The key feature in the synthesis of topicdy-active carbonic anhydrase inhibitor MK-0507 (13b) is ... more The key feature in the synthesis of topicdy-active carbonic anhydrase inhibitor MK-0507 (13b) is a Ritter reaction that exhibits an unexpected tendency to proceed with retention of chirality. This phenomenon was further studied on model compounds free from potential diastereomeric effects. A mechanism involving traneannular stabilization of the sp2-hybridized center by sulfone oxygen is proposed with the net result of double inversion. A second key feature in the preferred sequence to MK-0507 involves the claeaic problem of how to maximize substitution over elimination. This problem manifests itself in the stereospecific alkylation of 2-mercaptothiophene with derivatized methyl (R)-3-hydroxybutyrate and is compounded by a subsequent Michael reaction leading to a loss of product chirality. Results are presented that eliminate this problem.
Enantiomerically pure MK-0417 has been prepared in nine steps from thiophene. The key reactions i... more Enantiomerically pure MK-0417 has been prepared in nine steps from thiophene. The key reactions in the sequence were an oxazaborolidine-catalyzed borane reduction followed by a tosylationJamine displacement. The borane reduction was studied in detail, and observations regarding substituents on the oxazaborolidine catalyst and the intricacies of the reaction are reported, as well as a mild method for recovering the enantiomerically pure amino alcohol derived from the catalyst. our substrate on large scale would be difficult and yeast gave the undesired enantiomer, we chose to optimize the
Radnóti, Miklós. 2015. Eclogues and Other Poems (trans. Jack Roberts). Szeged: Americana e-Books.... more Radnóti, Miklós. 2015. Eclogues and Other Poems (trans. Jack Roberts). Szeged: Americana e-Books. 88 pp.
Márai, Sándor. 2013. The Withering World (trans. John M. Ridland and Peter V. Czipott). Richmond,... more Márai, Sándor. 2013. The Withering World (trans. John M. Ridland and Peter V. Czipott). Richmond, Surrey, UK: Alma Books. 242 pp. Reviewed by Paul Sohar, Freelance Writer
Hargitai, Peter. 2014. Barbarian Fantasy. Gulfport, FL: ipubs.Reviewed by Paul Sohar, poet and tr... more Hargitai, Peter. 2014. Barbarian Fantasy. Gulfport, FL: ipubs.Reviewed by Paul Sohar, poet and translator
The key feature in the synthesis of topicdy-active carbonic anhydrase inhibitor MK-0507 (13b) is ... more The key feature in the synthesis of topicdy-active carbonic anhydrase inhibitor MK-0507 (13b) is a Ritter reaction that exhibits an unexpected tendency to proceed with retention of chirality. This phenomenon was further studied on model compounds free from potential diastereomeric effects. A mechanism involving traneannular stabilization of the sp2-hybridized center by sulfone oxygen is proposed with the net result of double inversion. A second key feature in the preferred sequence to MK-0507 involves the claeaic problem of how to maximize substitution over elimination. This problem manifests itself in the stereospecific alkylation of 2-mercaptothiophene with derivatized methyl (R)-3-hydroxybutyrate and is compounded by a subsequent Michael reaction leading to a loss of product chirality. Results are presented that eliminate this problem.
Enantiomerically pure MK-0417 has been prepared in nine steps from thiophene. The key reactions i... more Enantiomerically pure MK-0417 has been prepared in nine steps from thiophene. The key reactions in the sequence were an oxazaborolidine-catalyzed borane reduction followed by a tosylationJamine displacement. The borane reduction was studied in detail, and observations regarding substituents on the oxazaborolidine catalyst and the intricacies of the reaction are reported, as well as a mild method for recovering the enantiomerically pure amino alcohol derived from the catalyst. our substrate on large scale would be difficult and yeast gave the undesired enantiomer, we chose to optimize the
Radnóti, Miklós. 2015. Eclogues and Other Poems (trans. Jack Roberts). Szeged: Americana e-Books.... more Radnóti, Miklós. 2015. Eclogues and Other Poems (trans. Jack Roberts). Szeged: Americana e-Books. 88 pp.
Márai, Sándor. 2013. The Withering World (trans. John M. Ridland and Peter V. Czipott). Richmond,... more Márai, Sándor. 2013. The Withering World (trans. John M. Ridland and Peter V. Czipott). Richmond, Surrey, UK: Alma Books. 242 pp. Reviewed by Paul Sohar, Freelance Writer
Hargitai, Peter. 2014. Barbarian Fantasy. Gulfport, FL: ipubs.Reviewed by Paul Sohar, poet and tr... more Hargitai, Peter. 2014. Barbarian Fantasy. Gulfport, FL: ipubs.Reviewed by Paul Sohar, poet and translator
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