H-1 NMR spectroscopic studies of the stability of an oxazolidine condensation product

Condensation of (-)-norephedrine with excess formaldehyde under mild conditions leads to formation of the 2:1 condensation product N,N'-methylenebis(4-methyl-5-phenyl)oxazolidine compared with the reaction with 1 mol of formaldehyde, which leads to 4-methyl-5-phenyloxazolidine. H-1 and C-13 NMR spectroscopy was used to monitor the stability of this compound and its decomposition products. The 2:1 condensation product is found to be stable in CDC1(3) but breaks down rapidly in CD3OD to yield a 50:50 mixture of 4-methyl-5-phenyloxazolidine and 3-hydroxymethyl-4-methyl-5-phenyloxazolidine. Upon addition of D2O to this equimolar mixture, the latter compound decomposes to norephedrine and formaldehyde, whereas the former compound is stable. (C) 1997 by John Wiley & Sons, Ltd

Synthesis, NMR studies and conformational analysis of oxazolidine derivatives of the beta-adrenoreceptor antagonists metoprolol, atenolol and timolol

Formaldehyde-derived oxazolidine derivatives 4-7 of the beta-adrenoreceptor antagonists metoprolol 1, atenolol 2 and timolol 3 have been synthesised. Conformational analysis of 1-3 and the oxazolidine derivatives 4-7 has been performed using H-1 NMR spectroscopy and computational methods. The H-1 NMR studies show that for the aryloxypropanolamine beta-adrenoreceptor antagonists there is a predominance of the conformer in which the amine group is approximately antiperiplanar or trans to the aryloxymethylene group. Both H-1 NMR data and theoretical studies indicate that the oxazolidine derivatives 4-7 and the aryloxypropanolamine beta-adrenoreceptor antagonists 1-3 adopt similar conformations around the beta-amino alcohol moiety. Thus, oxazolidine ring formation does not dramatically alter the preferred conformation adopted by the beta-amino alcohol moiety of 1-3. Oxazolidine derivatives of aryloxypropanolamine beta-adrenoreceptor antagonists may therefore be appropriate as prodrugs, or semi-rigid analogues, when greater lipophilicity is required for drug delivery

Young mother (in the) hood: Gang girls' negotiation of new identities

This article examines the experiences of young women in street gangs who become mothers. Drawing on qualitative interviews with 65 young women in the San Francisco, CA, Bay Area, we examine their narratives about the transition to motherhood. In particular, we focus on the ways these young women negotiate femininities and attempt to reconcile their identities as young mothers and gang girls - both stigmatized identities. For many of the young women, motherhood entails a retreat from the street and a renewed emphasis on time spent in the home. While many receive (financial and childcare) support from their families, this also often means a diminution of the autonomy they experienced while more heavily involved in the gang. Issues of respect and respectability remain important for the young women, but the dimensions on which these are based change. © 2010 Taylor & Francis.link_to_OA_fulltex

Anomalies in the Reduction of the Schiff-Bases 5-(diethylamino)-2-(phenyliminomethyl)phenol and 2-[(4-Diethylaminophenyl)iminomethyl]-Phenol and Their Crystal-Structures

Two intermediate Schiff bases, 5-(diethylamino)-2-(phenyliminomethyl)phenol (1) and 2-[(4- diethylaminophenyl)iminomethyl]phenol (2), were encountered which proved difficult to reduce to their corresponding secondary amines with sodium borohydride. X-Ray crystallographic analyses showed that the molecules are virtually planar with intramolecular hydrogen bonding between the imino nitrogen and the phenolic oxygen. Bond lengths in the phenyl rings with the diethylamino substituents indicate a significant contribution from the quinonoid form for these ring systems