title: Crystal structure of betulinic acid methanol monosolvate.
abstract: The title compound [systematic name: 3β-hy-droxy-lup-20(29)-en-28-oic acid methanol monosolvate], C30H48O3·CH3OH, is a solvent pseudopolymorph of a naturally occurring plant-derived lupane-type penta-cyclic triterpenoid, which was isolated from the traditional Chinese medicinal plant Syzygium jambos (L.) Alston. The dihedral angle between the planes of the carb-oxy-lic acid group and the olefinic group is 12.17 (18)°. The A/B, B/C, C/D and D/E ring junctions are all trans-fused. In the crystal, O-H⋯O hydrogen bonds involving the hy-droxy and carb-oxy-lic acid groups and the methanol solvent mol-ecule give rise to a two-dimensional network structure lying parallel to (001).
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Neng-Hua
authors.initials: NH
authors.lastname: Chen
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Li
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Guo-Cai
authors.initials: GC
authors.lastname: Wang
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Yao-Lan
authors.initials: YL
authors.lastname: Li
keywords: Syzygium jambos (L.) Alston; betulinic acid; crystal structure; hydrogen bonding; lup-20(29)-en-28-oic acid; natural product