Amines aminomalonic acid

Other abbreviations used Prw, n-propyl Pr , i-propyl Bun, n-butyl Bft, i-butyroyl Fe, fenchyl Cap, capryline=or-amino-octanoic acid aThr, aWothreonine HyNle, (3-hydroxynorleucine MPA, methylphenethyl-amine, HMPA, hydroxymethylphenethylamine Ama, aminomalonic acid. 

The major development in the Knorr pyrrole synthesis has been access to the amine component. For example, use of preformed diethyl aminomalonate with 1,3-diketones affords much higher yields of pyrroles 14. Reaction of 6-dicarbonyl compounds with hydroxylamine 0-sulfonic acid gives pyrroles 15 in one step. Weinreb a-aminoamides have found use in the Knorr pyrrole synthesis of a wide variety of pyrroles 16. °... 

Similarly, the methiodide was reacted with diethyl (2,2,2-trichloro-ethoxycarbonyl)aminomalonate as a nucleophile to give 118, which was then converted to the amine 119 by deprotection of the 2,2,2-trichloroethoxy-carbonyl group with zinc and potassium dihydrogen phosphate. Dehydrative cyclization of 119 to the azepinoindole 120 was achieved by heating 119 in the presence of a catalytic amount of pyridinium p-toluenesulfonate in dichloromethane. Hydrolysis of 120 with potassium hydroxide in methanol yielded the malonic acid derivative which was then readily decarboxylated on heating in aqueous ethanol to accomplish total syntheses of ( )-cis- and ( )-tranj-clavicipitic acid (84,85) in aratio 3 2 (Scheme 18) (57). 

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