Ring opening of bicyclic tertiary amines with cyclic chlorocarbaphosphazenes: reactions of (ClCN)2(Cl2PN) with 1,4-diazabicyclo[2.2.2]octane and quinuclidine †

Reddy, N. Dastagiri; Elias, Anil J.; Vij, Ashwani

doi:10.1039/a809788g

Cited by 22 publications

(9 citation statements)

References 9 publications

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“…In contrast to the numerous structurally characterized derivatives of the 6-membered carbophosphazenes, only a few examples of well-characterized 8-membered (PNCN) 2 rings are known. , The (PNCN) 2 heterocycle within 9 adopts a boat-twist conformation with a phosphoraniminato (Cl 3 PN) ligand positioned exo to the ring. The P−N bond within the Cl 3 PN ligand [1.518(2) Å] is considerably shorter than the remaining P−N bonds within the heterocycle [1.554(2) to 1.608(2) Å] (Table ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Linear and Cyclic Carbophosphazenes via an Oxidative Chlorination Strategy

et al. 2003

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The use of a mild, oxidative chlorination route for the synthesis of linear and cyclic carbophosphazenes is described. For example, chlorination of the linear PNCN chain Ph(2)P-N=C(Ph)-N(SiMe(3))(2) (1) with C(2)Cl(6) led to the clean formation of the previously known 8- and 6-membered rings [Ph(2)PNC(Ph)N](2) (2) and [Ph(2)PNC(Ph)NP(Ph)(2)N] (3), respectively. In a similar fashion, the N-alkyl-substituted PNCN derivatives, Ph(2)P-N=C(Ph)-N((t)Bu)SiMe(3) (4) and Ph(2)P-N=C(Ph)-N(i)Pr(2) (7) were readily converted by C(2)Cl(6) into the halogenated derivatives ClPh(2)P=N-C(Ph)=N(t)Bu (5) and [ClPh(2)P=N=C(Ph)-N(i)Pr(2)]Cl (8), respectively. Protonation of 5 was accomplished using HCl and gave the carbophosphazenium salt [ClPh(2)P=N-C(Ph)=N((t)Bu)H]Cl (6). In addition, the isolation of a rare 8-membered P(2)N(4)C(2) heterocycle [(Cl(3)P=N)ClPNC(Ph)NP(Cl)(2)NC(Ph)N] (9) from the reaction of PCl(5) and Li[PhC(NSiMe(3))(2)] is reported. Treatment of 9 with one equivalent of GaCl(3) led to the discovery of an unusual Lewis acid-induced ring contraction reaction whereby the (PNCN)(2) ring in 9 is converted into the novel 6-membered P(2)N(3)C heterocyclic adduct [(Cl(3)P=N)ClPNP(Cl)(2)NC(Ph)N].GaCl(3) (10) with concomitant release of PhCN. Structural characterization of compounds 1, 5, 6, and 8-10 by single-crystal X-ray diffraction is also provided.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Linear and Cyclic Carbophosphazenes via an Oxidative Chlorination Strategy

et al. 2003

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“…Solvents and other general reagents used in this work were purified according to standard procedures . [{NCCl} 2 {NPCl 2 }] ( 1 ), N,N,N′,N′ -tetramethylmethylenediamine, [{NC(NMe 2 )} 2 {NPCl 2 }] ( 2 ), and 3,5-dimethylpyrazole were prepared according to literature procedures. CuCl 2 (Lancaster), PdCl 2 (PhCN) 2 (Aldrich, U.S.A), NaN(CN) 2 (Aldrich, U.S.A), 1,1,3,3-tetramethylguanidine (Aldrich, U.S.A), PCl 5 (Aldrich, U.S.A), dimethylamine (SD Fine, India), and formaldehyde (SD Fine, India) were used as obtained.…”

Section: Methodsmentioning

confidence: 99%

Carbophosphazene-Supported Ligand Systems Containing Pyrazole/Guanidine Coordinating Groups

et al. 2011

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Carbophosphazene-based coordination ligands [{NC(NMe(2))}(2){NP(3,5-Me(2)Pz)(2)}] (1), [{NC(NEt)(2)}{NC(3,5-Me(2)Pz)}{NP(3,5-Me(2)Pz)(2)}] (2), [NC(3,5-Me(2)Pz)](2)[NP(3,5-Me(2)Pz)(2)] (3), [{NCCl}(2){NP(NC(NMe(2))(2))(2)}] (4), and [{NC(p-OC(5)H(4)N)}(2){NP(NC(NMe(2))(2))(2)}] (5) were synthesized and structurally characterized. In these compounds, the six-membered C(2)N(3)P ring is perfectly planar. The reaction of 1 with CuCl(2) afforded [{NC(NMe(2))}(2){NHP(O)(3,5-Me(2)Pz)}·{Cu(3,5-Me(2)PzH)(2)(Cl)}][Cl] (6). The ligand binds to Cu(II) utilizing the geminal [P(O)(3,5-Me(2)Pz)] coordinating unit. Similarly, the reaction of 2 with PdCl(2) afforded, after a metal-assisted P-N hydrolysis, [{NC(NEt)(2)}{NC(3,5-Me(2)Pz)}{NP(O)(3,5-Me(2)Pz)}·{Pd(3,5-Me(2)PzH)(Cl)}] (7). In the latter, the [P(O)(3,5-Me(2)Pz)] unit does not coordinate; in this instance, the Pd(II) is bound by a ring nitrogen atom and a carbon-tethered pyrazolyl nitrogen atom. The reaction of 3 with PdCl(2) also results in P-N bond hydrolysis affording [{NC(3,5-Me(2)Pz)(2)}{NP(O)(3,5-Me(2)Pz)}{Pd(Cl)}] (8). In contrast to 7, however, in 8, the Pd(II) elicits a nongeminal η(3) coordination from the ligand involving two carbon-tethered pyrazolyl groups and a ring nitrogen atom. Metalated products could not be isolated in the reaction of 3 with K(2)PtCl(4). Instead, a P-O-P bridged carbodiphosphazane dimer, [{NC(3,5-Me(2)Pz)NHC(3,5-Me(2)Pz)}{NP(O)}](2) (9), was isolated as the major product. Finally, the reaction of 5 with PdCl(2) resulted in [{NC(OC(5)H(4)N)}(2){NP(NC(NMe(2))(2))(2)}·{PdCl(2)}] (10). In the latter, the exocyclic P-N bonds are quite robust and are involved in binding to the metal ion. Compounds 6-10 have been characterized by a variety of techniques including X-ray crystallography. In all of the compounds, the bond parameters of the inorganic heterocyclic rings are affected by metalation.

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“…Despite these early observations and some sporadic reports, only recently has the quaternization and subsequent ring-opening of DABCO been used as a strategy for the synthesis of compound libraries bearing a 2-substituted ethylpiperazine group . Other bicyclic (e.g., quinuclidine) and nonbicyclic tertiary amines behave similarly under appropriate conditions.…”

Section: Introductionmentioning

confidence: 99%

The Reaction of DABCO with 4-Chloro-5H-1,2,3-dithiazoles: Synthesis and Chemistry of 4-[N-(2-Chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazoles

2015

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N-(4-Chloro-5H-1,2,3-dithiazol-5-ylidene)anilines react with DABCO in hot PhCl to give N-{4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazol-5-ylidene}anilines in high yields (70-92%). The reaction also works with 4-chloro-5H-1,2,3-dithiazol-5-one and -thione, giving the corresponding products in 85% and 76% yields, respectively. While the reaction of several (4-chloro-5H-1,2,3-dithiazol-5-ylidene)methanes with DABCO failed to give {4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazol-5-ylidene}methanes, these can be prepared in moderate yields via classical cycloaddition-retrocycloaddition strategies from 4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazole-5-thione. The 2-chloroethyl moiety on selected dithiazoles was also modified without cleavage of the 1,2,3-dithiazole by reaction with various nucleophiles, giving access to 4-[N-(2-substituted)piperazin-1-yl]-5H-1,2,3-dithiazoles in moderate to high yields.

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Ring opening of bicyclic tertiary amines with cyclic chlorocarbaphosphazenes: reactions of (ClCN)2(Cl2PN) with 1,4-diazabicyclo[2.2.2]octane and quinuclidine †

Cited by 22 publications

References 9 publications

Synthesis of Linear and Cyclic Carbophosphazenes via an Oxidative Chlorination Strategy

Synthesis of Linear and Cyclic Carbophosphazenes via an Oxidative Chlorination Strategy

Carbophosphazene-Supported Ligand Systems Containing Pyrazole/Guanidine Coordinating Groups

The Reaction of DABCO with 4-Chloro-5H-1,2,3-dithiazoles: Synthesis and Chemistry of 4-[N-(2-Chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazoles

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