The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,...The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.展开更多
A new perylenequinone, named hypomycin A, was isolated from the mycelia of Hypomyces sp.. Its structure was elucidated on the basis of spectroscopic methods.
Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone (PQ) in intramolecular proton transfer (IPT) process. It was found that there existed a maximum of dipole moment in...Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone (PQ) in intramolecular proton transfer (IPT) process. It was found that there existed a maximum of dipole moment in all IPT process except PQ anion (PQ) which possessed a minimum. Moreover, almost all states of PQ except ground state had high changes in dipole moment. All of these laid foundations to clarify solvent effects in IPT of PQ.展开更多
AIM To study the chemical constituents from the mycelia of Hypomyces sp. METHODS Silica gel column chromatography was employed for the isolation and purification. The structure of compound 1 was elucidated on the basi...AIM To study the chemical constituents from the mycelia of Hypomyces sp. METHODS Silica gel column chromatography was employed for the isolation and purification. The structure of compound 1 was elucidated on the basis of spectral analysis. RESULTS and CONCLUSION A new perylenequinone, named hypomycin B 1, was isolated from the mycelia of Hypomyces sp.展开更多
By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds o...By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.展开更多
Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the peryle...Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the perylenequinone molecule is of stable structure. and all substituents may cause the decrease of barriers for the hydrogen transfer reaction.展开更多
AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, single...AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers a-gainst the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79. 91 kJ/mol, respectively, (iii) Barriers against the IPT of cation and anion radical of PQ (PQ,+ and PC,-) are 65. 94 and 59.29 kJ/ mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89. 24 and 88. 07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven-membered side ring of HA has no marked influence on its barrier against IPT.展开更多
文摘The double oxidative coupling of methyl 8-bromo-3,4-dihydro- xy-5,7-dimethoxy-2-naphthylacetate and its solvent effect are studied. Demethylation followed by methylation or vice versa of dimethyl-2,11-dihy- droxy-4,6,7,9-tetramethoxy-3,10-perylenequinone-1,12-diacetate can be effected regioselectively and amenable to natural product synthesis.
文摘A new perylenequinone, named hypomycin A, was isolated from the mycelia of Hypomyces sp.. Its structure was elucidated on the basis of spectroscopic methods.
文摘Semiempirical quantum chemistry method AM1 was employed to calculate dipole moment of perylenequinone (PQ) in intramolecular proton transfer (IPT) process. It was found that there existed a maximum of dipole moment in all IPT process except PQ anion (PQ) which possessed a minimum. Moreover, almost all states of PQ except ground state had high changes in dipole moment. All of these laid foundations to clarify solvent effects in IPT of PQ.
文摘AIM To study the chemical constituents from the mycelia of Hypomyces sp. METHODS Silica gel column chromatography was employed for the isolation and purification. The structure of compound 1 was elucidated on the basis of spectral analysis. RESULTS and CONCLUSION A new perylenequinone, named hypomycin B 1, was isolated from the mycelia of Hypomyces sp.
基金Project supported by the National Natural Science Foundation of China.
文摘By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.
文摘Semi-empirical molecular orbital theory AMI method is employed to study the ortho-position substituent impact on intramolecular proton transfer reaction of perylenequinone. The calculation demonstrates that the perylenequinone molecule is of stable structure. and all substituents may cause the decrease of barriers for the hydrogen transfer reaction.
文摘AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers a-gainst the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79. 91 kJ/mol, respectively, (iii) Barriers against the IPT of cation and anion radical of PQ (PQ,+ and PC,-) are 65. 94 and 59.29 kJ/ mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89. 24 and 88. 07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven-membered side ring of HA has no marked influence on its barrier against IPT.
