POLYNITRO-SUBSTITUTED STRAINED-RING COMPOUNDS .2. 1,2-DINITROSPIROPENTANES

trans-1,2-Dinitrospiropentane was prepared in 43% yield from 1,1-bis(nitromethyl)cyclopropane, best obtained by dry-phase ozonolysis of the corresponding diamine. The structure of trans- 1,2-dinitrospiropentane was assigned on the basis of spectroscopic data, elemental analysis, and X-ray crystallographic data. The first pK(a) was determined to be 18.6-21.6 in DMSO solution with decomposition. Reaction of trans- 1,2-dinitrospiropentane with sodium methoxide and iodine gave a mixture of iodinated spiropentanes, from which, cis- and trans-1,2-diiodo-1,2-dinitrospiropentane could be isolated in pure form. These diiodides were stable at room temperature but gave off iodine upon melting at 150-160-degrees-C. Treatment with sodium thiosulfate in aqueous DMSO solution gave back the deiodinated dinitro compound. trans-1,2-Dinitrospiropentane reacted with lithium diisopropylamide and benzaldehyde in THF to afford a bis(nitroaldol) product in 59% yield.