title: rac-Diethyl 9-hy-droxy-9-methyl-7-phenyl-1,4-diaza-spiro-[4.5]decane-6,8-dicarboxyl-ate.
abstract: The title mol-ecule, C(21)H(30)N(2)O(5), is chiral with four stereogenic centres. The crystal is a racemate and consists of enanti-omeric pairs with the relative configuration rac-(6S*,7R*,8R*,9S*). The ethyl fragment of the eth-oxy-carbonyl group at position 6 is disordered in a 0.46 (3):0.54 (3) ratio. The crystal structure features inter-molecular N-H⋯O. Intra-molecular O-H⋯N and N-H⋯O hydrogen bonds also occur.
authors.affiliation: Baku State University, Z. Khalilov St. 23, Baku, AZ-1148, Azerbaijan.
authors.forename: Abel M
authors.initials: AM
authors.lastname: Maharramov
authors.forename: Arif I
authors.initials: AI
authors.lastname: Ismiyev
authors.forename: Bahruz A
authors.initials: BA
authors.lastname: Rashidov
authors.forename: Gunel M
authors.initials: GM
authors.lastname: Rahimova
authors.forename: Mirza A
authors.initials: MA
authors.lastname: Allahverdiyev