2.2- Diethyl-l,3-propanediol

For promoting penetration, the following polyol compounds are suitable (15) 2-Ethyl-2-methyl-l,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-l,3-propanediol, 2-ethyl-l,3-hexanediol, and 2,2,4-trimethyl-l,3-pentanediol. Among the above components, preferable examples include 2-ethyl-l,3-hexanediol and 2,2,4-tri-methyl-l,3-pentanediol. 

Typical procedure. 2,2-Diethyl-l,3-propanediol dicarbamate [382] To a stirred solution of phosgene (20 g, 0.2 mol) (for a safe source, see Chapter 7) in toluene (200 mL) at —10 °C, a cooled solution of 2,2-diethyl-l,3-propanediol (13.2 g, 0.1 mol) and antipyrine (38 g, 0.2 mol) in chloroform (100 mL) was added at such a rate that the temperature of the reaction mixture was maintained at —5 to 0 °C. The mixture was then allowed to warm slowly to room temperature and was left at this temperature overnight. The antipyrine hydrochloride formed was removed by filtration and the bis(chloroformate) was converted directly to the carbamate by treating the filtrate with gaseous ammonia with moderate cooling. The carbamate was separated by filtration, freed from ammonium chloride by extracting with 250 mL of cold water, and recrystallized from hot water 17.5 g (80%) of 2,2-diethyl-l,3-propanediol dicarbamate was obtained. 

Diethyl ethylmalonate Copper chromium oxide 150 5,000 2-Ethyl-l,3-propanediol 4... 

Synthesis CH, 1 H5C2OOC—C—CH2CH2CH3 COOC2H5 Diethyl methylpropyl-malonate Ether LiAlH4 CH3 1 HOCH2—C>-CH2CH2CH3 CH20H 2-Methyl-2-propyl-l, 3-propanediol ... 

Methyl-2-propyl-l, 3-propanediol is prepared by reacting diethyl methylpropyl malonate in ether in the presence of lithium aluminium hydride and then treated with dilute sulphuric acid. This on treatment with phosgene in toluene by means of dimethylaniline yields 2-methyl-2-propyl-3 -hydroxypropyl chlorocarbonate, which on reaction with n-butylamine forms 2-methyl-2-propyl-3-hydroxypropyl butylcarbamate. The resulting product on treatment with ethyl urethane in the presence of aluminium isopropoxide in boiling xylene yields ethanol during transesterification which is removed from the reaction mixture simultaneously and tybamate is obtained. 

Diethyl 2-methyl-2-propylmalonate 2-Methyl-2-propyl-l,3-propanediol... 

H-NMR (200.13 MHz with a sweep width of 3600 Hz) and C-NMR (50.33 MHz with a sweep width of 13.5 kHz) spectroscopy were used to study the microstructiu e of fiunarate-based polyesters for use in bioresorbable bone cement composites and the impact of their microstructure on the physical properties as well as hydrolysis of the cements [145]. Poly(propylene fumarate)s (PPF) were synthesized by the transesterification polycondensation of diethyl fumarate (DEE) with different diols ( )-l,2-propanediol (PD), (S)-(+)-l,2-propanediol, 2-methyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol in the presence of p-toluenesulfonic acid monohydrate (PTSA) or metal-containing catalysts zinc chloride, aluminum trichloride, ti-... 

To a —78 C solution of 23.1 mL (100 mmol) of triisopropyl borate and 8.15 mL (110 mmol) of 3-chloro-l-propene in 100 inL of dry THF is added dropwisc via a cannula over 0.5 h a solution of LDA (110 mmol prepared in 200 mL of THF from 110 mmol of diisopropylamine and 47.9 mL of 2.3 M butyllithium in hexane), This mixture is stirred for an additional 0.5 h at — 78 "C then a solution of 75.9 ntL of 2.9 M anhyd hydrogen chloride in diethyl ether is added and the mixture is allowed to warm to 25 °C. The mixture is concentrated in vacuo (20 Torr) and the residue extracted with three 100-mL portions of pentane, Filtration under nitrogen followed by distillation under reduced pressure provides 18.0 g (88%) of diisopropyl l-chloro-2-propenylboronate bp 95-96 "C/25 Torr. Transesterification of this intermediate with 1.3-propanediol provides the title compound in almost quantitative yield bp 110-112°C/20Torr. 

A solution of 52.2 g (0.31 mol) of ( )-(lS.2S)-2-amino-l-phenyl-l,3-propanediol and 0.37 mol of Ihe orthoester (previously distilled), in 90 mL of DMF is heated to 110 5C for 9.5 h and the solvent removed in vacuo. The resulting oil. which crystallizes on standing, is treated with 30 mL of diethyl ether, cooled in a dry ice- acetone bath, and the crystalline material is collected. This material is dissolved in 300 mL of diethyl ether, treated with charcoal, filtered, concentrated to 125 mL, and cooled to — 78 C. The crystalline product is washed with 10 mL of diethyl ether, previously cooled to — 78 C. 

Among the polycarbonates, PTMC in particular has been studied for biomedical use. PTMC is commonly derived by ring-opening polymerization (Fig. 9). The monomer, l,3-dioxan-2-one,is obtained by refluxing 1,3-propanediol in an excess of diethyl carbonate. Albertsson et al. have reported on the polymerization in bulk and solution using a number of initiators and catalysts [120,279, 280]. PTMC is aliphatic and has a low Tg (approximately -17 °C), it is thus in its... 

The following chiral reagents were employed for diastereomer formation before sample application and chromatography on silica gel or silica gel G TLC plates (L)-leucine Af-carboxyanhydride for D,L-dopa-carboxyl- " C separated with ethyl acetate/formic acid/water (60 5 35) mobile phase and detected by ninhydrin [7 f 0.38 (d)/0.56 (l)] [43] Af-trifluoroacetyl-L-prolyl chloride for D,L-amphetamine separated with chloroform/methanol (197 3) and detected by sulfuric acid/formaldehyde (10 1) (Rf 0.49 (d)/0.55 (l)) [44] Af-benzyloxycarbonyl-L-prolyl chloride for D,L-methamphetamine separated with n-hexane/ethyl acetate/acetonitrile/diisopropyl ether (2 2 2 1) and detected by sulfuric acid/formaldehyde (10 1) [/ f 0.57 (l)/0.61 (d)] [44] (l/ ,2/ )-(-)-l-(4-nitrophenyl)-2-amino-1,3-propanediol (levobase) and its enantiomer dextrobase for chiral carboxylic acids separated with chloroform/ethanol/acetic acid (9 1 0.5) and detected under UV (254 nm) light R[ values 0.63 and 0.53 for 5- and / -naproxen, respectively) [45] (5)-(4-)-a-methoxyphenylacetic acid for R,S-ethyl-4-(dimethylamino)-3-hydroxybutanoate (carnitine precursor) with diethyl ether mobile phase [/ f 0.55 R)/0J9 (5)] [46] and (5)-(4-)-benoxaprofen chloride with toluene/acetone (100 10, ammonia atmosphere) mobile phase and fluorescence visualization (Zeiss KM 3 densitometer 313 nm excitation, 365 nm emission) (respective R values of R- and 5-isomers of metoprolol, oxprenolol, and propranolol were 0.24/0.28, 0.32/0.38, and 0.32/0.39) [47]. 

Diethyl Ketone 1,3-Dimethylacetone 3-Pentanone 3-Chloro-l,2-Propanediol Chlorohydrin Methyl Bromoacetate Methyl Acrylate Methyl Propenoate Methyl Chloroacetate... 

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