4-Aminopyridine Catalyzed Direct and Regioselective Acylation of <i>N</i>-Tosylhydrazide

Namba, Kosuke; Shoji, Isamu; Nishizawa, Masatoyo; Tanino, Keiji

doi:10.1021/ol9021194

Cited by 22 publications

(11 citation statements)

References 20 publications

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“…Further protections of secondary alcohol and acylhydrazide proceeded smoothly to give 12 by treatment with tert -butyldimethylsilyl trifluoromethanesulfonate as a silylation reagent followed by di- tert -butyl dicarbonate in the presence of a catalytic amount of 4-dimethylaminopyridine. As we expected, Boc protection occurred on the nitrogen possessing the acyl group due to the acidity of NH protons and steric hindrance 49 . Treatment of 12 with triethylsilyl trifluoromethanesulfonate and 2,6-di- tert -butyl pyridine at −78 °C readily afforded silyl ketene aminal, and the crude product was treated with N -bromosuccinimide in a mixed solvent of tetrahydrofurane (THF) and methanol to give bromide 13 in an 82% two-step yield along with 7–14% of starting material 12 .…”

Section: Resultssupporting

confidence: 54%

Total synthesis of palau’amine

et al. 2015

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Palau'amine has received a great deal of attention in the past two decades as an attractive synthetic target by virtue of its intriguing molecular architecture and significant immunosuppressive activity. Here we report the total synthesis of palau'amine characterized by the construction of an ABDE tetracyclic ring core including a trans-bicylo[3.3.0]octane skeleton at a middle stage of total synthesis. The ABDE tetracyclic ring core is constructed by a cascade reaction of a cleavage of the N–N bond, including simultaneous formation of imine, the addition of amide anion to the resulting imine (D-ring formation) and the condensation of pyrrole with methyl ester (B-ring formation) in a single step. The synthetic palau'amine is confirmed to exhibit excellent immunosuppressive activity. The present synthetic route has the potential to help elucidate a pharmacophore as well as the mechanistic details of immunosuppressive activity.

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Section: Resultssupporting

confidence: 54%

Total synthesis of palau’amine

et al. 2015

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“…After the examination of various reaction conditions, we found that the regioselectivity of acylation of N tosylhydrazine depends on the presence of DMAP catalyst, i.e., N,N acyltosylhydrazines are the sole products in the presence of DMAP, whereas N acyl N tosylhydrazines are obtained without DMAP catalyst. 12 Although the origin of regioselectivity with DMAP catalyst is still unclear, investigations to elucidate the mechanism are currently underway in our laboratory. Next, the Hg(OTf) 2 catalyzed cyclization as a key reaction for construction of the E ring system was examined.…”

Section: Synthesis Of E Ringmentioning

confidence: 99%

Total Synthesis of Palau’amine

Namba

Takeuchi²,

Kaihara³

et al. 2017

J. Synth. Org. Chem. Jpn.

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Palau amine has received a great deal of attention in the past two decades as an attractive synthetic target by virtue of its intriguing molecular architecture and signi cant immunosuppressive activity. Here, we report the total synthesis of palau amine characterized by the Hg(OTf) 2 catalyzed construction of tetra substituted carbon center at the C16 position and the construction of an ABDE tetracyclic ring core including a trans bicylo[3.3.0]octane skeleton at a middle stage of total synthesis. The ABDE tetracyclic ring core is constructed by a cascade reaction of a cleavage of the N N bond, including simultaneous formation of imine, the addition of amide anion to the resulting imine (D ring formation), and the condensation of pyrrole with methyl ester (B ring formation) in a single step. The present synthetic route has the potential to help elucidate a pharmacophore as well as the mechanistic details of immunosuppressive activity.

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“…4-Dimethylaminopyridine (DMAP), a hypernucleophilic catalyst, was used to increase the acylation of TANI (with the aliphatic diacyl chlorides). 41 The use of protecting agents was not necessary as the targeted materials were obtained pure and in high yield, as evidenced by NMR, MALDI-TOF MS, FT-IR and elemental analysis. To obtain high quality resolved 1 H NMR spectra of the TANI-E n -TANI materials, phenyl hydrazine was used to reduce the materials to their LEB oxidation states.…”

Section: Synthesis and Characterisation Of Semiconducting Tani-e N -T...mentioning

confidence: 99%

Tuning structure and function in tetra(aniline)-based rod–coil–rod architectures

et al. 2013

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Here we report on our investigations into the aggregation behaviour and optoelectronic properties of organic (semi)conductor-containing p-conjugated rod-coil-rod triblock materials. The facile synthesis of these rod-like tetra(aniline) (TANI) containing materials was achieved by a one-step condensation reaction of mono-functional phenyl/NH 2 end-capped TANI and di-functional aliphatic diacyl chloride substrates. Simple variation of the n-alkyl spacer chain length impacted on the intermolecular amidemediated H-bonding interactions and allowed fine-tuning of dc-conductivity values over two orders of magnitude for thin films of plasticized and CSA-doped supported thin films. Initial investigations into the production of anisotropic functional structures yielded micrometer-sized spherical (vesicular or solid spheres) isotropic functional structures. This approach is identified as an area for further exploration.

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4-Aminopyridine Catalyzed Direct and Regioselective Acylation of N-Tosylhydrazide

Cited by 22 publications

References 20 publications

Total synthesis of palau’amine

Total synthesis of palau’amine

Total Synthesis of Palau’amine

Tuning structure and function in tetra(aniline)-based rod–coil–rod architectures

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