Quinamine

Palladium-catalyzed intramolecular transfer hydrogenation & cycloaddition of p-quinamine-tethered alkylidenecyclopropanes to synthesize perhydroindole scaffolds.[Pubmed:30474659]

Chem Commun (Camb). 2018 Dec 13;54(100):14085-14088.

A palladium(0)-catalyzed intramolecular transfer hydrogenation and cycloaddition of p-Quinamine-tethered alkylidenecyclopropanes (ACPs) to synthesize perhydroindole scaffolds has been reported in this communication. Mechanistic investigations on the basis of deuterium labeling experiments suggest that the reaction proceeded through an oxidative addition of Pd(0) into the distal bond of the ACP moiety to afford a trimethylenemethane (TMM)-Pd intermediate followed by transfer hydrogenation using alcohol.

(3 + 2)-Annulation of p-Quinamine and Aryne: A Strategy To Construct the Multisubstituted Hydrocarbazoles.[Pubmed:28657328]

Org Lett. 2017 Jul 7;19(13):3600-3603.

A strategy for the synthesis of multisubstituted hydrocarbazoles has been developed through (3 + 2)-annulation of p-Quinamines and arynes. In this way, new analogs of hydrocarbazoles with quaternary carbon center can be synthesized in satisfactory yield under mild conditions. Furthermore, this (3 + 2)-annulation can be easily scaled-up, and the products can be modified through simple transformation.

Synthesis of 4-aminotropones from [(sulfinyl or sulfonyl)methyl]-substituted p-quinamines.[Pubmed:17918757]

Chemistry. 2008;14(2):621-36.

An efficient synthesis of 4-aminotropones has been achieved in excellent yields by simple treatment of 4-amino-4-[(p-tolylsulfinyl)methyl]-2,5-cyclohexadienones (p-Quinamines) with NaH. The method allowed regiocontrolled access to 3-methyl, 5-methyl- and 3,5-dimethyl-substituted derivatives starting from p-Quinamines with adequate substituents at the cyclohexadienone moiety and/or at the carbon linked to the sulfur function. The p-Quinamines in turn were easily accessible from N-Boc p-anisidines (Boc=tert-butoxycarbonyl) by electrochemical oxidation in MeOH to quinone imine monoketals, followed by addition of a alpha-lithium sulfinyl carbanion to the imino group, and ketal hydrolysis. Oxidation of the sulfoxide gave the sulfonyl-substituted p-Quinamines that, upon basic treatment, behave similarly. The p-Quinamine 55 and bis-p-Quinamine 56, resulting in the addition of the anion derived from dimethyl sulfone to the p-quinonimine ketal 14, also gave the 4-aminotropone. The mechanism involves the initial formation of a alpha-sulfonyl carbanion, which intramolecularly attacks the cyclohexadienone giving a norcaradiene-like enolate intermediate, the evolution of which through a ring-expansion process, pushes off a methyl sulfinate anion or SO2. This efficient process fulfils the criteria of atom economy. The introduction of a proline substituent in the nitrogen of the starting p-Quinamine allowed the synthesis of an enantiopure 4-aminotropone, the asymmetric Diels-Alder reactions of which with maleimide occurred in a highly endo and pi-facial diastereoselective manner.

Ring expansion of sulfur substituted p-quinamines: regiospecific synthesis of 4-aminotropones.[Pubmed:15719098]

Chem Commun (Camb). 2005 Feb 28;(8):1007-9.

Synthesis of 4-aminotropones through a cyclization-ring expansion process occurs in a single step and with excellent yields from 4-amino-2,5-cyclohexadienones (p-Quinamines) bearing a 4-sulfinyl or sulfonyl methyl group.

Five new alkaloids from the leaves of Remijia peruviana.[Pubmed:15497937]

J Nat Prod. 2004 Oct;67(10):1667-71.

Three new indolylquinuclidine-type alkaloids, remijinine (1), epiremijinine (2), and 5-acetyl-apocinchonamine (3), and two new cinchonine-derived alkaloids, N-acetyl-deoxycinchonicinol (4) and N-acetyl-cinchonicinol (5), as well as the known alkaloids Quinamine, conQuinamine, cinchonine, and quinidine were isolated from the leaves of Remijia peruviana. The structures of the new alkaloids were elucidated on the basis of spectroscopic analysis, including homonuclear and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC, and HMBC). The relative configuration at C-7 for remijinine (1) and, in consequence, for epiremijinine (2) was established by X-ray crystal structure analysis of the former.

Alkaloid Production by Transformed Root Cultures of Cinchona ledgeriana.[Pubmed:17262435]

Planta Med. 1989 Aug;55(4):354-7.

Transformed root cultures of CINCHONA LEDGERIANA have been generated by infecting shoots cultured IN VITRO with AGROBACTERIUM RHIZOGENES LBA9402. These root cultures grow axenically in the absence of antibiotics or exogenous plant growth regulators in media containing Gamborg B5 salts at half or full strength with 3% (w/v) sucrose as the carbon source. They show a 6- to 8-fold increase in fresh weight in 28 days. Transformation has been confirmed by Southern blotting using [ (32)P]-labelled fragments from both the T (L)- and T (R)-DNA of the Ri plasmid. The cultures are shown to synthesise a range of quinoline alkaloids, of which quinine, cinchonidine, and quinidine are the major components. The level of these alkaloids changes with the age of the cultures, reaching a maximum at about 50 microg/g fresh weight after 45 days. In addition, the roots contain Quinamine and a number of other, unidentified, indole alkaloids, one of which is the major alkaloid present. Only about 1% of the total alkaloid present is released to the medium.