- DIRECT LITHIATION OF FUNCTIONALLY SUBSTITUTED ACRYLIC ACID DERIVATIVES; LITHIATION OF β-(2-FURANYL)- AND β-(2-THIENYL)-ACRYLIC ACIDS
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Direct C-lithiation of β-functionally-substituted acrylates yields versatile building units for syntheses of butenolides, tetronates, cyclopentenones and derivatives, which are portions of many natural products.A wide variety of α- and β-substituents are compatible with this lithiation: alkyl-, aryl- and electron donating substituents in α-position or for instance an electron withdrawing ester group in β-position.Lithiation of aminomethylene malonitrile derivative 17 led to a new azafulvene 18. β-(2-Furanyl)- and β-(2-thienyl)-acrylates (23-30) were directly C-lithiated in α-, β-, or 5-position and α- or 5-position, respectively.Reactions with different electrophiles were carried out.The presence of the unprotected electrophilic carboxylic group allows for interesting ring closure reactions, for instance with carbonyl compounds to butenolides 42 and 43.The three vinylic positions (α, β and C-5) are accessible to a highly site-selective successive lithiation and reaction with electrophiles, as demonstrated for the transformation of 25 to 45 via 42 and 44.
- Schmidt, R. R.,Hirsenkorn, R.
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- Hydrogenation of imino-bisnitriles - Synthesis of novel triamines
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The hydrogenation of iminonitriles and iminobisnitriles of type 1a-f is a particularly difficult process as the intermediate dieneamines are highly susceptible to addition reactions. A short general method of preparation and purification of 2-aminomethylene-1,3-diamine of type 2a-e by catalytic hydrogenation of iminobisnitriles is described. Copyright Taylor & Francis Group, LLC.
- Sundaramoorthi, Raji,Keenan, Terence P.
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p. 417 - 423
(2007/10/03)
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- Muscle relaxants. 3rd communication: Development of acrylic acid derivatives of potential muscle relaxing activity
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With reference to the occurrence of C=C partial structures and alkyl carboxylate groupings in muscle relaxants, the synthesis of acrylic acid derivatives by the aminomethinylation procedure has been followed up. From the reaction of s-triazine (1) with methyl acetoacetate (2a) and piperidine (5a), methyl 2-acetyl-3-piperidino acrylate (6a) arises. Analogously, 3-pyrrolidinoacrylophenone (6b) and 3-morpholinoacrylophenone (6c) are formed. In the same manner, the 3-component reaction comprising the interaction of 1 with malononitrile (7) and a secondary amine (5) gives rise to the formation of the aminomethylenemalononitrile structure 8.
- Kreutzberger,Kreutzberger
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p. 232 - 234
(2007/10/02)
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