Showing papers on "Oxazolidine published in 1992"
TL;DR: The incorporation of serine as oxazolidine protected “pseudo proline “in a host peptide results in the disruption of secondary structure formation thus increasing the solvation of the peptide chain.
133 citations
TL;DR: In this article, a single-crystal X-ray analysis of four alkenes that undergo stereoselective radical addition reactions was performed and the facial selectivity of radical additions was analyzed based upon their solid-state conformations.
Abstract: Single-crystal X-ray analysis of four alkenes that undergo stereoselective radical addition reactions are reported. The facial selectivity of radical additions to these alkenes is understood based upon their solid-state conformations. Alkenes which have a conformation placing a group at a position in space sterically protecting one the faces from addition undergo radical addition with diastereofacial selectivity. The structures of the alkenes are analyzed by the polar coordinates of groups relative to the alkenes center undergoing addition
56 citations
TL;DR: In this article, a chirality-controlling auxiliaries, a C2-symmetric 2,2-dimethylimidazolidine and 4-chiral 2, 2-dialkyloxazolidines, are readily prepared from a C 2-Symmetric 1,2 -ethanediamine and naturally occurring α-amino acids, respectively.
42 citations
TL;DR: In this article, photolysis of optically active oxazolidine carbene chromium complexes and lithiation-deuteration of α-oxazolidinone acetic esters were carried out.
Abstract: (S)- and (R)-[2- 2 H i ]glycine («chiral glycine») were synthesized in good yield with high deuterium incorporation and ee's of 82-86% by two different routes. Photolysis of optically active oxazolidine carbene chromium complexes and lithiation-deuteration of optically active α-oxazolidinone acetic esters were carried out. The stereoselectivities of the reactions of ketenes and chromium-bound ketenes with methanol-d were compared
35 citations
TL;DR: Iodolactonisation of heptadienoic acid derivatives 2 and 3 having oxazolidin-2-ones or a sultam as chiral auxiliary gave the chiral iodolactones 4 and 5 in moderate to excellent enantiselectivity as mentioned in this paper.
Abstract: Iodolactonisation of heptadienoic acid derivatives 2 and 3 having oxazolidin-2-ones or a sultam as chiral auxiliary gave the chiral iodolactones 4 and 5 in moderate to excellent enantiselectivity
29 citations
TL;DR: A facile method of synthesizing enantiomerically pure piperidine alkaloids, (R)-(−)-coniine and (2R,6S)-dihydropinidine, has been explored by employing the highly diastereoselective reaction of a 1,3-oxazolidine with Grignard reagents as mentioned in this paper.
Abstract: A facile method of synthesizing enantiomerically pure piperidine alkaloids, (R)-(−)-coniine and (2R,6S)-(−)-dihydropinidine, has been explored by employing the highly diastereoselective reaction of a 1,3-oxazolidine with Grignard reagents
27 citations
TL;DR: In this paper, the synthesis of (R)-N-benzyl-2-phenyl glycinol 1 with the methyl hemiacetal of ethyl glyoxylate leads to (2S,4R)-2-ethoxycarbonyl-4-phenyll-1,3-oxazolidine 2 as the major product, obtained as a pure enantiomer after column chromatography.
22 citations
TL;DR: The oxazolidine derivative exhibited the most potent activities against several ulcer-models in rat and was identified as the Diels-Alder reactionbreaker.
Abstract: 2, 2, -Disubstituted norbornenes (1, 2), 2, 2-Disubstituted norbornane (3), 2, 2, 3-trisubstituted norbornenes (4, 5), oxanorbornenes (6) and azanorbornenes (7) were synthesized by the Diels-Alder reaction using α, β-dehydroamino acids as a key step, and their antiulcer activities were examined. The oxazolidine derivative (1h) exhibited the most potent activities against several ulcer-models in rat.
18 citations
TL;DR: In this article, the synthesis and reactivity of 3-oxazolines were studied and 3-acyl-4-chlorooxazolidines were obtained from α-hydroxy aldehydes, ammonia, water and a second oxo compound (aldehyde or ketone) in one-pot reaction.
17 citations
Patent•
10 Jan 1992
TL;DR: In this paper, thermally stable compositions containing a polyfunctional aliphatic hindered isocyanate compound and an oxazolidine compound are disclosed, which are stable under hot melt conditions at elevated temperatures and can cure in the presence of moisture.
Abstract: Thermally stable compositions containing a polyfunctional aliphatic hindered isocyanate compound and an oxazolidine compound are disclosed. The materials are stable under hot melt conditions at elevated temperatures and can cure in the presence of moisture to afford polymeric or crosslinked materials. Due to the presence of the hindered isocyanate, the cured materials are substantially free of isocyanurate products formed through the trimerization reaction of the isocyanate compounds. The absence of trimerization products produce significantly improved hot melt materials particularly useful as adhesives and sealants. The cooperation between the hindered isocyanate compound and the oxazolidine agent result in a significant improvement in stability and performance.
13 citations
TL;DR: Two series of optically active complexes of the type trans-PtCl2(C2H4)(oxazolidine) (3) and trans-pdCl2PPh3)(oxasolidine), respectively, have been prepared and characterized as mentioned in this paper.
TL;DR: The syntheses are described of four conformationally restricted derivatives of muramic acid based on the α- d -glucopyrano[2,3- d ]oxazolidine ring system.
TL;DR: These five oxazolidines were tested in rats for ephedrine-like pharmacological activity using the hyperthermia and anorexia models and a possible tolerance to the anorectic effects of some of the compounds was observed.
Abstract: 1. 1. Five oxazolidines were synthesized by reaction of (−) ephedrine with aliphatic aldehydes. The aldehydes used were formaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde and trimethylacetaldehyde. 2. 2. These five oxazolidines were tested in rats for ephedrine-like pharmacological activity using the hyperthermia and anorexia models. 3. 3. All five oxazolidines caused significant elevation of body temperature in the hyperthermia model. The oxazolidine synthesized from (−) ephedrine and butyraldehyde caused greatest hyperthermia. 4. 4. Four oxazolidines caused significant anorectic responses. The oxazolidine synthesized from (−) ephedrine and isobutyraldehyde caused greatest anorexia. 5. 5. A possible tolerance to the anorectic effects of some of the compounds was observed.
Patent•
24 Sep 1992
TL;DR: Synergistic combinations of 2-(thiocyanomethylthio)benzothiazole and a mixture of 4,4-dimethyl oxazolidine and 3,4, 4-tri-methyloxazolerine for controlling the growth of at least one microorganism such as fungi and bacteria, in aqueous fluids, such as metalworking fluids as discussed by the authors.
Abstract: Synergistic combinations of 2-(thiocyanomethylthio)benzothiazole and a mixture of 4,4-dimethyl oxazolidine and 3,4, 4-tri-methyloxazolidine for use in controlling the growth of at least one microorganism, such as fungi and bacteria, in aqueous fluids, such as metalworking fluids.
TL;DR: The condensation of α-hydroxyaminoalcohols with aldehydes and acetone gave 3-hydroxoxazolidines and tautomeric N-(2-hydroethyl)-α-arylnitrones, whose oxidation by PbO2 in methanol leads to stable oxazolidine nitroxyl radicals with methoxy groups at C2 and C4.
Abstract: The condensation of α-hydroxyaminoalcohols with aldehydes and acetone gave 3-hydroxyoxazolidines and tautomeric N-(2-hydroxyethyl)-α-arylnitrones, whose oxidation by PbO2 in methanol leads to stable oxazolidine nitroxyl radicals with methoxy groups at C2 and C4.
Patent•
04 Aug 1992
TL;DR: In this article, the authors described spiro[1,2-benzisothiazole-3(2H),5'-oxazolidine]-2',4'-dione 1,1-dioxides characterized by the general formula (I), ##STR1## wherein R is lower alkyl containing 1 to 6 carbon atoms, cycloalkyl, allyl, benzyl, halogen substituted benzyl and aralkyl containing 7 to 10 carbon atoms; 3-phenyl-2-propynyl and the pharmaceutically acceptable
Abstract: This invention relates to novel spiro[1,2-benzisothiazole-3(2H),5'-oxazolidine]-2',4'-dione 1,1-dioxides characterized by the general formula (I), ##STR1## wherein R is lower alkyl containing 1 to 6 carbon atoms, cycloalkyl containing 5 to 6 carbon atoms, allyl, benzyl, halogen substituted benzyl, aralkyl containing 7 to 10 carbon atoms, halogen substituted aralkyl containing 7 to 10 carbon atoms; 3-phenyl-2-propynyl and halogen substituted 3-phenyl-2-propynyl and the pharmaceutically acceptable salts thereof, to the processes for their preparation, to methods for using the compounds, and to pharmaceutical compositions thereof. The compounds have pharmaceutical properties which render them beneficial for the treatment of diabetes mellitus and associated diabetic complications.
TL;DR: Asymmetric conjugate addition of various organometallic reagents to chiral α,β-unsaturated ester derived from L-glutamic acid is described in this article.
Abstract: Asymmetric conjugate addition of various organometallic reagents to chiral α,β-unsaturated ester derived from L-glutamic acid proceeded cleanly with almost complete diastereoface selection to furnish R-configurated adducts.
TL;DR: In this article, the compounds 2-(ethoxycarbonylmethyl)-δ2-l,3-oxazoline and 1-methyl-2-(methoxy carbonyl methylene)-1,3oxazolidine are hydrochlorinated at the C=N or C=C bond, respectively, with subsequent opening of the oxazolidines ring.
Abstract: The compounds 2-(ethoxycarbonylmethyl)-δ2-l,3-oxazoline and 1-methyl-2-(methoxycarbonylmethylene)-1,3-oxazolidine are hydrochlorinated at the C=N or C= C bond, respectively, with subsequent opening of the oxazolidine ring. Depending on the reaction conditions, this occurs regioselectively to form various products.
TL;DR: In this article, CCO2H is demonstrated to be a convenient method for preparing substituted N-methylaminoacids and the benzyloxycarbonyl is not removed and the methyl is not lost using this method.
Abstract: Hydrogenolysis of 3-benzyloxycarbonyloxazolidine-5-one and 3-benzyloxycarbonyl-4-benzyloxazolidine-5-one by Et3SiH in the presence of F3.CCO2H is demonstrated to be a convenient method for preparing substituted N-methylaminoacids. In contrast with catalytic hydrogenation on Pd/C catalyst, the benzyloxycarbonyl is not removed and the methyl is not lost using this method.
Patent•
12 Feb 1992
TL;DR: In this article, organotin compositions are prepared by dispersion of dibutyltin oxide in a dispersion medium comprising at least one substituted oxazolidine compound and, if appropriate, specially chosen water-tolerant organic solvents.
Abstract: The invention relates to organotin compositions, to a process for their production, and to their use in catalyzing the crosslinking reactions of cationic paint binders crosslinkable by transesterification and/or transurethanization and/or by the reaction of terminal double bonds. The organotin compositions are prepared by dispersion of dibutyltin oxide in a dispersion medium comprising at least one substituted oxazolidine compound and, if appropriate, specially chosen water-tolerant organic solvents. Cationic paints, especially cathodically depositable electrocoating paints, catalyzed by the organotin compositions have very good sedimentation stability in dilute paint batches and show no surface defects in the stoved paint films.
TL;DR: In this paper, photolysis of optically active oxazolidine carbene chromium complexes and lithiation-deuteration of α-oxazolidinone acetic esters were carried out.
Abstract: (S)- and (R)-[2- 2 H i ]glycine («chiral glycine») were synthesized in good yield with high deuterium incorporation and ee's of 82-86% by two different routes. Photolysis of optically active oxazolidine carbene chromium complexes and lithiation-deuteration of optically active α-oxazolidinone acetic esters were carried out. The stereoselectivities of the reactions of ketenes and chromium-bound ketenes with methanol-d were compared
Journal Article•
TL;DR: In this paper, Norephedrine derived 2methoxy-2-methyl oxazolidine 2 is an efficient stereoselective acetylating agent in reactions with stereogenic silylenolethers and silylketenethiolacetals.
Abstract: Norephedrine derived 2-methoxy-2-methyl oxazolidine 2 is an efficient stereoselective acetylating agent in reactions with stereogenic silylenolethers and silylketenethiolacetals. Moderate selectivity is also obtained upon acetylation of crotyltin reagents. The present methodology compares favorably with the previously reported enantioselective Claisen-type acylations.
TL;DR: A facile method of synthesizing enantiomerically pure piperidine alkaloids, (R)-(−)-coniine and (2R,6S)-dihydropinidine, has been explored by employing the highly diastereoselective reaction of a 1,3-oxazolidine with Grignard reagents as mentioned in this paper.
Abstract: A facile method of synthesizing enantiomerically pure piperidine alkaloids, (R)-(−)-coniine and (2R,6S)-(−)-dihydropinidine, has been explored by employing the highly diastereoselective reaction of a 1,3-oxazolidine with Grignard reagents
TL;DR: The title compound, prepared by kinetically controlled deprotonation of a stereohomogeneous 2-(2-oxocyclohexyl)-1,3-oxazolidine, undergoes highly anti-stereoselective aldol addition with alkanals as discussed by the authors.
Abstract: The title compound, prepared by kinetically controlled deprotonation of a stereohomogeneous 2-(2-oxocyclohexyl)-1,3-oxazolidine, undergoes highly anti -stereoselective aldol addition with alkanals.