Investigation of the glucose/propylamine reaction by HPLC

The reaction of glucose with propylamine has been investigated by HPLC. The main products detectable by UV absorption were 4-hydroxy-2-(hydroxymethyl)-5-methyl-3(2H)-furanone (4), 2,3-dihydro-3,5- dihydroxy-6-methyl-4H-pyran-4-one (5), 5-hydroxymethyl- 2-furancarbaldehyde, 3-(1,2,3-trihydroxypropyl)-1-propyl-2-pyrrolecarbaldehyde (6a) and 5-hydroxymethyl- 1-propyl-2-pyrrolecarbaldehyde (7a). The yield of products was highly dependent on the reaction conditions. In neutral solution mainly4 and5 were formed, whereas at pH 5.0 pyrroles dominated.

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Untersuchung der Reaktion zwischen Glucose und Propylamin mittels HPLC

Zusammenfassung Umsetzungen von Glucose mit Propylamin wurden mit Hilfe der HPLC untersucht. Die durch UV-Absorption detektierbaren Hauptprodukte sind: 4-Hydroxy-2-(hydroxymethyl)-5-methyl-3(2H)-furanon (4), 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-on (5), 5-Hydroxymethyl-2-furancarbaldehyd, 3- (1,2,3-Trihydroxypropyl)-1-propyl-2-pyrrolcarbaldehyd (6a) und 5-Hydroxymethyl-1-propyl-2-pyrrolcarbaldehyd (7a). Die Ausbeuten hängen sehr von den Reaktionsbedingungen ab. In neutraler Lösung werden überwiegend4 und5 abgebildet, während bei pH 5 Pyrrole dominieren.

     

COMPOSITIONAL DIFFERENCES BETWEEN SUPERCRITICAL FLUID EXTRACT AND SHORT-PATH DISTILLATES OF PETROLEUM SHORT RESIDUE

Short-path distillation (SPD) and supercritical fluid extraction (SFE) procedures were employed to obtain portions of a short residue (500^°C+). The physicochemical and compositional data of SF extract and SP distillates at four wall temperatures were obtained employing various analytical techniques such as vapour pressure osmometry, simulated distillation, infrared and mass spectrometry. The comparison of these data reveals that although the yield of SF extract is small under the present experimental conditions, it contains relatively higher concentrations of paraffins and alkylbenzenes as compared to SP distillates. The hydro carbon type distribution of distillates was found to be the same, independent of the wall temperature used. The comparison of overall composition of SF extract and SP distillates depicts that former is more suitable to be used as lube stocks.     

Formation of maltosine, a product of the Maillard reaction with a pyridone structure

Summary By heating N^a-acetyllysine with maltose or lactose, the pyridone8 not known up to now is formed, which is transformed into the lysine derivative9 when the acetyl group is split off. We propose the name maltosine for compound9. In contrast to maltosine, the well-known pyridosine, used in the determination of lysine damage, is an artificial product formed during acid protein hydrolysis. From the reaction mixtures of galactosyl isomaltol and an Amadori product of maltose with propylamine, the pyridinium betaines13 and14 can be isolated. They are intermediates in the formation of the pyridone12a.

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Bildung von Maltosin: Ein Produkt der Maillard-Reaktion mit Pyridonstruktur

Zusammenfassung Beim Erhitzen von N^a-Acetyllysin mit Maltose oder Lactose bildet sich u. a. das bisher nicht bekannte Pyridon8 aus dem nach Abspaltung der Acetylgruppe das Lysinderivat9 erhalten wird. Für die neue Substanz9 schlagen wir die Bezeichnung Maltosin vor. Im Gegensatz zum Maltosin ist das schon früher bekannte und zum Nachweis einer Lysinschädigung herangezogene Pyridosin ein Kunstprodukt der sauren Proteinhydrolyse. Aus den Umsetzungsgemischen von Galaktosylisomaltol und eines Amadoriprodukts der Maltose mit Propylamin lassen sich die Pyridiniumbetaine13 und14 isolieren. Sie sind Zwischenprodukte bei der Bildung des Pyridons12a.

     

Autocatalytic networks: the transition from molecular self-replication to molecular ecosystems

The transition from inanimate to animate chemistry is thought to involve self-organised networks of molecular species whose collective emergent property gives rise to the overall characteristics of living systems. In the past, simple autocatalytic networks have been constructed that display basic forms of cooperative behaviour. These include reciprocal catalysis, autocratic, and hypercyclic networks. The design and emergent properties of these novel molecular networks are reviewed here.     

Change in susceptibility of group B streptococci to penicillin G from 1968 through 1975

This report describes a study of 212 isolates of group B streptococci from sore throats over an 8-year period. A small but increasing percentage showed increased resistance to penicillin G when tested in an in vitro system.