Pyrindoles

Pyrindole — see Pyrrolo[l,2-a]pyridine Pyrithyldlone as sedative, 1, 165 Pyromeconic acid from comenic acid, 3, 710 occurrence, 3, 692... 

Several names have been used in the chemical literature for pyrrolo[l,2-a]pyridine including pyrrocoline, pyrindole, pyrrodine and 8-pyrrolopyridine, but the one which is now used by Chemical Abstracts, and which will be used in this chapter, is indolizine. The numbering of the system is shown in formula (1). The denomination of aza derivatives follows the replacement nomenclature system, e.g. 1-azaindolizine, etc. It should be noted that Chemical Abstracts follows the systematic fusion nomenclature 1-azaindolizine, for instance, is imidazo[l,2-a]pyridine. The cyclazine nomenclature is treated in Section 3.08.9.1. 

Perkin and Robinson introduced pyrindole as the first nomenclature for the fused pyrrole-p5Tidine system, numbering the ring as in structure 1. These workers originally proposed the structure 2-methyl-... 

The pyrindole nomenclature persisted until Kruber introduced the aza designation for 7-azaindole (2). This is the system which has been used most frequently. 

Rath synthesized 3-hydrazinopyridine and prepared its propionaldehyde and pyruvic acid hydrazones with the intention of using them to make pyrindoles (azaindoles). Although he indicated the work was to be described in a subsequent publication, no mention of it could be found. 

Pyrindoles s. Indolizines Pyrocarbonic acid esters s. Dicarbonic acid esters Pyrocatediol, protection of keto groups with - 16, 234 suppl. 27... 

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