Allyloxy Groups Research Articles

Enantiomeric Recognition of d- and l-Amino Acid Methyl Ester Hydrochlorides by New Chiral Bis-pyridino-18-crown-6 Substituted with Urea, and Diphenyl Groups

The article reports the synthesis and chiral recognition properties of a new chiral bis-pyridino-18-crown-6 (7), having urea, diphenyl, and allyloxy groups. The chiral bis-pyridino-18-crown-6 was prepared by a thirteen-steps procedure from the commercially available (S)-(+)-mandelic acid and chelidamic acid. The association constants (K a) (1.33 × 103–3.20 × 103) for enantiomeric recognition of d- and l-amino acid methyl ester hydrochlorides using the chiral bis-pyridino-18-crown-6 have been examined by 1H-NMR titration method in CDCl3 at 25 °C. The chiral bis-pyridino-18-crown-6 showed higher association constants for the d-series amino acid methyl ester (d-AlaOMe, d-LeuOMe, d-MetOMe) hydrochlorides as compared to the corresponding l-series (l-AlaOMe, l-LeuOMe, l-MetOMe) hydrochlorides.

Synthesis and crystal structure of 5,7-diallyloxy-4-methylcoumarin

The title compound, 5,7-diallyloxy-4-methyl-2H-[1]-benzopyran-2-one, (C16H16O4), was prepared by condensation of ethyl acetoacetate with phloroglucinol followed by allylation of the 5,7-dihydroxy-4-methylcoumarin thus obtained. The compound crystallizes into monoclinic space group P21/c with unit cell parameters a = 7.531(1) A, b = 22.596(4) A, c = 8.090(1) A, β = 92.74(2)°, Z = 4. The crystal structure was solved by direct methods using single crystal X-ray diffraction data and refined to R = 0.0596 for 2166 observed reflections. The coumarin moiety is perfectly planar, with dihedral angle between the two fused rings of 0.46(5)°. The two allyloxy groups have different behaviour, one of them being disordered. Molecules form chains of weak C–H $$ \cdots$$ O and C–H $$ \cdots$$ π hydrogen bonds.

Electrochemical Partial Fluorination of Organic Compounds. 80. Synthesis of Cyclic α-Arylthio-α-monofluorophosphonate Esters

[Reaction: see text]. Seven-membered cyclic alpha-monofluorophosphonate esters such as 2-allyloxy-3-fluoro-3-phenylthio-4,7-dihydro-[1, 2]-oxaphosphinine-2-oxide were successfully synthesized in moderate total yield as 41% from open-chain allyl phosphonates having an alpha-arylthio group as an electroauxiliary using an alternative sequence of anodic fluorination and ring-closing olefin metathesis (RCM). On the other hand, in an attempt to synthesize an eight-membered analogue, a different type of seven-membered fluorinated cyclic product was formed predominantly by the RCM reaction between the allyloxy groups.

Alkoxysilyl substituted oligo(phenylenevinylene)s: chromophores with reactive side chains

The synthesis and properties of highly luminescent oligo(phenylenevinylene)s (OPV) with curable alkoxysilyl groups are described. Two diethoxymethylsilane moieties are connected directly or through flexible spacers to monodisperse alkoxy-substituted OPVs via hydrosilylation of alkinyl and allyloxy groups, Heck reaction with silylstyrene or condensation of aldehydes with aminopropyl silanes. Hydrolysis of the alkoxysilanes yields silanols condensing to curable three-dimensional networks, thus allowing the transformation of small molecules to transparent and fluorescent films with well-defined chromophores.

Modification of Terpenoid Derivatives with Ruthenium Catalysts Generated in situ

Terpenoids derivatives containing geminal ethynyl and allyloxy groups are easily prepared from the corresponding ketones and aldehydes. The catalytic system generated in situ from [RuCl2(p-cymene)]2, 1,3-bis(mesityl)imidazolinium chloride and cesium carbonate is able to transform these substrates into a new class of terpenoids via cycloisomerisation of the enyne structure. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Preparation, Identification and Application of Dendritic Carbosilanes

Dendritic macromolecules using ((CH2=CHCH2)3-nSiMenCH2)2, ((CH2=CHCH2O)3-n SiMenCH2)2(MeSi(CH=CH2)O)4, MenSi(C≡CPh)4-n and ((PhC≡C)3-nMenSiCH2CH2)3C6H3, hyperbranched carbosilane (AB2and AB3 type) and siloxane polymer as core and allyl, allyloxy, propagyloxy, and pheylethynyl groups as a building block have been described.

A simple method for controlling dendritic architecture and diversity: A parallel monomer combination approach

A novel parallel monomer combination approach to manipulating the architectural disposition of dendritic macromolecules is described. It harnesses the synthetic speed and power of the double-stage convergent growth approach and classical parallel synthesis to prepare diverse series of dendrimers that possess a predetermined number and arrangement of "internal" functional moieties. This methodology is applied for the preparation of a novel family of poly(benzyl ether) dendrimers possessing 1-15 "internal" allyloxy groups, which are displayed in a highly controlled, layer-specific, generational manner.

Electrospray ionization tandem mass spectrometry for poly(propylene oxide) starting and end group analysis

Electrospray ionization tandem mass spectrometry was applied to study poly(propylene oxide) obtained in the presence of potassium hydride. It was found that the polyether chains possess different starting groups, i.e. those situated at the beginning of the polymer backbone. These were isopropoxy, hydroxy, methoxy and allyloxy groups when the polymerization was stopped by the addition of methyl iodide. Each macromolecule was terminated by the methoxy group in this case. Copyright 1999 John Wiley & Sons, Ltd.

Preparation and identification of dendritic carbosilanes containing allyloxy groups derived from 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (Me(CH2[dbnd]CH)SiO)4 and 1,2-bis(triallyloxysilyl)ethane ((CH2[dbnd]CHCH2O)3SiCH2)2

Synthesis and characterization of dendritic macromolecules using 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (Me(CH2CH)SiO)4 and 1,2-bis(triallyloxysilyl)ethane ((CH2CHCH2O)3SiCH2)2 as core molecules and allylalcohol/dichloromethylsilane as a building block have been described. The dendrimers containing dichloromethylsilyl-groups (GS-1P∼GS-4P and GH-1P∼GH-3P) were produced by the hydrosilation process of double bonds in vinyl and allyloxy-groups in the GS-n and GH-n type dendrimers with dichloromethylsilane in the presence of a platinum catalyst (Pt/C). The GH-n and GS-n type dendrimers containing allyloxysilyl-groups were prepared by the reaction of GH-nP and GS-nP type dendrimers containing Si–Cl bonds and allylalcohol in the presence of TMED at room temperature. The purification of the prepared GH-n and GS-n type dendrimers used simple column chromatography. The yields of the prepared dendrimers have been obtained almost quantitatively. The analyses of the 1H- and 13C-NMR, MALDI mass spectra, and elemental analysis made it possible to obtain the pure and unified dendrimers. In additive manner, the molar absorbities of each generation of GH-n and GS-n type dendrimers show increasing character by the increasing number of double bonds.

Second‐Generation Trifluoromethyl‐Substituted Chiral Dendrimers Containing Triply Branched Building Blocks: CF3 as sensitive NMR probe for ‘remote’ diastereotopicity

Abstract(S)‐4,4,4‐Trifluoro‐3‐hydroxybutanoic acid was used as a starting material for the synthesis of dendritic branches (16–21, 30–32) which were attached to a chiral triol (6 or ent‐6), derived from (R)‐3‐hydroxybutanoic acid, to give CF3‐substituted dendrimers (33–36, 38–40) and dendritic compounds (37) of 1st and 2nd generation. The key steps in these syntheses are diastereoselective aldol additions of dioxanone enolates (building blocks and intermediates 6–15, 22, 23, and 25–28) and Williamson etherifications of benzylic‐branch bromides with triols (intermediates and products 16–21, 28, and 30–40). The surfaces of the dendrimers are covered with MeO (33–35, 38–40) or allyloxy groups (36 and 37). The new dendrimers are characterized by NMR and mass spectroscopy. 19F‐NMR Signals of the CF3 groups reveal constitutional heterotopicities caused by substituents which are separated from the F‐nuclei by up to 15 bonds (through a 1,1′‐biphenyl‐4,4′‐diyl spacer!) (Fig. 6).

Synthesis and characterization of poly(N-acyl orN-aroyl ethylenimines) containing various pendant functional groups. IV. Poly (N-aroylethylenimines) with allyloxy and 3-hydroxy propyloxy groups

4-Allyloxy phenyl oxazoline was polymerized using methyl 4-nitrobenzene sulfonate as an initiator (M/I = 100/1) in o-dichlorobenzene. The olefin group in the resulting polymer, PAPO, was quantitatively transformed to a (SINGLE BOND)CH2 (SINGLE BOND)CH2 (SINGLE BOND)OH group by (1) hydroborating the olefin group using 9-BBN as a hydroborating agent in CHCl3/THF, and (2) oxidizing the hydroborated polymer. The polymer backbone is very stable in the hydroboration and oxidation environment. Both PAPO and the hydroxylated polymer, PAPO-OH, are crystalline and show birefringence. The PAPO-OH polymer crystallizes slowly due to its bulky side chain and strong interference of hydroxyl group with the packing of polymer molecules. However, once the polymer crystallizes, the side chains are extended and the (SINGLE BOND)OH groups do not hydrogen bond with the carbonyl groups in the polymer backbone. © 1996 John Wiley & Sons, Inc.

Rearragnement of 1-allyloxy-2-allylthio-4-methyl-benzene TO 2,4-dimethyl-6-allyl-7 hydroxy-2,3-dihydrobenzothiophene

1-Allyloxy-2-allylthio-4-methylbenzene rearranges in NN-diethylaniline at 215°C with migration of allyloxy and allylthio groups to form 2,4-dimethyl-6-allyl-7-hydroxy-2,3dihydrobenzothiophene.

Modification of polyurethane ureas containing allyloxy groups

Linear segmented polyurethane ureas containing allyloxy groups were modified by reaction with mercaptoethanol. The reaction was followed using elemental analysis and 1H NMR. The mechanical properties of these modified polymers were improved, and their hydrophilicity was enhanced. The polyurethane ureas modified by mercaptoethanol were further reacted with 4,4′-diphenylmethane diisocyanate and polyethyleneglycol to form comb-like blocks with pendant hydroxyl groups. These reactions were followed using 1H and 13C NMR. The modified polyurethane ureas were further characterized using SEC, mechanical analysis and water-uptake tests.

Synthesis and characterization of water-swellable polyurethane urea gels containing allyloxy groups. II

In this paper water-swellable polyurethane urea gels composed of allyloxy containing blocks are described. They were synthesized by chain extension with ethylenediamine of a mixture of two isocyanate terminated prepolymers. The latter were made by reaction of 4,4′-diphenylmethane diisocyanate with 3-allyloxy-1,2-propanediol and polyethyleneglycol, respectively. Proton NMR was used to determine the conversion and lengths of the allyloxy containing blocks. The reactions between 3-allyloxy-1,2-propanediol and 4,4′-diphenylmethane diisocyanate were carried out both in bulk and in solution. The reactions could only be driven to complete conversion in solution. The functionalized polyurethane ureas were characterized using SEC, DSC stress-strain measurements and water-uptake tests. The hydrophilicity of polyurethane urea gels decreased as the degree of functionalization increased. However, the water uptake was high for polymers containing a small amount of long allyloxy containing blocks.

Synthesis and characterization of water-swellable polyurethane urea gels containing allyloxy groups. I.

In this study functionalized water-swellable polyurethane ureas which were prepared by copolymerization of 3-allyloxy-1,2-propanediol with polyethyleneglycol, 4,4′-diphenylmethanediisocyanate and ethylenediamine are described. The number of reactive allyloxy groups in the polymer was determined using 1H NMR. Polymers containing 0.9 mmole or less allyloxy groups per g polymer were capable of forming water-swellable and flexible gels with good mechanical properties. The water uptake of the gels decreased as the number of allyloxy groups increased. The structure of the polymer shifted to a higher degree of phase mixing when allyloxy groups were introduced.

Substituent effects in carbohydrate chemistry, Part III+. Effects of C‐2 substituents on coupling reactions promoted by insoluble silver salts

AbstractCoupling reactions have been performed in the 2‐deoxy‐2‐azido‐α‐D‐glucopyranosyl bromide series (i.e. compounds 2, 3, and 4) and with the corresponding 2‐O‐methyl and 2‐O‐(2,2,2‐trifluoro‐ethyl)‐substituted α‐D‐glucopyranosyl bromides (i.e. compounds 1 and 7, respectively) using aglycon 5 in the presence of insoluble silver salt promoters. It was found that coupling of 2‐deoxy‐2‐azido derivatives gave much higher β/α ratios than did the corresponding reactions of the 2‐O‐alkylglucopyranosyl bromides. We assume that through‐bond interactions are responsible for these effects. Other substituent effects are also presented and it is concluded that β‐coupling reactions can be performed in the absence of a participating group at C‐2 if the glycons are appropriately protected. Thus, high β/α ratios may be obtained if acetoxy groups are present at C‐4 and/or 2‐azido‐2‐deoxy functions at C‐2, whereas benzyloxy or allyloxy groups, should be present at C‐3 and C‐6. Furthermore, coupling of galacto‐ and manno‐pyranosyl glycons also gives rise to higher β/α ratios than does coupling of the corresponding glucopyranosyl derivatives.