10104. α-Yohimbine

Nomenclature

CAS number: 131-03-3
17α-Hydroxy-20α-yohimban-16β-carboxylic acid methyl ester; corynanthidine; isoyohimbine; mesoyohimbine; rauwolscine.
C21H26N2O3; mol wt 354.44.
C 71.16%, H 7.39%, N 7.90%, O 13.54%.

Description and references

From bark of Corynanthe johimbe K. Schum., Rubiaceae: Hahn, Brandenburg, Ber. 60, 669 (1927); Wilbaut, van Gastel, Rec. Trav. Chim. 54, 88 (1935); from Rauwolfia canescens L., Apocynaceae: Mookerjee, J. Indian Chem. Soc. 18, 33 (1941), C.A. 35, 7967 (1941); Stoll et al., Helv. Chim. Acta 38, 270 (1955). Identity with corynanthidine: Janot, Goutarel, Bull. Soc. Chim. Fr. 1946, 535. Identity with isoyohimbine: Heinemann, Ber. 60, 15 (1934). Identity with rauwolscine: Chatterjee et al., Chem. Ind. (London) 1954, 491. Structure and stereochemistry: Le Hir et al., Bull. Soc. Chim. Fr. 1953, 1027; Wenkert, Liu, Experientia 11, 302 (1955); Aldrich et al., J. Am. Chem. Soc. 81, 2481 (1959); Janot et al., Bull. Soc. Chim. Fr. 1961, 637. Total synthesis: Tke et al., J. Org. Chem. 38, 2496 (1973).

Chemical structure

Properties

Crystals, mp 243-244°. [α]D19 18° (pyridine); [α]D19 27° (abs alcohol). pKa 6.34. uv max (methanol): 227, 281 nm (log ε 4.50, 3.93). Sol in warm methanol, ethanol; slightly sol in ether, benzene; practically insol in petr ether, water.

Derivative

Hydrochloride.
C21H26N2O3.HCl; mol wt 390.90.
C 64.52%, H 6.96%, N 7.17%, O 12.28%, Cl 9.07%.

Properties

Crystals, mp 288°. [α]D20 +55.5° (water).