Glycin

Glycin, or N-(4-hydroxyphenyl)glycine, is N-substituted p-aminophenol. It is a photographic developing agent used in classic B&W developer solutions. It is a derivative of the amino acid glycine. When fresh, it is typically characterized as thin plates of white or silvery powder, turning brown with age. It is sparingly soluble in water and most organic solvents; it is readily soluble in alkalies and acids.

Glycin is related to p-aminophenol and Metol. Compared to Metol, glycin has a carboxyl group attached to the methyl group of the Metol. This weakens the reduction potential of the compound and therefore Metol is superior as a developing agent. Glycin is rarely used as a developing agent today, primarily because of the reason above, and it is expensive and manufactured for specialty applications only. It also has limited shelf life compared to Metol and Phenidone.

Glycin can be synthesized by a number of ways. One method is to react p-aminophenol with chloracetic acid in a solvent and purify glycin.

Other uses of glycin can be found in some procedures of analytical chemistry.