Beiträge zur Stereochemie organischer Verbindungen. II. Über die räumliche Anordnung der Atome im Pentaerythritmolekül

Synthesis and processability into textile structures of radiopaque, biodegradable polyesters and poly(ester‐urethanes)

“…As a consequence, the starter molecule able to initiate ring‐opening polymerization of the lactone monomer should have both reactive hydroxy functions to open the lactone and a relatively large number of iodine atoms. For this purpose we decided to esterify 2,2‐dimethyl‐(1,3‐dioxane‐5,5‐diyl)dimethanol (MAPE), a readily available diprotected pentaerythritol, with 2,3,5‐triiodobenzoic acid by a conventional active ester method using DCC/DMAP to activate the iodine‐containing acid. After cleavage of the cyclic acetal ring 2,2‐bis (hydroxylmethyl)propane‐1,3‐diyl‐bis(2,3,5‐triiodobenzoate) (TIBA‐PE) was obtained.…”

The Chemical Reactions of Pentaerythritol and its Derivatives.

“…Savary (133) has found that esterification of fatty acids with an excess of pentaerythritol in boiling phenol gives mainly monoesters, which can be purified from the other esters by fractional crystallization. Diesters of pentaerythritol have been prepared indirectly by Orthner and Freyss (119) by esterification of the monoisopropylidene derivative, followed by hydrolysis of the ketal grouping. The acid tetrasulfate has been prepared from pentaerythritol by Kraft (92) by the action of chlorosulfonic acid, and is easily isolated through its soluble barium The simple non-polymeric esters which have been prepared from pentaerythritol are listed in table 5.…”

“…By heating together pentaerythritol and arsenious oxide (52) he isolated a crystalline compound CsHeChAs, m.p. 102-103°C., probably having the following structure: Orthner and Freyss (119) have examined the specific conductivity of boric acid in the presence of pentaerythritol and its derivatives. No increase in conductivity was observed by the addition of the monoisopropylidene derivative of pentaerythritol, pentaerythrityl dimethyl ether, or pentaerythrityl dibenzoate, but pentaerythritol itself was found to cause an increase in conductivity and this was ascribed to the formation of the compound:…”

“…Orthner and Freyss (119) have put forward suggestions on the spatial arrangement of the groups in the pentaerythritol molecule, based on the fact that where- as pentaerythritol gives an increase of specific conductivity in boric acid solution, disubstituted pentaerythritol derivatives, such as the dimethyl ether and dibenzoate, give no increase.…”

Toward Novel Polyacetals by Transacetalation Techniques: Dendrimeric Diacetals

“…The subsequent acetalation of the monoacetal is less efficient, since there is actually a second weak EDG (acetal) function in the, e.g., para position to the aldehyde. Hence, protection/deprotection techniques were devised, using half-protected pentaerythritol (Scheme a) viz ., the known monobenzal-pentaerythritol ( 2 ),5a the dibenzyl ether ( 3 ),5b and the dibenzoate ( 4 ) . The transacetalation processes were generally catalyzed by pyridinium p- tosylate (PPTS).…”