Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
  • C07D201/02—Preparation of lactams
  • C07D201/08—Preparation of lactams from carboxylic acids or derivatives thereof, e.g. hydroxy carboxylic acids, lactones or nitriles

Definitions

• the present invention relates to the preparation of decarbonylation products of carboxylic acids substituted at the alpha-carbon atom. More particularly, the present invention relates to the preparation of decarbonylation products of alpha-hydroxylamino-carboxylic caids.
• alpha-hydroxy-carboxylic acids are treated with a strong acid, whereby carbon monoxide and water are split off, so that an aldehyde is obtained.
• an alphahydroxy-carboxylic acid whose alpha-carbon atom is not bound to a hydrogen atom, but attached to an alkyl or aryl group can be used to prepare the corresponding ketone.
• a process has now been found in which decarbonylation of alpha-hydroxylamino-carboxylic acids is carried out with a strong acid, whereby the corresponding lactam or other material is obtained, with the splitting off of carbon monoxide from the carboxylic acids.
• a nitrogen-contaning product is obtained, e.g., oximes, amides and lactams.
• alpha-hydroxylamino-carboxylic acids which may be used are the normal or branched alphahydroxylamino-alkane carboxylic acids, e.g., alpha-hydroxylamino-n-valeric acid, alpha hydroXylamiuo-ncaproic acid, and alpha-hydroxylamino-isobutyric acid; and alpha-hydroxylamino-cyclo-alkane carboxylic acids, e.g., alpha-hydroxylamino-cyclohexane carboxylic acid and alpha-hydroxylamino-cycloheptane carboxylic acid.
• the alpha-hydroxylamino-carboxylic acids which can be employed in the process of the present invention contain at least 2 carbon atoms and preferably contain from 2 to 13 carbon atoms.
• the decarbonylation according to the invention is carried out by means of a strong acid, e.g., phosphoric acid, polyphosphoric acid, hydrochloric acid, sulfuric acid and oleum, or a mixture of liquid sulfur dioxide and sulfur trioxide.
• a strong acid e.g., phosphoric acid, polyphosphoric acid, hydrochloric acid, sulfuric acid and oleum, or a mixture of liquid sulfur dioxide and sulfur trioxide.
• the amount of strong acid which should be used in the reaction mixture can be varied within wide limits. In general, we prefer to use an amount of strong acid corresponding to at least about 4 moles of acid to one mole of alpha-hydroxylamino-carboxylic acid in the reaction mixture.
• the reaction can be carried out at atmospheric pressure and it is not necessary to apply a higher or a lower pressure. Therefore, the reaction can be carried out by the use of simple apparatus.
• the temperature at which the decarbonylation is carried out can be varied within wide limits. It is not necessary to use very high temperatures, e.g., above 250 C., as in most cases the process can be realized at room temperature or low temperature, e.g., 10 to 30 C. If the reaction is carried out in the presence of sulfur trioxide, spontaneous evolution of gas will occur at this low temperature, as a result of carbon monoxide being split off. This gas evolution is promoted if stirring takes place.
• the nature of the alpha-hydroxylamino-carboxylic acid used as the starting product and the nature of the decar-bonylation products desired should be taken into consideration. If, for instance, the starting product is alpha-hydroxylamino-isobutyric acid, mainly acetone oxime will be formed at a relatively low temperature of 10-25 C., while mainly N-methylacetamide will be obtained at a relatively high temperature of -150 C.
• Example I In a 5-liter reaction vessel equipped with a stirrer, 150 g. of alpha-hydroxylamino-cyclohexane carboxylic acid is dissolved in 500 ml. of sulfuric acid (concentration 96% by weight). While the solution is being stirred, 500 ml. of oleum (sulfur trioxide content 20% by weight) is slowly added over a period of 0.5 hr., at a temperature of 20 C., and after this addition stirring is continued for one more hour at the same temperature.
• sulfuric acid concentration 96% by weight
• reaction mixture is chilled by pouring onto 5 kg. of crushed ice. Then suflicient amount of ammonia is added to neutralize the reaction mixture to a pH value of 7.
• Example II The decarbonylation of 208 g. of alpha-hydroxylamino-cycloheptane carboxylic acid is carried out in a similar way as described in Example I.
• Example III In a 10-liter reaction vessel provided with a stirrer, 795 g. of alpha-hydroxylamino-cyclohexane carboxylic acid is dissolved in 5 liters of polyphosphoric acid (phosphorus pentoxide content 82% by weight). While being stirred, the solution is heated to C. in 0.5 hr., after which stirring is continued at this temperature for 1.5 hours.
• polyphosphoric acid phosphorus pentoxide content 82% by weight
• reaction mixture is chilled by pouring onto 10 kg. of ice, and the process is continued as described in Example I.
• the amount of carbon monoxide collected is 99% of the theoretical amount, and the amount of butyramide obtained is 700 g. (yield 81%).
• Example V In the apparatus described in Example III, 1071 g. of alpha-hydroxylamino-isobutyric acid is dissolved in 2.5 liters of sulfuric acid (100%). While the solution is being stirred, 2.5 liters of oleum (sulfur trioxide content 20%) is slowly added over a period of 1 hour, at a temperature of 15-20 C.; during this addition, gas is evolved. Stirring in continued at the said temperature for another 2 hours, and the reaction mixture is then subjected to further treatment as described in Example I.
• oleum sulfur trioxide content 20%
• the amount of carbon monoxide collected is 80% of the theoretical amount, and acetoxime is obtained in an amount of 280 g. (yield 52% at this degree of conversion).
• Example VI The decarbonylation described in Example V is repeated at a higher temperature. In this process 685 g. of alpha-hydroxylamino-isobutyric acid is dissolved in 1.6 liters of sulfuric acid (100%), and the solution is slowly heated in 1 hour to a temperature of 120 C. During this heating, a slow evolution of gas took place.
• the amount of carbon monoxide collected is 81% of the theoretical amount,- and in this process 334 g. of N-methyl-acetamide is obtained (yield 99% of this degree of conversion).
• alpha-hydroxylamino-carboxylic acids which comprises treating an alpha-hydroxylarnino-carboxylic acid selected from the group consisting of normal alpha-hydroxylaminoalkane carboxylic acids containing from 2 to about 13 carbon atoms, branched-chain alpha-hydroxylamino-alkane carboxylic acids containing from 2 to about 13 carbon atoms, and alpha-hydroxylamino-cycloalkane carboxylic acids containing from about to about 13 carbon atoms, with a strong acid selected from the group consisting of phosphoric acid, polyphosphoric acid, hydrochloric acid, sulfuric acid and oleum, and a mixture of sulfur dioxide and sulfur trioxide, to form a nitrogencontaining product selected from the group consisting of oximes, amides and lactams.
• an alpha-hydroxylarnino-carboxylic acid selected from the group consisting of normal alpha-hydroxylaminoalkane carboxylic acids containing from 2 to about 13 carbon atoms
• the process for preparing acetoxime comprising: dissolving alpha-hydroxylamino-isohutyric acid in sulfuric acid, maintaining the mixture at a temperature of from about to about 25 C., and adding at least 2 moles of oleum per mole of alphahydroxylamino-isobutyric acid dissolved in said mixture to produce the acetoxime.
• the process for preparing butyramide comprising: dissolving alpha-hydroxylamino-n-valeric acid in sulfuric acid, maintaining the mixture at a temperature of from about i 10 to about 150 C.
• omega-oenantholactam comprising:

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Citations (1)

• 1964
  • 1964-07-18 NL NL6408265A patent/NL6408265A/xx unknown
• 1965
  • 1965-07-12 US US471393A patent/US3369017A/en not_active Expired - Lifetime
  • 1965-07-13 DE DEST24125A patent/DE1256218B/de active Pending
  • 1965-07-14 CH CH990865A patent/CH484059A/de not_active IP Right Cessation
  • 1965-07-15 GB GB30134/65A patent/GB1105166A/en not_active Expired
  • 1965-07-16 BE BE667020D patent/BE667020A/xx unknown

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