. Can. J. Chem. 60,2295Chem. 60, (1982. Several syntheses of the previously unknown 1,2-dihydro-3H-pyrrolo[l,2-a]pyrrole-l-carboxylic acid and various 5-and 6-substituted derivatives thereof have been devised. Some of these processes have been extended to the heretofore unreported 5,6,7,8-tetrahydropyrrolo[l,2-a]pyridine-8-carboxylic acid and 5,6,7,8-tetrahydro-9H-pyrrolo[l,2-a]azepine-9-carboxylic acid derivatives.Two new processes were developed for the conversion of pyrroles into the corresponding pyrrol-2-acetic acid esters. Both processes were based on the use of the readily available ethoxalylpyrrole derivatives as the starting material. One sequence involved saponification of the a-keto ester, followed by Wolff-Kishner reduction of the crude a-keto acid salt and subsequent esterification of the acetic acid derivative thus produced. The second synthesis commenced with reduction of the 2-ethoxalpyrrole with sodium borohydride to the a-hydroxy ester, which was further reduced to the acetic acid ester with an equimolar mixture of triphenylphosphine and triphenylphosphine diiodide.
Evaluation of a series of lactam heterocyclic analogues of cilostamide (2) as inhibitors of cyclic AMP phosphodiesterase derived from both human platelets and rat heart in comparison with their corresponding methoxy-substituted heterocycles has revealed that the N-cyclohexyl-N-methyl-4-oxybutyramide side chain of 2 is an important lipophilic and/or steric pharmacophore. Attachment of this side chain to the parent heterocycle of the potent cyclic AMP phosphodiesterase inhibitor anagrelide (3) afforded the hybrid structure RS-82856 (1), shown to be more potent than either of its progenitors as an inhibitor of cyclic AMP phosphodiesterase or of ADP-induced platelet aggregation. The available in vitro data suggest that 1 possesses potentially useful antithrombotic and cardiotonic properties.
The syntheses of (±)-PGEi and (±)-ll-deoxyprostaglandins in the E: and Fi series have been carried out by conjugate addition of bis(triethyl phosphite)copper(I) cyanide vinyllithium to the substituted cyclopentenones la and lb, and subsequent elaboration of vinylamylcarbinol side chain via the intermediate carboxaldehydes 3b and 3d. The intermediate 3d was also converted to (±)-9-oxo-13-czs-prostenoic acid (6c). These transformations are characterized by high yields and ease of operation. The synthesis of prostaglandins has been the subject of considerable synthetic effort during the past several years. In the course of this work a number of elegant syntheses of prostaglandins have been developed, but, in general, these approaches are lengthy and rather complex in nature.2
Die Umsetzung des Bromids (I) mit dem [aus den Komponenten (II) und (III) gebildeten] Enamin (V) liefert das Pyrrol (IVa) (Hantzsche Pyrrolsynthese) ; Cyclisierung des aus (IVa) über das Mesylat (IVb) erhältlichen Iodids (IVc) gibt das Pyrrolopyrrol (VIa), das über die Stufen (VIb), (VIc) in den Ester (VIIa) bzw. dessen Verseifungsprodukt (VIIb) übergeführt wird.
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