Ilford Multigrade paper developer

[snusmumriken]

Out of curiosity, I looked up the MSDS for Ilford Multigrade paper developer, to see what the ingredients are. It lists:
1-Phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone
Diethylenetriamine Pentaacetic Acid Na5
HYDROQUINONE
Potassium Carbonate
Sodium hydroxide

Can anyone suggest what role the first two ingredients play? The names are unfamiliar to me, and I can't find any info about them.

 

[Lachlan Young]

1-Phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone

Dimezone S - an evolution of Phenidone with certain improved characteristics (including seemingly favourably broadening the range of its usable relationship with HQ) within photographic uses.

Diethylenetriamine Pentaacetic Acid Na5

DTPA - a modern & highly effective chelating agent.