Showing papers on "Oxazolidine published in 1990"
TL;DR: Regioselective alkylation and reduction of N-(9-phenylfluoren-9-yl)serine-derived oxazolidine andOxazolidinone ketones stereoselectively provides γ-alkyl-β-hydroxy-α-amino diols that are oxidized to yield γ
Abstract: Regioselective alkylation and reduction of N-(9-phenylfluoren-9-yl)serine-derived oxazolidine and oxazolidinone ketones stereoselectively provides γ-alkyl-β-hydroxy-α-amino diols that are oxidized to yield γ-alkyl-β-hydroxy-α-amino acids
66 citations
TL;DR: In this paper, a variety of tertiary amides were converted to chromium aminocarbene complexes by reaction with Na 2 Cr(CO) 5 and trimethylsilyl chloride.
Abstract: A variety of tertiary amides was converted to chromium aminocarbene complexes by reaction with Na 2 Cr(CO) 5 and trimethylsilyl chloride. Photolysis of these carbene complexes in methanol or tert-butyl alcohol solvent produced α-amino esters in good to excellent yield. Aminocarbene complexes containing chiral oxazolidine groups were synthesized and photolyzed in alcohol to produce chiral α-amino esters in 50-93% de
59 citations
TL;DR: In testing for antifungal activity against a mouse systemic Candida albicans infection, (4R,5R)-3-acyl-4-methyloxazolidine derivatives 4 exhibited remarkably high efficacy after oral or parenteral dosing.
Abstract: Triazole compounds with an oxazolidine ring were designed and synthesized as a potential inhibitor of the fungal cytochrome P450 14 alpha-demethylase. In testing for antifungal activity against a mouse systemic Candida albicans infection, (4R,5R)-3-acyl-4-methyloxazolidine derivatives 4 exhibited remarkably high efficacy after oral or parenteral dosing. The potent activity of 4 is hypothesized to be a consequence of a structural similarity between 4 and lanosterol, a target molecule of the cytochrome P450 14 alpha-demethylase. Highly stereoselective synthesis of these oxazolidines is also described.
34 citations
TL;DR: Tris-(hydroxymethyl)-aminomethane reacts with various aromatic or heterocyclic aldehydes, leading to new mono- or bicyclic oxazolidine derivatives as discussed by the authors.
33 citations
Patent•
27 Apr 1990
TL;DR: In this paper, the oxazolidine moisture scavenger/curing agent can be monocyclic oxazolisine or bicyclic oxozolidine and the hydroxyl curing agent is a polyhydric compound, which can be used with an organic solvent, a catalyst, and/or fillers to speed the curing reaction or improve the physical and mechanical properties of the final polymer product.
Abstract: Isocyanate prepolymer compositions can be cured quickly and thoroughly in the presence of atmospheric moisture by reacting them with a curing system that includes a mixture of (1) an oxazolidine moisture scavenger and curing agent and (2) a hydroxyl curing agent. The oxazolidine moisture scavenger/curing agent can be monocyclic oxazolidine or bicyclic oxazolidine. The hydroxyl curing agent preferably is a polyhydric compound. If desired, an organic solvent, a catalyst, and/or fillers can be used with the invention in order to speed the curing reaction or improve the physical and mechanical properties of the final polymer product. The present invention enables high quality polyurethane/polyurea polymers to be formed in thick layers under various environmental conditions, including humidity, that render the invention suitable for use in the field.
29 citations
TL;DR: In this paper, a β-hydroxyaspartic acid derivative suitably protected for incorporation into peptides by solid phase synthesis, was synthesized from N-Boc-(R)-serine via the intermediate.
Abstract: (2S,3S)-N-Boc-3-(benzyloxy)aspartic acid β-benzyl ester (2), a β-hydroxyaspartic acid derivative suitably protected for incorporation into peptides by solid-phase synthesis, was synthesized from N-Boc-(R)-serine via the intermediate. [4R-(R*,R*)]-4-[hydroxy[2-(trimethylsilyl)ethynyl]methyl]-2,2,-dimethyl-3-oxazolidinecarboxylic acid 1,1-dimethylethyl ester (5). Key transformations involved the ruthenium tetraoxide mediated oxidation of the ethynyl moiety to form the β-carboxylic acid and, after esterification and oxazolidine ring hydrolysis, dichromate oxidation of the resulting primary alcohol to the α-carboxylic acid. The method is suitable for the preparation of gram quantities of 2
29 citations
TL;DR: In this article, β-Unsaturated esters bearing a chiral oxazolidine or perhydropyrrolo[1,2-c]imidazole auxiliary at the β-position have been prepared and applied to the cycloadditions with N-metalated azomethine ylides derived from α-(benzylideneamino) esters.
Abstract: α,β-Unsaturated esters bearing a chiral oxazolidine or perhydropyrrolo[1,2-c]imidazole auxiliary at the β-position have been prepared and applied to the cycloadditions with N-metalated azomethine ylides derived from α-(benzylideneamino) esters. These reactions are found to proceed with an exclusively high diastereofacial selectivity to give 2,4-pyrrolidinedicarboxylates with four consecutive chiral centers after the removal of chiral auxiliary. Detailed stereochemistry in the transition state is discussed.
24 citations
TL;DR: Dehydrocyanation of the derivatives could be achieved to reproduce the oxazolidine ring upon treatment with HCl or AgNO3 and antitumor activity of 10 was extended to B-16 melanoma.
Abstract: Cyanation of quinocarcin readily opened the oxazolidine ring to provide DX-52-1 (2), which was a key compound in the synthesis of quinocarcin derivatives. Various electrophilic reactions toward aromatic ring of DX-52-1 were examined, and 10-substituted (e.g., halogen, nitro, formyl, cyano, hydroxy, etc.) analogs were prepared. Dehydrocyanation of the derivatives could be achieved to reproduce the oxazolidine ring upon treatment with HCl or AgNO3. 10-Chloride 10 and 10-bromide 11 were the most promising among the derivatives prepared. Antitumor activity of 10 was extended to B-16 melanoma.
20 citations
TL;DR: In this paper, the diastereoselective CC bond forming reaction via heteroconjugate addition strategy was expanded for asymmetric synthesis, where a valinol derivative was employed as chiral template to induce chelation control in the addition of alkyls and alkynyls.
18 citations
TL;DR: In this article, a diastereo and enantioselective synthesis of compound 11 a potential useful intermediate for the lactone portion of mevinolin and compactin was developed.
16 citations
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.
Patent•
10 May 1990
TL;DR: Novel silicon-organic compounds containing an oxazolidine group are defined by the general formula (I): ##STR1## wherein R 1, R 2, R 3, R 4, R 5, X, n and y have the meanings reported in the description as mentioned in this paper.
Abstract: Novel silicon-organic compounds containing an oxazolidine group are defined by the general formula (I): ##STR1## wherein R 1 , R 2 , R 3 , R 4 , R 5 , X, n and y have the meanings reported in the description. These compounds are capable of co-cross-linking and to act as adhesion promoters on various polar substrates, in compositions based on poly-isocyanates, polyepoxides or polacrylates, in the field of sealants and adhesives.
TL;DR: Asymmetric conjugate addition of various organometallic reagents to chiral α,β-unsaturated ester derived from L-glutamic acid is described in this paper.
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: A new method for the synthesis of steroid 17alpha-hydroxy-17-carboxyesters and 17 alpha-Hydroxy- 17- carboxamides is described and attempts to synthesize the title compounds from these products were unsuccessful.
TL;DR: Dimethyl oxazolidine and tetrahydro-2H-1, 3-oxazine ring substituted ketene N, O-acetal 3 and 4 were synthesized by the reaction of ketene S, S-acetals 2 with the corresponding amino alcohols.
Patent•
08 Feb 1990
TL;DR: A one-part, storage-stable moisture-curable composition useful as an adhesive, coating and sealant comprising a urethane oxazolidine and an aromatic polyfunctional isocyanate is described in this paper.
Abstract: A one-part, storage-stable moisture-curable composition useful as an adhesive, coating and sealant comprising a urethane oxazolidine and an aromatic polyfunctional isocyanate. The urethane oxazolidine can have structures such as:
TL;DR: In this article, 3-Alkyl-2-aryloxazolidines are oxidized with 3-chloroperoxybenzoic acid to produce the corresponding oxazolidine N-oxides.
Abstract: 3-Alkyl-2-aryloxazolidines are oxidized with 3-chloroperoxybenzoic acid to produce the corresponding oxazolidine N-oxides. These N-oxides undergo thermal rearrangement to give 2-alkyl-6-aryl-3,4-dihydro-2H-1,5,2-dioxazines in 55-85% yield.
TL;DR: In this article, the reactivities of the oxazolidine ring between cis and trans isomers for HBDOZs were studied kinetically and it was shown that the reaction times for oxazolines are about 10 times faster than those for BDOZs having 11b-methyl (MBDOZ) and 11bphenyl groups.
Abstract: Oxazolidine ring-opening and ring-closing reactions of 11b-hydrogen(11b-nonsubstituted)benzodiazepinooxazoles (HBDOZ) and the subsequent hydrolysis of the diazepine ring were studied kinetically. The difference in the reactivities of the oxazolidine ring between cis and trans isomers (referring to substitutents at the 2- and 11b-positions) for HBDOZs is small, compared with those for BDOZs having 11b-methyl (MBDOZ) and 11b-phenyl groups (PBDOZ) reported previously. The reactions of the oxazolidine ring for HBDOZ occur about 10 times faster than those for MBDOZ and PBDOZ. For HBDOZ, hydrolysis of the amide bodn of the diazepine ring takes place rather than that of the iminium bond, in contrast to the cases of MBDOZs and PBDOZs.
Patent•
25 Oct 1990
TL;DR: In this paper, a 3-(2-bromopropionyl)-substituted derivative was obtained in high yield by trimethylsilylation of an oxazolidine-2-one derivative followed by removing an amine hydrochloride as a by-product and then by reaction with a 2- bromophropioninyl halide.
Abstract: PURPOSE:To obtain a 3-(2-bromopropionyl)-substituted derivative in high yield by trimethylsilylation of an oxazolidine-2-one derivative followed by removing an amine hydrochloride as a by-product and then by reaction with a 2- bromopropinyl halide. CONSTITUTION:A compound of formula I (R1 to R4 are each 1 to 4C alkyl, phenyl, benzyl, H or forming 2 to 6C alkylene chain by combination of R1 and R2 and of R3 and R4) is reacted with trimethyl chlorosilane and a tertiary amine (e.g. triethylamine) at 10 to 40 deg.C to carry out trimethylsilylation followed by removing a tertiary amine hydrochloride as a by-product through filtration. The resultant system is reacted with a 2-bromopropionyl halide to obtain the objective compound of formula II. This compound is important as a raw material for beta-lactam type antibiotics. By the above process, the objective compound can be obtained in high yield with little by-product formation without using reactants undesirable for handling.
Patent•
25 Oct 1990
TL;DR: In this paper, a compound of formula I (X is halogen) is reacted with 0.5 to 5 molar times of a carbonate (e.g. K2CO3) at -10 to 120 deg.C for 1 to 50hr in a basic polar organic solvent (such as DMF) to obtain the objective compound of the formula I.
Abstract: NEW MATERIAL:A compound of formula I [R is (substituted)aryl or heteroaryl; R and R are each H or alkyl]. EXAMPLE:N-(1'-phenyl-2',2'-dimethyl)ethenyl-2,4-oxazolidine dione. USE:Antimicrobial agents for agricultural and horticultural use. PREPARATION:A compound of formula II (X is halogen) is reacted with 0.5 to 5 molar times of a carbonate (e.g. K2CO3) at -10 to 120 deg.C for 1 to 50hr in a basic polar organic solvent (e.g. DMF) to obtain the objective compound of the formula I. In the reaction, addition of a chlorocarbonic ester compound (e.g. methyl chlorocarbonate) will easily advance the reaction and obtain the objective compound in high yield.
Patent•
25 Oct 1990
TL;DR: In this paper, a 2-aminoethanol and phosgene were used to obtain a compound useful as a raw material for beta-lactam type antibiotics.
Abstract: PURPOSE:To obtain in high yield the subject compound useful as a raw material for beta-lactam type antibiotics by reaction between a 2-aminoethanol and phosgene while adding an inorganic base and keeping the pH of the reaction liquid alkali side CONSTITUTION:(A) A compound of formula I (R1 to R4 are each 1 to 4C alkyl, phenyl, benzyl, H or forming 2 to 6C alkylene chain by combination of R1 and R2 and of R3 and R4) and (B) phosgene reacted at 10 to 50 degC at the molar ratio of 1: (105 to 13) in the presence of water or a water-organic solvent mixture while adding an inorganic base (pref NaOH) and keeping the pH of the reaction liquid at 9 to 14 (pref 10 to 13), thus obtaining the objective compounds of formula II By the above method, each amount of the phosgene and the inorganic base and be saved enough, and the inorganic salts as by- product can also be easily separated
Patent•
04 Sep 1990
TL;DR: In this paper, the general formula I (I) is defined, where the linking carbon atom is replaced by one to three members selected from the group consisting of C1-C4alkyl, halogen or C1 -C(O)-R12.
Abstract: Compounds of the general formula I (I) wherein R1 is hydrogen, C1-C12alkyl, C5-C7cycloalkyl, phenyl or benzyl, R2 is hydrogen or C1-C4alkyl, or R1 and R2, together with the linking carbon atom, form a 5- or 6-membered ring, and R3, R4, R5 and R6 are identical or different and are hydrogen, C1-C12alkyl, phenyl or phenyl substituted by 1 to 3 members selected from the group consisting of C1-C4alkyl, halogen or C1-C4alkoxy or are a group of formula -CH2OR11, where R11, where R11 is C1-C12alkyl, phenyl or phenyl substituted by 1 to 3 members selected from the group consisting of C1-C4alkyl, halogen or C1-C4alkoxy, or are -C(O)-R12, and R12, and R12 is C1-C12alkyl, R7 is C1-C4alkylene, R8 is C1-C8alkylene, R9 is C1-C4alkyl, or two radicals R9 together are C1-C4alkylene, and R10 is C1-C4alkyl or phenyl, q is a value from 0 to 2, X is -S-or -NH-, Y is O or S, and Z is an organic radical which is derived from a polyisocyanate or a polyisothiocyanate containing at least three three NCO or NCS groups respectively, n is a value>/=1 and m is a value >/=1, with the proviso that n+m>/=3, are suitable for use as couplers, especially for moisture-curable polyurethane resins.
TL;DR: A succinct synthesis of a new bicyclic γ-lactam designed to possess antibacterial activity containing an oxazolidine ring is described in this article, where the synthesis is shown to be feasible.
Abstract: A succinct synthesis of a new bicyclic γ-lactam designed to possess antibacterial activity containing an oxazolidine ring is described.
TL;DR: In this article, a synthesis of (R)- or (S)-2-alkyl-1,2,3,6-tetrahydropyridines, starting from either phenyl glycinol and Zincke's salt, and proceeding via the new oxazolidine derivative as a key intermediate, is described.
Abstract: A synthesis of (R)- or (S)-2-alkyl-1,2,3,6-tetrahydropyridines (1), starting from (R)- or(S)-phenylglycinol and Zincke's salt (2), and proceeding via the new oxazolidine derivative (5) as a key intermediate, is described.
TL;DR: In this article, isopropylidenetriphenylphosphorane reacts with oxazolidine 4 with excellent π-face selectivity, obtaining high optical purity after removal of the chiral auxiliary.
Abstract: isopropylidenetriphenylphosphorane reacts with oxazolidine 4 with excellent π-face selectivity. The title compound is obtained in high optical purity after removal of the chiral auxiliary.
TL;DR: Very high inversion barriers (ΔGo≠ = 86.7−93.4 kJ·mol−1) were found for these oxazolidine rings as discussed by the authors.
Abstract: Ring inversion of eight substituted 2-phenyl-4, 4-dimethyloxazolidines in o-dichlorobenzene-d4 was studied by 1H DNMR. Very high inversion barriers (ΔGo≠ = 86.7–93.4 kJ·mol−1) were found for these oxazolidine rings. The magnitude of the inversion barrier is dependent on the polarity of the substituent on the phenyl group. A linear correlation is present between the ΔGo≠ of the inversion and the substituent constant, σ+, of the substituent.