foxy2 (Distinctive Doe)
03-20-02 23:50
No 285765
      Piperonal to MDP2P  Bookmark   

Here is a novel route, maybee a French speaker could translate the important stuff.

Methyl 3,4-dihydroxybenzyl ketones.    
Hinkley, David F.; Budavari, John.
Patent FR1450200

Abstract
The title compounds are prepared and can be used as chemical intermediates.  Thus, a solution of 60g 3,4-(MeO)2C6H3CHO (veratraldehyde) in 500ml C6H6 is cooled to 0C, a mixture of 30g NaOMe and 44.1ml MeCHClCO2Me (2-Chloropropionic acid methyl ester, 17639-93-9) added in 30 min. at 2-5C, and the mixture agitated for approximately 1 hour at approximately 20C to give Me a-methyl-a,b-epoxy-b-(3,4-dimethoxyphenyl)propionate (I).  A concentrated solution of I in C6H6 is treated with 400ml MeOH, the mixt. heated to 75C, 240ml 10% NaOH added in 30 min., and the mixture heated to 82C and treated with 50ml water to give Na a-methyl-a,b-epoxy-b-(3,4-dimethoxyphenyl)propionate (II).  An aqueous solution of II is heated to 100C for 30 min., 70ml concentrated HCl added, and the mixture heated 30 min. at 100C to give Methyl 3,4-dimethoxybenzyl ketone, which can be used in the preparation of 3,4-(HO)2C6H3CH2CMe(NH2)CO2H.  Similarly prepd. are 3,4-(HO)2C6H3CH2COMe (b0.05 165-8), 4,3-HO(MeO)C6H3CH2COMe, and methyl piperonyl ketone.



Those who give up essential liberties for temporary safety deserve neither liberty nor safety
 
 
 
 
    foxy2
(Distinctive Doe)
03-21-02 00:02
No 285767
      2-Chloropropionic acid methyl ester synthesis  Bookmark   

2-Chloropropionic acid methyl ester.    
Nagy, Kalman; Imre, Janos; Kiss, Jozsef, Mrs.; Halmos, Jozsef. 
HU  37908  A2  19860328  Patent  written in Hungarian.

Abstract
Me 2-chloropropionate, useful as a drug intermediate, is prepared by reacting 1 mol 2-chloropropionic acid with (greater than or equal to) 1.4 mol MeOH, using polyphosphoric acid catalyst.  Thus, a mixt. of 108.6 g 2-chloropropionic acid, 128.8 g MeOH, and 0.8 g polyphosphoric acid was refluxed for 1 h, followed by the addition of a solution of 2.5 g NaCl and 0.5 g Et3N in 100 mL water and neutralization with NaHCO3, to give 89.9% Me 2-chloropropionate.

Those who give up essential liberties for temporary safety deserve neither liberty nor safety
 
 
 
 
    foxy2
(Distinctive Doe)
03-21-02 00:20
No 285770
      2-Chloropropionic acid synthesis  Bookmark   

Patent US2010685
Patent US3671584

Purification
Patent US3772157

In German
Patent DE3422672
Patent DE1768536

Preparation of 2-chlorocarboxylic acids as materials for drugs and agrochemicals. 
Japanese patent 63287743
Abstract
RCHClCO2H (I; R = C1-4 n-alkyl) are prepd. by chlorination of aliph. carboxylic acid using anhydrides of I as the catalysts.  A mixt. of 3000 g propionic acid and 570 g (EtCO)2O was treated with Cl at 115-125 for 23 h and then water was added to the mixt. to give 5370 g reaction mixt. contg. 97.1% MeCHClCO2H. 

Those who give up essential liberties for temporary safety deserve neither liberty nor safety