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Bendfort Rock Ranger District – One of the best experts on this subject based on the ideXlab platform.

S. J. Shenoy – One of the best experts on this subject based on the ideXlab platform.

  • Condensed heterotricycles: Pyrido(1,2,3-de)(1,4)benzoxazines, pyrido(1,2,3-ef)(1,5)benzoxazepines and pyrido(1,2,3-fg)(1,6) benzoxazocines
    Proceedings of the Indian Academy of Sciences – Chemical Sciences, 1992
    Co-Authors: K. Nagarajan, A. Nagana Goud, R. K. Shah, S. J. Shenoy
    Abstract:

    Cyclization of N-(2-haloacyl)-8-hydroxy-l,2,3,4-tetrahydroqumolines 4 – 7 and 9 with alkali affords pyridobenzoxazinones 21 – 24 and 26 respectively and of the 4-chlorobutyramide 13 with NaH, the benzoxazocinone 31 . Exposure of 3-chloropropionamide 12 to NaH affords acrylamide 15 , benzoxazepinone 28 or methyl benzoxazinone 22 or mixtures thereof under various conditions. 28 undergoes rapid base-catalysed ring contraction to 22 . NaH-catalysed ring closure of acrylamide 15 affords mixtures of 22 and 28 , while from the crotonamides 16 and 17 , the methylbenzoxazepinones 29 and 30 are obtained preponderantly, the former amide yielding only traces of the ethyl benzoxazinone 23 . 29 shows no propensity for ring contraction to give 23 . The cinnamoyl derivatives 18 , 19 and 20 are cyclized to benzyl benzoxazinones 24 , 27 and 25 , respectively. The intermediacy of the phenyl benzoxazepinone 39 in the formation of 24 has been established by deuteration studies. Benzylidene benzoxazinone 41 is obtained from dibromocinnamamide 14 and propiolamide 40 . Dichloracetamides 8 and 10 undergo interesting ring closure to compounds 45 – 54 upon treatment with amines. The course of electrophilic reactions of the lactams depends upon the ring size.

  • Condensed heterotricycles: Pyrido(1,2,3-de)(1,4)benzoxazines, pyrido(1,2,3-ef)(1,5)benzoxazepines and pyrido(1,2,3-fg)(1,6) benzoxazocines
    Proceedings of the Indian Academy of Sciences – Chemical Sciences, 1992
    Co-Authors: K. Nagarajan, A. Nagana Goud, R. K. Shah, V. Ranga Rao, S. J. Shenoy
    Abstract:

    Cyclization of N-(2-haloacyl)-8-hydroxy-l,2,3,4-tetrahydroqumolines 4 – 7 and 9 with alkali affords pyridobenzoxazinones 21 – 24 and 26 respectively and of the 4-chlorobutyramide 13 with NaH, the benzoxazocinone 31 . Exposure of 3-chloropropionamide 12 to NaH affords acrylamide 15 , benzoxazepinone 28 or methyl benzoxazinone 22 or mixtures thereof under various conditions. 28 undergoes rapid base-catalysed ring contraction to 22 . NaH-catalysed ring closure of acrylamide 15 affords mixtures of 22 and 28 , while from the crotonamides 16 and 17 , the methylbenzoxazepinones 29 and 30 are obtained preponderantly, the former amide yielding only traces of the ethyl benzoxazinone 23 . 29 shows no propensity for ring contraction to give 23 . The cinnamoyl derivatives 18 , 19 and 20 are cyclized to benzyl benzoxazinones 24 , 27 and 25 , respectively. The intermediacy of the phenyl benzoxazepinone 39 in the formation of 24 has been established by deuteration studies. Benzylidene benzoxazinone 41 is obtained from dibromocinnamamide 14 and propiolamide 40 . Dichloracetamides 8 and 10 undergo interesting ring closure to compounds 45 – 54 upon treatment with amines. The course of electrophilic reactions of the lactams depends upon the ring size.

K. Nagarajan – One of the best experts on this subject based on the ideXlab platform.

  • Condensed heterotricycles: Pyrido(1,2,3-de)(1,4)benzoxazines, pyrido(1,2,3-ef)(1,5)benzoxazepines and pyrido(1,2,3-fg)(1,6) benzoxazocines
    Proceedings of the Indian Academy of Sciences – Chemical Sciences, 1992
    Co-Authors: K. Nagarajan, A. Nagana Goud, R. K. Shah, S. J. Shenoy
    Abstract:

    Cyclization of N-(2-haloacyl)-8-hydroxy-l,2,3,4-tetrahydroqumolines 4 – 7 and 9 with alkali affords pyridobenzoxazinones 21 – 24 and 26 respectively and of the 4-chlorobutyramide 13 with NaH, the benzoxazocinone 31 . Exposure of 3-chloropropionamide 12 to NaH affords acrylamide 15 , benzoxazepinone 28 or methyl benzoxazinone 22 or mixtures thereof under various conditions. 28 undergoes rapid base-catalysed ring contraction to 22 . NaH-catalysed ring closure of acrylamide 15 affords mixtures of 22 and 28 , while from the crotonamides 16 and 17 , the methylbenzoxazepinones 29 and 30 are obtained preponderantly, the former amide yielding only traces of the ethyl benzoxazinone 23 . 29 shows no propensity for ring contraction to give 23 . The cinnamoyl derivatives 18 , 19 and 20 are cyclized to benzyl benzoxazinones 24 , 27 and 25 , respectively. The intermediacy of the phenyl benzoxazepinone 39 in the formation of 24 has been established by deuteration studies. Benzylidene benzoxazinone 41 is obtained from dibromocinnamamide 14 and propiolamide 40 . Dichloracetamides 8 and 10 undergo interesting ring closure to compounds 45 – 54 upon treatment with amines. The course of electrophilic reactions of the lactams depends upon the ring size.

  • Condensed heterotricycles: Pyrido(1,2,3-de)(1,4)benzoxazines, pyrido(1,2,3-ef)(1,5)benzoxazepines and pyrido(1,2,3-fg)(1,6) benzoxazocines
    Proceedings of the Indian Academy of Sciences – Chemical Sciences, 1992
    Co-Authors: K. Nagarajan, A. Nagana Goud, R. K. Shah, V. Ranga Rao, S. J. Shenoy
    Abstract:

    Cyclization of N-(2-haloacyl)-8-hydroxy-l,2,3,4-tetrahydroqumolines 4 – 7 and 9 with alkali affords pyridobenzoxazinones 21 – 24 and 26 respectively and of the 4-chlorobutyramide 13 with NaH, the benzoxazocinone 31 . Exposure of 3-chloropropionamide 12 to NaH affords acrylamide 15 , benzoxazepinone 28 or methyl benzoxazinone 22 or mixtures thereof under various conditions. 28 undergoes rapid base-catalysed ring contraction to 22 . NaH-catalysed ring closure of acrylamide 15 affords mixtures of 22 and 28 , while from the crotonamides 16 and 17 , the methylbenzoxazepinones 29 and 30 are obtained preponderantly, the former amide yielding only traces of the ethyl benzoxazinone 23 . 29 shows no propensity for ring contraction to give 23 . The cinnamoyl derivatives 18 , 19 and 20 are cyclized to benzyl benzoxazinones 24 , 27 and 25 , respectively. The intermediacy of the phenyl benzoxazepinone 39 in the formation of 24 has been established by deuteration studies. Benzylidene benzoxazinone 41 is obtained from dibromocinnamamide 14 and propiolamide 40 . Dichloracetamides 8 and 10 undergo interesting ring closure to compounds 45 – 54 upon treatment with amines. The course of electrophilic reactions of the lactams depends upon the ring size.

Patrick Baylère – One of the best experts on this subject based on the ideXlab platform.

  • Synthetic, cyclovoltammetric and UV-photoelectron spectroscopic studies of 2,3-dihydro-1H-1,3,2-diazaboroles and 1,3,2-diazaborolidines
    Organometallics, 2005
    Co-Authors: L Weber, I. Domke, W. Greschner, Karinne Miqueu, Anna Chrostowska, Patrick Baylère
    Abstract:

    The oxidation potentials Eox of a series of 2,3-dihydro-1H-1,3, 2-diazaboroles tBuNCH=CHN(tBu)BR (1a-i) and of the corresponding saturated 1,3,2-diazaborolidines 2a (R = NH2), 2b (OMe), 2c (Me), 2d (NMe2), 2e (H), 2f (SMe), 2g (SnMe3), 2h (Br), 2i (CN) were determined by cyclovoltammetry in CH2Cl 2 solution. The potentials Eox of the irreversible electrochemical oxidations range from Eox = -288 mV (1a) to 752 mV (1i). In contrast to this, Eox of the corresponding diazaborolidines are anodically shifted by 260 mV (1d, 2d) to 752 mV (1b, 2b) and vary from 280 mV (2a) to 1164 mV (2i). Gas-phase photoelectron spectra of representatives of both series of compounds were recorded and assessed by density functional calculations. The first ionization potentials of the 2,3-dihydro-1H-1,3,2- diazaboroles range in the series le (7.1 eV) < 1f (7.3 eV) < le = 1h (7.4 eV) < 1i (7.7 eV). They differ by less than 0.3 eV from the first ionization potentials determined for the saturated analogues [1st IP for 2c (7.3 eV) < 2e = 2f (7.4 eV) < 2h (7.7 eV)]. © 2005 American Chemical Society.

George A. Olah – One of the best experts on this subject based on the ideXlab platform.

  • Superacidic activation of 1- and 3-isoquinolinols and their electrophilic reactions.
    The Journal of organic chemistry, 2002
    Co-Authors: Konstantin Yu. Koltunov, G. K. Surya Prakash, Golam Rasul, George A. Olah
    Abstract:

    Isomeric 1- and 3-isoquinolinols (11 and 12) when activated in CF3SO3H−SbF5 acid system undergo selective ionic hydrogenation with cyclohexane to give 5,6,7,8-tetrahydro-1(2H)- and 5,6,7,8-tetrahydro-3(2H)-isoquinolinones (22 and 27). Under the influence of aluminum chloride similar products were also obtained along with 3,4-dihydro-1(2H)- and 1,4-dihydro-3(2H)-isoquinolinones (23 and 28), respectively. Compounds 11 and 12 also condense with benzene in the presence of aluminum halides, under mild conditions, to give 3,4-dihydro-3-phenyl-1(2H)- and 1,4-dihydro-1-phenyl-3(2H)-isoquinolinones (24 and 29), respectively. Prolonged reaction time or catalysis under strongly acidic HBr−AlBr3 provides an alternative reaction pathway to yield 5,6-dihydro-6,8-diphenyl-1(2H)- and 5,6,7,8-tetrahydro-6,8-diphenyl-3(2H)-isoquinolinones (25 and 30), respectively. Products 24 and 29 were also found to revert back to 11 and 12 in the presence of aluminum halides in o-dichlorobenzene. The mechanism of these intriguing react…