Betulin

Betulin
Names
	IUPAC name Lup-20(29)-ene-3β,28-diol
	Systematic IUPAC name (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-3a-(Hydroxymethyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysen-9-ol
	Other names Betulinol, betuline, betulol, betulinic alcohol, trochol
Identifiers
CAS Number	473-98-3 ;
3D model (JSmol)	Interactive image; Interactive image;
ChEMBL	ChEMBL23236 ;
ChemSpider	65272 ;
ECHA InfoCard	100.006.797
EC Number	207-475-5;
KEGG	C08618 ;
PubChem CID	72326;
UNII	6W70HN7X7O ;
CompTox Dashboard (EPA)	DTXSID101019934 ;
	InChI InChI=1S/C30H50O2/c1-19(2)20-10-15-30(18-31)17-16-28(6)21(25(20)30)8-9-23-27(5)13-12-24(32)26(3,4)22(27)11-14-29(23,28)7/h20-25,31-32H,1,8-18H2,2-7H3/t20-,21+,22-,23+,24-,25+,27-,28+,29+,30+/m0/s1 Key: FVWJYYTZTCVBKE-ROUWMTJPSA-N ; InChI=1/C30H50O2/c1-19(2)20-10-15-30(18-31)17-16-28(6)21(25(20)30)8-9-23-27(5)13-12-24(32)26(3,4)22(27)11-14-29(23,28)7/h20-25,31-32H,1,8-18H2,2-7H3/t20-,21+,22-,23+,24-,25+,27-,28+,29+,30+/m0/s1 Key: FVWJYYTZTCVBKE-ROUWMTJPBQ;
	SMILES O[C@H]5CC[C@@]4([C@@H]3[C@@]([C@]2([C@@H]([C@@H]1[C@](CO)(CC[C@H]1C(=C)C)CC2)CC3)C)(C)CC[C@H]4C5(C)C)C; CC(=C)[C@@H]1CC[C@]2([C@H]1[C@H]3CC[C@@H]4[C@]5(CC[C@@H](C([C@@H]5CC[C@]4([C@@]3(CC2)C)C)(C)C)O)C)CO;
Properties
Chemical formula	C30H50O2
Molar mass	442.728 g·mol−1
Appearance	solid with needle-like crystals
Melting point	256 to 257 °C (493 to 495 °F; 529 to 530 K)
Solubility in water	insoluble
Solubility	slightly soluble in ethanol and benzene; soluble in diethyl ether, ethyl acetate and ligroin
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Betulin is an abundant, naturally occurring triterpene. It is commonly isolated from the bark of birch trees, hence its name, from betula. It forms up to 30% of the dry weight of silver birch bark. It is also found in birch sap. Inonotus obliquus contains betulin.

The compound in the bark gives the tree its white color which appears to protect the tree from mid-winter overheating by the sun. As a result, birches are some of the northernmost occurring deciduous trees.