Title:  Tremetone 
CAS Registry Number:  4976-25-4 
CAS Name:  1-[2,3-Dihydro-2-(1-methylethenyl)-5-benzofuranyl]ethanone 
Additional Names:  2,3-dihydro-2-isopropenyl-5-benzofuranyl methyl ketone;  2-isopropenyl-2,3-dihydro-5-acetylbenzofuran 
Molecular Formula:  C13H14O2 
Molecular Weight:  202.25 
Percent Composition:  C 77.20%, H 6.98%, O 15.82% 
Literature References:  Principal ketone suspected of being the active toxin of Eupatorium urticaefolium Reichard, Compositae (white snakeroot).  Isoln and structure:  Bonner, DeGraw, Tetrahedron 18, 1295 (1962).  Synthesis of dihydrotremetone:  DeGraw, Bonner, ibid. 1311.  Synthesis of racemic tremetone:  DeGraw et al., ibid. 19, 19 (1963); Bohlmann, Buehmann, Ber. 105, 863 (1972).  Abs config:  Bonner et al., Tetrahedron 20, 1419 (1964).  Review:  Christensen, Econ. Bot. 19, 293-300 (1965). 
Properties:  Liquid.  [a]D28 -59.6° (c = 5.52 in absolute ethanol).  nD25 1.5658.  d428 1.080.  uv max (ethanol):  227, 280, 285 nm (e 11,950, 12,600, 12,300). 
Optical Rotation:  [a]D28 -59.6° (c = 5.52 in absolute ethanol) 
Index of refraction:  nD25 1.5658 
Absorption maximum:  uv max (ethanol):  227, 280, 285 nm (e 11,950, 12,600, 12,300) 
Density:  d428 1.080 
  
Derivative Type:  Dihydrotremetone  
Additional Names:  (R)-1-[2,3-Dihydro-2-(1-methylethyl)-5-benzofuranyl]ethanone 
Molecular Formula:  C13H16O2 
Molecular Weight:  204.26 
Percent Composition:  C 76.44%, H 7.90%, O 15.67% 
Properties:  Liquid.  bp 216-221°.  [a]D25 -47.0° (c = 1.78 in abs ethanol).  uv max (ethanol):  231, 279 nm (e 39,500; 18,800). 
Boiling point:  bp 216-221° 
Optical Rotation:  [a]D25 -47.0° (c = 1.78 in abs ethanol) 
Absorption maximum:  uv max (ethanol):  231, 279 nm (e 39,500; 18,800) 
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