Huiling Liu - Academia.edu (original) (raw)

Papers by Huiling Liu

Research paper thumbnail of Economical Synthesis of 13C-Labeled Opiates, Cocaine Derivatives and Selected Urinary Metabolites by Derivatization of the Natural Products

Molecules, 2015

The illegal use of opiates and cocaine is a challenge worldwide , but some derivatives are also v... more The illegal use of opiates and cocaine is a challenge worldwide , but some derivatives are also valuable pharmaceuticals. Reference samples of the active ingredients and their metabolites are needed both for controlling administration in the clinic and to detect drugs of abuse. Especially, 13 C-labeled compounds are useful for identification and quantification purposes by mass spectroscopic techniques, potentially increasing accuracy by minimizing ion alteration/suppression effects. Thus, the synthesis of [acetyl-13 C4]heroin, [acetyl-13 C4-methyl-13 C]heroin, [acetyl-13 C2-methyl-13 C]6-acetylmorphine, [N-methyl-13 C-Ometyl-13 C]codeine and phenyl-13 C6-labeled derivatives of cocaine, benzoylecgonine, norcocaine and cocaethylene was undertaken to provide such reference materials. The synthetic work has focused on identifying 13 C atom-efficient routes towards these derivatives. Therefore, the 13 C-labeled opiates and cocaine derivatives were made from the corresponding natural products.

Research paper thumbnail of Synthesis and Fungicidal Activity of 2-Imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and Their 5-Arylidene Derivatives

Molecules, 2000

Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-ary... more Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-arylidene derivatives have been synthesized and tested for antifungal activity against seven agricultural fungi. 2-Imino-3-(2,4-dichloro-5-fluorophenylthiazol-2-yl)-4-thiazolidi-none and 2-imino-3-(2,4-dichlorophenylthiazol-2-yl)-4-thiazolidione, both of them new compounds, exhibited higher fungicidal effects than the other compounds prepared.

Research paper thumbnail of Evaluation of 13C- and 2H-labeled internal standards for the determination of amphetamines in biological samples, by reversed-phase ultra-high performance liquid chromatography–tandem mass spectrometry

Journal of Chromatography A, 2014

Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatog... more Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze for legal and illegal drugs. ISs labeled with 13 C, 15 N, and 18 O are expected to behave more closely to their corresponding unlabeled analytes, compared with that of the more classically used 2 H-labeled ISs. This study has investigated the behavior of amphetamine, 2 H 3 -, 2 H 5 , 2 H 6 -, 2 H 8 -, 2 H 11 -, and 13 C 6 -labeled amphetamine, during sample preparation by liquid-liquid extraction and LC-MS/MS analyses. None or only minor differences in liquid-liquid extraction recoveries of amphetamine and the SIL-ISs were observed. The chromatographic resolution between amphetamine and the 2 H-labeled amphetamines increased with the number of 2 H-substitutes. For chromatographic studies we also included seven additional 13 C 6 -amphetamines and their analytes. All the 13 C 6 -labeled ISs were co-eluting with their analytes, both when a basic and when an acidic mobile phase were used. MS/MS analyses of amphetamine and its SIL-ISs showed that the ISs with the highest number of 2 H-substitutes required more energy for fragmentation in the collision cell compared with that of the ISs with a lower number. The findings, in this study, support those of previous studies, showing that 13 C-labeled ISs are superior to 2 H-labeled ISs, for analytical purposes.

Research paper thumbnail of Chemo-enzymatic synthesis of the antidepressant duloxetine and its enantiomer

Chirality, 2000

Sodium borohydride reduction of 3-chloro-1-(2-thienyl)-1-propanone gave the corresponding racemic... more Sodium borohydride reduction of 3-chloro-1-(2-thienyl)-1-propanone gave the corresponding racemic alcohol which was kinetically resolved with lipase B from Candida antarctica as catalyst to yield the chiral building blocks (S)-3-chloro-1-(2thienyl)-1-propanol and the corresponding (R)-butanoate. The enantiopure chiral building blocks were converted into Duloxetine and its enantiomer.

Research paper thumbnail of Economical Synthesis of 13C-Labeled Opiates, Cocaine Derivatives and Selected Urinary Metabolites by Derivatization of the Natural Products

Molecules, 2015

The illegal use of opiates and cocaine is a challenge worldwide , but some derivatives are also v... more The illegal use of opiates and cocaine is a challenge worldwide , but some derivatives are also valuable pharmaceuticals. Reference samples of the active ingredients and their metabolites are needed both for controlling administration in the clinic and to detect drugs of abuse. Especially, 13 C-labeled compounds are useful for identification and quantification purposes by mass spectroscopic techniques, potentially increasing accuracy by minimizing ion alteration/suppression effects. Thus, the synthesis of [acetyl-13 C4]heroin, [acetyl-13 C4-methyl-13 C]heroin, [acetyl-13 C2-methyl-13 C]6-acetylmorphine, [N-methyl-13 C-Ometyl-13 C]codeine and phenyl-13 C6-labeled derivatives of cocaine, benzoylecgonine, norcocaine and cocaethylene was undertaken to provide such reference materials. The synthetic work has focused on identifying 13 C atom-efficient routes towards these derivatives. Therefore, the 13 C-labeled opiates and cocaine derivatives were made from the corresponding natural products.

Research paper thumbnail of Synthesis and Fungicidal Activity of 2-Imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and Their 5-Arylidene Derivatives

Molecules, 2000

Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-ary... more Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-arylidene derivatives have been synthesized and tested for antifungal activity against seven agricultural fungi. 2-Imino-3-(2,4-dichloro-5-fluorophenylthiazol-2-yl)-4-thiazolidi-none and 2-imino-3-(2,4-dichlorophenylthiazol-2-yl)-4-thiazolidione, both of them new compounds, exhibited higher fungicidal effects than the other compounds prepared.

Research paper thumbnail of Evaluation of 13C- and 2H-labeled internal standards for the determination of amphetamines in biological samples, by reversed-phase ultra-high performance liquid chromatography–tandem mass spectrometry

Journal of Chromatography A, 2014

Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatog... more Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze for legal and illegal drugs. ISs labeled with 13 C, 15 N, and 18 O are expected to behave more closely to their corresponding unlabeled analytes, compared with that of the more classically used 2 H-labeled ISs. This study has investigated the behavior of amphetamine, 2 H 3 -, 2 H 5 , 2 H 6 -, 2 H 8 -, 2 H 11 -, and 13 C 6 -labeled amphetamine, during sample preparation by liquid-liquid extraction and LC-MS/MS analyses. None or only minor differences in liquid-liquid extraction recoveries of amphetamine and the SIL-ISs were observed. The chromatographic resolution between amphetamine and the 2 H-labeled amphetamines increased with the number of 2 H-substitutes. For chromatographic studies we also included seven additional 13 C 6 -amphetamines and their analytes. All the 13 C 6 -labeled ISs were co-eluting with their analytes, both when a basic and when an acidic mobile phase were used. MS/MS analyses of amphetamine and its SIL-ISs showed that the ISs with the highest number of 2 H-substitutes required more energy for fragmentation in the collision cell compared with that of the ISs with a lower number. The findings, in this study, support those of previous studies, showing that 13 C-labeled ISs are superior to 2 H-labeled ISs, for analytical purposes.

Research paper thumbnail of Chemo-enzymatic synthesis of the antidepressant duloxetine and its enantiomer

Chirality, 2000

Sodium borohydride reduction of 3-chloro-1-(2-thienyl)-1-propanone gave the corresponding racemic... more Sodium borohydride reduction of 3-chloro-1-(2-thienyl)-1-propanone gave the corresponding racemic alcohol which was kinetically resolved with lipase B from Candida antarctica as catalyst to yield the chiral building blocks (S)-3-chloro-1-(2thienyl)-1-propanol and the corresponding (R)-butanoate. The enantiopure chiral building blocks were converted into Duloxetine and its enantiomer.