1.3.2- Dioxazolidine ring

Chemical shifts of 19F attached to a 1,3,4-dioxazolidine ring were reported in CHEC-II(1996), where other 19F chemical shifts for fluorinated substituents are also included <1996CHEC-II(4)498>. Some new data for the chemical shifts of trifluoromethyl substitutents of several 1,4,2-dithiazolidine derivatives are as expected with from -62.5 to -67.5 (CCI3F as internal standard). Thus for the adamantyl dithiazolidines 35 SF appears at -65.2 to -67.5 depending on the aryl substituents, while the 19F chemical shifts of dithiazolidines 36-38 are as follows compound 36 S at -63.44 and -67.07 compound 37 6t- at -63.75 <1998EJ0459> compound 38 6 at -62.5 for X=0 and -62.58 for X = S <2000T4231>. 

A twisted envelope conformation with N as flap was deduced for 1,3,2-dioxazolidine (30 R = = H) from the AA BB spectrum of the ring protons combined with an isochronism... 

The dithiazolidine (44) <77CCC2672> and dioxazolidine (45) <69JOC2269> are ring systems in which the fragmentation pattern, has been used to affirm the structures. In the latter case the absence of CO2 primary loss allows differentiation from the isomeric oxadiazolidone (46) co-product. A new technique, e.g. the neutralization-reionization mass spectrometry (NRMS) in combination with... 

Cycloaddition. Nitrobenzene can undergo cycloaddition to a strained alkene such as (Z,E)-l,5-cyclooctadiene (1) to form a 1,3,2-dioxazolidine (2). The reaction proceeds in THF at room temperature over a period of 5 days. The adducts are formed more rapidly and in higher yield when the benzene ring... 

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