Synthesis of bridging analogs of pyrrolizidine alkaloids

Reactions of fused pyrrole-2,3-diones with binucleophiles

“…45 This approach consisted of an interaction of pyrrolobenzoxazinetriones 1 with 2,2,4-trimethyl-1,2-dihydrobenzo[f]isoquinoline 23, and resulted in the formation of substituted benzo[f]pyrrolo[2,1-а]isoquinoline-9-spiro-2-pyrroles 25 (Scheme 11). While continuing studies on analogous transformations, Konovalova and coworkers 47,48 examined the reaction of the same pyrrolobenzoxazinetriones with a spiro heterocyclic enamine containing an additional functional group (ester moiety). ]tetradec-5′-ene)]-14′-carboxylates 29 (Scheme 13), whose structure was confirmed by the X-ray diffraction data.…”

Five-membered 2,3-dioxoheterocycles: LXXIX. Three-component condensation of 1H-pyrrol-2,3-diones with acetonitriles and dimedone. Crystal and molecular structure of substituted spiro[chromene-4,3′-pyrrole]

“…Yield 89%, mp 243-244°C. IR spectrum, ν, cm -1 : 3399, 3328, 3214 (NH 2 ), 2191 (CN), 1734 (C 2' =O), 1674 (COO, C 5 =O) 1. H NMR spectrum, δ, ppm: 0.84 t (3H, CH 2 CH 3 , J 7.4 Hz), 1.01 s (3H, Me), 1.08 s (3H, Me), 2.22 d, 2.35 d (2H, C 8 H 2 , J 15.6 Hz), 2.40 d, 2.69 d (2H, C 6 H 2 , J 17.7 Hz), 3.77 m (2H, OCH 2 CH 3 ), 4.47 s (2H, CH 2 Ph), 7.06-7.41 group of signals (12H, 2Ph + NH 2 ).…”

“…We carried out the reaction of 5-phenyl-4-ethoxycarbonyl-1H-pyrrole-2,3-diones Ia-Id [4] with substituted acetonitriles [malononitrile (IIa) and methyl cyanoacetate (IIb)] and dimedone in the ratio 1 : 1 : 1 by boiling the solution of the reagents in anhydrous benzene in the presence -------------------* For Communication LXXVIII, see [1]. ** For preliminary communication, see [5].…”

“…1 H and 13 C NMR spectra were registered on a spec- No correction for extinction was done (μ 0.086 mm -1 ). The structure was solved by the direct method applying the program SIR92 [6] followed by a series of calculations of the electron density maps.…”

Synthesis of dispiro heteroanalogs of pyrrolizidine alkaloids: crystal and molecular structure of substituted 3',4'',5-trioxodispiro[(2'',5''-cyclohexadiene)-1''(4''H),7'-[7H]pyrrolizine-2'(3'H),2-[2H]pyrrole]-1'-carboxamide

“…1,2 Nucleophilic transformations of 3-aroyl-1H-pyrrolo[2,1-c] [1,4]benzoxazine-1,2,4-triones by the action of OH-and NH-mono-and NH,NH-, NH,OH-, and NH,SH-binucleophiles are convenient methods for the synthesis of carbonyl derivatives of five-and six-membered nitrogen-containing heterocycles, ensembles of such heterocycles, and fused heterocyclic systems. 1,5 .0 8,12 ]tetradecane system 7,8 E, respectively (Scheme 1). During continuing studies on analogous transformations, we have now examined the reaction of pyrrolobenzoxazinetriones with a spiro heterocyclic enamine containing an additional functional amide group NH 2 -substituted 2-(3,3-dimethyl-8-oxo-2-azaspiro [4.5]deca-6,9-dien-1-ylidene)acetamides.…”