6305-93-7Relevant academic research and scientific papers
Hydrogen-bonded double strands: Crystal structure and spectroscopic properties of a 2,2′-dipyrryl ketone
Huggins, Michael T.,Tipton, Adrianne K.,Chen, Qingqi,Lightner, David A.
, p. 825 - 838 (2000)
The synthesis, crystal structure determination, conformational analysis, and spectroscopic properties of 3,3′-diethyl-4,4′-dimethyl-2,2′-dipyrryl ketone (1) are reported. The dipyrryl ketone is a model for the dipyrrole core of 10-oxobilirubin, a presumed metabolite in alternate pathways of excretion of the yellow pigment of jaundice, bilirubin. In the crystal, 1 adopts a helical conformation, with a molecule of one helicity being hydrogen-bonded to two molecules of the opposite helicity. Thus, 1 self-assembles via hydrogen bonding into supramolecular double-stranded arrays, where molecules of the same helicity comprise one strand and are paired through hydrogen bonding to molecules of opposite helicity in the second strand. In the observed molecular conformation each pyrrole ring and adjacent carbonyl group are rotated into an sc conformation (torsion angle ～ 29°), with each N-H pointing in the same direction as the C=O. Molecular mechanics/dynamics calculations predict the sc,sc conformation, absent hydrogen bonding, to be the most stable, but only by a few tenths of a kj/mol. In CHCl3, 1 is monomeric according to vapor pressure osmometry studies (MWobs = 251 ± 10 vs. MWcalc = 244). 1H NMR NH chemical shifts in CDCl3 suggest a predominantly anti orientation of the C = O and pyrrole NHs, which is opposite to the orientation observed in the crystal.
Oxidation of substituted 2-methylpyrroles with perhalogenated metalloporphyrins: A one-pot synthesis of dipyrromethanes
Karunaratne, Veranja,Dolphin, David
, p. 603 - 604 (1996)
A variety of substituted 2-methylpyrroles underwent allylic oxidation with the perchlorinated metalloporphyrin 2 and iodosylbenzene in TFA/CH2Cl2 (9:1). Subsequent addition of an α-free pyrrole to the same reaction mixture afforded a
Oxidation of pyrrole α-methyl to methoxymethyl with ceric triflate
Thyrann, Thomas,Lightner, David A.
, p. 315 - 318 (1996)
Pyrrole α-methyl methyl ethers can be prepared in high yield by oxidation of pyrrole α-methyl groups with ceric triflate in methanol when the pyrrole ring also has an α-carboxylic acid ester group, and high yields of dipyrrylmethanes may be obtained in a one-pot oxidation-solvolysis reaction.
Dipyrrole borane class compound (BODIPY) and its preparation method and application
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Paragraph 0098; 0099; 0100; 0101, (2016/10/07)
The invention discloses a formaldehyde detection probe compound and a detection method. The compound is a high fluorescence quantum efficiency fluorescence dye based on dipyrrol borane BODIPY. The compound and alkali substances used in the invention generate a reversible reaction for forming a compound. The detection of formaldehyde is based on alkali reaction in the compound, and the reaction result causes the BODIPY to regenerate and develop colors, and simultaneously recover fluorescence. The detection method is a novel detection reagent which can be recycled. On the other hand, based on the high fluorescence quantum efficiency characteristics of the BODIPY compounds, the detection reagent has high sensitivity and lower detection limit.
Syntheses of per-15N labeled etioporphyrins I-IV and a related tetrahydrobenzoporphyrin for applications in organic geochemistry and vibrational spectroscopy
Lash, Timothy D.,Chen, Shaohua
, p. 11577 - 11600 (2007/10/03)
Nitrogen-15 labeled pyrroles have been prepared from commercially available 15N glycine or sodium nitrite using the Barton-Zard, Knorr, and Kleinspehn approaches. These pyrroles were used as intermediates in the synthesis of per-15N labeled porphyrins needed for the analysis and assignment of vibrational spectra for sedimentary porphyrins. Etioporphyrin-I was prepared via pyrromethene intermediates, while etioporphyrins II-V and a related tetrahydrobenzoporphyrin were synthesized via stepwise routes involving the copper(II) mediated cyclization of a,c-biladienes as the key step. Detailed analyses of both the proton and carbon-13 NMR spectra provide nitrogen-15 coupling constants for these important structures.
Porphyrins with exocyclic rings. Part 10.1 Synthesis of meso,β- propanoporphyrins from 4,5,6,7-tetrahydro-1H-indoles
Lash, Timothy D.
, p. 359 - 374 (2007/10/03)
Benzyl (6) and tert-buty1 3-methyl-4,5,6,7-tetrahydro-1H-indole-2- carboxylates (28) were easily prepared from cyclohexanone using a variation of the Knorr pyrrole condensation. Regioselective oxidation with lead tetraacetate gave the corresponding 7-acetoxy derivatives, or related solvolysis products, and subsequent reaction with 5-unsubstituted pyrrole-2- carboxylates in the presence of p-toluenesulfonic acid in acetic acid gave a series of 7-pyrrolyltetrahydroindoles 16 in excellent overall yields. Cleavage of the protective ester units, followed by acid-catalyzed condensation with diformyldipyrrylmethanes 19 under modified MacDonald '2 + 2' conditions gave good yields of meso,β-propanoporphyrins 26. This chemistry was sufficiently versatile that a porphyrin with two six-membered exocyclic rings (34) could be prepared by the same methodology. On the other hand, attempts to cyclize an a,c-biladiene 37 incorporating a six-membered carbocyclic ring gave moderate to poor yields of the required meso,β- propanoporphyrin 26a, probably due to a deleterious steric interaction between the carbocyclic ring and an adjacent alkyl substituent. Nonetheless, the results described below demonstrate the value of this approach for the synthesis of sedimentary cycloalkanoporphyrins.
Oxidation of 2-methylpyrroles with perchlorinated iron(III) metalloporphyrin catalysts: A versatile synthesis of symmetric and asymmetric dipyrromethanes
Karunaratne, Veranja,Dolphin, David
, p. 1467 - 1473 (2007/10/03)
Abstract: A variety of substituted 2-methylpyrroles (3-8) were oxidized using the metalloporphyrin catalysts iron(III) meso-tetra(2,6-dichloro-3- sulphonatophenyl)-β-octachloroporphyrin chloride 1 and iron(III) meso- tetra(2,6-dichlorophenyl)-β-octachloro
Thermochemistry of Solution of Linear Pyrroles
Berezin, M. B.,Semeikin, A. S.,V'yugin, A. I.
, p. 1265 - 1268 (2007/10/03)
The enthalpies of solution of a series of symmetrically substituted linear pyrroles in benzene, tetrachloromethane, chloroform, dimethylformamide, and pyridine were measured calorimetrically at 298 K.The effect of substituents in pyrrole molecules on the energy characteristics of their solvation by organic solvents is discussed.
