Acid-binding Agent Research Articles

Pyryliumverbindungen. 43 [1]. Arylsubstituierte 5‐(2‐Dialkylamino‐thiazol‐5‐yl)‐pentadienone aus 2,4,6‐Triaryl‐pyryliumsalzen und 2‐Dialkylamino‐4‐arylthiazolen

Pyrylium Compounds. 43. Arylsubstituted 5‐(2‐Dialkylamino‐thiazol‐5‐yl)‐pentadienones from 2,4,6‐Triarylpyrylium Salts and 2‐Dialkylamino‐4‐aryl‐thiazoles2,4,6‐Triarylpyrylium salts 1 react with 2‐dialkylamino‐4‐aryl‐thiazoles 7 (used in substance or prepared in situ from α‐thiocyanato‐acetophenones 9) in the presence of an appropriate acid‐binding agent (e.g. piperidine acetate or sodium acetate) to give 5‐(2‐dialkylamino‐4‐aryl‐thiazol‐5‐yl)‐1,3,5‐triaryl‐penta‐2,4‐dien‐1‐ones 8. As reaction medium aliphatic alcohols (ethanol, n‐propanol), dipolar aprotic solvents (acetonitrile) or chlorinated hydrocarbons (methylene chloride, chloroform) can be used. On the other hand, under the same conditions 2‐amino‐4‐phenyl‐thiazole (10) reacts with salts of type 1 via pyrylium ring transformation yielding 2,4,6‐triaryl‐1‐(4‐phenyl‐thiazol‐2‐yl)‐pyridinium perchlorates 11.

Studies on the Phospholipid Requirement of Glucose 6-Phosphatase

Abstract The role of phospholipid in rat liver microsomal glucose 6-phosphatase has been investigated with the use of phospholipase A and phospholipase C to alter the microsomal phospholipids. The phospholipase C-treated preparation lost a maximum of 80 to 90% of the original activity, and 70% of the microsomal phospholipid was hydrolyzed. Addition of phospholipid completely restored the original activity. The soluble and insoluble products of the phospholipase C treatment had no effect on the inactivation of glucose 6-phosphatase or the subsequent reactivation by phospholipid. The relative effectiveness of various single and mixed phospholipids, with respect to reactivation of the lipid-deficient, phospholipase C-treated glucose 6-phosphatase, was compared. Lecithin, which represents 53% of the microsomal phospholipid, was essentially all hydrolyzed by phospholipase C, but it was ineffective in reactivation. Phosphatidyl ethanolamine, which represents 23% of the phospholipid, was 60% hydrolyzed by phospholipase C, and it was the most effective individual phospholipid in terms of maximal reactivation. Lysolecithin, a trace component in microsomes, was the most effective phospholipid in reactivation at low concentrations, but inhibited at higher levels. In contrast to the phospholipase C-treated preparation, the phospholipase A-treated samples were quite unstable; i.e. the ability to reactivate glucose 6-phosphatase with phospholipid was rapidly lost. In the presence of bovine serum albumin, a fatty acid-binding agent, there was essentially no loss of activity during incubation with phospholipase A. Lysolecithin, another product of the phospholipase A action, was shown to satisfy the phospholipid requirement of the lipid-deficient phospholipase C-treated preparation; thus, the phospholipase A products have contradictory effects on glucose 6-phosphatase activity.