Esterification of propanoic acid with 1,2-propanediol: catalysis by cesium exchanged heteropoly acid on K-10 clay and kinetic modelling

Kinetic modelling of the molecular weight distribution (MWD) of polymer obtained by an anionic polymerization with two types of growth centres in a dynamic equilibrium, having different growth rates and lifetimes comparable to the polymerization time, was made for low monomer conversions. On the basis of distribution of the growth centres according to the total time spent in the fast growth state, it was shown that MWD of the resulting polymer are mostly bimodal at the beginning of the polymerization and change to unimodal MWD at sufficiently high polymerization degrees depending on the equilibrization rate. When all centres are in the fast state in the beginning, MWD are essentially unimodal throughout. A hint of trimodality is observed in some cases, in an extent hardly detectable in real chromatograms. Hence, a polymodal MWD can be explained only when more than two growth centres with different growth rates are assumed.

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Mesomorphic Behaviour of Saturated and Monounsaturated C18 and C22 Fatty Acid Esters of Cholesterol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19940833 ◽

1994 ◽

Vol 59 (4) ◽

pp. 833-840

Author(s):

Slavomír Pirkl

Keyword(s):

Phase Transitions ◽

Fatty Acid ◽

Fatty Acid Esters ◽

Aliphatic Esters ◽

Acid Esters

The phase transitions and effective optical rotary power of saturated and monounsaturated aliphatic esters of cholesterol with 18 and 22 carbon atoms in the chain have been described. The effect of cis/trans isomerism on these properties is discussed.

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Synthesis of Normuramic Acid Carba Analog and Its Glycopeptide Derivative Resistant to β-Elimination Splitting of the Side Chain

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20001726 ◽

2000 ◽

Vol 65 (11) ◽

pp. 1726-1736 ◽

Cited By ~ 2

Author(s):

Miroslav Ledvina ◽

Radka Pavelová ◽

Anna Rohlenová ◽

Jan Ježek ◽

David Šaman

Keyword(s):

Ethyl Ester ◽

Alkaline Hydrolysis ◽

Benzyl Ester ◽

Side Chain ◽

Propanoic Acid ◽

Hydrolysis Of

Carba analogs of normuramic acid, i.e., 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid derivatives (nitrile or esters) 3a-3c were prepared by addition of radicals generated from benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[(methylsulfanyl)thiocarbonyl]- (2a) or -3-O-(phenoxythiocarbonyl)-α-D-glucopyranoside (2b) with Bu3SnH to acrylonitrile or acryl esters. Alkaline hydrolysis of ethyl ester 3c afforded 3-(benzyl 2-acetamido-2,3-dideoxy-4,6-O-isopropylidene-α-D-glucopyranosid-3-yl)propanoic acid (5). Coupling of acid 5 with L-2-aminobutanoyl-D-isoglutamine benzyl ester trifluoroacetate and subsequent deprotection of the intermediate 6 furnished N-[3-(2-acetamido-2,3-dideoxy-α-D-glucopyranosid-3-yl)propanoyl]-L-2-aminobutanoyl-D-isoglutamine (7).

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