title: Studies on solvatomorphism of betulinic acid.
abstract: Five solvates of betulinic acid with dimethyl sulfoxide (I), methanol (II), ethanol (III), isopropyl alcohol (IV), and 2-butanol (V) have been described in this work. Methods of X-ray crystallography, thermal analysis, and Fourier transform infrared spectroscopy were introduced for solvatomorphic identifications and characterizations. The orientation of isopropenyl and carboxylic groups might differ because of single-bonding rotations. The incorporation of solvents resulted in changes of the crystal symmetry, intermolecular arrangements, stoichiometry, hydrogen bonding interactions, and so on. Adducted solvents contributed most to the stability of crystal lattices and led to the formation of crystalline forms. Solvates II-V with their single-crystal structures determined have been reported for the first time.
authors.affiliation: Beijing City Key Laboratory of Polymorphic Drugs, Center of Pharmaceutical Polymorphs, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.affiliation: Beijing City Key Laboratory of Polymorphic Drugs, Center of Pharmaceutical Polymorphs, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China.
authors.forename: Ningbo
authors.initials: N
authors.lastname: Gong
authors.affiliation: Beijing City Key Laboratory of Polymorphic Drugs, Center of Pharmaceutical Polymorphs, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China.
authors.forename: Shiying
authors.initials: S
authors.lastname: Yang
authors.affiliation: Beijing City Key Laboratory of Drug Target and Screening Research, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China. Electronic address: dugh@imm.ac.cn.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Du
authors.affiliation: Beijing City Key Laboratory of Polymorphic Drugs, Center of Pharmaceutical Polymorphs, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China. Electronic address: luy@imm.ac.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D006860:Hydrogen Bonding; D053978:Pentacyclic Triterpenes; D012997:Solvents / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013818:Thermogravimetry; D014315:Triterpenes / Q000737:chemistry*; D000094062:Betulinic Acid
chemical_list: D053978:Pentacyclic Triterpenes; D012997:Solvents; D014315:Triterpenes; D000094062:Betulinic Acid
keywords: DSC; FTIR; XRPD; betulinic acid; crystal structure; solvate; solvatomorphism; thermogravimetric analysis