M. N. Sudheendra Rao

Cyclic SN compounds and phosphorus reagents—VII. Reactions of S4N4 with tertiary (amino)phosphines: Synthesis and characterization of (R2N)3PN-S3N3 derivatives and their addition products with norbornadiene. X-ray crystal structure of (C5H10N)3PN-S3N3

Abstract The reactions of the tertiary (amino)phosphines (R2N)3P [R2N = C4H8N-, C5H10N-, C6H12N-, OC4H8N-, and CH3NC4H8N-·] with S4N4 are described. The phosphiniminocyclotrithiazenes (R2N)3PN-S3N3 (1–5) are the only heterocyclic products isolated (60–80% yield). Excess (amino)phosphines cleave the heterocycles readily while norbornadiene reacts with them to give rise to the addition products, (R2N)3PN-S3N3·C7H8 (6–9) in small yields. The single crystal X-ray structure of (C5H10N)3PN-S3N3 (triclinic system, space group P1) gave the unit cell dimensions: a = 9.573(5), b = 10.372(6), c = 10.916(6) A, α = 85.46(3), β = 81.13(4), γ = 79.73(4)°, V = 1052.25 A3 and Z = 2. The structure has been compared with that of Ph3PN-S3N3 which is the only other compound of this type (R3PN-S3N3) whose X-ray structure is known.

Cyclic SN compounds and phosphorus reagents—XV [1]. Synthesis, spectral and X-ray structural characterization of (Ph)(DCA)(R)PNS3N3 [R(C2H5)2N—; (n-C4H9)2N—]

Abstract Room-temperature reactions of asymmetric phosphines, (Ph)(DCA)(R)P (R  Et2N—, Bu2nN—) with S4N4 in acetonitrile afforded phosphiniminocyclotrithiazenes, (Ph)(DCA)(R)PNS3N3 (R  Et2N—, I; Bu2nN—, II) in modest yields (ca 50%). The heterocycles have been characterized by spectroscopic [IR, UV-vis, NMR (1H and 31P) and mass] and single crystal X-ray diffraction methods. Strikingly, the angle at PN(4)S(1) is 135° in I, the largest observed so far and is 119.3° in II. This is also accompanied by the shortest exocyclic S(1)N(4) bond length of 1.537 A observed in the case of I. In the unit cell of II, two types of molecules with slightly differing degree of deviation of the tricoordinate sulfur (0.334 and 0.673 A from the mean plane [N(1)S(2)N(2)S(3)N(3)] are observed.

A convenient and high yield synthesis of tertiary (amino) phosphines by transamination route

Abstract Tris (diethylamino)phosphine affords tertiary (amino) phosphines of pyrrolidine, piperidine, hexamethyleneimine, morpholine and N-methylpiperazine in nearly quantitative yields by transamination route - an easy and convenient synthesis occuring under mild conditions.

Cyclic SN compounds and phosphorus reagents part 6. Reactions of S4N4 with symmetrical tertiary phosphines, R3P (R = t-C4H9, c-C6H11, C6H5CH2, p-MeOC6H4 and p-ClC6H4): Isolation and characterization of phosphinimino substituted cyclic sulphur nitrides

Unlike Ph3P, reactions of S4N4 with symmetrical tertiary phosphines, R3P (R = t-butyl, cyclohexyl, benzyl, p-methoxyphenyl and p-chlorophenyl) afford only the corresponding phosphiniminocyclotrisul-phurtrinitrides, R3PNS3N3 (I–V) in moderate to good yields. (p-ClC6H4)3P alone yields the disubstituted S4N4 derivative, 1,5-[(p-ClC6H4)3PN]2S4N4 (VI) in low yield which undergoes a ring contraction in solution. Among the red crystalline compounds I–V, those containing aliphatic substituents on phosphorus (I–III) are less stable both in solid and solution phases than those containing aromatic substituents (IV and V). Various spectroscopic data have been discussed.

High yield synthesis of cyclic phosphites, phosphates, sulphites and sulphates of catechol and glycol mediated by hypervalent silicon centres

Abstract Room temperature reactions of both tris(catecholato)silicate, M2[Si(o-C6H4O2)3] M=Na,Et3NH and glycolato silicate, K2[Si2(O2C2H4)5] with PCl3, POCl3, SOCl2 and SO2Cl2 proceed exothermally and afford easy isolation of the corresponding cyclic derivatives of catechol/glycol (1–8) in high yield, exemplifying the merit of hypervalent silicon centres in synthesis. (Et3NH)2[Si(o-C6H4O2)3] afford near quantitative conversions.

Stable chiral but racemic phosphines (R)(R′)(R″)P containing two different (amino) substituents : high yield synthesis and conversion to the respective phosphine sulphides

Abstract Reaction of PhPCl 2 with dicyclohexylamine followed by a secondary amine affords stable tertiary phosphine (Ph)(DCA)(NR 2 )P in good yield which reacts readily with sulphur to give the phosphine sulphide (Ph)(DCA)(NR 2 )P(S).

IR, Proton, and Carbon-13 NMR Spectral Characterization of Some Chiral and Achiral Aminophosphines and Their Selenides

Though aminophosphines have been known for a century, and a large variety of such compounds has been synthesized for different aspects of their chemistry, until now, no examples are available on phosphines containing three different amino substituents. In this study, the first examples of such chiral tris(amino)phosphines and o-phenylenedioxo(amino)phosphines were successfully synthesized using condensation reactions, and they were converted to their respective selenides using a simple oxidative addition reaction. The compounds are characterized by IR, 1H, and 13C NMR spectral techniques, and the spectral aspects are presented. The spectral studies (i) indicated that they are indeed powerful tools for structural elucidation of compounds; (ii) showed the effect of heavier selenium atom on the P–N bond rotation process; and (iii) further supported the fact that dipolar structure predominates over the π-bond structure for the aminophosphine selenides. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Crystal structure of (diphenyl)(morpholino)phosphiniminocyclotrithiazene

AbstractThe title compound (C6H5)2(OC4H8N)P=N−S3N3 crystallizes in the space group

Synthesis and Characterisation of Two Examples of Unsymmetrically Disubstituted Cyclotetrathiazenes, 1,5-(X)(Y)S4N4[X = Ph3PN- and Y = i) (p-CH3C6H4) Ph2PN- and ii) (P-CH3C6H4)2PhPN-]

P\bar 1