Cyclic Diester Research Articles

Two methods for the resolution of 10,10′-dihydroxy-9,9′-biphenanthryl

Two methods for the resolution of 10,10′-dihydroxy-9,9′-biphenanthryl were developed. The first involved salt formation with (−)-strychnine via its cyclic diester with phosphoric acid. The second method involved the formation of diastereomers (R)- and (S)-9,9′-biphenanthryl-10,10′-diyl N-((−)-α-methylbenzyl)phosphoroamidates.

ChemInform Abstract: Synthesis of Macrocyclic Diazanedicarboxylate and Diazenedicarboxylate Esters Containing a Steroid Skeleton: An Unusual Oxidation of Bromide to Bromine by a Strained Diazenedicarboxylate Ester. X‐Ray Molecular Structure of 3α‐(3‐Hydroxypropyl)‐24‐nor‐5β‐cholan‐7α‐ ol Diazane‐1,2‐dicarboxylate Cyclic Diester.

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.

Synthesis of macrocyclic diazanedicarboxylate and diazenedicarboxylate esters containing a steroid skeleton: an unusual oxidation of bromide to bromine by a strained diazenedicarboxylate ester. X-Ray molecular structure of 3α-(3-hydroxypropyl)-24-nor-5β-cholan-7α-ol diazane-1,2-dicarboxylate cyclic diester

A series of diazanedicarboxylates 23–26 bridged by steroidal moieties obtained from 3α-hydroxyethyl or 3α-hydroxypropyl derivatives of 12α-hydroxy-24-norcholane or 7α-hydroxy-24-norcholane were synthesized. NMR studies showed that these diazanedicarboxylates were rapidly oxidized to the corresponding diazenedicarboxylate esters with N-bromosuccinimide (or N-chlorosuccinimide) and pyridine. Upon storage the diazenedicarboxylate esters are slowly reduced back to the diazanedicarboxylate esters with concomitant oxidation of bromide to bromine, which could be trapped with cyclohexene. Although diazenedicarboxylate 27 could be trapped by Diels–Alder reaction with cyclopentadiene to give the expected diastereoisomeric adducts 30a and 30b, aqueous work-up regenerated diazanedicarboxylate 25 and traces of ring-opened compounds including compound 29. The crystal structure of 3α-hydroxypropyl-24-nor-3β-cholan-7α-ol diazanedicarboxylate diester 26 was determined.

Absolute configuration of 3,3′-dihydroxy-4,4′-biphenanthryl as determined by the stereochemistry of cyclic diester formation with 1,1′-binaphthyl-2,2′-dicarboxylic acid

Condensation of racemic 3,3′-dihydroxy-4,4′-biphenanthryl [(±)- 2] with ( R)-1,1′-binaphthyl-2,2′-dicarboxylic acid dichloride ( 5) allows cyclization of only (−)- 2 to give the 12-membered cyclic diester ( 7), the absolute configuration of which can be assigned ( R,R) from steric reasons. Thus, absolute stereochemistry of (−)- 2 is determined to be ( R).

ChemInform Abstract: Synthesis of a Dihydroxy‐Substituted Aminoxyl Spin Label and Its Crown Ether and Cyclic Diester Derivatives.

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.

Synthesis of a Dihydroxy-Substituted Aminoxyl Spin Label and its Crown Ether and Cyclic Diester Derivatives

A novel dihydroxy-substituted aminoxyl spin label, 4-hydroxy-3-(3'-hydroxypropyl)-2,2,6,6-tetramethylpiperidine-1-oxy (5), has been prepared. From this aminoxyl radical, a spin-labeled crown ether, 16,16,18,18-tetramethyl-2,5,8,11-tetraoxa-17-azabicyclo[ 13,4,0]-nonadecane-17-oxy (12), and a spin-labeled cyclic diester, 16,16,18,18-tetramethyl-3,10-dioxo-2,5,8,11-tetraoxa-17-azabicyclo[13,4,o]nonadecane-17-oxy (13), have been acquired. Other four new stable aminoxyl radicals 8,9,10, and 11 have also been obtained within the synthetic approach. It has been demonstrated that the cyclic ether compound (7) is generated by the reduction of its corresponding lactone which is sidely derived from the oxo-reduced species of 3 by intramolecular cyclization.

Mild Preparation of 1-Benzyloxyiminoalkylphosphonic Dichlorides: Application to the Synthesis of Cyclic Phosphonic Diesters and Cyclic Monoester Amides

1-Benzyloxyiminophosphonates (3) were converted under very mild conditions to the corresponding phosphonyl dichlorides (5). The application toward the synthesis of diastereomeric 1,3,2,-oxazaphospholidines (6/7), and diastereomeric 1,3,2-dioxaphosphorinanes (8/9) is reported. The structure of 9a was confirmed by X-ray analysis

Vibrational analysis of ring-opening polymerizations of glycolide, L-lactide and D,L-lactide

The i.r. and Raman spectra of glycolide, L-lactide and D,L-lactide in the solid state have been investigated in the 4000-100 cm −1 range. An assignment of the fundamental vibrations is given. The Raman spectra of aqueous solutions of these cyclic diesters showed ring-opening and the beginning of polymerization, characterized by the appearance of ester group bands and acid and alcohol end-group bands.

Interaction of vanadate with monosaccarides and nucleosides: A multinuclear NMR study

Proton, 13C and 51V nuclear magnetic resonance spectroscopy has been used to study the interaction of vanadate with several molecules containing more than one hydroxyl group, including various aldoses and nucleosides. The aldoses D-mannose and D-ribose mainly form tridentate complexes, of trigonal bipyramidal geometry, with vanadate at pH 7. These sugars use three consecutive hydroxyl groups, cis to each other, of their pyranose forms to bind vanadate in those cyclic triesters. Other aldoses, like D-glucose, which do not have this unique structural characteristic, do not form tridentate complexes, but can form weaker bidentate cyclic diesters using two consecutive pyranose cis hydroxyl groups. Of course, the pyranose forms of D-mannose and D-ribose, as well as the furanose form of D-ribose, also yield cyclic diesters of vanadate. All these aldoses form weak monodentate noncyclic monoesters of tetrahedral geometry using a single hydroxyl group. The nucleosides uridine, cytidine and adenosine form two complexes of trigonal bipyramidal geometry with vanadate. In these complexes, having 1:1 and 2:1 ligand-to-metal stoichiometries, the nucleosides form cyclic diesters with vanadate using their C 2′ and C 3′ hydroxyl groups.

A competitive enzyme-linked immunosorbent assay (ELISA) to detect retronecine and monocrotaline in vitro

Antibodies to the nonesterified pyrrolizidine nucleus, retronecine (155 mol.wt), were produced in rabbits and detected using an avidin-biotin antibody ELISA. A competitive ELISA for the detection of retronecine and the cyclic diester monocrotaline was also developed using the antiserum produced against the hapten conjugate, retronecine-bovine serum albumin. Retronecine was obtained by hydrolysis of monocrotaline, succinylated and directly coupled to bovine serum albumin or ovalbumin. Antibodies to the pyrrolizidine nucleus, retronecine, can be detected within 5 min after the addition of substrate using the avidin-biotin ELISA. Competitive inhibition of antibodies to retronecine is obtained by the addition of known amounts (0–11.42 μg/μl) of either the homologous antigen, retronecine, or the heterologous antigen, monocrotaline, however, retronecine acts as the better competitor.

Asymmetric Synthesis of Axially Chiral, Unsymmetrical Diphenic Acids via Intramolecular Ullmann Coupling Reaction

Abstract A practical route to unsymmetrical diphenic acids is described. Successive esterification of ethylene glycol with two different 2-halobenzoyl chlorides gave the corresponding mixed diester, which was treated with copper powder in boiling DMF under dilution conditions. Silica-gel column chromatography allowed ready separation of the intramolecularly coupled cyclic diester (30–60% yield) from other by-products accompanying the Ullmann reaction, and alkaline hydrolysis gave unsymmetrical diphenic acid. Axially chiral, unsymmetrical diphenic acids of more than 99% enantiomeric excess were obtained from the reaction of mixed diesters prepared from (R)-1,1′-bi-2-naphthol.

ChemInform Abstract: Diphenylacetic Acid from Benzilic Acid: An Ecologically and Economically Improved Procedure.

AbstractBenzilic acid (I) is dimerized in the presence of p‐toluenesulfonic acid under azeotropic removal of water, yielding the cyclic diester (II).

Studies on Ribonucleoside Hydrogenphosphonates. Effect of a Vicinal Hydroxyl Function on the Stability of H-Phosphonate Diester Bond

Abstract Stability of hydrogenphosphonate diester bond in the presence of a free vicinal hydroxyl function has been investigated on the example of ribonucleoside H-phosphonates. It was found that H-phosphonate diesters undergo immediate intramolecular cyclization, both with or without a base, affording 2′, 3′-cyclic H-phosphonate diesters.

Propellanes : XCVIII. Treading of anti, anti[20.3.3]propellane-24,27-diol by sebacic acid

A spherical cyclic diester has been prepared from the title components, separated from by-products, and purified by aid of double labelling of the components with 3H and 14C, respectively. The product may be viewed as a doubly-anchored rotaxane.

DIASTEREOSELECTIVITY IN THE ALKYLATION OF CHIRAL 2-AMINOMETHYL-1,3,2-DIOXAPHOSPHORINANE 2-OXIDES

Abstract The alkylation of chiral cyclic diesters of α-aminomethyl-phosphonate derivatives was investigated as a potential route to the asymmetric synthesis of phosphonic acid analogs of α-amino acids. The 1,3,2-dioxaphosphorinanes derived from d,l-2,4-pentanediol (1D-c and 1D-d), which adopt primarily the C-equatorial conformation, were compared to the homologs 1T-c and 1T-e derived from 2-methyl-2,4-pentanediol, in which the aminomethyl moiety is fixed in the axial configuration. While neither series shows high stereoselectivity (de ≤ 50%), it was shown that the two chiral auxiliaries produce asymmetric induction of the opposite sense.

Reaction of dilithiated 1,2-diesters with β-bromoethyloxirane. Synthesis of annelated γ-lactones

The reaction of cyclic vicinal diester dianions with β-bromoethyloxirane gives annelated γ-lactones.

Pyrolysis studies on polyalkylene phthalates

The synthesis and identification of pyrolysis products of five polyalkylene phthalates are reported. The pyrolysis products are separated in a capillary gas chromatograph and the products are identified using a mass selective detector. The major degradation products for the polyesters now investigated are phthalic anhydride and the appropriate diol. In nearly all the polyesters studied, cyclic ether from the diol and the cyclic diester formed from phthalic anhydride and the diol are detected. A wide variety of low molecular weight compounds and considerable quantities of complex mono- and diesters of phthalic acid are identified among the pyrolysis products. The mode of formation of the products identified by GC/MS analysis are discussed with reference to the general polyester degradation mechanism.

Enzymes and catalysts. I. Pig liver esterase-catalyzed hydrolysis of heterocyclic diesters.

The asymmetric hydrolysis of five-membered cyclic diesters was carried out by using pig liver esterase (PLE) as a catalyst. The absolute configurations of the resulting half esters and recovered diesters were established and the stereospecificity of PLE action in such systems was revealed.

Antifungal macrodiolide from Streptomyces sp.

Aerobic fermentation cultures of Streptomyces sp. produced an antifungal macrodiolide. This new antibiotic consists of two units of homononactic acid linked to form a cyclic diester. An unknown polypeptide was also isolated in trace quantities. The antibiotic with polypeptide complex showed high levels of antifungal activity compared with that of the macrodiolide alone. The macrodiolide also showed a stimulatory effect on some species of fungi. The production, purification, and characterization of these compounds are reported.

Oxidation of hydrocarbons. 15. A study of the oxidation of alkenes by methyltributylammonium permanganate

A study of the reduction of methyltributylammonium permanganate by a large number of alkenes in methylene chloride has dispelled a current uncertainty concerning the nature of the inorganic product obtained. It is colloidal manganese dioxide and not a manganate(V) cyclic diester as previously supposed. This product is stabilized in methylene chloride solutions by adsorption of the alkene, which decreases its polarity at the solvent interphase. The solubility of the colloid is therefore a function of both the concentration and the identity of the alkene. In certain (atypical) cases, where acidic compounds are present, the product is further reduced to manganese(III).