Zanthoxoaporphines A–C: Three new larvicidal dibenzo[de,g]quinolin-7-one alkaloids from Zanthoxylum paracanthum (Rutaceae)

• Fidelis N. Samita,
• Louis P. Sandjo,
• Isaiah O. Ndiege,
• Ahmed Hassanali and
• Wilber Lwande

Beilstein J. Org. Chem. 2013, 9, 447–452, doi:10.3762/bjoc.9.47

• and C-5 (δ 145.0), C-3a (δ 130.2) and C-3 (δ 139.5). Besides, long-range interactions were also observed between H-2 (δ 6.96) and carbon at δ 139.5 (C-3), 159.7 (C-1) and 123.1 (C-1a), which suggested the isoquinoline core. Further correlations were noted from H-11 (δ 8.18) to C-11a (δ 141.9), C-10 (δ

• 163.2) and C-9 (δ 114.8). Finally, the interaction between H-8 and C-7a in conjunction with the carbonyl signal revealed in the 13C NMR spectrum at δ 180.1, suggested a benzocyclohexenone scaffold. Combining the isoquinoline and the benzocyclohexenone skeletons led to the 7H-dibenzo[de,g]quinolone-7-one

• = 9.5 Hz) and 8.15 (H-3, J = 9.5 Hz) representing the methine groups of the isoquinoline part. The difference was found in the benzocyclohexenone part where an additional AB-pattern was observed at δ 7.52 (H-10, J = 8.6 Hz) and 7.07 (H-11, J = 8.6 Hz). The HMBC data (Figure 2) revealed interactions

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• synthesis of enantiomerically pure isoquinoline rings [34][37], but just a few examples of the enantioselective variant have been reported so far. Thus, as shown on Scheme 18, the cyclization of the aryllithium generated from 49a does not occur on the unsubstituted alkene, whereas the introduction of an

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• two terminal units of porphyrin–Zn noncovalently associated to a host molecule of bis-isoquinoline 13 (Figure 14). The exposure of azo derivative 13 to light of λ = 350 ± 10 nm leads to a mixture of isomers trans/cis 22:78. Irradiation of this mixture of isomers at λ > 420 nm returns the system to an

• that distances the porphyrin units, causing a mechanical spin rotation in the bis-isoquinoline molecule similar to a pedal. This device is effective if the porphyrin–Zn and bis-isoquinoline units remain associated during the photoisomerization, i.e., the dynamics of dissociation between these units is

• slower than the photoinduced movement itself. In this case, the dissociation constant is six orders of magnitude slower than the trans–cis photoisomerization, which ensures that the bis-isoquinoline unit is coordinated to azocompound 13 during the isomerization process of the azobenzene unit. Nanovehicle

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• -Methoxypyridine (7c) provided the desired product 3g in 78% isolated yield in only 6 h at room temperature (Table 2, entry 7). Isoquinoline (7d) and 4-acetylpyridine (7e) also underwent the reaction to provide the desired products in moderate yields (Table 2, entries 8–9), but required an elevated temperature (60

Multicomponent reaction access to complex quinolines via oxidation of the Povarov adducts

• Esther Vicente-García,
• Rosario Ramón,
• Sara Preciado and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2011, 7, 980–987, doi:10.3762/bjoc.7.110

• - and N-substituents [22][23][24][25] (for related isoquinoline oxidations, see [26][27]). Related oxidative processes involve, for instance, a cascade Povarov–hydrogen transfer reaction using Tf2NH as a catalyst and the imine as an oxidant, as recently described [28]. In addition, Povarov adducts

• , chemical manganese dioxide (CMD) has been widely used in this type of transformations, and already in 1982 the oxidation of tetrahydroisoquinoline (11, Scheme 2) was reported to yield the corresponding isoquinoline 12, the intermediate dihydroisoquinoline 13 being obtained as a by-product [26]. Later

Molecular rearrangements of superelectrophiles

• Douglas A. Klumpp

Beilstein J. Org. Chem. 2011, 7, 346–363, doi:10.3762/bjoc.7.45

• -polycyclic aromatic compounds has been developed utilizing charge migration [42][45]. For example, alcohol 155 reacts in superacid to give 5-methylbenzo[f]isoquinoline (158, Scheme 31) in good yield. This conversion involves formation of the 1,4-dication 156, which then undergoes charge migration to the 1,5

• -dication 157. Intramolecular cyclization and benzene elimination gives the benzo[f]isoquinoline system 158. Olah and coworkers have described a series of reactions involving glycols and related substrates in superacids [46]. These substrates are found to give protonated aldehydes and hydride shifts are

Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

• Tilman Lechel,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42

• route to isoquinoline derivatives. Experimental Deprotection of 3-alkoxypyridin-4-ols 1, typical procedures Cleavage of the benzyloxy group by hydrogenolysis A mixture of 1a (970 mg, 3.43 mmol) and palladium (365 mg, 10% on charcoal, 0.34 mmol) in methanol (6 mL) was stirred for one day under an

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Fused bicyclic piperidines and dihydropyridines by dearomatising cyclisation of the enolates of nicotinyl-substituted esters and ketones

• Heloise Brice,
• Jonathan Clayden and
• Stuart D. Hamilton

Beilstein J. Org. Chem. 2010, 6, No. 22, doi:10.3762/bjoc.6.22

• , especially when oxygen is excluded prior to and during the hydrogenation. Experimental 5-Benzoyl-5,6,7,8-tetrahydro-4aH-isoquinoline-2-carboxylic acid methyl ester (8) Methyl chloroformate (0.056 ml, 0.722 mmol) was added to a solution of 9 (45 mg, 0.144 mmol) and triethylamine (0.02 ml, 0.144 mmol) in