Chemical stability of a prostacyclin analog due to the absence of intramolecular catalysis

Bergman, N.-A.; Halvarsson, Torbjoern

doi:10.1021/jo00246a027

Cited by 13 publications

(4 citation statements)

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“…In the case of methyl 3-(chloromethyl)benzoate 15 , we report the first direct side-chain chlorination. Structure 15 is an important building block in the synthesis of taprostene, a stable prostacyclin analogue used as a vasodilator . The chlorination of ethylbenzene gave a 2°/1° selectivity of 10:1.…”

Section: Resultsmentioning

confidence: 99%

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

et al. 2017

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We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr reduced the reaction times considerably due to the formation of chain-carrying ·CBr radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.

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Section: Resultsmentioning

confidence: 99%

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

et al. 2017

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“…Thus, it was demonstrated that polymer chains grafted from nanoparticles by SI-ATRP were effective for preparing transparent bulk hybrids with improved refractive indices. With this procedure, phosphorus coupling agents (CPMP and IDP) can form stable M–O–P bonds with various inorganic oxides, and ATRP can be applicable to a variety of polymers. The present strategy is therefore applicable to many inorganic–organic hybrids.…”

Section: Resultsmentioning

confidence: 99%

Preparation of Transparent Bulk TiO₂/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO₂ Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization

Maeda

Fujita

Idota

et al. 2016

ACS Appl. Mater. Interfaces

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Transparent TiO/PMMA hybrids with a thickness of 5 mm and improved refractive indices were prepared by in situ polymerization of methyl methacrylate (MMA) in the presence of TiO nanoparticles bearing poly(methyl methacrylate) (PMMA) chains grown using surface-initiated atom transfer radical polymerization (SI-ATRP), and the effect of the chain length of modified PMMA on the dispersibility of modified TiO nanoparticles in the bulk hybrids was investigated. The surfaces of TiO nanoparticles were modified with both m-(chloromethyl)phenylmethanoyloxymethylphosphonic acid bearing a terminal ATRP initiator and isodecyl phosphate with a high affinity for common organic solvents, leading to sufficient dispersibility of the surface-modified particles in toluene. Subsequently, SI-ATRP of MMA was achieved from the modified surfaces of the TiO nanoparticles without aggregation of the nanoparticles in toluene. The molecular weights of the PMMA chains cleaved from the modified TiO nanoparticles increased with increases in the prolonging of the polymerization period, and these exhibited a narrow distribution, indicating chain growth controlled by SI-ATRP. The nanoparticles bearing PMMA chains were well-dispersed in MMA regardless of the polymerization period. Bulk PMMA hybrids containing modified TiO nanoparticles with a thickness of 5 mm were prepared by in situ polymerization of the MMA dispersion. The transparency of the hybrids depended significantly on the chain length of the modified PMMA on the nanoparticles, because the modified PMMA of low molecular weight induced aggregation of the TiO nanoparticles during the in situ polymerization process. The refractive indices of the bulk hybrids could be controlled by adjusting the TiO content and could be increased up to 1.566 for 6.3 vol % TiO content (1.492 for pristine PMMA).

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“…Preparation of 1-(2 ‘ -Thienyl)-1,4-butanediol (2). To a solution of 2-hydroxytetrahydrofuran ( 1 ) (88 mg, 1 mmol) in THF (5 mL) was added dropwise thienyllithium in THF solution (3.5 equiv) at 0 °C under stirring. After stirring at room temperature for 1.5 h, the reaction mixture was quenched with H 2 O, diluted with CHCl 3 , and then purified by pTLC (AcOEt/hexane, 1/1) to give 2 as colorless crystals in 88% yield: IR (KBr) 1440, 1480, 2850, 2900, 3060, 3150−3300 cm -1 ; HRMS (FAB, NBA + KI) calcd for C 8 H 12 O 2 SK m/e (M + K) 211.0195, found 211.0182; 1 H NMR (270 MHz, CDCl 3 ) δ 1.70 (2H, m, 3-CH 2 ), 1.90 (2H, m, 2-CH 2 ), 3.70 (2H, m, 4-CH 2 ), 4.90 (1H, t, 1-CH, J 1,2 = 3 Hz), 6.90−7.30 (3H, m, thiophene).…”

Section: Methodsmentioning

confidence: 99%

A Convenient Method for C-Azanucleosides Synthesis

et al. 1996

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Chemical stability of a prostacyclin analog due to the absence of intramolecular catalysis

Cited by 13 publications

References 2 publications

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

Preparation of Transparent Bulk TiO₂/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO₂ Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization

A Convenient Method for C-Azanucleosides Synthesis

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Chemical stability of a prostacyclin analog due to the absence of intramolecular catalysis

Cited by 13 publications

References 2 publications

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

Mild Aliphatic and Benzylic Hydrocarbon C–H Bond Chlorination Using Trichloroisocyanuric Acid

Preparation of Transparent Bulk TiO2/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO2 Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization

A Convenient Method for C-Azanucleosides Synthesis

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Preparation of Transparent Bulk TiO₂/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO₂ Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization