Phosphorylated indolizines

Abstract

Preparative methods o f synthesis of 1and 3-phosphino-indolizines by interaction between 2-substituted indolizines with phosphorus(III) halogenides in the presence of bases have been developed. I t was found that originally this reaction results in the formationof 1 -phosphino-indolizines which then undergo izommiation into 3-phosphino isomevs. One, two, or three indolizine substituents can be consecutively attached to the phosphorus atom. New methods of syntheses of 1,3-diphosphino-indolizines have been developed. 0 1993 VCH Publishers, Inc.

C-phosphorylation of n-methylpyrrole

“…As regards isomerizations in indolizine molecules, dichlorophosphino, dibromophosphino, and diphenylphosphino groups have been shown to migrate [5]. In the case of N-methylpyrrole, we failed to extend the 2 → 3 isomerization found to other phosphorus-containing groups.…”

5‐phosphorylated 1,2‐disubstituted imidazoles

“…As previously reported, 1,3-azoles can be directly C-phosphorylated with phosphorus(III) halides in pyridine in the presence of Et 3 N [13]. Under such conditions, 1-alkylimidazoles readily react with PHal 3 to give 2-phosphorylated products [14], whereas 1-aryl-2-methylimidazoles undergo phosphorylation at the methyl group [15].…”

C-acylation of electron-rich heterocyclic compounds with Kirsanov isocyanate

“…By NMR spectroscopy and analysis of literature data [11], we have shown that the electrophilic attack on indolizines 7a,b by the Kirsanov isocyanate occurs at position 3 of the heterocycle, as is the case with carbonyl chlorides [12] and haloid derivatives of P(III) acids [11].…”

“…After having been washed with acetonitrile (3 mL), the product was dried. 1 (11). Compound 11 was prepared analogously to compound (3b) in benzene.…”