| 摘要 |
Aldehydes of the formula <FORM:0665626/IV (b)/1> where R is an aliphatic group of 1-4 carbon atoms and R1 and R2 are hydrogen or similar aliphatic groups, are obtained by reacting R1-CH=CR2-CHO with nitro-malonic esters in the presence of an alkaline catalyst such as sodium ethoxide, triethylamine, tripropylamine or tributylamine. A solvent such as ethanol or benzene may be used. Examples show the reaction of acrolein with ethyl nitromalonate to give g -nitro-g g -dicarbethoxy-butyraldehyde, which forms a 2 : 4-dinitrophenylhydrazone. The methyl, propyl and butyl esters may also be used; methacrolein and crotonaldehyde are other suitable aldehydes. Amino-acids may be synthesized from the above nitro-aldehyde (R=Et, R1=R2=H) as follows: (1) the phenylhydrazone is ring-closed to give <FORM:0665626/IV (b)/2> which is then decarboxylated to the a -nitro-b -indolyl-propionic ester; the nitro group is then reduced and the product hydrolysed to give tryptophane; (2) the aldehyde cyanhydrin is dehydrated to the unsaturated nitrile, hydrogenated to 1 : 1-dicarbethoxy-1 : 5-diamino pentane which is then hydrolysed to lysine; (3) the aldehyde is converted into its oxime, aldimine, phenylhydrazone or semicarbazone and reduced to yield 1 : 1 - dicarbethoxy - 1 : 4 - diamino - butane; this can be hydrolysed to ornithine; (4) direct hydrogenation of the aldehyde yields (with spontaneous ring-closure) 2 : 2-dicarbethoxy-pyrrolidine which is hydrolysed and decarboxylated to give proline. It is also stated that the other aldehydes (R1 or R2=alkyl) may be used for the synthesis of alkyl-substituted amino acids. The Specification as open to inspection under Sect. 91 refers to compounds of the first formula above where R may be hydrogen. This subject-matter does not appear in the Specification as accepted.
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