10225-29-3Relevant academic research and scientific papers
Reactions of alkyl, benzyl and stannyl halides with Lewis acid complexed α-lithiated tertiary amines
Kessar,Singh,Singh,Singh
, p. 517 - 518 (2001)
α-amino stannanes can be obtained readily from tertiary amines through BF3 promoted deprotonation; in situ CsF treatment of BF3 complexed stannanes followed by lithium-transmetalation can be used to procure those α-alkylation product
Phosphazene base-catalyzed hydroamination of aminoalkenes for the construction of isoindoline scaffolds: Application to the total synthesis of aristocularine
Matsuoka, Junpei,Terashita, Maki,Miyawaki, Akari,Tomioka, Kiyoshi,Yamamoto, Yasutomo
supporting information, (2021/12/30)
A method for isoindoline synthesis via phosphazene base-catalyzed intramolecular hydroamination of aminoalkenes was developed. The reaction has a broad functional group tolerance, including for halide, cyano, and methoxy groups, and could also be used to
Alkaloid constituents from flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) with melanogenesis inhibitory activity in B16 melanoma cells
Nakamura, Seikou,Nakashima, Souichi,Tanabe, Genzo,Oda, Yoshimi,Yokota, Nami,Fujimoto, Katsuyoshi,Matsumoto, Takahiro,Sakuma, Rika,Ohta, Tomoe,Ogawa, Keiko,Nishida, Shino,Miki, Hisako,Matsuda, Hisashi,Muraoka, Osamu,Yoshikawa, Masayuki
, p. 779 - 787 (2013/02/25)
Methanolic extracts from the flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) were found to show inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. From the methanolic extracts, a new alkaloid, N-methylasimilobine N-oxide, was isolated together with eleven benzylisoquinoline alkaloids. The absolute stereostructure of the new alkaloid was determined from chemical and physicochemical evidence. Among the constituents isolated, nuciferine, N-methylasimilobine, (-)-lirinidine, and 2-hydroxy-1-methoxy-6a,7-dehydroaporphine showed potent inhibition of melanogenesis. Comparison of the inhibitory activities of synthetic related alkaloids facilitated characterization of the structure-activity relationships of aporphine- and benzylisoquinoline-type alkaloids. In addition, 3-30 μM nuciferine and N-methylasimilobine inhibited the expression of tyrosinase mRNA, 3-30 μM N-methylasimilobine inhibited the expression of TRP-1 mRNA, and 10-30 μM nuciferine inhibited the expression of TRP-2 mRNA.
Synthesis of 1-substituted tetrahydroisoquinolines by lithiation and electrophilic quenching guided by in situ IR and NMR spectroscopy and application to the synthesis of salsolidine, carnegine and laudanosine
Li, Xiabing,Leonori, Daniele,Sheikh, Nadeem S.,Coldham, Iain
supporting information, p. 7724 - 7730 (2013/07/19)
The lithiation of N-tert-butoxycarbonyl (N-Boc)-1,2,3,4- tetrahydroisoquinoline was optimized by in situ IR (ReactIR) spectroscopy. Optimum conditions were found by using n-butyllithium in THF at -50 °C for less than 5 min. The intermediate organolithium was quenched with electrophiles to give 1-substituted 1,2,3,4-tetrahydroisoquinolines. Monitoring the lithiation by IR or NMR spectroscopy showed that one rotamer reacts quickly and the barrier to rotation of the Boc group was determined by variable-temperature NMR spectroscopy and found to be about 60.8 kJ mol-1, equating to a half-life for rotation of approximately 30 s at -50 °C. The use of (-)-sparteine as a ligand led to low levels of enantioselectivity after electrophilic quenching and the "poor man's Hoffmann test" indicated that the organolithium was configurationally unstable. The chemistry was applied to N-Boc-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline and led to the efficient synthesis of the racemic alkaloids salsolidine, carnegine, norlaudanosine and laudanosine. Copyright
Alkali metal-mediated synthesis of 1- and 4-substituted N-alkyl-1,2,3,4-tetrahydroisoquinolines
Azzena, Ugo,Pisano, Luisa,Pittalis, Mario
, p. 401 - 409 (2007/10/03)
Reductive cleavage by electron transfer from Li or K metal of 1-alkoxy-substituted N-alkyltetrahydroisoquinolines led to the formation of organometallic derivatives. Quenching of these intermediates with electrophilic reagents afforded 1- or 4-substituted
A highly efficient synthesis of 1-methyl-, 1-benzyl-, and 1-phenyl-1,2,3,4-tetrahydroisoquinolines by a modified pummerer reaction
Shinohara, Tatsumi,Takeda, Akira,Toda, Jun,Terasawa, Noriyo,Sano, Takehiro
, p. 555 - 565 (2007/10/03)
(±)-1-Methyl- (13b), (±)-1-benzyl- (13c), and (±)-1-phenyl- (13d)-1,2,3,4-tetrahydroisoquinolines, which are supposed to participate in the pathogenesis of Parkinson's disease, were prepared by using a modified Pummerer reaction as a key step in excellent overall yields from the commercially available ketones (4b-c).
A practical triphenylcarbenium tetrafluoroborate mediated one-pot synthesis of 1-substituted N-alkyl-1,2,3,4-tetrahydroisoquinolines
De Costa,Radesca
, p. 887 - 890 (2007/10/02)
Treatment of 2-methyl-1,2,3,4-tetrahydroisoquinoline (1) with 1-2 molar equivalents of triphenylcarbenium tetrafluoroborate at 20°C in either chloroform or acetonitrile resulted in the formation of 2-methyl-3,4-dihydroisoquinolinium tetrafluoroborate (2), whereas triethylamine and N-methylpiperidine were unaffected under these reaction conditions. This hydride abstraction was exploited in a one-pot preparation of 1-functionalized 2-alkyl-1,2,3,4-tetrahydroisoquinolines. Thus, treatment of 2 with aqueous potassium hydroxide afforded 1-hydroxy-2-methyl-1,2,3,4-tetrahydroisoquinoline (9) (61% from 1). Similarly, potassium cyanide in acetonitrile provided 1-cyano-2-methyl-1,2,3,4-tetrahydroisoquinoline (10, 77%). Quenching of 2 with Grignard reagents in tetrahydrofuran afforded the corresponding 1-alkyl and 1-aryl substituted tetrahydroisoquinolines (31 to 78%). Interestingly, nitrile 10 reacted very rapidly (2 min at 0°C) with phenylmagnesium bromide to give 2-methyl-1-phenyl-1,2,3,4-tetrahydroisoquinoline (3, 100%), but failed to react with excess phenyllithium even at 20°C.
A New Method of α-Functionalization for Tertiary Amines by Nucleophilic Substitution of α-Siloxy Amines
Tokitoh, Norihiro,Okazaki, Renji
, p. 735 - 740 (2007/10/02)
α-Siloxy amines, which were easily prepared by "silicon Polonovski reaction" of tertiary amine N-oxides with trialkylsilyl trifluoromethanesulfonate, were treated with various nucleophiles to give the corresponding α-functionalized tertiary amines in moderate to good yields.This new method has to the advantage that it enables the α-substitution of amines not only by alkyl groups but also by alkenyl and aryl groups with sp2 carbon as a reaction center, since the introduction of such groups is difficult in electrophilic substitution of dipole-stabilized α-lithio amines.Besides the organometallics such as Grignard and organoaluminum reagents, trimethylsilyl cyanide and silyl enol ether could also be employed as nucleophiles in the presence of an appropriate Lewis acid.
