摘要:
Allyl alcohols are isomerized in aqueous solution in the presence of protonic acids, with the pH of the reaction mixture being adjusted to the range from 2 to 5 with an acid concentration below 0.16 mol per liter of the reaction mixture or with a buffer which comprises the protonic acid.
摘要:
Improved processes for preparation of the (S)-oxetines in high enantiomeric purity centers on resolution using simulated moving bed chromatography of a racemic precursor early in the oxetine synthesis. Resolution is effected with high enantiomeric purity, and subsequent reactions of the desired enantiomer performed with high optical specificity to maintain enantiomeric purity. The undesired enantiomer may be racemized and recycled to the resolution phase to avoid undesired losses.
摘要:
Epoxides containing hydroxy groups are rearranged enantioselectively using a chiral base to give allyl alcohols in high enantiomeric excess, e.g. ##STR1## If R.sup.3 .noteq.H, the reaction also has the effect of generating a chiral tetrasubstituted carbon atom.
摘要:
The invention relates to a process for preparing enantiomerically pure S(+)-propan-1,2-diol and R(-)-propan-1,2-diol from L(-)-lactide or D(+)-lactide, respectively.
摘要:
A novel derivative of (-)-6,6-dimethylbicyclo [3.1.1]ept-2-ene-2-ethanol (J. P. Bain, J. Am. Chem. Soc. 1946, vol. 68, page 638) is disclosed. The parent composition is marketed e.g. under the name nopol, v. The Aldrich-Europe Catalog Handbook of Fine Chemicals, item 3160-5 nopol 98% 128-50-7.The object of the present invention is the compound of formula (I): 4-(2-hydroxyethyl) -.alpha..alpha.dimethyl-5-hydroxy-3-cyclohexene-1-methanol, with the process for obtaining the same, which consists of the preparation of (-)-(6,6-dimethylbicyclo[3.1.1]ept-2-ene-2-ethanol epoxide, followed by hydration of the above compound. Finally, this invention comprises the pharmaceutical compositions containing the compound of formula (I) which have a mucosecretolytic pharmacological activity.
摘要:
The process for the manufacture of but-2-en-1-ol compounds by isomerizing but-3-en-1-ol compounds in the presence of a palladium catalyst and of hydrogen is improved by modifying the palladium catalyst with selenium or tellurium.The but-2-en-1-ols manufactured according to the invention are either solvents or valuable starting materials for the manufacture of solvents, dyes, surface coatings, paints and pesticides.
摘要:
A process for allylic rearrangement, particularly terpenoid allylic rearrangement, utilizing certain acid forming metals to form an ester or alcoholate (alcohologen) of the allylic alcohol to be rearranged, isomerizing and cleaving the alcohologen in the presence of a transition metal compound catalyst and recovering the rearranged alcohol.
摘要:
New cycloaliphatic unsaturated ketones and their use as perfuming and odour-modifying agents in the manufacture of perfumes and perfumed products, and as flavouring and taste-modifying agents in the preparation of foodstuffs in general and imitation flavours for foodstuffs, beverages, animal feeds, pharmaceutical preparations and tobacco products.Methods for the preparation of said cycloaliphatic unsaturated ketones.
摘要:
New cycloaliphatic unsaturated ketones and their use as perfuming and odour-modifying agents in the manufacture of perfumes and perfumed products, and as flavouring and tastemodifying agents in the preparation of foodstuffs in general and imitation flavours for foodstuffs, beverages, animal feeds, pharmaceutical preparations and tobacco products. Methods for the preparation of said cycloaliphatic unsaturated ketones.
摘要:
Production of buten-2-ol-4 compounds by isomerization of buten1-ol-4 compounds in the presence of palladium or a compound thereof and hydrogen. The products are solvents or starting materials for the production of solvents, dyes, surface coatings and pest control agents.