Electron ionization mass spectra of phosphorus‐containing heterocycles. II. 1,2,3,4,4a,5,6,7,8,8a‐decahydro‐1,3,2‐benzodiazaphosphinine 2‐oxides

Abstract

The electron ionization mass spectra of cis- and trans-fused 1,2,3,4,4a,5,6,7,8,8a-decahydro-1,3,2-benzodiazaphosphinine 2-oxides (1-17) were recorded, and the fragmentation pathways were established and compared with those of 1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphinine 2-oxides. In general, the mass spectral behaviors of the isomeric compounds were very similar and it was mostly impossible to differentiate them from each other on the basis of the relative abundances of their characteristic fragment ions. The compounds in which R(2) = Ph or OPh exhibited a series of common fragments, e.g. [R(2)H](+), R(2)PONHR(1(3)+), [M-C(3)H(7)](+) and [M-C(4)H(9)](+), the latter two ions being present in the spectra of only two of the derivatives with an N(CH(2)CH(2)Cl)(2) substituent on the P atom. When R(2) = Ph, numerous other alkyl radicals, alkenes and a cycloalkane were also ejected and these compounds also lost NH(2), NH(3), CH(3)N, CH(4)N or CH(3)NH(2). The compounds with an N(CH(2)CH(2)Cl)(2) substituent on the P atom most closely resembled their 3,1,2-O,N,P analogs in respect of the dominant role of this substituent.

Molecular Evolution Using Intramolecular Acyl Migration on myo‐Inositol Benzoates with Thermodynamic and Kinetic Selectors

“…ions of compounds 3b , 4a and 4b vary from 20 to 80%. The main fragmentation pathways of both the cis ‐ and the trans ‐fused isomers of 1 – 4 are similar (and comparable with those of the 1,3,4,2‐oxadiazaphosphinane 2‐oxides; ionization occurs at the bridgehead N atom)27 b since they are fragmented mainly by bond cleavages inside the condensed oxazaphosphino ring moiety. The two most important fragmentation routes of compounds 1 – 4 proved to be (i) loss of the fragments C 8 H, C 8 H 8 , C 8 H and (ii) loss of the whole fused heterocyclic ring system to yield the ion at m/z 191.…”

“…at m/z 345 and [M–R 1 PO 2 H] + at m/z 294 were observed. The [M–R 1 PO 2 H] + fragment ion of compounds 1 – 4 is already known from the mass spectra of the 1,3,4,2‐oxadiazaphosphinane 2‐oxides and 3,1,2‐O,N,P‐heterocycles,27b and other simple cyclophosphamides 17. This kind of elimination is important for stereochemical reasons and will be discussed later.…”

“…Finally, and very recently, three comprehensive reports on the EI mass spectra of cis ‐ and trans ‐annelated phosphorus‐containing heterocycle have been published 26, 27a,b…”

Selective Gas Adsorption and Unique Structural Topology of a Highly Stable Guest‐Free Zeolite‐Type MOF Material with N‐rich Chiral Open Channels

“…Syntheses and the conformational assignments of 1,4,6,7,8,8a‐hexahydropyrrolo[1,2‐ d ]1,3,4,2‐oxadiazaphosphinine 3‐oxides ( 1 and 2 ), 1,6,7,8,9,9a‐hexahydro‐4 H ‐pyrido[1,2‐ d ]1,3,4,2‐oxadiazaphosphinine 3‐oxides ( 3 , 4 and 8 ), 1,6,11,11a‐tetrahydro‐4 H ‐1,3,4,2‐oxadiazaphosphino[4,5‐ b ]isoquinoline‐3‐oxides ( 5 and 6a ) and 1,6,7,11b‐tetrahydro‐4 H ‐1,3,4,2‐oxadiazaphosphino‐[5,4‐ a ]isoquinoline‐3‐oxides ( 7 ) (Table 1) were reported previously 5, 6. In addition to the basic fragmentations of the compounds mentioned above, our main interest was in the detection of parallels and dissimilarities (caused by differences in ring size, ring fusion, P substitution and bridgehead N atom) relative to the 3,1,2‐O,N,P‐ and 1,3,2‐N,N,P‐heterocycles studied previously 7, 8…”

6-Membered P-Heterocycles: Ring-Condensed 1,3,2-Diheterophosphorinane 2-Chalcogenides

“…The axial or equatorial preference of the P substituents can shift the N-in/N-out equilibrium in a direction such that the substituents can occupy their preferred positions in the chair conformation, but both chair forms can depopulate towards more preferable skew conformations when the P configuration is unfavourable (Scheme 13). The fragmentations of compounds 81-94 and 101-114 have been thoroughly studied by means of electron ionization MS [69,70].…”