Pyrrolines

Pyrrolysine (symbol Pyl or O), encoded by the "amber" stop codon UAG, is a proteinogenic amino acid that is used in some methanogenic archaea and in bacteria. It consists of lysine with a 4-methylpyrroline-5-carboxylate in amide linkage with the εN of the lysine. Its pyrroline side-chain is similar to that of lysine in being basic and positively charged at neutral pH.

Pyrrolines, also known under the name dihydropyrroles, are three different heterocyclic organic chemical compounds that differ in the position of the double bond. Pyrrolines are formally derived from the aromate pyrrole by hydrogenation. 1-Pyrroline is a cyclic imine, whereas 2-pyrroline and 3-pyrroline are cyclic amines.

2-Acetyl-1-pyrroline (2AP) is an aroma compound and flavor that gives freshly baked bread, jasmine rice and basmati rice, the herb pandan (Pandanus amaryllifolius), and bread flowers (Vallaris glabra) their customary smell. Many observers describe the smell as similar to "hot, buttered popcorn", and it is credited for lending this odor to the scent of binturong (bearcat) urine. Fresh marking fluid (MF) and urine of the tiger (Indian, Amur or Siberian) and Indian leopard also have a strong aroma due to 2AP.

Pirprofen was a nonsteroidal anti-inflammatory drug (NSAID) that was brought to market by Ciba-Geigy in 1982 as a treatment for arthritis and pain. Its label was restricted after adverse events arose, including some cases of fatal liver toxicity. Ciba-Geigy voluntarily withdrew the drug from the market worldwide in 1990.

group of stereoisomers

MTSL (S-(1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-3-yl)methyl methanesulfonothioate) is an organosulfur compound that is used as a nitroxide spin label. MTSL is bifunctional, consisting of the nitroxide and the thiosulfonate ester functional groups. The nitroxide label is sterically protected, so it is relatively unreactive.

Spirotetramat (ISO Name) is a keto-enol insecticide developed by Bayer CropScience under the brand names Movento and Ultor.