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Nitroaromatic compounds represent one of the essential classes of molecules that are widely used as feedstock for the synthesis of intermediates, the preparation of nitro‐derived pharmaceuticals, agrochemicals, and materials on both laboratory and industrial scales. We herein disclose the efficient, mild, and catalytic ipso‐nitration of organotrimethylsilanes, enabled by an electrophilic N‐nitrosaccharin reagent and allows chemoselective nitration under mild reaction conditions, while exhibiting remarkable substrate generality and functional group compatibility. Additionally, the reaction conditions proved to be orthogonal to other common functionalities, allowing programming of molecular complexity via successive transformations or late‐stage nitration. Detailed mechanistic investigation by experimental and computational approaches strongly supported a classical electrophilic aromatic substitution (SEAr) mechanism, which was found to proceed through a highly ordered transition state. [ABSTRACT FROM AUTHOR]

A convenient one‐pot synthesis of quinoxaline‐2,3‐dione has been achieved by C−H hydroxylation of quinoxalin‐2(1H)‐one using TBN (tert‐butyl nitrite) as a promoter of the reaction in DMSO. First radical‐mediated nitration using TBN at C‐3 of quinoxalin‐2(1H)‐one and followed by hydroxylation with water via ipso‐substitution led to the quinoxaline‐2,3‐dione. [ABSTRACT FROM AUTHOR]

A convenient synthesis of 1,2,4-triazines bearing the moieties of (hetero)arylhydrazines at the position of C5 of the 1,2,4-triazine core is reported.

[Display omitted] Reaction between 5-cyano-3,6-di(het)aryl-1,2,4-triazines and arylhydrazines with the following aza-Diels–Alder autoclave reaction affords hardly available 2-amino-3,6-di(het)aryl-pyridines in up to 67% yield after two steps and in 75% yield for the one-pot way. The compounds obtained can be promising for medicinal chemistry. [ABSTRACT FROM AUTHOR]

Oxidation of the alkaloid skimmianine produced a formyl derivative that reacted with homoveratrylamine to give the product of nucleophilic ipso-substitution 3-formyl-4-(3,4-dimethoxyphenylethylamino)-7,8- dimethoxyquinolin-2-one. The presence of the formyl group in the latter stimulated its further ipso-substitution at the H atom in acidic solution to form 4-(3,4-dimethoxyphenylethylamino)-7,8-dimethoxyquinolin-2-one, the structure of which was confirmed by an X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] One-pot synthesis of cyclopentane-fused 5 ' -aryl-4- cycloalkylamino-2,2 ' -bipyridines based on the neat (200 °C) reaction of 3-(4-bromopyridin-2-yl)-1,2,4-triazines with enamines is reported. In the course of the transformation, consecutive aza -Diels–Alder reaction and nucleophilic substitution of bromine atom under the action of the liberating amine occur. The possibility of the solvent- and catalyst-free replacement of 4-positioned bromine atom in 2,2 '- bipyridines by amino moieties was demonstrated. [ABSTRACT FROM AUTHOR]

Background. The synthesis and pharmacological activity of condensed pyrimidine derivatives are studied, including by the example of thieno [2,3-d] pyrimidine derivatives and new derivatives of 2-substituted bicyclic thieno [2,3-] pyrimidin-4-ones. They are needed to develop new drugs. Purpose Study of the reactions of 2H-5,6-dimethyl-, 2H-5-methyl-6-ethoxycarbonyl, 2-oxo-5,6-dimethyl-, 2-thioxo-5,6-dimethylthienopyrimidin-4-ones and their methylated derivatives with nitrating mixture. Determination of factors affecting the nitration reaction and optimal reaction conditions. Analysis of the structure of the obtained substances using modern physical research methods. Methodology. Synthesized 2-oxo-5-nitro-6-methylthieno [2,3-d] pyrimidin-4-one, 2-thioxo-5,6-dinitrothieno [2,3-d] pyrimidin-4-one, 2H-3, 6-dimethyl-5-carboxylthieno [2,3-d] pyrimidin-4-one, 2-methylthio-3,6-dimethyl-5-carboxylthieno [2,3-d] pyrimidin-4-ones. The structure of the synthesized substances was confirmed by IR, 1H-NMR and mass spectrometry. Originality. For the first time obtained 2H-5-nitro-6-methyl-, 2-oxo-5-nitro-6-methyl-, 2H-5-carboxyl-3,6-dimethyl-, 2-oxo-5-carboxyl-1,3, 6-trimethylthieno [2,3-d] pyrimidine-4-ions by ipso exchange or oxidation of suitable thienopyrimidines with a nitrating mixture. The effect of temperature, reagents and molecules of the starting material on the course of the nitration reaction was studied. Findings It was determined that as a result of the nitration reaction, 5-nitro, 5-carboxylthieno [2,3-d] pyrimidine-4-ions are formed, depending on the presence of a proton or methyl group in the cases of N1 and N3. The resulting substances were analyzed by IR-, 1H-NMR and mass spectrometry and their corresponding structures were confirmed. [ABSTRACT FROM AUTHOR]

Syntheses of a range of chemically well‐defined oligopyrrole/benzenoid hybrids are described using tandem Suzuki‐Miyaura cross‐coupling/bromo‐desilyation reaction sequences for linking borylated pyrroles, halogenated pyrroles and/or dibromobenzenes to one another. By such means, including iterative variants, a range of all α‐linked, all β‐linked oligopyrroles as well as certain combinations thereof have been assembled, some of them for the first time. The conductivities of iodine‐treated thin films formed from certain such systems have been determined. [ABSTRACT FROM AUTHOR]

Electron‐rich arenes are oxidatively photochlorinated in the presence of catalytic amounts of bromide ions, visible light, and 4CzIPN as organic photoredox catalyst. The substrates are brominated in situ in a first photoredox‐catalyzed oxidation step, followed by a photocatalyzed ipso‐chlorination, yielding the target compounds in high ortho/para regioselectivity. Dioxygen serves as a green and convenient terminal oxidant. The use of aqueous hydrochloric acid as the chloride source reduces the amount of saline by‐products. [ABSTRACT FROM AUTHOR]

A general and catalyst-free protocol for the synthesis of pyrido-oxazepine-3-ols and benzo-oxazin-2-yl methanol via tandem epoxide opening followed by S N Ar reactions is reported. Oxirane derived from tribromopyridine undergoes epoxide opening followed by the S N Ar reaction, yielding seven-membered pyrido-oxazepine-3-ols. Predominantly 2-cyclized pyrido-oxazepine-3-ols observed in this reaction. Oxirane derived from tribromonitrobenzene undergoes epoxide opening followed by S N Ar reaction to produce six-membered benzo-oxazin-2-yl methanol. When oxirane treated with primary amine, mainly 2-cyclized benzo-oxazin-2-yl methanol is formed. furthermore, treatment of oxirane with secondary amine result in regio-selective 4-cyclized benzo-oxazin-2-yl methanol, accompanied by de-alkylation. A plausible reaction mechanism is proposed for the synthesis of benzo-oxazin-2-yl methanol, which proceeds via epoxide opening followed by a Smiles rearrangement. [Display omitted] [ABSTRACT FROM AUTHOR]

A convenient method for the obtaining of 3,6-diaryl-1,2,4-triazines substituted with residues of higher alcohols in the position of C5 via the ipso-substitution of cyano group in under the solvent free conditions was reported. This method indicates a new example for the functionalization of the 1,2,4-triazines via the substitution of the cyano group.

The synthesis of monoaryl‐λ3‐iodanes generally requires the oxidation of iodoarenes, but the functional group compatibility is often problematic when using oxidizable substrates such as heteroaromatic compounds. Although electrophilic aromatic substitution or ipso‐substitution reactions using iodine tricarboxylates have been studied as an alternative synthetic route to dicarboxyiodoarenes, several common heteroaromatic substrates such as indoles, quinolines, (benzo)furans, and (benzo)thiophenes have not been investigated to date. Here, we report that ipso‐substitution reactions of heteroaromatic stannanes using I(OAc)3 in the presence of 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) effectively provide diacetoxyiodoarenes, which can be converted into the corresponding iodonium ylides or be directly used in a one‐pot iodoarylation reaction. [ABSTRACT FROM AUTHOR]

Monoaryl‐λ3‐iodanes are potentially attractive arylating agents. They are generally synthesized from aryl iodides via oxidation, which can cause functional group incompatibility, especially when polyfunctionalized derivatives are desired. This work describes the direct synthesis of monoaryl‐λ3‐iodanes through a chemoselective ipso‐substitution reaction of arylgermanes and arylstannanes with iodine tris(trifluoroacetate). The generated iodanes were converted to iodonium ylides or used for further transformations in one pot. The presented method enables the preparation of polyfunctionalized monoaryl‐λ3‐iodanes. Polyfunctionalized monoaryl‐λ3‐iodanes were accessible by chemoselective ipso‐substitution of arylgermanes and arylstannanes with iodine tris(trifluoroacetate). The generated iodanes were converted to iodonium ylides or directly used for further transformation in one pot. The presented protocol is useful for the synthesis of IIII compounds containing oxidizable functional groups. [ABSTRACT FROM AUTHOR]

The Smiles rearrangement is an intramolecular SNAr reaction, breaking a C−X single bond and forming a new C−X or C−C bond though ipso substitution. Its vast scope, in terms of nucleophile, leaving group, and ring-size of the transition state, make it a powerful tool for arene functionalization, as it can be employed strategically to switch easily-forged bonds with more difficult connections that would be challenging to realize in the intermolecular mode. The reaction has received significantly renewed attention in recent years, as advances in areas such as arene C−X bond formation and radical generation have been harnessed for new arene syntheses through Smiles chemistry. In addition, new reaction modes have been discovered, such as the Clayden rearrangement of lithiated ureas, creating innovative applications for Smiles rearrangements in asymmetric arylation. This Minireview will discuss advances in these areas in the recent literature, covering both two-electron, polar Smiles rearrangements along with single-electron radical transformations. [ABSTRACT FROM AUTHOR]

The phosphorus/boron-substituted hexatriene systems 6 undergo thermally induced electrocyclic ring closure to yield the cyclohexadiene-derived P/B frustrated Lewis pairs (FLPs) 7. Subsequent TEMPO oxidation gives the phenylene-bridged FLPs 8. Both systems activate dihydrogen and the thermally robust FLPs undergo carbon-carbon coupling reactions at a mesityl group upon treatment with dimethyl acetylenedicarboxylate at elevated temperatures. [ABSTRACT FROM AUTHOR]

In a preceding work with dopant assisted-atmospheric pressure photoionization (DA-APPI), an abundant ion at [M + 77] was observed in the spectra of pyridine and quinoline with chlorobenzene dopant. This contribution aims to reveal the identity and route of formation of this species, and to systematically investigate structurally related analytes and dopants. Compounds containing N-, O-, and S-lone pairs were investigated with APPI in the presence of fluoro-, chloro-, bromo-, and iodobenzene dopants. Computational calculations on a density functional theory (DFT) level were carried out to study the reaction mechanism for pyridine and the different halobenzenes. The experimental and computational results indicated that the [M + 77] ion was formed by nucleophilic aromatic ipso-substitution between the halobenzene radical cation and nucleophilic analytes. The reaction was most efficient for N-heteroaromatic compounds, and it was weakened by sterical effects and enhanced by resonance stabilization. The reaction was most efficient with chloro-, bromo-, and iodobenzenes, whereas with fluorobenzene the reaction was scarcely observed. The calculated Gibbs free energies for the reaction between pyridine and the halobenzenes were shown to increase in the order I < Br < Cl < F. The reaction was found endergonic for fluorobenzene due to the strong C-F bonding, and exergonic for the other halobenzenes. For fluoro- and chlorobenzenes the reaction was shown to proceed through an intermediate state corresponding to [M + dopant], which was highly stable for fluorobenzene. For the bulkier bromine and iodine, this intermediate did not exist, but the halogens were shown to detach already during the approach by the nucleophile. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Quantum chemical calculations of energies, electronic structures, and molecular geometries of 3,5,6-trimethylthieno[2,3- d]pyrimidin-4-one ( 1), tricyclic 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-substituted 5,6-dimethylthieno[2,3- d]pyrimidin-4-ones ( 2- 4), carboxylic acids 5- 8 resulting from oxidation of compounds 1- 4 at the methyl group in position 5 of thienopyrimidine, methyl esters of these acids ( 9- 12), and products of ipso-nitration of esters ( 13- 16) were performed in terms of the HF and DFT (B3LYP) approximations with the 3-21G basis set. Also, calculations for mixed anhydrides of nitric acid and carboxylic acids 17- 20 were carried out. The possible causes of differences in the behaviors of 3-unsubstituted and 3-substituted thieno[2,3- d]pyrimidin-4-ones were discussed. [ABSTRACT FROM AUTHOR]

The quantum chemical calculations of the energies, electronic structures, and geometries for the products and intermediates of the ipso-nitration of 5,6-dimethyl-substituted 2-oxo- and 2-thioxothieno[2,3- d]pyrimidin-4-ones, as well as 6-methyl-5-nitrothieno[2,3- d]pyrimidin-4-one and 3,6-dimethyl-4-oxo-3,4-dihydrothieno[2,3- d]pyrimidine-5-carboxylic acid formed under the action of a nitrating mixture on 5,6-dimethylthieno[2,3- d]pyrimidin-4-one and 3,5,6-trimethylthieno[2,3- d]pyrimidin-4-one, respectively, were performed in terms of the HF and DFT (B3LYP) approximations in the 3-21G basis set. Taking into account the substituent effects in the pyrimidine cycle, solvents, and prototropic tautomerism, possible reasons for the predominant ipso-substitution of the methyl group at the C(5) atom by the nitro group of the thienopyrimidine system and differences in behavior of 3-unsubstituted and 3-substituted thieno[2,3- d]pyrimidin-4-ones were considered. [ABSTRACT FROM AUTHOR]

Treatment of 5-iodo-1,3,6-trimethyluracil with 50% HSO gives 1,3,6-trimethyluracil; with 5-bromo-1,3,6-trimethyluracil, a mixture of 1,3,6-trimethyluracil and 6-bromomethyl-1,3-dimethyluracil is obtained. 5-Chloro-1,3,6-trimethyluracil remains inert under these conditions. According to the DFT modeling of the reactions of 5-halo-1,3,6-trimethyluracils, a nucleophilic agent can abstract either Hal or the methyl proton from the carbocation formed by protonation of the starting halouracil at position 5, which accounts for the formation of two products from the 5-bromo derivative. Under similar conditions, 6-methyluracil dibromohydrin yields N-bromo-5-bromo-6-hydroxymethyluracil. Bromination or chlorination of 5-hydroxymethyl- or 5-formyl-6-methyluracils follows the ipso-substitution scheme leading to 6-methyluracil 5-halo- and 5,5-dihalohydrins. [ABSTRACT FROM AUTHOR]

Our studies with Sphingobium xenophagum Bayram show that this bacterial strain degrades ?-quaternary 4-nonylphenols by an ipso-substitution mechanism, whereby the nonylphenol substrates are initially hydroxylated at the ipso position to form 4-hydroxy-4-nonylcyclohexa-2,5-dienones (quinols). Subsequently, the ?-quaternary side chains are able to detach as short-living cations from these intermediates. Alkyl branches attached to the carbocation help to delocalize and thereby stabilize the positive charge through inductive and hyperconjugative effects, which explains why only alkyl moieties of ?-quaternary nonylphenols are released. This view is corroborated by experiments with S. xenophagum Bayram, in which the alkyl chains of the non-?-quaternary 4-(1-methyloctyl) phenol (4-NP2) and 4-n-nonylphenol (4-NP1) were not released, so that the bacterium was unable to utilize these isomers as growth substrates. Analysis of dead end metabolites and experiments with 18O labeled H2O and O2 clearly show that in the main degradation pathway the nonyl cation derived from ?-quaternary quinols preferentially combines with a molecule of water to yield the corresponding alcohol and hydroquinone. However, the incorporation of significant amounts of O2-derived oxygen into the nonanol metabolites derived from degradation of certain ?,?-dimethyl substituted nonylphenols by strain Bayram strongly indicates the existence of a minor pathway in which the cation undergoes an alternative reaction and attacks the ipso-hydroxy group, yielding a 4-alkoxyphenol as an intermediate. Additional growth experiments with strain Bayram revealed that also the two alkoxyphenols 4-tert-butoxyphenol and 4-n-octyloxyphenol promote growth. Furthermore, strain Bayram's ipso-hydroxlating activity is able to transform also bisphenol A.

Abstract: Based on an ortho-lithiation protocol of 2,2′-dibromo-1,1′-binaphthyl four tetrasubstituted binaphthyls, 2,2′-dibromo-3,3′-diiodo-, 3,3′-dibromo-2,2′-diiodo-, 2,2′,3,3′-tetrabromo-, and 2,2′,3,3′-tetraiodo-1,1′-binaphthyls have been prepared in excellent yield which in turn proved to be versatile key intermediates in the synthesis of various 2,2′,3,3′-tetrasubstituted 1,1′-binaphthyl derivatives. [Copyright &y& Elsevier]

Abstract: Several imidazo and pyrimido[1,2-a]pyrimidinones of type 1 and 2 were synthesized through intramolecular cyclization of pyrimidines 9 or pyrimidinones 10 bearing a variety of β and γ-aminoalcohols at the 2-position. Ring closure of the pyrimidinones of type 10 under Mitsunobu conditions lead to mixtures of both bicyclic regioisomers 1 and 2 . Treatment of pyrimidines of type 9 with H2SO4 provided an efficient and operationally simple one-pot hydrolysis–cyclization procedure for obtaining imidazo and pyrimido[1,2-a]pyrimidinones 1 in good yields as the sole regioisomeric bicyclic product. [Copyright &y& Elsevier]

The metabolism of the 5HT2c agonist BVT.2938, 1-(3-{2-[(2-ethoxy-3-pyridinyl)oxy]ethoxy}-2-pyrazinyl)-2(R)-methylpiperazine, was studied in vitro by incubation with rat, monkey and human liver microsomes as well as cryopreserved hepatocytes, followed by liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS analysis on a quadrupole-time of flight mass spectrometer for structural elucidation. Deuterium exchange on column was used to differentiate between hydroxylation and N-oxidation. Liver microsomes were incubated in two different buffer systems with optimum conditions for cytochrome P450 activity or UDP-glucuronosyltransferase activity. The major phase I metabolites of BVT.2938 originated from O-deethylation of the pyridine ring, O-dealkylation of the ethylene bridge, pyrazine ring hydroxylation, hydroxylation of pyridine ring and piperazine ring N-hydroxylation. When a hydrogen carbonate buffer system was supplemented with UDPGA, the piperazine carbamoyl-glucuronide from the parent compound was identified together with several glucuronides of the phase I metabolites. The metabolite pattern in hepatocytes was similar to microsomes except that the sulphate at the N-position of the piperazine ring of BVT.2938 was identified, while the carbamoyl-glucuronide was missing. Excellent correlation was obtained between radioactivity detection and the chemiluminescent nitrogen detector when the nitrogen content of the analytes was taken into account. [Copyright &y& Elsevier]

Ultraviolet irradiation of arylnitramines in 2,6-di-tert-butylphenol results in the transfer of the nitro group intermolecularly to produce the corresponding 4-nitrophenol together with nitroanilines in addition to oxidation products, diphenoquinone and the diphenolic compounds. Thermolysis of arylnitramines or N-alkylarylnitramines at controlled temperatures either alone or in phenolic solvent, produce the corresponding p- and/or o-nitroanilines together with 4-nitrophenol, diphenoquinone and diphenol in addition to crystals of their dimeric product quinhydrone. No dimerization products of the arylamino radicals are detected. However, evolution of nitrogen, nitrogen dioxide and water drops are detected. Thermolysis of primary arylnitramines in β-naphthol results in separation of free radicals substitution product, 1-arylazo-2-naphthols as major products with evolution of nitrogen dioxide. However, such rearrangement products are not produced with secondary N-alkylarylnitramines. Other products of homolytic substitution of halogen by nitro group are identified. [Copyright &y& Elsevier]

Minisci-type radical carbamoylation of 1-bromo-β-carboline (1) gives the 3-substituted product in low yield, whereas 1-acetyl-β-carboline (3a) reacts under ipso-substitution of the acetyl group. Cyanations of the N-oxides of 1 and 3a occur under clean ipso-substitution of the groups in 1-position. 1-Methyl derivatives show no tendency to react under ipso-substitution. [ABSTRACT FROM AUTHOR]

The thermocyclisation of phenylenediamine-bis(methylene Meldrum''s acid) derivatives has been investigated. Those of o-phenylenediamines give 1,10-phenanthroline derivatives, while those of m- and p-phenylenediamines lead to the preferential formation of angular diazatricycles. Thus, for example, the di-Meldrum''s acid derivative of 2,5-dichloro-1,4-phenylenediamine gives, via ipso-substitution, the unexpected angular product 19. [Copyright &y& Elsevier]

Five naturally-occurring protoberberines have been synthesized in enantioenriched form by alkylation by two different 2-trimethylsilylbenzyl chlorides of four tetrahydroisoquinolines, derivatized with Meyers'' formamidine valinol methyl ether chiral auxiliary. Silyl-directed Pictet–Spengler cyclization of the ensuing 3,4-dimethoxy-2-trimethylsilylbenzyl tetrahydroisoquinolines leads to four of the target protoberberines in excellent yield and complete regioselectivity. In the fifth case, the 3,4-methylenedioxy analog gives a mixture of protoberberine and a product of ring closure at C6 of the benzyl moiety in a 3:4 ratio. [Copyright &y& Elsevier]

Evidence for multiple functional active oxidants in cytochrome P450-catalyzed reactions was previously obtained in this laboratory with mutants in which proton delivery was perturbed by replacement of the highly conserved threonine residue in the active site by alanine, thus apparently interfering with the conversion of the peroxo-iron to the hydroperoxo-iron and the latter to the oxenoid-iron species. These enzymes have now been employed to examine the reaction in which cytochrome P450 in liver microsomes is known to effect ipso-substitution, the elimination of p-substituents in phenols to yield hydroquinone. As shown with purified NH2-truncated cytochromes in a reconstituted enzyme system, the reaction exhibits an absolute requirement for cytochrome P450 and NADPH–cytochrome P450 reductase. Under optimal conditions truncated cytochrome P450 2E1 is active with 10 of the p-substituted phenols examined. Of particular interest, the corresponding cytochrome with threonine-303 replaced by alanine is from 1.5- to 50-fold higher in activity with the p-chloro, -bromo, -nitro, -cyano, -hydroxymethyl, -formyl, and -acetyl derivatives, and the reaction with the p-benzoyl, -methyl, and -t-butyl compounds is catalyzed by the mutant enzyme only. The results implicate the hydroperoxo-iron species as an electrophilic active oxidant in cytochrome P450-catalyzed aromatic ipso-substitution. [Copyright &y& Elsevier]

A novel dinitro secondary metabolite, 2-nitro-4-(2′-nitroethenyl)phenol from a marine source, has been prepared via highly accelerated, microwave assisted, nitration reactions using mild reagents. ipso-Substitution of a carboxy group by a nitro group is discussed. [Copyright &y& Elsevier]

The products of reaction of o-phenylenedioxytrichlorophosphorane with arylacetylenes were identified as 4-aryl-2-chloro-2-oxo-5,6-(4-chlorobenzo)phosphorin-3-enes using1H,13C,31P NMR, and IR spectroscopy and high-resolution mass spectrometry. [ABSTRACT FROM AUTHOR]

Monoaryl-λ 3 -iodanes are potentially attractive arylating agents. They are generally synthesized from aryl iodides via oxidation, which can cause functional group incompatibility, especially when polyfunctionalized derivatives are desired. This work describes the direct synthesis of monoaryl-λ 3 -iodanes through a chemoselective ipso-substitution reaction of arylgermanes and arylstannanes with iodine tris(trifluoroacetate). The generated iodanes were converted to iodonium ylides or used for further transformations in one pot. The presented method enables the preparation of polyfunctionalized monoaryl-λ 3 -iodanes., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The Smiles rearrangement has been revived in the recent literature as a method of preparing diverse sets of molecules containing aryl functionality. Recent progress in heteroatom arylation, in particular, has been a key enabling step for this chemistry, as O, N and S‐arylation can now be reliably achieved to set‐up aryl transfer through Smiles processes. In their Minireview on page 8992 ff., C. M. Holden and M. F. Greaney discuss recent advances in Smiles chemistry. [ABSTRACT FROM AUTHOR]