Lewis acid mediated nucleophilic substitution reactions of 2-alkoxy-3,4-dihydro-2H-1-benzopyrans: regiochemistry and utility in the synthesis of 3,4-dihydro-2H-1-benzopyran-2-carboxylic acids
Organocatalyst-Mediated Dynamic Kinetic Enantioselective Acylation of 2-Chromanols
作者:Daniel A. Glazier、John M. Schroeder、Jitian Liu、Weiping Tang
DOI:10.1002/adsc.201800994
日期:2018.12.3
We recently developed a novel chiral catalyst‐directed dynamic kinetic diastereoselective acylation of hemiacetals for the synthesis of carbohydrates. In this update, we describe a catalytic method for the dynamic kinetic enantioselective acylation of 2‐chromanols using benzotetramisole derived catalysts. High yields and enantiomeric excesses were obtained for a broad range of acylated 2‐chromanols
The invention relates to compounds of the formula ##STR1## wherein R.sup.1 is hydrogen or lower alkyl; R.sup.2 is hydrogen or halogen; R.sup.3, R.sup.4 and R.sup.5 are hydrogen, acyl or lower alkyl; R.sup.6 and R.sup.7, independently, are hydrogen or lower alkyl; X is alkylene.sub.3-7 ; and n is an integer of zero to four; provided that only one of R.sup.3, R.sup.4 or R.sup.5 can be acyl; enantiomers thereof, and, when R.sup.7 is hydrogen, salts thereof with pharmaceutically acceptable bases. The compounds of formulas I and II are useful as agents for the treatment of allergic conditions.
Process for producing aspartame derivatives, process for purifying aspartame derivatives, production intermediates, and process for producing production intermediates
申请人:AJINOMOTO CO., INC.
公开号:US20020127320A1
公开(公告)日:2002-09-12
N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester derivatives, which are useful as sweeteners, may be conveniently produced by subjecting a 2-hydroxychroman derivative having various substituents on the benzene ring and aspartame to a reductive alkylation reaction. These compounds may be purified by subjecting such a derivative containing one or more impurities to a crystallization step to crystallize the same.
Further, there are provided a process for producing dialkoxychroman derivatives useful as intermediates for the production of such aspartame derivatives in the above process, and novel dialkoxychroman derivatives thus produced, which are excellent as the production intermediate.
PROCESSES FOR PRODUCING AND PURIFYING ASPARTAME DERIVATIVES AND PROCESS FOR PRODUCING PRODUCTION INTERMEDIATES
申请人:Ajinomoto Co., Inc.
公开号:EP1227104A1
公开(公告)日:2002-07-31
There are provided a process for producing an N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester derivative, which is useful as a sweetener, by subjecting a 2-hydroxychroman derivative having various substituents in a benzene ring and an aspartame to a reductive alkylation reaction, and a process for purifying the same by subjecting such derivative containing impurity(ies) to a crystallization step to crystallize the same.
Further, there are provided a process for producing a dialkoxychroman derivative useful as a production intermediate for the above aspartame derivative in the above process, and novel dialkoxychroman derivatives thus produced, and excellent as the production intermediate.