Alkaline solvolysis of diaminophosphates

Mollin, J.; Láznička, Jiří; Kašpárek, František

doi:10.1135/cccc19830232

Cited by 4 publications

(4 citation statements)

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“…Pentylamine A has ah igher basicity than the other amino compounds (for comparison, the pK a of pentylamine is 10.63, [67] while the pK a 3.0 for benzhydrazide [68] 4.23 for O-benzyl hydroxylamine [69] and 5.21 for phenylhydrazine [70] ). Pentylamine A has ah igher basicity than the other amino compounds (for comparison, the pK a of pentylamine is 10.63, [67] while the pK a 3.0 for benzhydrazide [68] 4.23 for O-benzyl hydroxylamine [69] and 5.21 for phenylhydrazine [70] ).…”

Section: B) Competitive Reactions Of Two Amino Compounds Withmentioning

confidence: 99%

Kinetic Selectivity and Thermodynamic Features of Competitive Imine Formation in Dynamic Covalent Chemistry

Kulchat

Chaur

Lehn

2017

Chemistry A European J

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The kinetic and thermodynamic selectivities of imine formation have been investigated for several dynamic covalent libraries of aldehydes and amines. Two systems were examined, involving the reaction of different types of primary amino groups (aliphatic amines, alkoxy-amines, hydrazides and hydrazines) with two types of aldehydes, sulfobenzaldehyde and pyridoxal phosphate in aqueous solution at different pD (5.0, 8.5, 11.4) on one hand, 2-pyridinecarboxaldehyde and salicylaldehyde in organic solvents on the other hand. The reactions were performed separately for given amine/aldehyde pairs as well as in competitive conditions between an aldehyde and a mixture of amines. In the latter case, the time evolution of the dynamic covalent libraries generated was followed, taking into consideration the operation of both kinetic and thermodynamic selectivities. The results showed that, in aqueous solution, the imine of the aliphatic amine was not stable, but oxime and hydrazone formed well in a pH dependent way. On the other hand, in organic solvents, the kinetic product was the imine derived from an aliphatic amine and the thermodynamic products were oxime and hydrazone. The insights gained from these experiments provide a basis for the implementation of imine formation in selective derivatization of mono-amines in mixtures as well as of polyfunctional compounds presenting different types of amino groups. They may in principle be extended to other dynamic covalent chemistry systems.

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Section: B) Competitive Reactions Of Two Amino Compounds Withmentioning

confidence: 99%

Kinetic Selectivity and Thermodynamic Features of Competitive Imine Formation in Dynamic Covalent Chemistry

Kulchat

Chaur

Lehn

2017

Chemistry A European J

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“…The hydroxylamine moiety is an interesting functional group with the potential to enrich compound collections, in which it is currently under-represented, by increasing the fraction of sp 3 -hybridized atoms (Fsp 3 ) without the synthetic complication of an additional stereogenic center. This is because the low basicity of the hydroxylamine function (p K a hydroxylamine in water = 5.93) , and the modest barrier to inversion (∼15 kcal·mol –1 ) − together ensure that at physiological pH the pyramidal nitrogen is not protonated in aqueous solution and undergoes rapid inversion of configuration. As such, hydroxylamines carrying two different nitrogen substituents can be considered as surrogates of chiral alcohols and ethers that avoid the need for asymmetric synthesis.…”

mentioning

confidence: 99%

Synthesis of N,N,O-Trisubstituted Hydroxylamines by Stepwise Reduction and Substitution of O-Acyl N,N-Disubstituted Hydroxylamines

Dhanju

Crich

2016

Org. Lett.

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Diverse N,N,O-trisubstituted hydroxylamines, an under-represented group in compound collections, are readily prepared by partial reduction of N-acyloxy secondary amines with diisobutylaluminum hydride followed by acetylation and reduction of the so-formed O-acyl-N,N-disubstituted hydroxylamines with triethylsilane and boron trifluoride etherate. Use of carbon nucleophiles in the last step, including allyltributylstannane, silyl enol ethers, and 2-methylfuran, gives N,N,O-trisubstituted hydroxylamines with branching α- to the O-substituent. N,N-Disubstiuted hydroxylamines are conveniently prepared by reaction of secondary amines with dibenzoyl peroxide followed by diisobutylaluminum hydride reduction.

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“…2.5, [ 34,35 ] while O‐ethylhydroxylamine (a representative molecule for O , O ′‐1,3‐propanediylbishydroxylamine) has a reported p K a of 4.65. [ 36 ] This is the opposite trend in stress relaxation to that reported by Yesilyurt et al. for their phenylboric acid esters.…”

Section: Resultsmentioning

confidence: 60%

“…2.5, [34,35] while O-ethylhydroxylamine (a representative molecule for O,O′-1,3propanediylbishydroxylamine) has a reported pK a of 4.65. [36] This is the opposite trend in stress relaxation to that reported by A) The shear storage modulus (G') obtained for each formulation. By successively replacing 0.2 mol equiv hydrazone with oxime, we can tune the final hydrogel modulus from 0.22 to 2.78 kPa.…”

Section: Designing Schiff-base Dynamic Covalent Hydrogelsmentioning

confidence: 67%

Tuning Hydrogels by Mixing Dynamic Cross‐Linkers: Enabling Cell‐Instructive Hydrogels and Advanced Bioinks

Morgan

Fernández‐Pérez

Moroni

et al. 2021

Adv Healthcare Materials

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Rational design of hydrogels that balance processability and extracellular matrix (ECM) biomimicry remains a challenge for tissue engineering and biofabrication. Hydrogels suitable for biofabrication techniques, yet tuneable to match the mechanical (static and dynamic) properties of native tissues remain elusive. Dynamic covalent hydrogels possessing shear-thinning/self-healing (processability) and time-dependent cross-links (mechanical properties) provide a potential solution, yet can be difficult to rationally control. Here, the straightforward modular mixing of dynamic cross-links with different timescales (hydrazone and oxime) is explored using rheology, self-healing tests, extrusion printing, and culture of primary human dermal fibroblasts. Maintaining a constant polymer content and cross-linker concentration, the stiffness and stress relaxation can be tuned across two orders of magnitude. All formulations demonstrate a similar flow profile after network rupture, allowing the separation of initial mechanical properties from flow behavior during printing. Furthermore, the self-healing nature of hydrogels with high hydrazone content enables recyclability of printed structures. Last, a distinct threshold for cell spreading and morphology is observed within this hydrogel series, even in multi-material constructs. Simple cross-linker mixing enables fine control and is of general interest for bioink development, targeting viscoelastic properties of specific cellular niches, and as an accessible and flexible platform for designing dynamic networks.

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Alkaline solvolysis of diaminophosphates

Abstract: Mechanism of alkaline solvolysis of phenyl diaminophosphates is discussed on the basis of its selectivity, activation entropy and steric effects. All methods used show that the reaction proceeds by SN2 mechanism via an intermediate, containing a pentavalent phosphorus.

Cited by 4 publications

References 0 publications

Kinetic Selectivity and Thermodynamic Features of Competitive Imine Formation in Dynamic Covalent Chemistry

Kinetic Selectivity and Thermodynamic Features of Competitive Imine Formation in Dynamic Covalent Chemistry

Synthesis of N,N,O-Trisubstituted Hydroxylamines by Stepwise Reduction and Substitution of O-Acyl N,N-Disubstituted Hydroxylamines

Tuning Hydrogels by Mixing Dynamic Cross‐Linkers: Enabling Cell‐Instructive Hydrogels and Advanced Bioinks

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