Conformational Study of Some Saturated 2-[Bis(2-chloroethyl)amino]-1,3,2-benzoxazaphosphorinane 2-Oxides

Tapio Viljanen, Petri Tähtinen, Kalevi Pihlaja, Ferenc Fülöp

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Conformational analyses of cis- and trans-fused 2-[bis(2-chloroethyl)amino]-3,4,4a,5,6,7,8,8a-octahydro-l,3,2- benzoxazaphosphorinane 2-oxides and their 3-methyl and 3-benzyl derivatives were performed by 1H, 13C, 31P, and variable-temperature NMR methods. Depending on the P-2 configuration and the substituent on N-3, different equilibria between chair-chair and chair-twist-boat conformations were found for the trans-fused isomers. The N-3 substituent shifts the equilibrium toward the chair-twist-boat to an extent varying in the sequence methyl > benzyl > hydrogen. In the cis-fused isomers, the nature of the N-3 substituent affects the equilibrium between the O-in and O-out conformations in the same sequence.

Original languageEnglish
Pages (from-to)618-627
Number of pages10
JournalJournal of Organic Chemistry
Issue number3
Publication statusPublished - Feb 6 1998


ASJC Scopus subject areas

  • Organic Chemistry

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