SYNTHESIS OF PHOSPHORIC ACID ESTERS OF α-METHYLCHOLINE, β-METHYLCHOLINE, AND HOMOCHOLINE

1965 ◽  
Vol 43 (8) ◽  
pp. 1343-1352 ◽  
Author(s):  
Erich Baer ◽  
Paul Cooper
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Silver Carbonate ◽  
Catalytic Hydrogenolysis ◽  
Hydrolysis Of ◽  
Acid Esters

The synthesis of the phosphoric acid esters of α-methylcholine, β-methylcholine, and homocholine is described. The esters were obtained by phosphorylating the iodides of α-methylcholine, β-methylcholine, and homocholine with diphenylphosphoryl chloride and pyridine, converting the iodides of the diphenylphosphoric acid esters of the respective cholines into the corresponding phosphates by consecutive treatment with silver carbonate and phosphoric acid, and removing the protective phenyl groups by catalytic hydrogenolysis. The rates of hydrolysis of the phosphoric acid esters of α- and β-methylcholine and homocholine in 2 N hydrochloric acid at 125° were determined.

Metallomicelles as catalysts of the hydrolysis of carboxylic and phosphoric acid esters

1991 ◽  
Vol 56 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Paolo Scrimin ◽  
Paolo Tecilla ◽  
Umberto Tonellato
Keyword(s):  
Phosphoric Acid ◽  
Hydrolysis Of ◽  
Acid Esters

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

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