A Convenient Synthesis of Simple Tetrahydroisoquinolines

Ruchirawat, Somsak; Chaisupakitsin, Malinee; PATRANUWATANA, N.; Cashaw, Jesse L.; Davis, Virginia E.

doi:10.1080/00397918408076803

Cited by 28 publications

(14 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, the 6,7-dihydroxy-2-methylisoquinolinium chloride surface ligand (Figure 1a) was synthesized from homoveratrylamine (1), which was converted with formaldehyde in a combined Pictet−Spengler/Eschweiler−Clarke reaction to 6,7dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline (2) (Figure 1b). 66 After oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) to 6,7-dimethoxy-2-methylisoquinolinium chloride (3), DHMIQ was obtained by acidic cleavage of the methyl ethers. In the second step, TiO 2 NPs were prepared hydrothermally from titanium(IV) butoxide with oleic acid and oleylamine in ethanol, 67 yielding NPs of spherical to elongated shape and a typical size on the order of 10 nm (Figure S1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…First, the 6,7-dihydroxy-2-methylisoquinolinium chloride surface ligand (Figure a) was synthesized from homoveratrylamine ( 1 ), which was converted with formaldehyde in a combined Pictet–Spengler/Eschweiler–Clarke reaction to 6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline ( 2 ) (Figure b) . After oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) to 6,7-dimethoxy-2-methylisoquinolinium chloride ( 3 ), DHMIQ was obtained by acidic cleavage of the methyl ethers.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The spectral data match those reported in the literature. 66,94 Synthesis of 6,7-Dimethoxy-2-methylisoquinolinium Chloride (3). 6,7-Dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline (1.00 g, 4.83 mmol, 1.0 equiv) was dissolved in acetonitrile (80 mL), and DDQ was added (2.19 g, 9.65 mmol, 2.0 equiv).…”

Section: ■ Conclusionmentioning

confidence: 99%

See 2 more Smart Citations

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

et al. 2018

View full text Add to dashboard Cite

Photosynthesis is an efficient mechanism for converting solar light energy into chemical energy. We report on a strategy for the aerobic photocyanation of tertiary amines with visible and near-infrared (NIR) light. Panchromatic sensitization was achieved by functionalizing TiO 2 with a 2methylisoquinolinium chromophore, which captures essential features of the extended π-system of 2,7-diazapyrenium (DAP 2+ ) dications or graphitic carbon nitride. Two phenolic hydroxy groups make this ligand highly redoxactive and allow for efficient surface binding and enhanced electron transfer to the TiO 2 surface. Non-innocent ligands have energetically accessible levels that allow redox reactions to change their charge state. Thus, the conduction band is sufficiently high to allow photochemical reduction of molecular oxygen, even with NIR light. The catalytic performance (up to 90% chemical yield for NIR excitation) of this panchromatic photocatalyst is superior to that of all photocatalysts known thus far, enabling oxidative cyanation reactions to the corresponding α-cyanated amines to proceed with high efficiency. The discovery that the surface-binding of redox-active ligands exhibits enhanced light-harvesting in the red and NIR region opens up the way to improve the overall yields in heterogeneous photocatalytic reactions. Thus, this class of functionalized semiconductors provides the basis for the design of new photocatalysts containing non-innocent donor ligands. This should increase the molar extinction coefficient, permitting a reduction of nanoparticle catalyst concentration and an increase of the chemical yields in photocatalytic reactions.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

et al. 2018

View full text Add to dashboard Cite

show abstract

“…quantitative yield and with 98 % ee. After reduction of the nitro moiety (with NaBH 4 /NiCl 2 ·6H 2 O [15] ) and cyclization, [16] the key intermediate 7 was obtained in 73 % yield and > 99 % ee. After treating 7 with hydrochloride in ethanol, optically pure (R)-cherylline was obtained in excellent yield (70 % overall yield).…”

mentioning

confidence: 99%

Rhodium‐Catalyzed Highly Enantioselective Addition of Arylboronic Acids to 2‐Nitrostyrenes by tert‐Butanesulfinylphosphine Ligand

Lang

Chen

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

Chiral 2,2-bisarylethylamines constitute a broad class of framework in biologically important targets. [1] Typical examples include potential protein kinase B (PKB) inhibitor 1, [1a] dihydrexidine 2 [1b] (a full dopamine D1 receptor agonist), and cherylline 3 [1d] (an alkaloid isolated from amaryllidaceae plants, which exhibits central nervous activity). The most direct and attractive method to obtain chiral 2,2-bisarylethylamines utilizes the asymmetric 1,4-addition of aryl reagents to 2-nitrostyrenes as the key step, followed by a simple reduction. Although the organocatalytic 1,4-type Friedel-Crafts reaction demonstrated good enantioselectivities for this transformation, specific substrates are required. [2] Among asymmetric transition-metal-catalyzed reactions, the Rh-catalyzed 1,4-addition of arylboronic acids to electron-deficient olefins is one of the most important tools for asymmetric C À C bond formation. [3][4] In 2000, Hayashi reported the first example of a Rh-BINAP-complexcatalyzed asymmetric addition of arylboronic acids to aliphatic nitroalkenes and impressive results were achieved. [5] However, the addition of arylboronic reagents to arylnitroalkenes is a challenge in the field of asymmetric catalysis and development of effective catalysts for this transformation is desirable. [3b, 6] Very recently, significant progress was achieved by Lin and co-workers, who utilized a C 2 -symmetric chiral diene as a ligand and potassium trifluoroborates, as organoboron reagents (generated in situ), to achieve good to excellent enantioselectivies. [7] In this context, we report a highly efficient transformation in the Rh/sulfoxide-phosphine-catalyzed enantioselective addition of arylboronic acids to 2-nitrostyrenes under mild conditions with excellent enantioselectivity. Based on this transformation, the first asymmetric synthesis of cherylline was reported. [8] Recent studies in our laboratory have focused on transition-metal-catalyzed asymmetric reactions by using our concise chiral sulfoxide-phosphine ligands L1-L4 [9] and bis-sulfoxide ligands L5, [10] which utilize the tert-butylsulfinyl moiety as a ligating entity and a chiral source. [11] These ligands showed excellent results in the Rh-catalyzed 1,4-addition of arylboronic acids to enones. We expect that these chiral sulfoxide ligands could also generate exciting results in the addition of arylboronic acids to 2-nitrostyrenes.We initially conducted the model reaction of p-CH 3 O-nitrostyrene 4 a with PhB(OH) 2 5 m in the presence of Rh/ sulfoxide-phosphines L1-L4, or Rh/bis-sulfoxide L5 (4 mol %) and aqueous KOH in dichloromethane at 40 8C.To our delight, with the exception of L1, ligands L2-L4 can promote the reaction to generate the desired product 6 am with moderate yields (75-78 %) and good enantioselectivities within 5 h (79-84 % enantiomeric excess (ee)), Table 1, entries 1-4). Unfortunately, the C 2 -symmetric chiral bis-sulfoxide L5 did not work well in this reaction, although it is an excellent ligand in the addition of arylboronic rea...

show abstract

“…Cactaceae: Is laya minor (5) Fumariaceae: Corydalis aurea (29) Corydalis ophiocarpa (34) Corydalis pallida (29,30) Corydalis stricta (27) Monimiaceae: Doryphora sassafras (31) Papaveraceae: Papaver bracteatum (23) Ranunculaceae: Thalictrum dasycarpum (32) Thalictrum rugosum (35) Synthetic (22,23,26,28,29,33) 12. N-METHYLCORYPALLINE (IODIDE) C12H18N02I 335,0378 IR: (KBr) 3370, 1620, 1610, 1530 (27) lH NMR: 100 MHz (CF3COOH) (27) MS: 207, 206, 177, 164, 150, 142, 127 (27) Source: (17) (HC1) 248°( Et0H/Et20) (36,6) 243° (37) 254-256°(EtOH) (38, 39) 253°(EtOH/H20) (11, 17) UV: (HC1) (H20) 203 IR: (HC1) (KBr) 2900, 2750, 1610, 1510, 1245, 1210, 1100, 1000, 840, 790(6) *H NMR: (HC1) 80 MHz (D20 (6) CDC13 (39) 13C NMR: (14,40) MS: (HC1) 193 (90), 192 (57), 178 (9), 165 (17), 164 (100), 149(14), 121 (16) (6) Sources:…”

mentioning

confidence: 99%

Simple Isoquinoline Alkaloids

Menachery¹,

Lavanier²,

Wetherly³

et al. 1986

J. Nat. Prod.

View full text Add to dashboard Cite

A Convenient Synthesis of Simple Tetrahydroisoquinolines

Cited by 28 publications

References 9 publications

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

Rhodium‐Catalyzed Highly Enantioselective Addition of Arylboronic Acids to 2‐Nitrostyrenes by tert‐Butanesulfinylphosphine Ligand

Simple Isoquinoline Alkaloids

Contact Info

Product

Resources

About

A Convenient Synthesis of Simple Tetrahydroisoquinolines

Cited by 28 publications

References 9 publications

TiO2 Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

TiO2 Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

Rhodium‐Catalyzed Highly Enantioselective Addition of Arylboronic Acids to 2‐Nitrostyrenes by tert‐Butanesulfinylphosphine Ligand

Simple Isoquinoline Alkaloids

Contact Info

Product

Resources

About

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons

TiO₂ Nanoparticles Functionalized with Non-innocent Ligands Allow Oxidative Photocyanation of Amines with Visible/Near-Infrared Photons