This Post
PermalinkURI
URI Label
Revisions
Export:
XML (With Files)
PNG Image
Archives
May 2013 (1)April 2013 (1)
October 2012 (1)
August 2012 (1)
July 2012 (1)
June 2012 (7)
May 2012 (8)
April 2012 (2)
March 2012 (6)
February 2012 (10)
January 2012 (3)
October 2011 (1)
September 2011 (7)
August 2011 (5)
March 2011 (1)
February 2011 (1)
January 2011 (4)
December 2010 (3)
November 2010 (5)
October 2010 (12)
September 2010 (5)
Sections
Compound Index (1)Data (1)
Experiments (78)
Notes (1)
Ongoing Experiments (3)
SDF data (1)
Mnr
1-10 (2)MNR1-10 (1)
21-30 (9)
11-20 (1)
31-40 (2)
Tools
Show/Hide QR CodeShow/Hide Keys
Determination of the optical rotation of the 2 enantiomers of PZQ in dependence of ee and concentration
See also: Optical rotation of S-(+)-Praziquanamine
Enantiopure samples of R-(-)-PZQ and S-(+)-PZQ donated from Intervet Innovation GmbH, Germany (Schwabenheim)
Separation method: Chiral column chromatography performed on microcrystalline cellulose triacetate [1].
R-(-)-PZQ:
m.p. 111-112°C (lit.[2] m.p. = 113-115°C).
[α]D20 = -139° (c=1, EtOH)
(lit. [2] [α]D20 = 126.9 (c = 1, EtOH 99.%) [α]D20 = 135.0 (c = 1, CHCl3)).
S-(+)-PZQ:
m.p. 110-111°C.
[α]D20 = -136.5° (c=1, EtOH).
Determination of the optical rotation in dependence of the ee (in %)
To a solution of R-(-)-PZQ (c = 1, EtOH) was added a solution of S-(+)-PZQ (c = 1, EtOH) (vol/vol) to give a total volume of 1 mL.
Chart 1: Optical rotation α as a function of the ee
Determination of the optical rotation in dependence of the concentration:
A solution of R-(-)-PZQ (c = 1, EtOH) was diluted with EtOH to the concentration given in the tables below.
4 dilution series were performed to determine the mean value of the optical rotation α (lage deviations for diluted solutions)
Series1- Series4
Chart 2: Optical rotation α as a function of the concentration c (for Series4)
Chart 3: Mean value of the optical rotation [α] in dependence of the concentration c ([α] = α / l * c, and l=1, α and c are given in tables Series1 - Series4)
Results:
- Linear dependence of the optical rotation α of PZQ on the ee (determined for a concentration c = 1 in DCM)
- Linear dependence of the optical rotation α of R-(+)-PZQ on the concentration
References:
[1] "Taste, A New Incentive to Switch to (R)-Praziquantel in Schistosomiasis Treatment", T. Meyer, H. Sekljic, S. Fuchs, H. Bothe, D. Schollmeyer and C. Miculka, PLoS Neglected Tropical Diseases 2009, 3, 1, e357
[2] "Enantioselective synthesis of (R)-(−)-praziquantel (PZQ)", P. Roszkowski J. K. Maurin and Zbigniew Czarnocki, Tetrahedron: Asymmetry,2006, 17, 9, 15, 1415-1419. (doi:10.1016/j.tetasy.2006.04.023)
See also: Optical rotation of S-(+)-Praziquanamine
Scheme
Enantiopure samples of R-(-)-PZQ and S-(+)-PZQ donated from Intervet Innovation GmbH, Germany (Schwabenheim)
Separation method: Chiral column chromatography performed on microcrystalline cellulose triacetate [1].
R-(-)-PZQ:
m.p. 111-112°C (lit.[2] m.p. = 113-115°C).
[α]D20 = -139° (c=1, EtOH)
(lit. [2] [α]D20 = 126.9 (c = 1, EtOH 99.%) [α]D20 = 135.0 (c = 1, CHCl3)).
S-(+)-PZQ:
m.p. 110-111°C.
[α]D20 = -136.5° (c=1, EtOH).
Determination of the optical rotation in dependence of the ee (in %)
To a solution of R-(-)-PZQ (c = 1, EtOH) was added a solution of S-(+)-PZQ (c = 1, EtOH) (vol/vol) to give a total volume of 1 mL.
Table1
Chart 1: Optical rotation α as a function of the ee
Chart: Dependency optical rotation - ee
Determination of the optical rotation in dependence of the concentration:
A solution of R-(-)-PZQ (c = 1, EtOH) was diluted with EtOH to the concentration given in the tables below.
4 dilution series were performed to determine the mean value of the optical rotation α (lage deviations for diluted solutions)
Series1- Series4
Series1
Series2
Series3
Series4
Chart 2: Optical rotation α as a function of the concentration c (for Series4)
Chart alpha in dependency of c
Chart 3: Mean value of the optical rotation [α] in dependence of the concentration c ([α] = α / l * c, and l=1, α and c are given in tables Series1 - Series4)
Chart [alpha] in dependency of c
Results:
- Linear dependence of the optical rotation α of PZQ on the ee (determined for a concentration c = 1 in DCM)
- Linear dependence of the optical rotation α of R-(+)-PZQ on the concentration
References:
[1] "Taste, A New Incentive to Switch to (R)-Praziquantel in Schistosomiasis Treatment", T. Meyer, H. Sekljic, S. Fuchs, H. Bothe, D. Schollmeyer and C. Miculka, PLoS Neglected Tropical Diseases 2009, 3, 1, e357
[2] "Enantioselective synthesis of (R)-(−)-praziquantel (PZQ)", P. Roszkowski J. K. Maurin and Zbigniew Czarnocki, Tetrahedron: Asymmetry,2006, 17, 9, 15, 1415-1419. (doi:10.1016/j.tetasy.2006.04.023)
Attached Files
Scheme
Table1
Chart Dependency optical rotation - ee
Series1
Series2
Series3
Series4
Chart [alpha] in dependency of c
Chart alpha in dependency of c
Chart: Dependency optical rotation - ee