84129-60-2Relevant academic research and scientific papers
Enantiospecific Total Synthesis of the Sarpagine Related Indole Alkaloids Talpinine and Talcarpine as Well as the Improved Total Synthesis of Alstonerine and Anhydromacrosalhine-methine via the Asymmetric Pictet-Spengler Reaction
Yu, Peng,Wang, Tao,Li, Jin,Cook, James M.
, p. 3173 - 3191 (2007/10/03)
The enantiospecific total synthesis of talpinine 1 and talcarpine 2 has been accomplished from D-(+)-tryptophan in 13 steps (11 reaction vessels) in 10% and 9.5% overall yields, respectively. Moreover, this synthetic approach has been employed for the improved synthesis of alstonerine 3 and anhydromacrosalhine-methine 4 in 12% and 14% overall yield, respectively. A convenient synthetic route for the enantiospecific, stereospecific preparation of the key intermediate (-)-Na-H, Nb-benzyl tetracyclic ketone 15a via the asymmetric Pictet-Spengler reaction on a multihundredgram scale has been developed. A diastereocontrolled (>30:1) anionic oxy-Cope rearrangement and the intramolecular rearrangement to form ring-E and an Nb-benzyl/Nb-methyl transfer reaction also served as key steps. This general approach can now be utilized for the synthesis of macroline/ sarpagine related indole alkaloids and their antipodes for biological screening.
General approach for the synthesis of ajmaline/sarpagine indole alkaloids: Enantiospecific total synthesis of (+)-ajmaline, alkaloid G, and norsuaveoline via the asymmetric Pictet-Spengler reaction
Li, Jin,Wang, Tao,Yu, Peng,Peterson,Weber,Soerens,Grubisha,Bennett,Cook
, p. 6998 - 7010 (2007/10/03)
A general approach (oxyanion-Cope strategy) for the synthesis of sarpagine/ajmaline indole alkaloids has been developed. (+)-Ajmaline 1 and alkaloid G 2 as well as norsuaveoline 3 have been synthesized from D-(+)-tryptophan in enantiospecific fashion via
Pictet-Spengler reactions in aprotic media. The total synthesis of (±) suaveoline
Trudell,Soerens,Weber,Hutchins,Grubisha,Bennett,Cook
, p. 1805 - 1822 (2007/10/02)
The first total synthesis of the indole alkaloid (±)-suaveoline 1 (a macroline-related base and a member of the sarpagine/ajmaline class of alkaloids) was completed in a stereocontrolled fashion. The serial synthesis employed three intramolecular reaction
STEREOSPECIFICITY IN THE PICTET-SPENGLER REACTION. ENANTIOSPECIFIC SYNTHESIS OF (6S,10S)-(-)-5-METHYL-9-OXO-12-BENZYL-6,7,8,9,10,11-HEXAHYDRO-6,10-IMINO-5H-CYCLOOCTINDOLE, A TEMPLATE FOR PREPARATION OF MACROLINE/SARPAGINE ALKALOIDS
Zhang, Lin-Hua,Bi, Ying-Zhi,Yu, Fu-Xiang,Menzia, Gerald,Cook, James M.
, p. 517 - 547 (2007/10/02)
The synthesis of the tetracyclic ketone was carried out in enantiospecific fashion (>98percent ee) via the 1,3-transfer of chirality from Na-methyl, Nb-benzyl tryptophan methyl ester to the trans diastereomer in the Pictet-Spengler reaction.Although the condensation of 14 with aldehyde (15) in refluxing benzene generated the tetrahydro β-carbolines (4b/5b) in a kinetic ratio (72:28), epimerization (C-1) of the cis diastereomer into the trans isomer occurred stereospecifically under acidic conditions.Dieckmann cyclizatin of either the Na-methyl, Nb-benzyl-cis-(+)-5b or trans-(-)-4b diastereomer provided the cis-bicyclo-azanonane system at approximately the same rate, although the β-keto esters were antipodal, in contrast to results reported in the Na-benzyl series by Magnus.
PICTET-SPENGLER REACTIONS IN APROTIC MEDIA. STEREOSPECIFIC CONVERSION OF OPTICALLY ACTIVE CIS-1,3-DISUBSTITUTED 1,2,3,4-TETRAHYDRO-β-CARBOLINES INTO THEIR CORRESPONDING TRANS DIASTEREOMERS
Zhang, Lin-Hua,Cook, James M.
, p. 1357 - 1364 (2007/10/02)
The Pictet-Spengler reaction in refluxing benzene of D-(+)-Na-methyl-Nb-benzyltryptophan methyl ester 1 and methyl 3-formyl-propionate 2, regioselectively, furnished the trans-1,3-disubstituted-1,2,3,4-tetrahydro-β-carboline 3 (72percent) with no detectable racemization at position-3. The optically active cis-diastereomer 4 (28percent), which accompanied 3, was converted (CH3OH, HCl, heating) into the trans isomer 3 via the ring-cleaved carbocation intermediate 7, followed by stereospecific intramolecular cyclization.
PICTET-SPENGLER REACTIONS IN APROTIC MEDIA. Nb-BENZYL PROMOTED RETENTION OF OPTICAL ACTIVITY IN THE SYNTHESIS OF AN INDOLO SUBSTITUTED AZABICYCLONONANE, A KEY TEMPLATE FOR THE SYNTHESIS OF MACROLINE ALKALOIDS.
Zhang, Lin-hua,Cook, James M.
, p. 2795 - 2802 (2007/10/02)
The Nb-benzyl group (see 7) has been employed in the Pictet-Spengler reaction in refluxing benzene to provide complete retention of optical activity in this process.The tetrahydro-β-carbolines 3b (trans) and 4b (cis) were independently converte
Stereochemistry of Methyl 2-Benzyl-3-methoxycarbonyl-9-methyl-1,2,3,4-tetrahydro-9H-pyridoindole-1-propionate
Shimizu, Masato,Ishikawa, Masayuki,Komoda, Yasuo,Nakajima, Terumi,Yamaguchi, Keiichi,Yoneda, Naoto
, p. 463 - 474 (2007/10/02)
The Pictet-Spengler reaction of Na-methyl-Nb-benzyltryptophan methyl ester hydrochloride (4a) with methyl 3-formylpropionate was carried out in 50percent aqueous MeOH under reflux to afford methyl trans-2-benzyl-3-methoxycarbonyl-9-m
ASYMMETRIC SYNTHESIS OF (1S)-(-)-TRYPARGINE
Shimizu, Masato,Ishikawa, Masayuki,Komoda, Yasuo,Nakajima, Terumi,Yamaguchi, Keiichi,Sakai, Shin-ichiro
, p. 3453 - 3456 (2007/10/02)
(1S)-(-)-Trypargine 8(1a) was synthesized from (1S,3R)-(-)-2-benzyl-3-(methoxycarbonyl)-1,2,3,4-tetrahydro-9H-pyridoindole-1-propionic acid (3a), prepared by the asymmetric Pictet-Spengler reaction of Nb-benzyl-(D)-tryptophan methyl este
