Triallyl monomer bearing adamantane‐like core derived from naturally occurring myo‐inositol: Synthesis and polyaddition with dithiols

This paper deals with a triallyl monomer bearing a rigid adamantane‐like core derived from myo‐inositol, a naturally occurring cyclic hexaol. The core structure of the monomer can be readily constructed by orthoesterification of myo‐inositol. The polyaddition of the triallyl monomer with dithiols based on the thermally induced radical thiol‐ene reaction gives the corresponding networked polymers. These networked polymers exhibit much higher thermal stability than the comparative networked polymers obtained from a triallyl monomer bearing less rigid cyclohexyl core. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1193–1199     

Radical polymerizations of two stereoisomeric trimethacrylates with rigid adamantane‐like cores from naturally occurring myo‐inositol

Two stereoisomeric trimethacrylates, T1 and T2 , which share a common adamantane‐like rigid core, were synthesized from naturally occurring myo‐inositol, and their radical polymerization behaviors were investigated. For the synthesis of T1 , myo‐inositol was converted to triol 1 , bearing one equatorial hydroxyl group and two axial hydroxyl groups, by orthoesterification, which was used as a precursor. For the synthesis of T2 , 1 was converted to triol 2 , bearing three axial hydroxyl groups, which was used as a precursor. Investigations on the radical polymerization of T1 and T2 , which potentially accompanies the cyclopolymerization of the axially oriented methacrylate moieties, revealed significant differences between the two. (1) The polymerization of T1 affords networked and thus insoluble polymers PT1 , while that of T2 affords less crosslinked and thus soluble polymers PT2 . (2) The amount of residual methacrylate moieties was larger in PT2 than in PT1 . (3) PT2 had higher thermal stability than PT1 , though PT2 contained a larger amount of unreacted methacrylate moieties. These tendencies were successfully correlated with the difference in cyclopolymerization efficiency between the polymerizations of the two monomers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1743–1748     

Synthesis of hydroxyl‐bearing polyurethanes from naturally occurring myo‐inositol

A route from naturally occurring myo‐inositol to hydroxyl‐bearing polyurethanes has been developed. The diol prepared from the bis‐acetalization of myo‐inositol with 1,1‐dimethoxycyclohexane was reacted with a rigid diisocyanate, 1,3‐bis(isocyanatomethyl)cyclohexane to afford the corresponding polyurethane, of which glass transition temperature (T_g) was quite high as 192 °C. The polyurethane contains side chains inherited from the acetal moieties of the diol monomer and was treated with trifluoroacetic acid to hydrolyze the acetal moieties and afford the target polyurethane functionalized with hydroxyl groups. The presence of many hydroxyl groups in the side chains, which can form hydrogen bonds with each other, resulted in a high T_g, 186 °C. In addition, the hydroxyl groups were reacted with isocyanates to achieve further side‐chain modifications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1358–1364     

Synthesis of partially bio-based triepoxides from naturally occurring myo-inositol and their polyadditions

Partially bio-based triepoxides, 1,3,5-tri-O-methyl-2,4,6-tri-O-(oxiran-2-yl-methyl)-myo-inositol ( 4 ) and 2,4,6-tri-O-(oxiran-2-yl-methyl)-myo-inositol 1,3,5-orthoacetate ( 5 ), were synthesized from naturally occurring myo-inositol. These two triepoxides differ from each other in terms of rigidity of the core structure; while the former triepoxide has a more flexible cyclohexane core, the latter has a highly rigid adamantane-like orthoester core. Triepoxide 5 readily reacted with nucleophilic monomers such as diamines, dithiol, and trithiol to yield networked polymers. The glass transition temperatures (T_gs) of these polymers were higher than those of comparable networked polymers obtained by the polyaddition of triepoxide 4 with the same nucleophilic monomers, implying that the rigidity of the orthoester moiety contributed to the efficient restriction of the polymer chain in the synthesized networked polymers.     

Cationic ring‐opening polymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐allyl‐β‐D‐glucopyranose as a convenient synthesis of dextran

For the convenient synthesis of (1→6)‐α‐D ‐glucopyranan, i. e., dextran ( 4 ), ring‐opening polymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐allyl‐β‐D ‐glucopyranose ( 1 ) has been carried out using BF₃·OEt₂. With a ratio of [BF₃·OEt₂]/[ 1 ] = 0.5 at 0 °C for 140 h, the yield and M_n of the obtained polymer are 84.0% and 21 700, respectively. The polymer consists of (1→6)‐α‐linked 2,3,4‐tri‐O‐allyl‐D ‐glucopyranose ( 2 ) which is similar to the results for the cationic ring‐opening polymerization of 1,6‐anhydro‐2,3,4‐tri‐O‐methyl‐β‐D ‐glucopyranose and 1,6‐anhydro‐2,3,4‐tri‐O‐ethyl‐β‐D ‐glucopyranose. Polymer 2 was isomerized using tris(triphenylphosphine)‐chlororhodium as the catalyst in toluene/ethanol/water to yield polymeric 2,3,4‐tri‐O‐propenyl‐(1→6)‐α‐D ‐glucopyranan ( 3 ). Deprotection of the propenyl ether linkage of 3 was then performed using hydrochloric acid in acetone to give 4 .     

L‐arabinitol‐based functional polyurethanes

Three new polymerizable diols, based on mono‐, di‐, and tri‐O‐allyl‐L ‐arabinitol derivatives, were prepared from L ‐arabinitol as versatile materials for the preparation of tailor‐made polyurethanes with varied degrees of functionalization. Their allyl functional groups can take part in thiol‐ene reactions, to obtain greatly diverse materials. This “click” reaction with 2‐mercaptoethanol was firstly studied on the highly hindered sugar precursor 2,3,4‐tri‐O‐allyl‐1,5‐di‐O‐trityl‐L ‐arabinitol, to apply it later to macromolecules. A polyurethane with multiple pendant allyl groups was synthesized by polyaddition reaction of 2,3,4‐tri‐O‐allyl‐L ‐arabinitol with 1,6‐hexamethylene diisocyanate, and then functionalized by thiol‐ene reaction. The coupling reaction took place in every allyl group, as confirmed by standard techniques. The thermal stability of the novel polyurethanes was investigated by thermogravimetric analysis and differential scanning calorimetry (DSC). This strategy provides a simple and versatile platform for the design of new materials whose functionality can be easily modified. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of oligo(spiroketal)s by polycondensation of silyl ethers derived from naturally occurring myo‐inositol with 1,4‐cyclohexanedione

Oligo(spiroketal)s (OSKs) were synthesized from myo‐inositol, a naturally occurring cyclic compound bearing six hydroxyl groups. The successful synthesis of OSKs was achieved using silyl ethers 2 derived from 1,4‐di‐O‐alkylated myo‐inositol 1 as monomers, which underwent polycondensation with 1,4‐cyclohexanedione (CHD) at 0 °C in the presence of trimethylsilyl triflate as a catalyst. Because of the irreversible nature of the condensation reaction of silyl ethers with ketones, the resulting OSKs 7 had higher molecular weights than previously reported OSKs that were obtained by polycondensation of tetraols 1 with CHD, where backward hydrolysis of the ketal functions occurred. In addition, another series of OSKs, 8, were synthesized using silyl ethers 3 derived from 2,5‐di‐O‐alkylated myo‐inositol 6 , which are more symmetric monomers than silyl ethers 2 . Silyl ethers 3 underwent efficient polycondensation with CHD, whereas tetraol 6 did not, demonstrating that the derivation of such tetraols into the corresponding silyl ethers is a powerful strategy to access OSKs. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2407–2414     

Water‐mediated intermolecular interactions in 1,2‐O‐cyclohexylidene‐myo‐inositol: a quantitative analysis

The syntheses of new myo‐inositol derivatives have received much attention due to their important biological activities. 1,2‐O‐Cyclohexylidene‐myo‐inositol is an important intermediate formed during the syntheses of certain myo‐inositol derivatives. We report herein the crystal structure of 1,2‐O‐cyclohexylidene‐myo‐inositol dihydrate, C₁₂H₂₀O₆·2H₂O, which is an intermediate formed during the syntheses of myo‐inositol phosphate derivatives, to demonstrate the participation of water molecules and hydroxy groups in the formation of several intermolecular O—H…O interactions, and to determine a low‐energy conformation. The title myo‐inositol derivative crystallizes with two water molecules in the asymmetric unit in the space group C 2/c , with Z = 8. The water molecules facilitate the formation of an extensive O—H…O hydrogen‐bonding network that assists in the formation of a dense crystal packing. Furthermore, geometrical optimization and frequency analysis was carried out using density functional theory (DFT) calculations with B3LYP hybrid functionals and 6‐31G(d), 6‐31G(d,p) and 6‐311G(d,p) basis sets. The theoretical and experimental structures were found to be very similar, with only slight deviations. The intermolecular interactions were quantitatively analysed using Hirshfeld surface analysis and 2D (two‐dimensional) fingerplot plots, and the total lattice energy was calculated.     

Insertion Homo‐ and Copolymerization of Diallyl Ether

The previously unresolved issue of polymerization of allyl monomers CH₂?CHCH₂X is overcome by a palladium‐catalyzed insertion polymerization of diallyl ether as a monomer. An enhanced 2,1‐insertion of diallyl ether as compared to mono‐allyl ether retards the formation of an unreactive five‐membered cyclic O‐chelate (after 1,2‐insertion) that otherwise hinders further polymerization, and also enhances incorporation in ethylene polymers (20.4 mol %). Cyclic ether repeat units are formed selectively (96 %–99 %) by an intramolecular insertion of the second allyl moiety of the monomer. These features even enable a homopolymerization to yield polymers (poly‐diallyl ether) with degrees of polymerization of DP_n≈44.     

Rigid triol and diol with adamantane‐like core derived from naturally occurring myo‐inositol and their polyaddition with diisocyanates

Two orthoester derivatives 1 and 2 that are easily accessible from naturally occurring myo‐inositol were exploited as new triol‐ and diol‐type monomers bearing a rigid adamantane‐like structure to polyaddition with diisocyanates that gave the corresponding networked and linear polyurethanes. DSC analysis of the networked polyurethanes revealed their high glass transition temperatures ranging from 155 to 248 °C, suggesting the contribution of the rigidity of the adamantane‐like structure introduced at the nodes of the networked polyurethanes 6. Besides, the polyaddition of 2 with diisocyanates gave the corresponding linear polyurethanes 4, of which glass transition temperatures were high, ranging from 105 to 177 °C, presumably by virtue of the rigidity of the adamantane‐like structure introduced into the main chains. T_gs of the networked polyurethanes 6 were higher than those of the linear polyurethanes 4. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3498–3505     

Dipolar S=O...C=O and C—H...O interactions in the molecular organization of 4,6‐di‐O‐acetyl‐2‐O‐tosyl‐myo‐inositol 1,3,5‐orthoesters

In the absence of conventional hydrogen bonding, the molecules of 4,6‐di‐O‐acetyl‐2‐O‐tosyl‐myo‐inositol 1,3,5‐orthoformate, C₁₈H₂₀O₁₀S, (I), and 4,6‐di‐O‐acetyl‐2‐O‐tosyl‐myo‐inositol 1,3,5‐orthobenzoate, C₂₄H₂₄O₁₀S, (II), are associated via C—H...O interactions. Molecules of (II) are additionally linked via dipolar S=O...C=O contacts. It is interesting to note that the sulfonyl O atom involved in the dipolar S=O...C=O contacts does not take part in any other interaction, indicating the competitive nature of this contact relative to the weak hydrogen‐bonding interactions.     

Functionalized PEG‐b‐PAGE‐b‐PLGA triblock terpolymers as materials for nanoparticle preparation

A series of poly(ethylene glycol)‐block‐poly(allyl glycidyl ether) (PEG‐b‐PAGE) macroinitiators are prepared using the living anionic ring‐opening polymerization (AROP) technique, and applied for further copolymerization studies. To overcome the low reactivity of the secondary hydroxyl end‐group of the PAGE block, a primary hydroxyl group is introduced into the macroinitiators via trityl and tert‐butyl‐dimethylsilane protective groups. The modified macroinitiators are used for copolymerization by applying different amounts of PEG‐b‐PAGE (5, 10, and 15%) and different PLGA lengths. To study their properties, nanoparticles from selected polymers are prepared and characterized by dynamic light scattering and scanning electron microscopy showing spherical particles with diameters around 200 nm and low PDI_particle values of 0.03–0.1. An advantage of the obtained polymers is the presence of double bonds in the side chain, which enables the modification via, for example, thiol‐ene reactions. For this purpose tertiary 2‐(dimethylamino)ethanethiol), acetylated thiogalactose and thiomannose are attached onto the double bonds of the PAGE‐blocks. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2163–2174     

Controlled synthesis of polyepichlorohydrin with pendant cyclic carbonate functions for isocyanate‐free polyurethane networks

Poly(allyl glycidyl ether) and poly(allyl glycidyl ether‐co‐epichlorohydrin) were prepared by monomer‐activated anionic polymerization. Quantitative and controlled polymerization of allyl glycidyl ether (AGE) giving high molar mass polyether was achieved in a few hours at room temperature in toluene using tetraoctylammonium salt as initiator in presence of an excess of triisobutylaluminum ([i‐Bu₃Al]/[NOct₄Br] = 2?4). Following the same polymerization route, the copolymerization of AGE and epichlorohydrin yields in a living‐like manner gradient‐type copolymers with controlled molar masses. Chemical modification of the pendant allyl group into cyclic carbonate was then investigated and the corresponding polymers were used as precursors for the isocyanate‐free synthesis of polyurethane networks in presence of a diamine. Formation of crosslinked materials was followed and characterized by infrared and differential scanning calorimetry. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Radical Polymerization of methacrylates with an adamantane‐like rigid core derived from naturally occurring myo‐inositol

Trimethacrylate and dimethacrylate with rigid adamantane‐like cores were synthesized from myo‐inositol orthoester, and their radical homopolymerization and copolymerization with methyl methacrylate (MMA) were investigated. The radical homopolymerization of trimethacrylate yielded a networked polymer with higher thermal stability than that of a networked polymer synthesized by radical homopolymerization of 1,3,5‐cyclohexanetriol‐derived trimethacrylate, demonstrating the effect of adamantane‐like core rigidity on the increase in thermal stability. Further, dimethacrylate underwent cyclopolymerization, forming a macrocyclic structure in the repeating unit, as the two methacrylate groups were oriented axially from the rigid orthoester‐core and thus located close to each other. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2411–2420     

Ambient‐temperature copper‐catalyzed atom transfer radical polymerization of methacrylates in ethylene glycol solvents

The use of ethylene glycol solvents in the room‐temperature atom transfer radical polymerization (ATRP) of various hydrophobic and hydrophilic methacrylates is demonstrated. Unlike many of the very polar solvents described in the literature for room‐temperature ATRP, these solvents have good solvency for a wide range of polymers and monomers and are cheap and relatively nontoxic. Ethylene glycols with one hydroxyl and one methoxy group, such as tri(ethylene glycol) monomethyl ether (TEGMME), provide optimal results. The polymerization of methyl methacrylate in TEGMME with CuBr/N,N,N′N′,N″‐pentamethyldiethylenetriamine as the catalyst requires the addition of CuCl₂ at the beginning of the reaction to produce well‐controlled polymerizations. This leads to polymers with predictable molecular weights and relatively narrow polydispersities. Polymerization in solvents that are fully methoxy‐capped terminate prematurely because of catalyst precipitation. The electrochemical behavior of copper complexes in selected solvents is examined to determine why these solvents provide good rates at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1588–1598, 2005     

Rigid diol bearing 6‐6‐6 fused ring system derived from naturally occurring myo‐inositol and its polyaddition with diisocyanates

Naturally occurring myo‐inositol was developed into a highly rigid diol by converting its 3,4‐ and 1,6‐vicinal diols in trans configuration into the corresponding butane‐2,3‐diacetals. The resulting diol bearing 6‐6‐6 fused ring system, in which conformational change is strictly suppressed, was combined with diisocyanates to perform polyadditions. The resulting polyurethanes were analyzed by differential scanning calorimetry, and it was found that their glass transition temperatures were much higher than those of the previously reported myo‐inositol‐derived polyurethanes, which were synthesized from a myo‐inositol‐derived diol bearing 5‐6‐5 fused ring system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3798–3803     

Synthesis and Fe(III)‐complexation ability of polyurethane bearing kojic acid skeleton in the main chain prepared by polyaddition of aliphatic hydroxyl groups without protection of phenolic hydroxyl groups

Polyaddition of a kojic acid dimer and diisocyanates yielded polyurethane with metal‐coordination ability owing to the phenolic hydroxyl groups of kojic acid. Although the kojic acid dimer contains two phenolic and two aliphatic hydroxyl groups, 1,5‐diazabicyclo[4.3.0]non‐5‐ene catalyzed polymerization proceeded through highly selective reactions of the aliphatic hydroxyl groups without any protection of the phenolic hydroxyl groups. The resulting polymers complexed with FeCl₃, and specific colorizations were observed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Thiol‐ene clickable hyperscaffolds bearing peripheral allyl groups

Radical catalyzed thiol‐ene reaction has become a useful alternative to the Huisgen‐type click reaction as it helps to expand the variability in reaction conditions as well as the range of clickable entities. Thus, direct generation of hyperbranched polymers bearing peripheral allyl groups that could be clicked using a variety of functional thiols would be of immense value. A specifically designed AB₂ type monomer, that carries two allyl benzyl ethers groups and one alcohol functionality, was shown to undergo self‐condensation under acid‐catalyzed melt‐transetherification to yield a hyperbranched polyether that carries numerous allyl end‐groups. Importantly, it was shown that the kinetics of polymerization is not dramatically affected by the change of the ether unit from previously studied methyl benzyl ether to an allyl benzyl ether. The peripheral allyl groups were readily clicked quantitatively, using a variety of thiols, to generate an hydrocarbon‐soluble octadecyl‐derivative, amphiphilic systems using 2‐mercaptoethanol and chiral amino acid (N‐benzoyl cystine) derivatized hyperbranched structures; thus demonstrating the versatility of this novel class of clickable hyperscaffolds. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

The effect of the core on the thermotropic behavior of three‐arm star poly[11‐(4′‐cyanophenyl‐4′′‐phenoxy)undecyl acrylate]s synthesized by atom transfer radical polymerization

“Three‐arm star” poly[11‐(4′‐cyanophenyl‐4′′‐phenoxy)undecyl acrylate]s were synthesized by atom transfer radical polymerization (ATRP) of 11‐(4′‐cyanophenyl‐4′′‐phenoxy)undecyl acrylate using two new trifunctional initiators: 1,3,5‐tri‐ (methyl 2‐bromopropionate)benzene and 2,4,6‐tri[4′‐methyl(2′′‐bromopropionate)phenoxymethyl]mesitylene. The polymers synthesized with 1,3,5‐tri(methyl 2‐bromopropionate)benzene (series II) contained 14–127 repeat units according to gel permeation chromatography relative to linear polystyrene (GPC_PSt) and 13–271 repeat units according to GPC with a light scattering detector (GPC_LS). Those synthesized with 2,4,6‐tri[4′‐methyl(2′′‐bromopropionate)phenoxymethyl]mesitylene (series III) contained 14–87 repeat units according to GPC_PSt and 10–120 repeat units according to GPC_LS. The absolute molecular weight, size, and shape of both series of polymers were characterized by light scattering in CH₂Cl₂, and their thermotropic behavior was analyzed using differential scanning calorimetry; both types of properties were compared to those of the other architectures, especially the corresponding three‐arm star poly[11‐(4′‐cyanophenyl‐4′′‐phenoxy)undecyl acrylate]s synthesized previously using 1,3,5‐trisbromomethylmesitylene as the initiator. The size and shape of the three‐arm star polymers in CH₂Cl₂ are similar, although the isotropization temperature in the solid state decreases and the breadth of the isotropization transition increases with increasing size and flexibility of the trifunctional core. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4363–4382, 2008     

(–)‐epi‐Inosose‐2

The structure of the title compound, C₆H₁₀O₆, was determined to confirm the position of the keto group in the mol­ecule prepared enantioselectively by a bioconversion from myo‐inositol. There are two independent mol­ecules showing similar geometry.