1,3-Diol esters ethylene derivs

Macrocyclization of esters of allylglycine with diols has been successfully used to prepare derivatives of 2,7-diaminosuberic acid [861,864]. The latter are surrogates of cystine, and therefore of interest for the preparation of peptide mimetics. For unknown reasons protected allylglycine derivatives can not be directly dimerized by self metathesis [864]. However, catechol [864], ethylene glycol [861], and 1,2- or 1,3-di(hydroxymethyl)benzene derivatives [860] of allylglycine are suitable templates for the formal self metathesis of this amino acid via RCM. 

If a diastereomeric mixture of (S,S)-2,5-dimethyl-3.4-hexanediol esters 2 and 3 reacts with methylmagnesium bromide, the result is kinetic resolution, as verified for R1 = Bn. The diastereomeric mixture was prepared from the racemic ethylene glycol a-chloro boronic ester via transesterification with chiral diol. The products isolated were (S,S)-2,5-dimethyl-3,4-hexanediol [(/ )-2-phcnyl-l-methylethyl]boronate, diastereomeric ratio >95 5 as indicated by the rotation of the (/ )- -phenyl-2-propanol derived by deboronation with hydrogen peroxide, and (S,S)-2,5-dimethyl-3.4-hexanediol methylboronate. Phenylacetaldehyde was identified by 1H NMR4. 

The ADMET polymerization of sugar-based monomers is much less explored than the ROMP approach, and only a few examples have been reported to date. Bui and Hudlicky prepared a,oo-dienes derived from a biocatalytically synthesized diene diol, from which chiral polymers (up to 20 kDa) with D-c/uro-inositol units were prepared via ADMET in the presence of 1 mol% of C4 [169]. Furthermore, several ot,co-dienes containing D-mannitol, D-ribose, D-isomannide, and D-isosorbide have been synthesized by Enholm and Mondal [170]. Also in this study, C4 was used to catalyze the ADMET polymerizations at 1 mol% catalyst loading. As pointed out by the authors, the viscosity increased as the reactions progressed and vacuum had to be applied to efficiently remove the released ethylene. Unfortunately, the polymers obtained were not further analyzed. As already mentioned above, Fokou and Meier have also reported the ADMET polymerization of a fatty acid-/D-isosorbide-based a,co-diene [126]. Furthermore, Krausz et al. have synthesized plastic films with good mechanical properties by cross-linking fatty esters of cellulose in the presence of C3 [171-173]. 

The carboxyl group in acrylates and methacrylates can be esterified with various other alcohols, including diols such as ethylene glycol, diethyleneglycol, etc. In addition to the free acids and their esters, to this class can be added other derivatives of acrylic acid such as poly(acrylonitrile) [-CH2-CH(CN)-]n, poly(acrylamide) [-CH2-CH(CONH2)-]n,... 

PET is produced from teraphthalic acid and ethylene glycol, while PBT is made with butylene diol. The diacid is obtained by catalytic oxidation of para-xylene (a by-product of the petrochemical industry) while ethylene glycol is obtained from ethylene oxide (an oxidized derivative of ethylene).The terephthallic acid is preferably replaced by the ester dimethyl-terephthalate... 

Anderson and Haslewood (19) explored the preparation of these derivatives from 3 -hydroxy-6-keto-5rt-cholanoic acid in a manner analogous to that outlined in Fig. 6. The known 3a,7 -dihydroxy-6-keto-5a-cholanoic acid (90) was esterified, and the product converted to a crystalline ethylene thioketal. Treatment of the latter with Raney nickel provided allolithocholic acid and several fractions of unidentified material. From one of these fractions an acid (A) was obtained, m.p. 240-241 °C [ ]D+60i 1 from the succeeding fraction an acid (B) was converted to the methyl ester (C), m.p. 156-158°C [a]D4-58 1 °. The Md for (C) (Found-1-235) agrees reasonably well with the calculated value for a 3/3,7(3-diol (4-190) or a 3a,7 3-diol (4-197). In a similar sequence of reactions Ziller (91) obtained a methyl ester, m.p. 158-159°C RRe 1.42 on 3% QF-1 free acid, m.p. 240-241 °C. Subsequent experiments have shown that the monohydro.xy acids derived from this diol are the 3p- and 7 -ols, suggesting that this acid is the unreported 3j3,7/3-dihy-droxy-5a-cholanoic acid (170). 

Zhou et al. described the synthesis of pH-sensitive biodegradable PUs. They used a novel pH-sensitive macrodiol containing acid-cleavable hydrazone linkers, poly(E-caprolactone)-hydrazone-poly(ethylene glycol)-hydiazone- ly(E-caprolactone) diol (PCL-Hyd-PEG-Hyd-PCL). The macrodiol was used with L-lysine ethyl ester diisocyanate (LDI) and L-lysine-derived tripeptide as chain extender [47]. These PUs could self-assemble into micelles in aqneons solutions. Later, the same research group synthesized pH-sensitive polymers nsing 1,4-bntanediol as chain extenders and suggested its use as antitumor drug carriers [41]. 

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