Convenient Methods for the Preparation of <i>p</i>-Dialkylaminophenylacetylenes

Akiyama, Shuzo; Nakatsuji, Shin’ichi; Yoshida, Keiko; Nakashima, Kenichiro; Hagiwara, Toshimitsu; Tsuruta, Haruki; Yoshida, Toshio

doi:10.1246/bcsj.56.361

Cited by 23 publications

(13 citation statements)

References 3 publications

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“…4-Ethynyl- N , N -diethylaniline has been reported previously, but was prepared in the present work by an alternative route, as follows. 4-Iodo- N , N -diethylaniline (3.73 g, 13.5 mmol), PdCl 2 (PPh 3 ) 2 (95.2 mg, 0.136 mmol), CuI (27.6 mg, 0.145 mmol), and trimethylsilylacetylene (1.95 mL, 1.36 g, 13.8 mmol) were stirred in NEt 3 (40 mL) at room temperature for 17 h. The solvent was removed under reduced pressure and the residue washed through a silica plug with petrol; the solvent was removed from the resulting orange solution to give an orange oil (3.29 g, 98%) identified as 4-trimethylsilylethynyl- N , N -diethylaniline.…”

Section: Methodsmentioning

confidence: 99%

Convergent Synthesis of Alkynylbis(bidentate phosphine)ruthenium Dendrimers

et al. 2003

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The “first-generation” alkynylruthenium dendrimers 1,3,5-C6H3(4-C⋮CC6H4C⋮C-trans-[Ru(dppe)2]C⋮C-3,5-C6H3{4-C⋮CC6H4C⋮C-trans-[Ru(4-C⋮CC6H4R)(dppe)2]}2)3 [R = H (19), NO2 (20)], containing nine dialkynylruthenium centers, have been prepared by convergent synthesis. Reaction of 3 equiv of 1-iodo-4-trimethylsilylethynylbenzene with triethynylbenzene, under Sonogashira coupling conditions, followed by deprotection with tetra-n-butylammonium fluoride affords 1,3,5-C6H3(4-C⋮CC6H4C⋮CH)3 (2), which is reacted with cis-[RuCl2(L)2] (L = dppe, dppm) to afford the octopolar, triruthenium dendritic cores 1,3,5-C6H3{4-C⋮CC6H4C⋮C-trans-[RuCl(L)2]}3 [L = dppe (5), L = dppm (6)] via the vinylidene intermediates [1,3,5-C6H3{4-C⋮CC6H4CHC-trans-[RuCl(L)2]}3](PF6)3 [L = dppe (3), L = dppm (4)]. Reaction of 5 with terminal alkynes 4-HC⋮CC6H4R (R = H, NO2, NEt2) affords a series of related dialkynylruthenium zero-generation dendrimers 1,3,5-C6H3{4-C⋮CC6H4C⋮C-trans-[Ru(4-C⋮CC6H4R)(dppe)2]}3 [R = H (7), NO2 (8), NEt2 (9)]. Reaction of 3 equiv of trans-[Ru(4-C⋮CC6H4C⋮CH)(C⋮CPh)(dppe)2] with 1,3,5-triiodobenzene under Sonogashira coupling conditions also affords 7, together with the homo-coupled trans,trans-[(dppe)2(PhC⋮C)Ru(4,4‘-C⋮CC6H4C⋮CC⋮CC6H4C⋮C)Ru(C⋮CPh)(dppe)2]. The first-generation dendrimers 19 and 20 are prepared by coupling core 5 with the dendrons 1-(HC⋮C)C6H3-3,5-{4-C⋮CC6H4C⋮C-trans-[Ru(4-C⋮CC6H4R)(dppe)2]}2 [R = H (17), NO2 (18)]. Thus, reaction of 1-(Me3SiC⋮C)C6H3-3,5-(4-C⋮CC6H4C⋮CH)2 (12), obtained from 1-iodo-3,5-dibromobenzene through a series of Sonogashira coupling and transhalogenation reactions, with cis-[RuCl2(dppe)2] affords 1-(Me3SiC⋮C)C6H3-3,5-{4-C⋮CC6H4C⋮C-trans-[RuCl(dppe)2]}2 (13), which can be reacted with appropriately functionalized terminal alkynes to afford the series 1-(Me3SiC⋮C)C6H3-3,5-{4-C⋮CC6H4C⋮C-trans-[Ru(4-C⋮CC6H4R)(dppe)2]}2 [R = H (14), NO2 (15), NEt2 (16)]. Desilylation of 16 proceeds with decomposition; in contrast, treatment of 14 and 15 with tetra-n-butylammonium fluoride gives 17 and 18, which are coupled with 5 under basic conditions to afford the dendritic complexes 19 and 20 via in situ deprotonation of the vinylidene complex intermediates. A transmission electron micrograph of 19 supported on alumina reveals molecules that are approximately 6 nm in diameter, in agreement with molecular modeling studies.

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Section: Methodsmentioning

confidence: 99%

Convergent Synthesis of Alkynylbis(bidentate phosphine)ruthenium Dendrimers

et al. 2003

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“…( Z ) - β -Bromo-4-( N , N -dimethylamino)styrene (2f): eluted with 5% EtOAc in hexane on alumina; pale yellow crystals; mp 49−50 °C (hexane); R f = 0.36 (10% EtOAc in hexane); 1 H NMR (300 MHz, CDCl 3 ) δ 2.98 (6H, s), 6.16 (1H, d, J = 8.0 Hz), 6.70 (2H, d, J = 9.1 Hz), 6.93 (1H, d, J = 8.0 Hz), 7.65 (2H, d, J = 9.1 Hz).…”

Section: Methodsmentioning

confidence: 99%

Stereoselective Hydrogenolysis of 1,1-Dibromo-1-alkenes and Stereospecific Synthesis of Conjugated (Z)-Alkenyl Compounds

et al. 1998

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The Pd-catalyzed hydrogenolysis of 1,1-dibromoalkenes with Bu3SnH occurs at room temperature stereoselectively to give (Z)-1-bromo-1-alkenes. We sought to determine the optimal reaction conditions and illustrate the scope of this method with 32 dibromoalkenes including alkenyl- and alkynyl-conjugated 1,1-dibromo-1-alkenes 7a−h and 2,2-disubstituted 1,1-dibromo-1-alkenes 9a−f. Triphenylphosphine was the best ligand for the Pd-catalyzed hydrogenolysis. A wide range of solvents can be used for this reaction excluding EtOH, AcOH, and CHCl3. However, the reaction proceeds even in these solvents with the addition of a cosolvent or radical scavenger. The reaction of 1,1-diiodo-1-alkene (3) gave a mixture of (Z)-1-iodo-1-alkene (4), (Z)-1-tributylstannyl-1-alkene (5), and a terminal alkene 6, while that of 1,1-dichloroalkene did not occur. This selectivity can be explained by the stereoselective insertion of Pd(0) to a trans bromine−alkenyl carbon bond, successive transmetalation with Bu3SnH, and reductive elimination. The Suzuki and Sonogashira couplings of the resulting (Z)-1-bromo-1-alkenes with alkenyl(dialkoxy)borane and terminal alkyne occurred to give conjugated polyenes and enynes stereospecifically. The Pd-catalyzed hydrogenolysis of 1,1-dibromo-1-alkene and successive cross-coupling can be carried out either in a stepwise manner or in one-pot under the same Pd catalysis. These two processes should be useful for the synthesis of geometrically pure polyene and enyne with a Z-alkenyl unit.

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“…DACET was synthesised following a procedure described in the literature [15]. 1H-NMR (CDC13): 6 = 2.98 (s, 7H, 2 × CH 3 + CH), 6.63 (d, 2H, J = 8 Hz, arom.…”

Section: Methodsmentioning

confidence: 99%

Absence of dual fluorescence with 4-(dimethylamino) phenylacetylene. A comparison between experimental results and theoretical predictions

Zachariasse

Grobys

Tauer

1997

Chemical Physics Letters

114

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From ab initio electronic structure calculations it has been predicted that 4-(dimethylamino)phenylacetylene (DACET) will undergo an exothermic intramolecular charge transfer (ICT) reaction with dual fluorescence even under isolated-molecule conditions. Photostationary and time-resolved fluorescence measurements reveal however that an ICT reaction does not occur with DACET under any condition of solvent polarity or temperature studied. DACET is similar to 4-(methyl)aminobenzonitrile, which shows only fluorescence from a locally excited state, but is clearly different from the dual fluorescent 4-(dimethyl)aminobenzonitrile (DMABN). The energy gap A E(S 1,$2) of DACET is larger than that of DMABN, supporting the importance of this gap in these ICT reactions.

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Convenient Methods for the Preparation of p-Dialkylaminophenylacetylenes

Cited by 23 publications

References 3 publications

Convergent Synthesis of Alkynylbis(bidentate phosphine)ruthenium Dendrimers

Convergent Synthesis of Alkynylbis(bidentate phosphine)ruthenium Dendrimers

Stereoselective Hydrogenolysis of 1,1-Dibromo-1-alkenes and Stereospecific Synthesis of Conjugated (Z)-Alkenyl Compounds

Absence of dual fluorescence with 4-(dimethylamino) phenylacetylene. A comparison between experimental results and theoretical predictions

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