作者:Isuru Dissanayake、Jacob D. Hart、Emma C. Becroft、Christopher J. Sumby、Christopher G. Newton
DOI:10.1021/jacs.0c06306
日期:2020.8.5
5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels-Alderreaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels-Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from
[EN] YIELD-EFFICIENT PROCESS FOR THE PRODUCTION OF HIGHLY PURE 2-METHYL-1,4-NAPHTHOQUINONE AND ITS DERIVATIVES<br/>[FR] PRODUCTION À FORT RENDEMENT DE 2-MÉTHYL-1,4-NAPHTOQUINONE D'UNE GRANDE PURETÉ ET DE SES DÉRIVÉS
申请人:LONZA AG
公开号:WO2011085945A1
公开(公告)日:2011-07-21
The present invention discloses a process for the production of 2-methyl-1,4-naphthoquinone and its bisulfite adducts, comprising the following steps: a) oxidizing 2-methyl-naphthalene (2-MNA) to achieve an organic phase containing 2-methyl-naphthoquinone (2-MNQ) and 6-methyl-naphthoquinone (6-MNQ); b) subjecting said organic phase to treatment with an aqueous solution of a bisulfite salt to extract preferentially the 6-MNQ isomer from the organic phase; c) separating said organic phase from the aqueous phase; d) subjecting the organic phase of process step c) to a second bisulfitation step with an aqueous solution of a bisulfite salt, resulting in an organic phase containing 2-MNA and trace amounts of 2-MNQ and an aqueous phase containing 2-MSB and trace amounts of 6-MSB; e) optionally removing interfering bisulfite ions from the aqueous phase of process step c); f) raising the pH of the aqueous phase from step c) or e) to higher than 8,5 in the presence of a solvent resulting in an organic phase containing 2-MNQ; g) combining the organic phase from step f) with the organic phase being treated in the process step d); h) recycling the organic phase from step d) back to step a) to be used as solvent for the oxidation reaction of 2-MNA.