- Dynamic Kinetic Resolution of Phosphinic Acid Derivatives via Nucleophilic Substitution at Phosphorus Center
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Reaction of racemic phosphinic acid derivatives with chiral alcohols proceeds with predominant formation of one diastereomer. The highest level of enrichment has been obtained for transesterfication of racemic methyl benzylphenylphosphinate (64% de). The
- Strzelecka, Dorota,Baok, Olga,Borowski, Piotr,Stankevi?, Marek
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p. 4922 - 4932
(2018/12/14)
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- Efficient esterification of carboxylic acids and phosphonic acids with trialkyl orthoacetate in ionic liquid
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An operationally simple, inexpensive, efficient, and environmentally friendly esterification of various carboxylic acids, phosphonic acids, and phosphinic acids with triethyl orthoacetate or trimethyl orthoacetate under neutral conditions in a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was successfully carried out to provide the corresponding ethyl esters or methyl esters in high yields.
- Yoshino, Tomonori,Imori, Satomi,Togo, Hideo
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p. 1309 - 1317
(2007/10/03)
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- Facile preparation of polymer-supported methyl sulfonate and its recyclable use for methylation of carboxylic acids and amines
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A simple and efficient one-pot procedure for the preparation of polymer-supported methyl sulfonate from the reaction of polymer-supported sulfonic acid with trimethyl orthoacetate was achieved, and it could be successfully used for efficient methylation of carboxylic acids, phosphonic acids, sulfinic acids, amines, thiol, and phenol. Moreover, the polymer reagent could be recovered, regenerated, and reused easily for the same reactions. Georg Thieme Verlag Stuttgart.
- Yoshino, Tomonori,Togo, Hideo
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p. 517 - 519
(2007/10/03)
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- Organophosphorus Compounds. XIX. Synthesis of 2,3-Dihydro-1H-1,2-benzazaphosphole 2-Oxides, Variously Substituted on Nitrogen and Phosphorus, by N-P Cyclization of Zwitterionic Intermediates
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2-Phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (7a) was prepared by thermolysis of the corresponding zwitterionic amino phosphinic acid (4), or its hydrochloride salt (1).Thermolysis of methyl (2-aminobenzyl)phenylphosphinate (5a) was accompanied by intermolecu;ar O->N transmethylation to give, after cyclization, 1-methyl-2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (9a); similarly, the ethyl ester (5b) gave the N-ethyl heterocycle (9b). Reaction of 2-phthalimidobenzyl bromide (13a) with diethyl methylphosphonite (14b) gave ethyl (2-phthalimidobenzyl)methylphosphinate 15a).Hydrolysis of (15a) afforded (2-aminobenzyl)-methylphosphinic acid (16), and thermolysis of this produced 2-methyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (18a). 1-Methyl-2-methoxy-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (24) was synthesized in an analogous manner. Base catalyzed N-alkylation of the benzazaphosphole derivatives (7a) and (18a) was readily achieved, and the interconversion of 2-oxides and 2-sulfides was accomplished by conventional methods.
- Collins, David J.,Drygala, Peter F.,Swan, John M.
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p. 2517 - 2536
(2007/10/02)
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