- AN IMPROVED PROCESS FOR THE PREPARATION OF FROVATRIPTAN
-
A process for the preparation and purification of Frovatriptan of formula (I) and its enantiomers, particuariy the R- enantiomer is disclosed, comprising formation of the di-p-toluoyltartaric acid salt of Frovatriptan.
- -
-
Page/Page column 14-15
(2012/11/13)
-
- Chemoselective and chemospecific protection and deprotection of a carbonyl group using polystyrene divinylbenzene sulfonic acid
-
Chemospecific protection of one carbonyl group of two identical carbonyls of 2,2-dialkyl-1,3-cyclohexanedione and chemoselective protection of aliphatic or aromatic carbonyls in the presence of conjugated carbonyl compounds using cross-linked polystyrene divinyl benzene sulfonic acid (SPS) as a heterogeneous catalyst has been demonstrated. Copyright
- Verma, Sanjeev K.,Sathe, Manisha,Kaushik
-
experimental part
p. 1701 - 1707
(2010/07/15)
-
- METHOD FOR PRODUCING CARBONYL COMPOUND AN PRO-OXIDANT USED FOR PRODUCTION OF CARBONYL COMPOUND
-
The invention provides a process for the preparation of a carbonyl compound in high efficiency by oxidizing an alcohol. The process for the preparation of a carbonyl compound of the present invention includes a step of oxidizing an alcohol in the presence of a compound of the formula (I) or a derivative or a salt thereof, and an oxidant, wherein R1 and R2 independently represent hydrogen, a halogen, a nitro or acidic group, or an alkyl or alkoxy group, each of which optionally has a substituent, or R1 and R2 combine the two carbon atoms to which they are boned to form an aromatic ring.
- -
-
Page/Page column 12; 14-15
(2009/08/16)
-
- PREPARATION OF CYCLIC, KETALIZED KETONES BY FAVORSKII REARRANGEMENT AND THE USE THEREOF FOR THE PREPARATION OF GLUCOKINASE ACTIVATOR 70
-
Methodologies for the alpha-monohalogenation of acid sensitive ketones, especially cyclic, acid-sensitive, ketalized ketones. As one approach, the ketone is reacted with a halogen donor compound, e.g., N-chlorosuccinimide, in anhydrous, highly polar organic reagents such as dimethylformamide (DMF). As another monohalogenation approach, it has been observed that organic salts generated from amines and carboxylic acids catalyze the monohalogenation of ketalized ketone in reagents comprising alcohol solvent (methanol, ethanol, isopropanol, etc.). The monohalogenation is fast even at -5°C. The salt can be rapidly formed in situ from ingredients including amines and/or carboxylic acids without undue degradation of the acid sensitive ketal. Aryl ketones are monooxygenated using iodosylbenzene. This methodology is applied to monohalogenation of an acid sensitive monoketal ketone. The ability to prepare monohalogenated, acid sensitive ketones facilitates syntheses using halogenated, acid sensitive ketones. As just one example, facile synthesis of halogenated, acid sensitive ketones provides a new approach to synthesize the S-ketal-acid S-MBA (S-methylbenzylamine) salt useful as an intermediate in the manufacture of a glucokinase activator. As an overview of this scheme, a monohalogenated, cyclic, ketalized ketone is prepared using monohalogenation methodologies of the present invention. The halogenated compound is then subjected to a Favorskii rearrangement under conditions to provide the racemic acid counterpart of the desired chiral salt. The desired chiral salt is readily recovered in enantiomerically pure form from the racemic mixture.
- -
-
Page/Page column 23
(2008/06/13)
-
- A new efficient deprotection of azines, hydrazones and oximes. An excellent route for exchanging oxygen isotopes in carbonyls
-
Carbonyls, protected as azines or other C=N derivatives can be deprotected by HOF·CH3CN in seconds to the corresponding ketone or aldehyde in very good yields. This reaction also offers a very efficient route for replacing the oxygen atom of most carbonyls with any other oxygen isotope, for example, [18]O.
- Carmeli, Mira,Rozen, Shlomo
-
p. 763 - 766
(2007/10/03)
-
- Process for the preparation of monoketals of 1,4-cyclohexanedione including 1, 4-cyclohexanedione mono-2,2-dimethyl trimethylene ketal
-
There is provided a process for preparation of a monoketal compound of the structure that includes reacting 1,4-cyclohexanedione of the structure with a diol of the structure in a halogenated organic solvent in the presence of an acid catalyst, wherein X is a substituted or unsubstituted ethylene or propylene. Various embodiments and variants are provided.
- -
-
-
- SYNTHESIS OF CIS- AND TRANS-1-METHYLCYCLOHEXANE-1,4-DIOLS AND THEIR 4-HEMISUCCINATE ESTERS
-
Stereoselective syntheses of the previously uncharacterized cis- and trans-1-methylcyclohexane-1,4-diols and their conversion to 4-hemisuccinate esters are described.
- Bushweller, John H.,Anzalone, Luigi,Spencer, Thomas A.
-
p. 745 - 754
(2007/10/02)
-
- 1,2,4-TRIOXANES AS MASKED, DUAL PURPOSE, FUNCTIONAL GROUPS
-
1,2,4-Trioxanes readily undergo reductive cleavage upon treatment with zinc and acetic acid to furnish the corresponding 1,2-diols and C3-derived carbonyl compounds in high yield.
- Jefford, Charles W.,Rossier, Jean-Claude,Boukouvalas, John
-
p. 673 - 676
(2007/10/02)
-
- Synthesis of ketones with calcium hypochlorite
-
The present invention pertains to a process for preparing ketones employing a silica catalyzed oxidation of a secondary alcohol with calcium hypochlorite in acetonitrile.
- -
-
-
- A FACILE AND EFFICIENT METHOD FOR MONOKETALIZATION OF 1,4-CYCLOHEXANEDIONE
-
Using a suitable hydrocarbon solvent such as hexane, continuous extraction of an aqueous solution of 1,4-cyclohexanedione containing 2,2-dimethyl-1,3-propanediol in molar excess and sulfuric acid as a catalyst afforded 1,4-cyclohexanedione mono-2,2-dimethyltrimethylene ketal (1b) in 85percent yield.
- Babler, James H.,Spina, Kenneth P.
-
-