Gramine

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Gramine
Chemical structure of gramine
Identifiers
CAS number 87-52-5 YesY
ChemSpider 6625 YesY
KEGG C08304 YesY
ChEMBL CHEMBL254348 YesY
Jmol-3D images Image 1
Properties
Molecular formula C11H14N2
Molar mass 174.24 g/mol
Melting point 138-139 °C
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Gramine (also called donaxine) is a naturally occurring indole alkaloid present in several plant species. Gramine may play a defensive role in these plants, since it is toxic to many organisms.[1]

Occurrence[edit]

Gramine has been found in the giant reed, Arundo donax,[2][3]Acer saccharinum (Silver Maple),[4] Hordeum,[1][3] and Phalaris[3] plant species.

Synthesis[edit]

Despite being widely available in several plant species, gramine is far easier to synthesize directly from indole via a Mannich reaction with dimethylamine and formaldehyde.

Gramine can be synthesized from indole

Uses[edit]

Gramine is used mostly in synthetic organic chemistry as a starting material for tryptophan syntheses.

All reactions of gramine follow the same general reaction scheme. Gramine is reacted with a strong electrophile, such as methyl iodide, to form the quaternary ammonium salt 2. The ammonium salt will undergo a Hofmann elimination or Michael addition to give the very active intermediate 3, which can accept a wide range of nucleophiles to give the desired product 4.

Retromichael addition of gramine

Toxicity[edit]

The LD50 of gramine is 44.6 mg/ kg iv in mice and 62.9 mg/ kg iv in rats.[5] Numerous studies have been done on the toxicity in insects harmful to crops for use as a possible insecticide.[6]

Gramine is a norepinephrine reuptake inhibitor in synaptic vesicles.[citation needed] Resulting effects of extra norepinephrine raises blood pressure and heart rate.

References[edit]

  1. ^ a b Corcuera, L. J. (1993). "Biochemical Basis of the Resistance of the Barley to Aphids". Phytochemistry 33 (4): 741–747. doi:10.1016/0031-9422(93)85267-U. 
  2. ^ Orechoff, A.; Norkina, S. (1935). "Über die Alkaloide von Arundo Donax L.". Berichte der Deutschen Chemischen Gesellschaft 68 (3): 436–437. doi:10.1002/cber.19350680312. 
  3. ^ a b c Cheeke, P. R. (1989). Toxicants of Plant Origin, Alkaloids. CRC Press. p. 172. ISBN 0-8493-6990-8. 
  4. ^ Pachter, I. J.; Zacharias, D. E.; Ribeiro, O. (1959). "Indole Alkaloids of Acer saccharinum (the Silver Maple), Dictyoloma incanescens, Piptadenia colubrina, and Mimosa hostilis". Journal of Organic Chemistry 24 (9): 1285–1287. doi:10.1021/jo01091a032. 
  5. ^ Erspamer, V. (1954). "Pharmacology of Indolealkylamines". Pharmacological Reviews 6 (4): 425–487. PMID 13236482. 
  6. ^ Corcuera, L. J. (1984). "Effects of Indole Alkaloids from Gramineae on Aphids". Phytochemistry 23 (3): 539–541. doi:10.1016/S0031-9422(00)80376-3.