Reaction Of Diol Research Articles

Semicrystalline Polymers via Ring-Opening Polymerization: Preparation and Polymerization of Alkylene Phthalate Cyclic Oligomers.

Preparation of cyclic oligomeric alkylene phthalates via pseudo-high dilution condensation of alkylene diols with iso- and terephthaloyl chlorides and conversion to high molecular weight polyesters via ring-opening polymerization is described. Sterically unhindered amines such as quinuclidine or 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyze the condensation significantly faster than other tertiary amines and are useful for carrying out this conversion in high yield, in the first direct reaction of diol and diacid chloride to form cyclic polyesters. The mixtures of oligomeric cyclics melt at 150-200 degrees C, providing liquids of low viscosity. Ring-opening polymerization using tin or titanate catalysts affords high molecular weight polymers within minutes. Complete polymerization of PBT oligomeric cyclics can be achieved at 180-200 degreesC, significantly below the polymer's melting point of 225 degreesC, and with molecular weights as high as 445 x 10(3). Polymers formed via such a process are more crystalline than conventionally prepared polyesters.

Synthesis of 2-deoxy-3,5-di-O-benzoyl-2,2-difluoro-D-ribose from D-glucose and D-mannose. A formal synthesis of gemcitabine

Abstract The title compound 2-Deoxy-3,5-di-O-benzoyl-2,2-difluoro-D-ribose (17), was synthesised from D-glucose and from D-mannose. The key steps of the synthesis from D-glucose are obtaining the 3,3-difluoropyranose 9 by reacting the ulose 7 with DAST, and their conversion into the difluorofuranoside 17 by a degradative reaction of diol 16. Starting from D-mannose the synthesis obtains the 3,3-difluoroglycal 22 by reaction of the ulose 18 with DAST and oxidation-elimination of selenoglycoside 21. Ozonolysis of 22 gives the difluorofuranose 17.

ねじれ型アミドの合成，構造，反応

We have found amides of which C (O) -N bonds are extremely twisted. The structures were elucidated by 13C NMR, IR and UV spectroscopies, and X-ray analysis. Since the twisted amides are highly reactive compared to the planar ones, these were used for the acylation of hydroxy groups under neutral conditions. In the reaction of diols containing primary and secondary hydroxy groups with the amides, the primary one was selectively acylated. For diols containing alcoholic and phenolic hydroxy groups, the acylation selectively gave the corresponding alkyl esters. Furthermore, axially chiral twisted amides served as asymmetric acylating agents for sec-alcohols. We also investigated the effects of the C (O) -N bond rotation of the amides on the 13C, 15N, and 17O NMR chemical shifts, and IR carbonyl absorption. As the twist angle increased, the δ13C, δ17O and vC=o values increased, whereas, the δ15N value decreased. It was also found that the 13C (O) -15N coupling constants depend on the twist angles.The 1JC (O) , N value decreased with increasing twist angles.

Investigation of the one-flask synthesis of porphyrins bearing meso-linked straps of variable length, rigidity, and redox activity

The reactions of 18 dialdehydes have been examined in the two-step one-flask room temperature porphyrin synthesis. Efficient alkylation methods were established for the reaction of diols and diacids with m-bromomethylbenzaldehyde. Dialdehydes linked at the o,o′-or m,m′-positions were converted to strapped porphyrins in yields up to 25%, while the one p,p′-linked dialdehyde that was examined failed to give porphyrin. The resulting porphyrins bear straps joining adjacent meso-positions rather than across the face of the porphyrin. Dialdehydes incorporating rigid groups provided improved yields in some but not all cases. The yield of strapped porphyrin exhibited a maximum at 10−2 M reactant concentrations. The o,o′-strapped porphyrins exist as atropisomers that are sufficiently stable to interconversion at room temperature to be separable chromatographically. No atropisomers of m,m′-strapped porphyrins could be separated, though some could be observed by 1H NMR spectroscopy. For two different m,m′-strapped porphyrins, the ΔG‡ values for interconversion of the atropisomers were found to be 66 and 68 kJ/mol. The outer rings in these strapped porphyrins range in size from 14 to 24 atoms. Five porphyrins with bridging redox-active groups (ferrocene or anthraquinone) have been prepared in one-flask reactions, including a porphyrin bearing one ferrocene and one anthraquinone in straps across adjacent meta-substituted phenyl sites.

ChemInform Abstract: Activity of Cu‐ and Fe‐Containing Catalysts in the Reaction of Diols with Ammonia in the Presence of Hydrogen.

AbstractChemInform 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.

Techniques for Postcolumn Derivatization in Gas Chromatography-Mass Spectrometry II

In the first part of this series, methods and reactions for further characterizing GC peaks by adding various reagents between gas chromatographic and mass spectrometric analyses were described. Here four additional reactions that provide much useful information are reported, including the reaction of diols with phenylboronic acid, the reaction of amines with nitric oxides, and the reaction of quinones and aldehydes with hydrazine.

ChemInform Abstract: Convenient Synthesis of Lactones by the Reaction of Diols with N‐ Haloamides.

AbstractChemInform 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.

Convenient Synthesis of Lactones by the Reaction of Diols with N-Haloamides

Abstract Reaction of 1,4-butanediol or 1,5-pentanediol with N-haloamides such as N-chlorosuccinimide, N-bromosuccinimide, N-bromoacetamide, isocyanuric chloride, and N,N-dichlorobenzene-sulfonamide under mild conditions gave γ -butyrolactone or δ-valerolactone, respectively, in high yields.

Siloxane, Phosphate, and Hypervalent Formation in Cyclic Silicon and Phosphorus Reactions

Abstract Comparative reactions of phosphites and chlorosilanes with diols, S[R1R2C6H2OH]2, capable of forming eight-membered ring systems, were studied. With (CH2)4SiCl2 a bicyclic silane formed, S[R1R2C6H2O]4, whereas with SiC14, a hydrolysis reaction dominated yielding a cyclic disiloxane product, {(S[(t-Bu)2C6H2O]2-Si(OCH2CF3)} 20, whose X-ray structure showed a ∼50% displacement toward a trigonal bipyramid from a tetrahedron due to a Si[sbnd]S interaction. Hydrolysis reactions also ensued in reactions of P(OXyl)3 and P(OCH2CF3)3 with diols giving acyclic and cyclic phosphates, respectively, e.g., S(Me2C6H2)2(OH)OP(O)(OXyl)2 and S[(t-Bu)-McC6H2O]2P(O)(OCH2CF3). With the rigorous exclusion of moisture, the diol reaction with P(OCH2CF3)3 led to a hexacoordinated structure, via a P[sbnd]S interaction, S[(t-Bu)MeC6H2O]2P(OCH2CF3)3, shown to be ∼70% displaced toward an octahedron from a square pyramid based on X-ray analysis. With P(NMe2)3, a bicyclic oxyphosphorane formed, [S(Me2C6H2O)2]2PNMe2, which showed no evidence for P[sbnd]S coordination. Hydrolysis processes in the case of phosphorus are shown to correlate with the nature of the leaving group and are proposed to involve a hexacoordinated intermediate.

ChemInform Abstract: Inversion of Regioselectivity in Reactions of Diols Through the Use of Hexamethylenestannylene Acetals as Intermediates.

AbstractChemInform 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.

ChemInform Abstract: Reaction of Diols and Triols with Trialkyl Orthoesters: Facile One‐Pot Formation of Oxacyclic Compounds from Triols.

AbstractChemInform 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.

Inversion of regioselectivity in reactions of diols through the use of hexamethylenestannylene acetals as intermediates

Hexamethylenestannylene acetals obtained from a variety of carbohydrate-derived terminal 1,2-diols give good to excellent regioselectivity for tosylation at the secondary oxygen. In contrast, non-cyclic dialkylstannylene acetals react mainly at the primary oxygen. These results are attributed to the greater stability of the dominant stannylene acetal dimers for hexamethylenestannylene acetals.

Reaction of Diols and Triols with Trialkyl Orthoesters: Facile One-Pot Formation of Oxacyclic Compounds from Triols

Reaction of diols and triols with trialkyl orthoesters was studied and facile one-pot formation of oxacyclic compound from triols was developed

Selective Acylation and Alkylation Reactions of Diols Using Dibutyltin Dimethoxide

Selective Acylation and Alkylation Reactions of Diols Using Dibutyltin Dimethoxide

Effects of functional group interactions on the bimolecular and dissociation reactions of diols

The influence of functional group interactions on the bimolecular and dissociation reactions of diols were examined in a quadrupole ion trap mass spectrometer. Reactions of dimethyl ether ions with diols resulted in formation of (M + H) + ions and (M + 13) + ions (by net methyne additin). The product distribution depended on the relative separation of the hydroxyl groups within each diol, with the more proximate diols producing the greatest abundance of (M + 13) + ions compared to (M + H) + ions. The enhancement of the formation of (M + 13) + ions is attributed to the capability for electrostatic interactions between the hydroxyl groups and the electropositive methylene group of the methoxymethylene reagent ion. The enhancement is most significant for diols that can adopt five- or to a lesser extent six-membered ring transition states (i.e., any 1,2 or 1,3 diol). Collision-activated dissociation (CAD) techniques, including both sequential activation experiments (MS n ) and comparison of CAD spectra for model compounds, suggest that the (M + 13) + ions are protonated cyclic diethers.

Preparation and Reaction of Cyclic Oxalate of Diols

Abstract Cyclic oxalates were efficiently prepared by the reaction of diols with ethyl oxalyl chloride in the presence of triethylamine. They were stable under acidic conditions but cleaved to diols under basic conditions.

Evidence for the importance of π-π-attractive interactions in Enantioselective Diels-Alder reactions chiral catalysts of type (RO) 2TiCl 2

Reaction of diol 4 with Ti(Oi-Pr) 4 followed by SiCl 4 results in formation of the Ti (IV) complex 5 which is an exceptionally effective catalyst for enantioselective Diels-Alder reactions. The origin of the high enantioselectivities which have been observed (>95 : 5) probably lies in attractive π-π interaction between an aromatic group and the dienophile as indicated in formula 7.

Selective Monoalkylation of Acyclic Diols by Means of Dibutyltin Oxide and Fluoride Salts.

Fluoride anion was found to promote monoalkylation reaction of diols by the stannylene acetal method, and selective monoalkylation of various acyclic diols was accomplished in good yields under mild conditions by employing this new method. Functional groups such as carboxylic acid ester, carboxamide, carbamate, nitrile, alkyl chloride, and ether were not affected under the reaction conditions.

Selective monoetherification and monoesterificatton of diols and diacids under phase-transfer conditions

Research on the selectivity of etherlfication reactions of diols and esterification reactions of diacids by alkyl halides under phase-transfer catalysis has shown that under such conditions, selectivity of monoetherification increases in the order prim < sec < tert diols, though overall yield of monoether decreases from sec to tert diols. Monoesterification of diacids was accomplished with a high degree of selectivity. Optimal extraction of diols and diacids was found to correspond in general to chain lengths of around 5 carbons. This could mean that the complex formed between the catalyst and the anion to react is stabilized for certain carbon lengths by inner solvation in virtue of its spatial conformation.

ChemInform Abstract: The Reaction of Diols with Triphenylphosphine and Diisopropyl Azodicarboxylate. Part 2. Formation of Cyclic Phosphoranes from 1,5‐1,12‐Diols.

ChemInformVolume 18, Issue 52 Organoelement Compounds ChemInform Abstract: The Reaction of Diols with Triphenylphosphine and Diisopropyl Azodicarboxylate. Part 2. Formation of Cyclic Phosphoranes from 1,5-1,12-Diols. M. VON ITZSTEIN, M. VON ITZSTEIN Sch. Sci., Griffith Univ., Nathan, Queensl. 4111, Aust.Search for more papers by this authorI. D. JENKINS, I. D. JENKINS Sch. Sci., Griffith Univ., Nathan, Queensl. 4111, Aust.Search for more papers by this author M. VON ITZSTEIN, M. VON ITZSTEIN Sch. Sci., Griffith Univ., Nathan, Queensl. 4111, Aust.Search for more papers by this authorI. D. JENKINS, I. D. JENKINS Sch. Sci., Griffith Univ., Nathan, Queensl. 4111, Aust.Search for more papers by this author First published: December 29, 1987 https://doi.org/10.1002/chin.198752248Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue52December 29, 1987 RelatedInformation