Crystalline N-nitrosothialdine (2) has been prepared in 38% yield by treating thialdine (1) with n-butyl nitrite and acetic acid in hexane. X-Ray crystallography of 2 revealed that its three methyl groups are a11 cis and, rather surprisingly, all equatorial; this finding contrasts sharply with results for other nitrosamine heterocycles which have been investigated, whose bulky alpha substituents are forced into a primarily axial orientation by the large steric ...
