The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Santosh G. Tilve - One of the best experts on this subject based on the ideXlab platform.
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synthesis of Hygrine norHygrine pseudohygroline and hygroline via nef reaction
Tetrahedron Letters, 2011Co-Authors: Chinmay Bhat, Santosh G. TilveAbstract:Abstract Synthesis of tropane alkaloids (−)-Hygrine, (−)-norHygrine and sedum alkaloids (−)-pseudohygroline and (−)-hygroline is described from l -proline via Henry and Nef reactions.
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Synthesis of (−)-Hygrine, (−)-norHygrine, (−)-pseudohygroline and (−)-hygroline via Nef reaction
Tetrahedron Letters, 2011Co-Authors: Chinmay Bhat, Santosh G. TilveAbstract:Abstract Synthesis of tropane alkaloids (−)-Hygrine, (−)-norHygrine and sedum alkaloids (−)-pseudohygroline and (−)-hygroline is described from l -proline via Henry and Nef reactions.
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Syntheses of (‐)‐Hygrine (V) and (‐)‐NorHygrine (VI) via Wacker Oxidation.
ChemInform, 2010Co-Authors: Mahesh S. Majik, Santosh G. TilveAbstract:Key step is the Wacker oxidation for the formation of carbonyl compound (IV) in a regioselective manner.
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syntheses of Hygrine v and norHygrine vi via wacker oxidation
ChemInform, 2010Co-Authors: Mahesh S. Majik, Santosh G. TilveAbstract:Key step is the Wacker oxidation for the formation of carbonyl compound (IV) in a regioselective manner.
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syntheses of Hygrine and norHygrine via wacker oxidation
Tetrahedron Letters, 2010Co-Authors: Mahesh S. Majik, Santosh G. TilveAbstract:Abstract Hygrine is an important biosynthetic intermediate for tropane alkaloids. A synthesis of (−)-Hygrine starting from l -proline is described. The acetonyl side chain of Hygrine was fashioned through the Wittig reaction followed by regioselective Wacker oxidation. In addition, this Letter provides the first synthesis of (−)-norHygrine.
Hyeung-geun Park - One of the best experts on this subject based on the ideXlab platform.
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total synthesis of Hygrine via asymmetric phase transfer catalytic alkylation
ChemInform, 2006Co-Authors: Jeonghee Lee, Byeong Seon Jeong, Sangsup Jew, Hyeung-geun ParkAbstract:The first enantioselective synthesis of (+)-Hygrine (1) is reported. 1 was obtained in 12 steps with 29% overall yield and 97% ee via asymmetric phase-transfer catalytic alkylation and ring-closing metathesis as key steps. The absolute configuration of (+)-Hygrine could be directly confirmed as R.
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Total Synthesis of (+)-Hygrine via Asymmetric Phase-Transfer Catalytic Alkylation
Journal of Organic Chemistry, 2006Co-Authors: Byeong Seon Jeong, Jin-mo Ku, Hyeung-geun ParkAbstract:The first enantioselective synthesis of (+)-Hygrine (1) is reported. 1 was obtained in 12 steps with 29% overall yield and 97% ee via asymmetric phase-transfer catalytic alkylation and ring-closing metathesis as key steps. The absolute configuration of (+)-Hygrine could be directly confirmed as R.
Byeong Seon Jeong - One of the best experts on this subject based on the ideXlab platform.
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total synthesis of Hygrine via asymmetric phase transfer catalytic alkylation
ChemInform, 2006Co-Authors: Jeonghee Lee, Byeong Seon Jeong, Sangsup Jew, Hyeung-geun ParkAbstract:The first enantioselective synthesis of (+)-Hygrine (1) is reported. 1 was obtained in 12 steps with 29% overall yield and 97% ee via asymmetric phase-transfer catalytic alkylation and ring-closing metathesis as key steps. The absolute configuration of (+)-Hygrine could be directly confirmed as R.
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Total Synthesis of (+)-Hygrine via Asymmetric Phase-Transfer Catalytic Alkylation
Journal of Organic Chemistry, 2006Co-Authors: Byeong Seon Jeong, Jin-mo Ku, Hyeung-geun ParkAbstract:The first enantioselective synthesis of (+)-Hygrine (1) is reported. 1 was obtained in 12 steps with 29% overall yield and 97% ee via asymmetric phase-transfer catalytic alkylation and ring-closing metathesis as key steps. The absolute configuration of (+)-Hygrine could be directly confirmed as R.
A M Bermejo - One of the best experts on this subject based on the ideXlab platform.
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application of Hygrine and cuscoHygrine as possible markers to distinguish coca chewing from cocaine abuse on wdt and forensic cases
Forensic Science International, 2014Co-Authors: N C Rubio, Maria Jesus Tabernero, Luca Anzillotti, Sabina Stranorossi, Marcello Chiarotti, J L Gonzalez, A M BermejoAbstract:Abstract The objectives of present work are twofold. First, we want to verify that Hygrine and cuscoHygrine are good markers to distinguish between chewing coca leaves and cocaine abuse. Secondly, we try to develop a quick and easy qualitative method to determine the two mentioned markers. We analyzed two kinds of urine samples: the first group consisted of twenty-four (24) subjects: urine samples were obtained from various types of workers (e.g. doctors, chemists, nurses, technicians, painters, contractors, employees and some retired persons) who admitted chewing coca leaves. Frequency of the habit of chewing coca leaves was variable. They practiced “coqueo” between two (2) and forty-four (44) years. Sixteen (16) of them used alkaline substances to enhance the extraction of cocaine from the leaves The second group of urine samples consisted on thirty-eight (38) cocaine abusers, from forensic cases from Spain and Argentina. A GC/MS qualitative method, performed after liquid–liquid extraction, was developed and validated (the parameters studied were selectivity/specificity, LOD and stability), and then applied to the urine samples. Hygrine and cuscoHygrine are good markers to distinguish between chewing coca leaves and cocaine abuse, and the qualitative method presented can be used successfully in workplace drug testing and forensic cases.
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Hygrine and cuscoHygrine as possible markers to distinguish coca chewing from cocaine abuse in workplace drug testing
Forensic Science International, 2013Co-Authors: C Rubio, Maria Jesus Tabernero, Luca Anzillotti, Sabina Stranorossi, Marcello Chiarotti, A M BermejoAbstract:A B S T R A C T Cocaine abuse is widespread all over the world, and is performed generally by sniffing, injecting or smoking cocaine or crack. The distinction between the recreational use of cocaine from the practice of the so called ‘‘coqueo’’ is still an issue in those countries where this habit is diffused and where it is not considered an addiction, by this reason is necessary to develop a method for to distinguish the coca chewers and cocaine abusers. The use of an unique marker to distinguish between cocaine abuse and chewing of coca leaves is of fundamental importance in those countries where this habit is diffused. Certain alkaloids of the leaves of Erythroxylum coca are lost during the process of extraction/purification of cocaine and it is not possible to find them neither in seizures of chlorhidrate of cocaine nor urine samples of cocaine abusers. These markers are the Hygrine and cuscoHygrine that are present in the leaves of E. coca. A fast GC/MS method involving a liquid:liquid extraction procedure with tertbutylmethylether (TBME) is proposed for the determination of some alkaloids in cocaine leaves, cocaine seizures and biological samples. All specimens were alkalinized to pH 9 with a carbonate/bicarbonate buffer and then extracted with TBME. The analysis was carry out by GC/MS with electron impact at 70 eV and in full scan mode. The results demonstrate that Hygrine and cuscoHygrine are not found neither in the urine of cocaine abusers nor in cocaine seizures. For this reason this compounds could be considered as markers of coca chewing. This developed method permits to distinguish coca chewing from cocaine abuse in workplace drug testing through the analysis of urine samples.
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Hygrine and cuscoHygrine as possible markers to distinguish coca chewing from cocaine abuse in workplace drug testing
Forensic Science International, 2013Co-Authors: C Rubio, Maria Jesus Tabernero, Luca Anzillotti, Sabina Stranorossi, Marcello Chiarotti, A M BermejoAbstract:A B S T R A C T Cocaine abuse is widespread all over the world, and is performed generally by sniffing, injecting or smoking cocaine or crack. The distinction between the recreational use of cocaine from the practice of the so called ‘‘coqueo’’ is still an issue in those countries where this habit is diffused and where it is not considered an addiction, by this reason is necessary to develop a method for to distinguish the coca chewers and cocaine abusers. The use of an unique marker to distinguish between cocaine abuse and chewing of coca leaves is of fundamental importance in those countries where this habit is diffused. Certain alkaloids of the leaves of Erythroxylum coca are lost during the process of extraction/purification of cocaine and it is not possible to find them neither in seizures of chlorhidrate of cocaine nor urine samples of cocaine abusers. These markers are the Hygrine and cuscoHygrine that are present in the leaves of E. coca. A fast GC/MS method involving a liquid:liquid extraction procedure with tertbutylmethylether (TBME) is proposed for the determination of some alkaloids in cocaine leaves, cocaine seizures and biological samples. All specimens were alkalinized to pH 9 with a carbonate/bicarbonate buffer and then extracted with TBME. The analysis was carry out by GC/MS with electron impact at 70 eV and in full scan mode. The results demonstrate that Hygrine and cuscoHygrine are not found neither in the urine of cocaine abusers nor in cocaine seizures. For this reason this compounds could be considered as markers of coca chewing. This developed method permits to distinguish coca chewing from cocaine abuse in workplace drug testing through the analysis of urine samples.
Juan Carlos Colmenares - One of the best experts on this subject based on the ideXlab platform.
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a short synthesis of Hygrine
ChemInform, 2008Co-Authors: Enzo B Arevalogarcia, Juan Carlos ColmenaresAbstract:The synthesis of the alkaloid Hygrine in a series of six steps starting from readily available proline N-methyl derivative (5) is described.
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A short synthesis of (+)-Hygrine
Tetrahedron Letters, 2008Co-Authors: Enzo B. Arévalo-garcía, Juan Carlos ColmenaresAbstract:The synthesis of the alkaloid Hygrine in a series of six steps starting from readily available proline N-methyl derivative (5) is described.