Syntheses for preparing 1,4-diketopyrrolo [3,4-c]pyrroles
AssigneeSun Chemical Corporation
InventorsTerrence R. Chamberlain, Craig Thornley
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Abstract
A synthesis for preparing asymmetrical 1,4-diketopyrrolo[3,4-c]pyrroles involving: (a) reacting a β-ketoamide with a strong base; (b) halogenating the same or a different β-ketoamide; (c) reacting the reaction products of step (a) and (b) to form a succinamide; and (d) heating the succinamide in the presence of a Lewis Acid. Symmetrical 1,4-diketopyrrolo [3,4-c]pyrroles are synthesized by oxidatively dimerizing the reaction product of step (b) to form a succinamide; and heating the succinamide in the presence of a Lewis Acid.
Claims17
A synthesis for preparing an asymmetrical or symmetrical 1,4-diketopyrrolo[3,4-c]pyrrole of formula I:
- wherein R1, R3, R2, and R4 are each independently selected from hydrogen, C1-C20 alkyls, cycloalkyls, aralkyls, or isocyclic or heterocyclic aromatic radicals;
- comprising the steps of:
- (a) reacting a β-ketoamide of either formula II:
- or, alternatively, a β-ketoamide of formula III:
- with a strong base to form an alkali metal or alkaline earth metal salt, wherein R1, R2, R3 and R4 are as previously defined;
- (b) halogenating a β-ketoamide of either formula II or formula III thereby forming a halogenated β-ketoamide;
- (c) reacting said alkali metal or alkaline earth salt formed in step (a) with said halogenated β-ketoamide, thereby forming a succinamide of the formula IV:
- wherein R1, R2, R3 and R4 are as previously defined;
- (d) heating the succinamide in the presence of a Lewis Acid or acid chloride to produce said 1,4-diketopyrrolo[3,4-c]pyrrole.
A synthesis for preparing a symmetrical 1,4- diketopyrrolo[3,4-c]pyrrole of the formula V:
- wherein
- R1 and R2 are each independently selected from hydrogen, C1-C20 alkyls, cycloalkyls, aralkyls, or isocyclic or heterocyclic aromatic radicals;
- and which synthesis comprises the steps of:
- (a) reacting a β-ketoamide of the formula VI:
- wherein R2 and R1 are as previously defined;
- with a strong base, thereby forming an alkali or alkaline earth metal salt;
- (b) oxidatively dimerizing said alkali or alkaline earth metal salt, thereby forming a succinamide of the formula VII:
- wherein R1 and R2 are as previously defined;
- (c) heating said succinamide in the presence of a Lewis acid or acid chloride to effect ring closure.
Dependencies are inferred from the claim text.