A useful synthesis of pyrroles from nitroolefins

Barton, Derek H. R.; Kervagoret, J.; Zard, Samir Z.

doi:10.1016/s0040-4020(01)89069-4

Cited by 357 publications

(151 citation statements)

References 28 publications

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“…The various D-ring structures in analogs 13-20 were prepared as follows. First, the regioisomers of tosylpyrroles were prepared by Barton's method (38), followed by rearrangement reaction of the tosyl groups of 2-tosylpyrroles (19). Next, conversion of 2-tosylpyrroles to 5-tosylpyrrolinones (corresponding to the structure of the D-ring in Fig.…”

Section: Methodsmentioning

confidence: 99%

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

Hanzawa

Inomata

Kinoshita

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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Phytochrome B (PhyB), one of the major photosensory chromoproteins in plants, mediates a variety of light-responsive developmental processes in a photoreversible manner. To analyze the structural requirements of the chromophore for the spectral properties of PhyB, we have designed and chemically synthesized 20 analogs of the linear tetrapyrrole (bilin) chromophore and reconstituted them with PhyB apoprotein (PHYB). The A-ring acts mainly as the anchor for ligation to PHYB, because the modification of the side chains at the C2 and C3 positions did not significantly influence the formation or difference spectra of adducts. In contrast, the side chains of the B-and C-rings are crucial to position the chromophore properly in the chromophore pocket of PHYB and for photoreversible spectral changes. The side-chain structure of the D-ring is required for the photoreversible spectral change of the adducts. When methyl and ethyl groups at the C17 and C18 positions are replaced with an n-propyl, n-pentyl, or n-octyl group, respectively, the photoreversible spectral change of the adducts depends on the length of the side chains. From these studies, we conclude that each pyrrole ring of the linear tetrapyrrole chromophore plays a different role in chromophore assembly and the photochromic properties of PhyB.

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Section: Methodsmentioning

confidence: 99%

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

Hanzawa

Inomata

Kinoshita

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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“…The classic methods for the synthesis of pyrroles described in the literature are Knorr (11Á14), Hantzsch (15), PaalÁKnorr (16Á20), and BartonÁZard (21,22) reactions. The PaalÁKnorr reaction, in which 1,4-dicarbonyl compounds react with primary amines under slightly acidic conditions, is a very attractive approach.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of highly substituted pyrroles using ultrasound in aqueous media

Almeida

2012

Green Chemistry Letters and Reviews

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A two-step protocol for the synthesis of highly substituted pyrroles in aqueous media and without catalyst is described. The first step is the dimerization of a 1,3-dicarbonyl compound by ceric ammonium nitrate/ultrasound to produce a tetracarbonyl derivative. This derivative is then combined with an amine in the absence of any catalysts to obtain the pyrrole via a PaalÁKnorr reaction. This route is an improvement when compared with classical methodologies toward Green Chemistry objectives.

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“…The solvent was evaporated, and the residue was partitioned between EtOAc and water. The organic layer was successively washed with a saturated aqueous solution of NaHSO 3 , a solution of NaHCO 3 , and brine, and then dried over (14). To a suspension of NaH (34 mg, 60% in mineral oil, 0.8 mmol) in THF (1 mL) was added a catalytic amount of 18-crown-6 (32 mg, 0.12 mmol), suspended in THF (1 mL), and a solution of compound (Z)-8a (52 mg, 0.12 mmol) in THF (2 mL), followed by the addition of 1,2-dibromoethane (3 mL).…”

Section: Methodsmentioning

confidence: 99%