Pyrroles reactions

The assumption of these conjugated double bonds makes possible a tetracyclic nucleus which accords with the suggestion previously made by the authors that these alkaloids might be structurally related to the diterpenes. It may also be noted that one of the nitric acid oxidation products of pseudaconitine has been recorded as unexpectedly giving a pyrrole reaction on destructive distillation. ... 

From S. tuberosa, Loureiro, Lobstein and Grumbach obtained stemonine, C H3304N, m.p. 160 , [a]D 4- 76-5 , which gives pyrrole reactions and whose pharmacological action is described. (For another stemonine see p. 765.) Suzuki s investigation of the same plant led to a different result, the isolation of the alkaloid tuberostemonine. 

Urine ( -aminolevuli nic acid) Dilution of sample reaction with ethylacetoacetate and ethylacetate to form -amino-levulinic acid-pyrrole reaction with Erhlich s reagent Spectrophotometry No data No data Tomokuni and Ichiba 1988... 

Keywords Acetylacetates, 2-Amino-2-deoxyaldoses, Barbituric acids, C-Glyco-sides, Dimedone, Furans, Garcia-Gonzalez reaction, Green chemistry, Hexoses, Meldrum s acid, Penta-2,4-dione, Pentoses, Pyrroles, Reactions in water, Tetrahy-drofuranylfurans... 

Furans give 2,5-cycloadducts on irradiation with alkynes (equation 75) . Thiophens probably behave similarly , but the product isolated is a substituted benzene which arises by extrusion of sulphur from the adduct (equation 76). The photochemical reaction with thiophen involves a triplet excited state of the thiophen, but both furan and thiophen cycloadditions can also be brought about thermally , (compare the pyrrole reaction in equation 74). 

In the early amidation approach, 2 may be assembled by condensation of aldehyde-amide 4 with 5-fluorooxindole 3. The aldehyde-amide would arise from a Knorr pyrrole reaction involving oxime 5 (derived from t-butyl acetoacetate) and (3-ketoamide 6, which can, in turn, be synthesized from diketene 7 and A,iV-diethylethylenediamine 8. 

In the late amidation approach, free base 2 may be synthesized from acid-aldehyde 9, 5-fluorooxindole 3, and A,A-diethylethylenediamine 8. Acid aldehyde 9 can be synthesized from diester 10 which would arise out of a Knorr pyrrole reaction involving oxime 5 and ethyl acetoacetate 11. 

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