[2.2]Metacyclophanes having hydroxy groups on the bridge

Sahade, Daniel A.; Mataka, Shuntarō; Sawada, Tsuyoshi; Tsukinoki, Takehito; Tashiro, Masashi

doi:10.1016/s0040-4039(97)00743-0

Cited by 18 publications

(3 citation statements)

References 5 publications

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“…On the other hand, we have been investigating for some time the reduction of some functions in water as a hydrogen source. For examples, we have previously reported the reduction and reductive coupling of imines ( , ) or carbonyl compounds ( − ) and the dehalogenation of aromatic halides ( − ) using metals in an aqueous solution. Moreover, we also found that the reaction of 4-chlorobiphenyl 1 with Raney Ni−Al alloy, in a diluted aqueous alkaline solution at 90 °C was very effective for the dehalogenation process, yielding biphenyl 2 (in 10% aqueous NaOH solution) or cyclohexylbenzene 3 (in 0.5% aqueous KOH solution), respectively () (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Dehalogenation of Aromatic Halides Using Metallic Calcium in Ethanol

Mitoma

Nagashima

Simion

et al. 2001

Environ. Sci. Technol.

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The scope and limitations of the dehalogenation of aromatic halides 1 and 4a-p using metallic calcium in ethanol at room temperature were revealed. The cleavage of the carbon-chlorine bond on the aromatic ring bearing electron-donating group was difficult compared to the one bearing electron-withdrawing group. Moreover, we applied this method to the dechlorination of polychlorinated biphenyls (PCBs) in transformer oil. It was also found that the dechlorination took place easily under mild conditions. The existence of PCBs residue in the reaction at room temperature was less than 0.04% according to the GC-MS analysis. The chlorine was identified as calcium chloride.

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Section: Introductionmentioning

confidence: 99%

Dehalogenation of Aromatic Halides Using Metallic Calcium in Ethanol

Mitoma

Nagashima

Simion

et al. 2001

Environ. Sci. Technol.

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“…In 2008, we have reported new synthetic method of DHP (Scheme 2) [17]. Tetrahydroxy-[2.2]MCP 12 was prepared from benzene-dialdehyde derivative 11 in one step [21,22]. The MCP 12 has the potential to be the intermediate of DHPs, because the MCP 6 has two trans-diols at its both bridge positions and their reduction could give a MCPD, which is an equivalent of DHP 9.…”

Section: Preparation Of Parent Dhpmentioning

confidence: 99%

Chirality and Circular Polarized Properties of Photochromic Polyaromatic Molecules

Sawada¹,

Kubo²,

Nanamura³

2019

Chirality From Molecular Electronic States

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Dihydropyrenes (DHPs) are a particularly interesting class of photochromic polyaromatic molecules due to their negative photochromism in UV-Vis spectra. Asymmetric heterocyclic-[e]-annelated DHPs were prepared by new synthetic routes and their photochromism was studied. The optical resolution of heterocyclic-[e]-annelated DHPs was performed by chiral HPLC systems and their enantiomers indicate the photochromism for UV-Vis, and CD spectra. The absolute structures of the enantiomers were determined by using spectra predicted with time-dependent density functional theory. Photoswitchable circular dichroism properties of asymmetric heterocyclic-[e]-annelated DHPs have potential as the molecular device to control the circular polarized light.

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“…2 However, the coupling reactions of aromatic dicarbonyl compounds have been limited, until now, to the synthesis of macrocyclic compounds such as porphyrin derivatives 3 and cyclophane compounds. 4 There are also some reports concerning the polymerization of benzene-1,4-dicarbaldehyde to poly-(1,4-phenylene ethane-1,2-diol) by using Mukaiyama's reagent. 5 When aromatic dialdehydes 1a ^d are treated with aluminium powder and an aqueous alkaline solution in methanol, 1,2-bis(formyl-substituted aryl)ethane-1,2-diols 2a ^d are formed as the main products in which only one carbonyl group of 1 is reduced, the other remaining unreacted.…”

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confidence: 99%