In the crystal structure of the title compound, C 17 H 15 NOS, the molecules form centrosymmetric dimers through pairs of N-HÁ Á ÁO hydrogen bonds. The seven-membered ring adopts a distorted half-chair conformation.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean (C-C) = 0.003 Å R factor = 0.045 wR factor = 0.138 Data-to-parameter ratio = 18.4For details of how these key indicators were automatically derived from the article, see

Spiro compounds represent an important class of naturally occuring substances, which in many cases exhibit interesting biological properties. Highly substituted pyrrolidines have attracted much interest since they constitute the main structural element of many alkaloids and pharmacologically active compounds. The β-lactam ring plays a key role in biological activity, and the selectivity of the β-Lactam ring can be influenced decisively by the attached substituent. 1 β-lactams with a substituent at the N atom, which is easily removable under mild conditions, have found wide applicability in the synthesis of bicyclic β-lactam antibiotics. 2 In view of its medicinal importance, crystal and molecular structure determinations of the title compound were undertaken.A mixture of 4-formyl-3-phenyl-1-N-(p-methoxy phenyl) azitidine-2-one (1 mmol), sarcosine (N-methyl glycine) (1 mmol) and -4-(E)-3-(4-methoxy)-phenacylidene oxindole was refluxed in dry toluene for 12 h at 110˚C using the Dean-Stark apparatus. After completion of the reaction, toluene was evaporated under reduced pressure. The crude product was purified by column chromatography. The product was further recrystallised using ethyl acetate.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.004 A Ê R factor = 0.044 wR factor = 0.126 Data-to-parameter ratio = 14.3For details of how these key indicators were automatically derived from the article, see

In the title compound, C12H12O4, the hydr­oxy O and the C and O atoms of the acetyl group are almost coplanar [maximum deviation = 0.0356 (1) Å] with the benzene ring. The dihedral angle between the benzene ring and the plane through the non-H atoms of the methacrylo­yloxy group is 86.1 (1)°. In the crystal structure, mol­ecules are linked by two C—H⋯O hydrogen bonds, forming dimers with graph-set descriptor R 2 2(16). A strong intra­molecular O—H⋯O hydrogen bond is also observed.