The reactions of 2,2-difluoro-4-methylnaphtho[l,2-e] -1,3,2-dioxaborin and Its [2,1-e] Isomer with Carbonyl compounds and with Aniline

2,2-Difluoro-4-methylnaphtho[l,2-e]-l,3,2-dioxaborin ( 1 ) and its [2,1-e]isomer ( 2 ) react with equimolecular quantities of carbonyl compounds, giving colored ethylenic derivatives. With aniline, 1 and 2 give the corresponding oxazaborins 21 and 22 . The structures of 1 and 2 are discussed.     

Effect of hydration on the luminescence properties of 2,2-difluoro-4-methylnaphto[2,1-e]-1,3,2-dioxaborine. Quantum chemical modeling and experiment

The effect of hydration on the spectral luminescence properties of solutions of 2,2-difluoro-4-methylnaphto[2,1-e]-1,3,2-dioxaborine in organic solvents is studied. Quenching of luminescence and color changes of the solutions associated with hydration of luminophore molecules were observed. Quantum chemical modeling of the structure of the hydrate complex is carried out.     

Influence of hydration on the optical properties of 2,2-difluoro-4-methylnaphtho-[1,2-e]-1,3,2-dioxaborine. Quantum chemical modeling and experimental study

The influence of hydration on the spectral-luminescence properties of 2,2-difluoro-4-methylnaphtho-[1,2-e]-1,3,2-dioxaborine in organic solvents was investigated. The hydration of luminophore molecules was found to cause changes in the luminescence spectrum and bleaching of the solutions. The quantum chemical modeling of the electronic structure and absorption spectra of the compound under study and its hydrated complex was performed by the density functional theory (DFT) with the use of the B3LYP5 functional. The results of calculations confirmed the experimentally observed features.     

17O and 11B NMR spectroscopic study of substituted benzo[d]-2,2-difluoro-1,3,2-oxoniaoxaboratins

¹⁷O NMR data are reported for 10 benzo[d]-2,2-difluoro-1,3,2-oxoniaoxaboratins derived from various ortho-hydroxyacetophenones and for 2,2-difluoro-1,3,2-oxoniaoxaboratins derived from related hydroxyacetyl naphthalenes and hydroxybenzophenones. The signal for the carbonyl-like oxygen for these compounds is substantially shielded and appears at 288 ± 22 δ. The single bonded oxygen signal for the 1,3,2-oxoniaoxaboratins appears at 122 ± 6 δ, except for the naphthalene analogs, whose signal appears at 146 ± 10 δ. The ¹¹B NMR signal for these compounds is insensitive to structural changes and appears at 0.85 ± 0.25 δ. © 1995 John Wiley & Sons, Inc.     

Crystal structure and luminescence of 2,2-difluoro-4,6-(4-methylphenyl)-1,3,2-dioxaborine

The crystal structure, luminescence properties of 2,2-difluoro-4,6-(4-methylphenyl)-1,3,2-dioxaborine (CH₃C₆H₄COCHCOC₆H₄CH₃BF₂) crystals and solutions at different concentrations are examined at T 296 K and 156 K.     

Crystal structure and luminescence properties of 4-(4-benzoyloxy-2-hydroxyphenyl)-2,2-difluoro-6-phenyl-1,3,2-dioxaborine

The crystal structure of 4-(4-benzoyloxy-2-hydroxyphenyl)-2,2-difluoro-6-phenyl-1,3,2-dioxaborine (1) was determined by X-ray diffraction analysis. π-π-Stacking interaction between the molecules results in joining the molecules into a three-dimensional layered framework. Luminescence of the aggregates is observed in concentrated solutions of compound 1. Two routes of excimer formation in crystal were revealed by steady-state and time-resolved luminescence spectroscopy: via excitation of single molecules and via excitation of aggregates.     

On the condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-dioxaborines with cyano acetic acid derivatives. Formation and transformation of 3-cyano-4-methyl-benzo[b]pyran-2-ones and their 2-imine precursors

Summary By condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-2H-dioxaborines (12) with cyano acetic acid derivatives in presence of weak bases, 3-cyano-4-methyl-benzo[b]pyran-2-ones (13) or their 3-cyano-4-methyl-benzo[b]pyran-2-imine precursors (14) are available in satisfactory yields.

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Zur Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen mit Cyanessigsäure- Derivaten. Bildung und Umwandlung von 3-Cyano-4-methyl-benzo[b]pyran-2-onen und ihrer 2-Imino-Vorstufen

Zusammenfassung Durch Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen (12) mit Cyanessigsäure-Derivaten in Gegenwart von Hilfsbasen entstehen in befriedigenden Ausbeuten 3-Cyan-4-methyl-benzo[b]pyran-2-one (13) oder ihre 3-Cyan-4-methyl-benzo[b]pyran-2-imino-Vorstufen (14).

     

On the formation and solvolysis of 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines

The condensation of aryl methyl ketones 6 with acetic anhydride 4a in the presence of the boron trifluoride-acetic acid adduct 7 gives rise to the formation of 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines 8 in satisfactory yields. The stable 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines 8 can be transformed by hydrolysis into the corresponding aroylacetones 9. The reaction was optimized so as to avoid the formation of by-products, such as 2,4-diaryl-6-methylpyrylium tetrafluoroborates 11 or self-condensation products. © 1997 John Wiley & Sons, Inc.     

Crystal structure and luminiscent properties of 2,2-difluoro-4-(9H-hluorene-2-YL)-6-methyl-1,3,2-dioxaborine

The crystal structure of 2,2-difluoro-4-(9H-fluorene-2-yl)-6-methyl-1,3,2-dioxaborine (C₁₃H₉COCH × COCH₃BF₂) (1) is determined. The structural and spectral luminescent characteristics of 1 are compared to those of its electron analogue: 2,2-difluoro-4-(4-phenylphenyl)-6-methyl-1,3,2-dioxaborine (C₆H₅C₆H₄ × COCHCOCH₃BF₂).     

Mannich reactions. Synthesis of 4,5-dihydropyrrolo[l,2-a]quinoxalines, 2,3,4,5-tetrahydro-lH-pyrrolo[l,2-a] [l,4]diazepines and 5,6-dihydro-4H-pyrrolo[ 1,2-a] [ 1,4]benzodiazepines

l-(2-Aminophenyl)pyrrole (I) and l-[2-(aminomethyl)]phenylpyrrole hydrochloride (III) undergo cyclization reactions with aldehydes and ketones to form 4,5-dihydropyrrolo[l,2-a]- quinoxalines and 5,6-dihydropyrrolo[l,2-a][l,4]benzodiazepines, respectively. It was also found that the use of the free base of compounds corresponding to III do not cyclize directly but lead instead to the intermediate Schiff bases which are subsequently cyclized to the desired benzodiazepines by treatment with hydrochloric acid.     

Regioselective synthesis of novel N2- and N4-substituted 7-methylpyrazolo[4,5-e][1,2,4]thiadiazines

The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one1,1-dioxide (5) was synthesized and its novel mono N2- or N4-substituted derivatives 6 and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios of NaH and alkyl halides. Based on the regioselective alkylation conditions found a facile one-pot synthesis of N2,N4-disubstituted pyrazolo[4,5-e][1,2,4] thiadiazines 8 was developed. The structures of the newly synthesized compounds were confirmed by IR,(1)H-NMR, (13)C-NMR and MS spectral analysis.     

Reaction of 2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole-5-carbonylchloride with phenylacetylene: predominant formation of 2-(2-chloro-2-phenylethenyl)-2,2-dichlorobenzo[d]-1,3,2-dioxaphosphole-5-carbonylchloride

The reaction of 2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole-5-carbonylchloride with phenylacetylene in benzene (80 °C) afforded 2-(2-chloro-2-phenylethenyl)-2,2-dichlorobenzo[d]-1,3,2-dioxaphosphole-5-carbonylchloride (yield >95%) as a result of the electrophilic cis-addition of the phosphorus(v) derivative at the triple bond of acetylene with retention of coordination of the P atom. Hydrolysis of this compound affords predominantly 2-hydroxy-5-(hydroxycarbonyl)phenyl (2-chloro-2-phenylethenyl)phosphonate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 377–379, February, 2006.     

Higher carbene homologues: Naphtho[2,3-d]-1,3,2λ2-diazagermole, -diazastannole,and attempted reduction of 2,2-dichloronaphtho[2,3-d]-1,3,2-diazasilole

N,N′-Dineopentyl-2,3-diaminonaph-thalene 1, obtained by reaction of 2,3-diaminonaph-thalene with pivaloyl chloride and subsequent re-duction, was dilithiated and cyclodisubstituted with SiCl₄ to give dichloro-dineopentyl-naphtho[2,3-d]-1,3,2-diazasilole 2. Treatment of 2 with two equivalents of potassium in THF caused cleavage of the Si–N ring. A silylene could not be detected. The corresponding cyclic diaminogermylene 3 and diamino-stannylene 4 were obtained by direct ring closure of 1–Li₂ with GeCl₂·dioxane or SnCl₂, respectively. The compounds are structurally characterized by NMR and MS. The properties of 3 and 4 are compared with those of related germylenes and stannylenes. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:439–444, 1998     

Synthesis of 4-arylcarbamoyl-5-(2-hydroxynaphthylazo)imidazoles and 1-substituted naphtho[2,1-e]imidazo[5,1-c][1,2,4]triazines

The reactions of β-naphthol with 5-diazoimidazoles and imidazolyl-5-diazonium salts containing chemically different carboxamide groups in position 4 were studied. Heterocyclization of 4-arylcarbamoyl-5-(2-hydroxynaphthylazo)imidazoles formed in these reactions was investigated. The presence of the NH fragment in the amide group prevents this process, the reaction giving instead 3-substituted 3,7-dihydroimidazo[4,5-d][1,2,3]triazin-4-ones, which is due to reversibility of C-azo coupling. Methods for modification of 1-ethoxycarbonyl group in the naphtho[2,1-e]imidazo[5,1-c][1,2,4]triazine system were developed and used to prepare substituted carboxamides inaccessible by other routes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1208–1213, July, 2006.