Preparation of a number of α‐ and β‐monoglycerides and determination of their purity by means of periodic acid

Abstract

The preparation of a number of a-and p-monoglycerides and the behaviour of the compounds in question towards periodic acid is described.With a view to an investigation of the migration of the acyl group in monoglycerides in acid medium (performed in [1950][1951] , about which a detailed publication is soon to appear 1, we had to have at our disposal a widely varied series of a-and firnonoglycerides of great purity. Below we are giving a description of the preparation of the monoglycerides involved in some way or another in the work in question, most of which monoglycerides were still unknown, and of the determination of their purity by means of periodic acid*. Preparation of the a-monoglycerides.Practically all the monoglycdides af thh type were obtained by the method of Fischer, Bergmann and Biitwind 8 , i.e. by acdation of a~-&mpmpyh&neglyced ("acetone glycerol") with the aid of the re@red acyl chloride or acyl bromilde in the prwence o f an excess of dry pyridine and hydrolysis of the y"acyl-a~-isoprapyEideneglycerol &us formed with dilute hydrochloric acid.The description uf the preparation of a-monobenzoylg.lyceral given below is ,meant to serve as an example of our standard procedure. Unless otherwise stated, the preparation af the other a-monoglycerideis taok place in t3e same way.

The Heats of Combustion, Formation, and Isomerization of Isomeric Monoglycerides1,2

“…Pure aliphatic and aromatic 2-monoglycerides have been prepared and characterized,4-8 and their rearrangement to 1-monoglycerides have been studied under acid, alkaline, and thermal conditions.9•10 The rearrangement was recently demonstrated to be a reversible reaction, 2-monoglyceride 1-monoglyceride, in which the 1-isomer is the predominant component in the equilibrium. 10 Clarke and Stegeman1 11 determined the heats of combustion for a single pair of monoglycerides, the monopalmitins, whose enthalpy difference provided the heat of isomerization evolved in the rearrangement. Their value of -9.52 kcal.…”

Synthesis of tritium‐labelled iohexol

“…The synthesis of d-tosyl-[3H] glycerol was performed by a modified procedure of Van Lohuizen et ai. ( 3 ) . One gram of 2-[3H] glycerol (L) was converted with acetone in the presence of p-toluenesulfonic acid and molecular sieves into the acetonide z, which was then allowed to react with p -t o l u e n e s u l f o n y l c h l o r i d e to give the tosylate 3.…”