6519-27-3Relevant academic research and scientific papers
A three enzyme system to generate the Strychnos alkaloid scaffold from a central biosynthetic intermediate
Tatsis, Evangelos C.,Carqueijeiro, Inês,Dugé De Bernonville, Thomas,Franke, Jakob,Dang, Thu-Thuy T.,Oudin, Audrey,Lanoue, Arnaud,Lafontaine, Florent,Stavrinides, Anna K.,Clastre, Marc,Courdavault, Vincent,O'Connor, Sarah E.
, (2017/08/29)
Monoterpene indole alkaloids comprise a diverse family of over 2000 plant-produced natural products. This pathway provides an outstanding example of how nature creates chemical diversity from a single precursor, in this case from the intermediate strictosidine. The enzymes that elicit these seemingly disparate products from strictosidine have hitherto been elusive. Here we show that the concerted action of two enzymes commonly involved in natural product metabolism - A n alcohol dehydrogenase and a cytochrome P450 - produces unexpected rearrangements in strictosidine when assayed simultaneously. The tetrahydro-β-carboline of strictosidine aglycone is converted into akuammicine, a Strychnos alkaloid, an elusive biosynthetic transformation that has been investigated for decades. Importantly, akuammicine arises from deformylation of preakuammicine, which is the central biosynthetic precursor for the anti-cancer agents vinblastine and vincristine, as well as other biologically active compounds. This discovery of how these enzymes can function in combination opens a gateway into a rich family of natural products.
Total Syntheses of Naucleamides A-C and E, Geissoschizine, Geissoschizol, (E)-Isositsirikine, and 16-epi-(E)-Isositsirikine
Li, Lei,Aibibula, Paruke,Jia, Qianlan,Jia, Yanxing
, p. 2642 - 2645 (2017/05/24)
A divergent approach for the enantioselective total synthesis of eight monoterpenoid indole alkaloids was developed. The approach allows the first total syntheses of naucleamides A-C and E in only 6-8 steps and also enables the efficient synthesis of geissoschizine, geissoschizol, (E)-isositsirikine, and 16-epi-(E)-isositsirikine in 10-11 steps from commercially available crotonic aldehyde. The synthesis features a one-pot organocatalyzed asymmetric Michael addition/Pictet-Spengler reaction. Notably, biomimetic synthesis of naucleamide E was achieved by oxidative cyclization of naucleamide A.
ALKALOIDS FROM RHAZYA STRICTA
Atta-Ur-Rahman,Zaman, Khurshid,Perveen, Shahnaz,Habib-Ur-Rehman,Muzaffar, Anjum,et al.
, p. 1285 - 1294 (2007/10/02)
Chemical investigations of roots and leaves of Rhazya stricta have resulted in the isolation of the new indole alkaloids, 16R-19,20-E-isositsirikine acetate, leepacine and dihydroeburnamenine, along with six known alkaloids.Among these, (-)-16R,21R-O-methyleburnamine, 2-ethyl-3-indole, (20S)-19,20-dihydrocondylocarpine and N-acetylaspidospermidine have been isolated for the first time from R. stricta.Spectral studies on (+)-21S-eburnamenine and the glycoalkaloid strictosamide have also been undertaken. --- Key Word Index: Rhazya stricta; Apocynaceae; indole alkaloide; glycoalkaloids; 13C NMR.
Total syntheses of (+)-geissoschizine, (±)-geissoschizine, and (±)-(Z)-isositsirikine. Stereocontrolled synthesis of exocyclic double bonds by stereospecific iminium ion-vinylsilane cyclizations
Overman,Robichaud
, p. 300 - 308 (2007/10/02)
(+)-Geissoschizine (1) was prepared in an efficient and stereocontrolled fashion in 11 steps and 7.5% overall yield from (S)-tryptophanamide (20). Key steps are the stereoselective 1,4-addition of cuprate 13a to tetracyclic intermediate 8, which establish
Preparation and H(3) Isomerization of C(15)-Substituted Deplancheine Derivatives. Synthesis of Geissoschizol and Geissoschizine
Wenkert, Ernest,Guo, Ming,Pestchanker, Mauricio J.,Shi, Yao-Jun,Vankar, Yashwant D.
, p. 1166 - 1174 (2007/10/02)
A series of indoloquinolizidines have been prepared by the two-step scheme of nucleophile addition to 1-tryptophyl-3-acylpyridinium salts or their vinylogues and subsequent, acid-catalyzed cyclization.Acid-induced hydrolysis, decarboxylation, and reduction of the resultant vinylogous urethanes has opened an approach to antirhine and yielded C(15)-substituted deplancheine derivatives.Functional group manipulation of the latter has permitted the syntheses of geissoschizol and geissoschizine.
Trapping of Intermediates in the Interconversion of Heteroyohimbine Alkaloids
Kan, Christiane,Kan, Siew-Kwong,Lounasmaa, Mauri,Husson, Henri-Philippe
, p. 269 - 272 (2007/10/02)
The isolation of (Z)-isositsirikines 8 and 9 in the course of NaBH4 reduction of 19-epicathenamine 2 demonstrates the intermediacy of the (Z)-conjugated iminium salt 5 in the interconversion of the heteroyohimbine alkaloids.A 400 MHz 1H NMR study carried out on compounds 1, 2, and 6-9 permitted the determination of all the chemical shifts and most of the coupling constants.
