THE ANHYDROUS RACEMATE OF THE CARCINOSTATIC AGENT CYCLOPHOSPHAMIDE AND THE BICYCLIC DEGRADATION PRODUCT ,3,2-DIAZA-PHOSPHOLO[2,1-B][1,3,2]OXAZAPHOSPHORINE 9-OXIDE
Pg. Jones et al., THE ANHYDROUS RACEMATE OF THE CARCINOSTATIC AGENT CYCLOPHOSPHAMIDE AND THE BICYCLIC DEGRADATION PRODUCT ,3,2-DIAZA-PHOSPHOLO[2,1-B][1,3,2]OXAZAPHOSPHORINE 9-OXIDE, Acta crystallographica. Section C, Crystal structure communications, 52, 1996, pp. 2359-2363
Anhydrous racemic cyclophosphamide, ethyl)-tetrahydro-2H-1,3,2-oxazaph
osphorin-2-amine 2-oxide, C7H15Cl2N2O2P, (1)], displays a chair confor
mation with an axial phosphoryl O atom and approximately planar geomet
ry at the N atoms. The molecules are linked by N-H ... O=P hydrogen bo
nds into chains. One chloroethyl side chain is extended, the other is
gauche. The C-Cl bond lengths are Cl1-C5 1.789(2) and C12-C7 1.791(2)A
. The bicyclic degradation product, 1,3,2-diazaphospholo[2,1-b][1,3,2]
oxazapgisogirube 9-oxide, C7H14ClN2O2P, (2), is formed by intramolecul
ar alkylation at the ring N atom of (1). The major change of bond leng
th upon annelation is observed for P-N2, the ring P-N bond in (1), whi
ch is lengthened from 1.633 (2) to 1.6593 (14) Angstrom. The angle N1-
P-N2, incorporated into the five-membered ring in (2), narrows from 10
5.84(8) to 97.36(7)degrees. The remaining chloroethyl side chain is ga
uche. The C-Cl bond length is 1.790 (2) Angstrom.