STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES. XXVII. SYNTHESIS AND STRUCTURE OF TRICHLOROETHYLIDENE GLYCEROL

1930 ◽  
Vol 2 (2) ◽  
pp. 131-143 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain ◽  
A. Paquet
Keyword(s):  
Sulphuric Acid ◽  
Methyl Ether ◽  
Ring Closure ◽  
Cyclic Acetal ◽  
Satisfactory Explanation ◽  
Carbonyl Derivative ◽  
Cyclic Acetals ◽  
Polyhydroxy Compounds

A discussion is given as to the nature of the factors involved in the mechanism of the formation of cyclic acetals and ketals from carbonyl and polyhydroxy derivatives. It is shown that in the two reactions involved, namely, the primary formation of a half-acetal, followed by removal of water and ring-closure, the polarity of the carbonyl derivative plays a very important rôle. Chloral combines with polyhydroxy compounds to give exceptionally stable half-acetals, which can be converted into the cyclic derivatives by the use of strong dehydrating agents.In contrast with the behavior of other aldehydes it is found that the condensation of chloral with glycerol yields only one ring compound, namely the five-membered derivative. No satisfactory explanation of this can, as yet, be given.The identity of the trichloroethylidene glycerol obtained by the condensation of glycerol and chloral under the influence of concentrated sulphuric acid has been established as a five-membered cyclic acetal by a comparison of the properties of its methyl ether with those of trichloroethylidene glycerol α-methyl ether prepared from glycerol α-methyl ether.

STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES.: PART XXVI. STRUCTURE OF ACETONE GLYCEROL

1930 ◽  
Vol 2 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain
Keyword(s):  
Low Temperature ◽  
Methyl Ether ◽  
Neutral Medium ◽  
Satisfactory Explanation ◽  
Isopropylidene Glycerol

The condensation of acetone with glycerol has been carried out in a neutral medium, at a low temperature, and the product shown to consist entirely of the five-membered isopropylidene-glycerol ketal. Based on this fact, the use of the substance for the determination of the structure of fats is therefore warranted. Isopropylidene-glycerol and its acetate readily hydrolyse on heating with water.No satisfactory explanation can, as yet, be offered for the non-formation of the six-membered ketal under the conditions outlined.Acetone, as previously shown by other workers, is capable of forming a six-membered cyclic ketal with glycerol-β-methyl ether, dihydroxy acetone, pentaerythritol and certain carbohydrates.

THE SORPTION OF ACIDS BY WOOL

1949 ◽  
Vol 27b (12) ◽  
pp. 879-889 ◽  
Author(s):  
R. Donovan ◽  
P. Larose
Keyword(s):  
Hydrochloric Acid ◽  
Adsorption Isotherm ◽  
Sulphuric Acid ◽  
Sodium Sulphate ◽  
Langmuir Adsorption Isotherm ◽  
Langmuir Equation ◽  
Recent Application ◽  
Satisfactory Explanation ◽  
Isotherm Equation ◽  
Langmuir Adsorption

The amount of acid sorbed by wool from solutions of sulphuric acid of four different strengths (namely, 0.0505, 0.0339, 0.0182, and 0.0101 molar) and containing sodium sulphate in amounts varying up to 0.16 molar has been determined. It has been found that the presence of the salt has little effect on the quantity of acid sorbed within those limits. The results are analyzed in the light of the theory of Gilbert and Rideal but this theory fails to give a satisfactory explanation of the results obtained. It is possible, however, to explain the results of the authors' experiments on the basis of the recent application of the Donnan equilibrium by Peters and Speakman. The Langmuir adsorption isotherm equation has been applied to data on the absorption of hydrochloric acid and of sulphuric acid by wool. The data appear to fit the Langmuir equation and give, for the maximum combining capacity, values that agree well with those estimated in other ways.

STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: LII. THE PREPARATION, SEPARATION AND IDENTIFICATION OF THE ISOMERIC PROPYLIDENE, ISOBUTYLIDENE, t-AMYLIDENE AND DIBROMOETHYLIDENE GLYCEROLS AND THE GENERAL PROPERTIES OF GLYCEROL CYCLIC ACETALS

1936 ◽  
Vol 14b (12) ◽  
pp. 415-426 ◽  
Author(s):  
Saul M. Trister ◽  
Harold Hibbert
Keyword(s):  
Physical Properties ◽  
Sulphuric Acid ◽  
Direct Synthesis ◽  
Marked Influence ◽  
Cyclic Acetals ◽  
General Properties ◽  
The Difference ◽  
Acetal Condensation

The condensation of propionaldehyde, isobutyraldehyde, trimethylacetaldehyde and dibromoacetaldehyde with glycerol has been carried out in the presence of a catalyst (40% sulphuric acid) at 90 °C., and the resulting products have been shown to consist in each case of a mixture of the five- and six-membered cyclic acetals. The separation of these isomers from the acetal mixture was rendered possible by the difference in the physical properties of their benzoates. The structure of the latter was proved by saponification, methylation, hydrolysis and isolation of the resulting glycerol α- and glycerol β-methyl ethers respectively.With the isomers from dibromoacetaldehyde this method could not be used, owing to the labile character of the bromine atoms in presence of alkali. Their structures were proved by direct synthesis of the five-membered acetal benzoate from glycerol α-benzoate and dibromoacetaldehyde.The data obtained provide additional evidence of the marked influence exerted by the polar character of the aldehyde on the extent and character of acetal condensation. Increase in the electronegative character increases the amount formed of the five-membered acetal and decreases that of the six-membered. Trimethylacetaldehyde condensed readily with glycerol in absence of a catalyst. Lowering of temperature, in presence of the catalyst, favored the formation of the six-membered acetals, in agreement with the earlier work of van Roon. The results further confirm the Hibbert-Michael Ring Partition Principle.A general comparison is made of the physical properties of the ethylidene–, propylidene–, isobutylidene–, t–amylidene–, bromoethylidene–, and dibromoethylidene glycerol acetals.By substituting diphenylamine for aniline in the synthesis of trimethylacetaldehyde from trimethylpyruvic acid the yield is increased from 25 to 40%.

Chemistry of the Podocarpaceae. XXII. Aspects of the chemistry of Totara-8,11,13-trien-13-ol

1969 ◽  
Vol 22 (9) ◽  
pp. 1975 ◽  
Author(s):  
RC Cambie ◽  
DR Crump ◽  
RN Duve
Keyword(s):  
Sulphuric Acid ◽  
Methyl Ether ◽  
Major Product ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Birch Reduction ◽  
Transannular Cyclization ◽  
Lithium Aluminium ◽  
Fragmentation Reactions

Attempts have been made to effect fragmentation reactions with bromo- tetralone systems related to 6α-bromo-13-hydroxytotara-8,11,13-trien-7- one (VII), a compound which affords a secoditerpenoid (IX) when treated with DMSO-NaHCO3. On treatment with sulphuric acid in acetone, the mono- epoxide derivative (XXVIII) of the methyl ether of the secoditerpenoid undergoes a novel aromatization to a naphthalenic aldehyde (XXXI) by successive transannular cyclization and fragmentation reactions. ��� A 7β-hydroxy configuration has been confirmed for the major product from reduction of 13-acetoxytotara-8,11,13-trien-7-one (VIII) with lithium aluminium hydride. 13-Methoxytotara-8,11,13-triene (II) has been deisopropylated and then subjected to Birch reduction in an attempt to effect a high yield conversion into (+)-podocarp-8(14)-en- 13-one (XXXVII), a potentially useful intermediate for synthesis.

CYCLIC COMPOUNDS CONTAINING A CARBONYL GROUP; A MECHANISM FOR THE FORMATION OF PYRYLLIUM SALTS FROM 1,5-DIKETONES

1933 ◽  
Vol 9 (6) ◽  
pp. 574-582 ◽  
Author(s):  
C. F. H. Allen ◽  
H. R. Sallans
Keyword(s):  
Carbonyl Group ◽  
Methyl Ether ◽  
Ring Closure ◽  
Closed Ring ◽  
Second Mode ◽  
Ring Structures ◽  
Group A ◽  
Plausible Mechanism ◽  
Cyclic Compounds

In the presence of alkali, cyclohexanone and its homologues add to chalcones to form either semicyclic diketones or dicyclic keto-alcohols; the latter contain a carbonyl bridge, and the former can be converted into closed ring structures and dehydrated to form substances having a carbonyl bridge. In these dicyclic ketones the bridge is not removed by heating, in contrast to the behavior of certain other compounds having a similar ring system.A second mode of ring closure gives rise to pyryllium salts; the isolation of a methyl ether has made it possible to devise a plausible mechanism for this hitherto obscure reaction. Four varieties of salts are described, the perchlorates being obtained by a different procedure than that previously employed.

STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: XLIII. CYCLIC ACETAL AND KETAL FORMATION FROM α-PHENYL GLYCEROL AS FURTHER EXAMPLES OF THE "RING PARTITION PRINCIPLE"

1932 ◽  
Vol 7 (6) ◽  
pp. 629-642 ◽  
Author(s):  
Muriel E. Platt ◽  
Harold Hibbert
Keyword(s):  
Methyl Ether ◽  
Condensation Product ◽  
Direct Synthesis ◽  
Cyclic Acetal ◽  
Partition Theory ◽  
Ring Compounds ◽  
Viscous Oil ◽  
Partition Principle ◽  
Isopropylidene Derivatives ◽  
Crystalline Forms

The work represents an extension of the "Hibbert-Michael ring partition theory" to the interaction of α-phenyl glycerol with acetone and p-nitrobenzaldehyde respectively. The α-phenyl glycerol was prepared in the form of a pure crystalline product from cinnamyl alcohol and on condensation with acetone yielded the two expected, isomeric, five-membered (dioxolane) ring compounds. These two isopropylidene derivatives were isolated and their structures definitely determined by the usual hydrolysis and methylation technique. In this manner the corresponding α- and γ-methyl ethers of α-phenyl glycerol were isolated, the identity of which had been previously settled by direct synthesis employing well-established reactions.The β-methyl ether of α-phenyl glycerol was obtained by methylating crystalline 1:3 p-nitrobenzylidene α-phenyl glycerol and then hydrolyzing the ether.Condensation of p-nitrobenzaldehyde with α-phenyl glycerol should yield, according to the "ring partition principle", one six- and two five-membered cyclic acetals.The crystalline isomer separating from the crude condensation product was shown to be the six-membered cyclic acetal. Removal of this left a viscous oil containing the five-membered acetals which, on methylation, and subsequent hydrolysis, yielded a small amount of the γ-methyl ether of α-phenyl glycerol, thus indicating the presence of some 1:2 p-nitrobenzylidene glycerol in the original reaction product. Due to the large number of theoretically possible five-membered rings it was not found possible to isolate, or prove the presence of, both five-membered acetals in the oil left after removal of the crystalline six-membered acetal. Presumably both of the structural five-membered acetals were formed, but due to their mutual solubility relations it was not possible to bring about a separation of crystalline forms.

scholarly journals Cyclic acetals as cleavable linkers for affinity capture

2015 ◽  
Vol 13 (31) ◽  
pp. 8445-8452 ◽  
Author(s):  
Siyeon Lee ◽  
Wei Wang ◽  
Younjoo Lee ◽  
Nicole S. Sampson
Keyword(s):  
Cyclic Acetal ◽  
Affinity Capture ◽  
Cyclic Acetals

A cyclic acetal moiety is an acid-sensitive linker for affinity capture and which provides an aldehyde for further elaboration.

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