLUTION: The oxazolidine derivative salt is represented by general formula (2) (wherein R 1 and R 2 are each aryl which may be substituted; R 3 is alkyl or aryl; R 4 is a hydrogen atom or alkyl; R 5 is alkyl, aryl or silyl; X is an organic acid to form a salt with an oxazolidine derivative skeleton) COPYRIGHT: (C)2011,JPO&INPIT
TL;DR: The kinetic and thermodynamic parameters of the Hg(II)-catalyzed cyclization of N-phenyl-2-vinyloxyethanamine indicated that the first reaction step is reversible coordination of mercury at the vinyloxy group, followed by closure of mercurated oxazolidine ring (the rate-determining step) as mentioned in this paper.
Abstract: The kinetic and thermodynamic parameters of the Hg(II)-catalyzed cyclization of N-phenyl-2-vinyloxyethanamine indicated that the first reaction step is reversible coordination of mercury at the vinyloxy group, followed by closure of mercurated oxazolidine ring (the rate-determining step); the latter undergoes demercuration to give 2-methyl-3-phenyloxazolidine either by the action of mercury salt anion or spontaneously.
Journal Article•
TL;DR: In this paper, an efficient synthesis of 2-substituted oxazolines from aldehydes and 2-amino alcohol using the combination of NaBrO3 with NaHSO3 is reported.
Abstract: An efficient synthesis of 2-substituted oxazolines from aldehydes and 2-amino alcohol using the combination of NaBrO3 with NaHSO3 is reported The in situ generated HOBr acts as dehydrogenating agent to convert the initially formed oxazolidine from aldehyde and 2-amino alcohol to furnish 2-substituted oxazolines This one-pot synthesis is characterized by mild reaction condition, broad scope, high yields, and its preparative simplicity
Patent•
16 Jul 2009
TL;DR: In this article, a method for positionally selectively producing a nitrogen-containing cyclic β-amino alcohol compound was proposed, in which the amino group of the hydrolyzate was protected by an azide compound, and the compound was then reacted with a ketone compound or an acetal compound in the presence of an acid.
Abstract: PROBLEM TO BE SOLVED: To provide a method for positionally selectively producing a nitrogen-containing cyclic β-aminoalcohol compound. SOLUTION: A method is provided for producing a compound represented by formula (X) which comprises hydrolyzing a compound obtained by reacting a compound represented by formula (IV) with an azide compound, subsequently protecting the amino group of the hydrolyzate, and reacting the amino-protected hydrolyzate with a ketone compound or an acetal compound in the presence of an acid. COPYRIGHT: (C)2009,JPO&INPIT
Dissertation•
01 Jan 2009
TL;DR: In this article, the catalytic asymmetric epoxidation of olefins mediated by chiral iminum salts was described, and a wider range of available temperatures was examined allowing optimization of both oxidative systems.
Abstract: This thesis describes the catalytic asymmetric epoxidation of olefins mediated by chiral iminum salts. The first chapter introduces some of the most novel and effective catalytic asymmetric methods for preparing chiral oxiranes.
The second chapter is divided into three sections. The first section of chapter two is dedicated to our efforts to develop new aqueous oxidative conditions using both hydrogen peroxide and sodium hypochlorite as efficient, green oxidants that remove the temperature boundaries observed with the use of Oxone® as the stoichiometric oxidant. A wider range of available temperatures was examined allowing optimization of both oxidative systems. Ethereal hydrogen peroxide was observed to mediate asymmetric epoxidation within an acetonitrile monophasic co-solvent system giving enantioselectivities of up to 56%. When sodium hypochlorite was used in a biphasic solvent system in conjunction with dichloromethane; it was observed to mediate oxidation of the substrate alkenes in up to 71% ee.
The second and third sections of chapter two are dedicated to our efforts to synthesize chiral iminium salts as catalysts for asymmetric epoxidation based on a biphenyl azepinium salt catalyst structure.
From previous work within the Page group, the asymmetric synthesis and subsequent defined stereochemistry of a chiral carbon atom α to the iminium nitrogen atom was shown to have significant effect on the enantiocontrol of epoxidation using the iminium salt catalyst. Work was completed on biphenyl azepinium salt catalysts, inserting an alkyl or aryl Grignard reagent into the iminium bond using a pre-defined dioxane unit as a chiral auxiliary. Oxidation of the subsequent azepine gave a single diastereoisomerically pure azepinium salt. The methyl analogue of this sub-family of azepinium catalysts has been shown to give up to 81% ee for epoxidation of 1-phenylcyclohexene, furthermore, the binaphthalene azepinium salt with an additional methyl group was also synthesized and was shown to give up to 93% for epoxidation of 1-phenylcyclohexene.
Continuation of the substitution α to the nitrogen atom gave rise to an interesting tetracyclic (biphenyl) azepinum salt catalyst. Construction of an asymmetric oxazolidine ring unit encapsulating the azepinium nitrogen and one of the methylene carbon atoms was achieved. In doing so two chiral centres α to the nitrogen atom were generated. The azepinium chiral carbon atom was populated by an addition methyl group with variation in the substitution on the oxazolidine chiral carbon atom. The benzyl analogue of this sub-family of tetracyclic azepinium catalysts has shown to give up to 79% ee for epoxidation 1-phenylcyclohexene.
The third chapter is the experimental section and is dedicated to the methods of synthesis and characterization of the compounds mentioned in the previous chapter.
X-ray reports regarding the crystallographic analysis of the structures presented in chapter two are provided in appendix A. Appendix B contains the analytical spectra for the determination of enantiomeric excess of the epoxides.
TL;DR: In the title compound, C12H15NO3, the ethoxybenzyl ring plane forms a dihedral angle of 60.3 (4)° with the mean plane of the oxazolidine ring.
Abstract: In the title compound, C12H15NO3, the ethoxybenzyl ring plane forms a dihedral angle of 60.3 (4)° with the mean plane of the oxazolidine ring. The molecules are linked through N—H⋯O hydrogen bonds into a chain running in the b direction.
TL;DR: In this paper, the authors proposed an enantioselective asymmetric addition of terminal alkynes to various aromatic and heteroaromatic aldehydes catalyzed by the readily available, low-cost, and reusable resin-supported oxazolidine 4 together with Ti(OiPr)4.
Abstract: Highly enantioselective asymmetric addition of terminal alkynes to various aromatic and heteroaromatic aldehydes catalyzed by the readily available, low-cost, and reusable resin-supported oxazolidine 4 together with Ti(OiPr)4 provides the chiral propargylic alcohols with good to excellent yields (up to 98%) and enantioselectivities (up to 95%) The immobilized catalyst can be recovered and used for five cycles
Patent•
08 Apr 2009
TL;DR: A compound selected from the group consisting of formula I-1, II-1 and III-1 was defined in this article, where the carbon to which they are attached formed an eight membered cycloalkyl ring.
Abstract: A compound selected from the group consisting of formula I-1, II-1, III-1 and IV-1: or a compound selected from the group consisting of: 2-(hydroxylamino)hexane, 3-(hydroxylamino)hexane, 2-(hydroxylamino)octane, and 3-(hydroxylamino)octane, wherein: R7 and R9 are independently linear C2-C17 alkyl; R11 is an unsubstituted linear C2-C17 alkyl; R8 is H or linear C1-C8 alkyl; R10 and R14 are independently H, linear C1-C8 alkyl, or CH2OH, or R9, R10, and the carbon to which they are attached form an eight membered cycloalkyl ring; R12 is H, an unsubstituted linear C1-C8 alkyl, or CH2OH, or R11, R12, and the carbon to which they are attached form a C9-C11 cycloalkyl ring; R13 is C2-C20 alkyl, C3-C12 cycloalkyl, aryl, or aryl-alkyl-; R14 is H or C1-C12 alkyl, or R13 and R14 together with the carbon to which they are attached form a C3-C12 cycloalkyl ring; R15 is H, or R14, R15, and the atoms to which they are attached form an oxazolidine ring that is optionally substituted with C1-C6 alkyl; and R16 is H, C1-C12 alkyl, C3-C12 cycloalkyl, or aryl; provided that: when the compound is selected from formula I-1, the total number of carbons in R7 and R8, together with the carbon to which they are attached, is 10 to 18; and the compound is not 1-nitrodecane, 2-nitrodecane, 1-nitroundecane, 2-nitroundecane, 3-nitroundecane, 4-nitroundecane, 5-nitroundecane, 6-nitroundecane, 1-nitrododecane, 2-nitrododecane, 3-nitrododecane, 4-nitrododecane, 5-nitrododecane, 6-nitrododecane, 1-nitrotridecane, 2-nitrotridecane, 3-nitrotridecane, 6-nitrotridecane, 1-nitrotetradecane, 1-nitropentadecane, 1-nitrohexadecane, 2-nitrohexadecane, 1-nitroheptadecane, 1-nitrooctadecane, or 2-nitrooctadecane; when the compound is selected from formula II-1, if R10 is H or linear C1-C8 alkyl, the total number of carbons in R9 and R10, together with the carbon to which they are attached, is 5 to 18; or if R10 is CH2OH, R9 is linear C12-C16 alkyl; and the compound is not 2-nitro-1-hexanol, 2-nitro-1-heptanol, 2-nitro-1-octanol, 2-methyl-2-nitro-1-heptanol, or 2-nitro-1-dodecanol; when the compound is selected from formula III-1, if R12 is H or linear C1-C8 alkyl, the total number of carbons in R11 and R12, together with the carbon to which they are attached, is 6 to 18; or if R12 is CH2OH, R11 is linear C7-C17 alkyl; and the compound is not 2-amino-1-heptanol, 2-amino-2-methyl-1-hexanol, 2-amino-1-octanol, 2-amino-2-ethyl-1-hexanol, 2-amino-1-nonanol, 2-amino-2-methyl-1-octanol, 2-amino-1-decanol, 2-amino-2-octyl-1,3-propanediol, 2-amino-2-butyl-1-hexanol, 2-amino-1-undecanol, 2-amino-1-dodecanol, 2-amino-2-decyl-1,3-propanediol, 2-amino-1-tridecanol, 2-amino-2-methyl-1-dodecanol, 2-amino-1-tetradecanol, 2-amino-2-dodecyl-1,3-propanediol, 2-amino-2-methyl-1-tridecanol, 2-amino-1-pentadecanol, 2-amino-2-tridecyl-1,3-propanediol, 2-amino-1-hexadecanol, 2-amino-2-tetradecyl-1,3-propanediol, 2-amino-2-methyl-1-pentadecanol, 2-amino-2-hexyl-1-decanol, 2-amino-1-heptadecanol, 2-amino-2-pentadecyl-1,3-propanediol, 2-amino-1-octadecanol, or 2-amino-2-hexadecyl-1,3-propanediol; and when the compound is selected from formula IV-1, if R13 is an ethyl group, R14 is not H; and the compound is not 5-propyl-1-aza-3,7-dioxabicyclo[3.3.0]octane, 4,4-diethyl-1-oxa-3-azacyclopentane, 3-oxa-1-azaspiro[4.4]nonane, 3-oxa-1-azaspiro[4.5]decane, or 3-oxa-1-azaspiro[4.7]dodecane.
TL;DR: The use of achiral N-acetyloxazolidine-2-thiones in the C-glycosylation of lactol acetates has allowed to prepare with high diastereoselectivity the expected trans 2,5-disubstituted tetrahydrofurans.
Abstract: The use of achiral N-acetyloxazolidine-2-thiones in the C-glycosylation of lactol acetates has allowed us to prepare with high diastereoselectivity the expected trans 2,5-disubstituted tetrahydrofurans. A study based on the role of the steric hindrance of the N-acetyloxazolidine-2-thiones is reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
TL;DR: In this article, 1,3-oxazoline-2-thiones can undergo direct Stille and Suzuki cross-coupling reactions under microwave activation to produce 2-aryloxazoles and 2-yloxazolines in reasonable to good yields.
Abstract: 1,3-Oxazoline- (OXT) and 1,3-oxazolidine-2-thiones (OZT) can undergo direct Stille and Suzuki cross-coupling reactions under microwave activation to produce 2-aryloxazoles and 2-aryloxazolines in reasonable to good yields.
TL;DR: In this paper, a practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2.5-oxocyclohexenepropionates with (R)-phenylglycinol.
Abstract: A practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2-substituted 6-oxocyclohexenepropionates 2 with (R)-phenylglycinol, the stereoselective hydrogenation of the resulting unsaturated tricyclic lactams, and the stereoselective reductive cleavage of the oxazolidine ring.