Phosphorus–nitrogen compounds. Part 50. Further studies on the formation of bicyclic cyclotetraphosphazatetraene derivatives

Abstract

The reactions of hexac hloro -2,6 -bis (et hylami no) cyclotetra p hosp hazatetraene, N, P, CI , ( N H Et ) *, with pyrrolidine, piperidine, morpholine, diethylamine, or cyclopropylamine give bicyclic N,P,(NRR'), (NHEt) (NEt), as well as monocyclic derivatives N,P,(NRR'),(NHEt), (NRR' = pyrrolidino, piperidino, morpholino, diethylamino, or cyclopropylamino). The reactions of N, P, CI , with cyclopropylamine give the bicyclic, N, P, ( NHC,H,),( NC,H,), and monocyclic, N, P, ( NHC,H,),, products, the former being the first structure of its kind with an a-branched alkyl group at the bridgehead to be isolated. Salient features of the 'H and ,' P n.m.r. spectra of these bicyclic phosphazenes are discussed and related to their structures. Likely reaction mechanisms are considered.Since the first report of a bicyclic compound based on cyclotetraphosphazatetraene in 1 975,, several studies devoted to the formation of this class of compounds have These involved the reactions of 2,6-trans-bis(primary alkylamino)hexachloro-derivatives N,P,CI,(NHR), with a secondary amine, oiz. d i m e t h ~l a m i n e , ~? ~ or the reactions of the octachloride N,P,CI, (1) with primary acyclic a m i n e ~~. ~. ~ NH,R [where undoubtedly N,P,CI,(NHR), is a reaction intermediate], to yield N,P,(NMe,),(NHR)(NR) and N,P,(NHR),( NR), respectively. These bicyclic derivatives were invariably accompanied by larger or smaller amounts of monocyclic products, N,P,(NMe,),(NHR), and N,P,-(NHR),, respectively, sometimes to the apparent exclusion of bicyclic derivatives. Variable amounts of resins were also formed. The reaction variables so far investigated included (a)the acyclic alkyl group R,,-, and it was reported that xbranching prevented bicyclic compound f ~r m a t i o n , ~ and (b) solvent effects,, the order of effectiveness in promoting bridgehead formation being CHCI, > CH,CI, $ MeCN Et,O, CCI,. With the last two solvents no bicyclic derivatives were reported.We now report: ( a ) the first bicyclic derivatives with a cyclic aliphatic amine, u k . cyclopropylamine, where branching occurs at the x-carbon, N,P,(NHC,H,),(NC,H,)(2); (b) the first bicyclic derivative where N,P,CI,(NHR), is allowed to react with another primary amine NH,R', uiz. N,P,(NHC,H,),-(NHEt)(NEt) (7); (c) the effect of varying the nature of the secondary amine, NHR,, in its reaction with N,P,CI,(NHEt), (3); ( d ) further solvent-effect studies; and ( e ) the effect of a tertiary base, triethylamine. We also discuss the likely reaction mechanisms leading to bicyclic phosphazene formation. ' has been isolated, but the maximum replacement by the dibenzylamino group in the monocycles has been confined to N,P3CI,[N(CH,Ph)2],14 and N4P4CI4[N(CH2Ph),],.' To test this steric hypothesis we

Phosphorus-nitrogen compounds: Part 15. Synthesis, anisochronism and the relationship between crystallographic and spectral data of monotopic spiro-crypta phosphazenes

“…[10][11][12] Hence, researchers have focused on the replacement reactions of halogen atoms of halophosphazenes by different nucleophiles, e.g. primary and secondary amines, [13][14][15] diamines, [16][17][18] diphenols, [19][20][21][22] diaza-crown ethers (coronands) [23][24][25][26] and aminophenols. 27 In addition, chlorophosphazene derivatives have attracted increased attention and a new class of chiral phosphazene bases have been synthesized and characterized.…”

The Reactions of Octachlorocyclotetraphosphazene with Difunctional Bis(2-Hydroxyethyl) Ether. Nuclear Magnetic Studies of the Products

“…(c) The A 4 (13), displays an A 4 spin system as well resonating at 2.87 ppm. In the foregoing spin system, second order effects are pronounced, especially in the ethoxy derivatives [40c].…”

“…On the other hand, the beta-methylene carbons give rise to a quintet structure at 68.26 ppm S. TURE as expected. 13 C NMR spectra of compounds 5, 6, 7, and 9 are presented in Figures 9 and 10.…”

“…The alteration in the three bond coupling is more dramatic and 3 J(POC) values are considerably higher in the tetramer derivatives. 13 C NMR NMR data are given in Table 4. …”

Phosphorus–nitrogen compounds: Part 31. Syntheses, structural and stereogenic properties, in vitro cytotoxic and antimicrobial activities, and DNA interactions of bicyclotetraphosphazenes containing bulky side group

“…A wide range of side groups (R 1 and R 2 , Fig. 1a) may be bonded to this skeleton, leading to products with a similarly diverse range of physical and chemical properties [14]. Previously, to our knowledge there were only two papers about 2,4-sas and 2,6-sas bicyclophosphazenes in the literature [8,9].…”