Solvent-free N-alkylation of 1,3,5-triaza-7: phospha-adamantane (PTA)

Article abstract of DOI:10.1080/10426507.2018.1539993

1,3,5-triaza-7-phosphaadamantane was alkylated under solvent-free conditions with CH₃I, CH₃-(CH₂)₃-Br, Br-(CH₂)₄-Br, OH-CH₂-CH₂Br, and CH₃CH₂OOCCH₂Br in a planetary ball mill with yields over 90%. Due to spontaneous resolution, both 1-(2-ethoxy-2-oxoethyl)-3,5-diaza-1-azonia-3,5-diaza-7-phosphaadamantane bromide (4) and (4-bromobutyl)-1-azonia-3,5-diaza-7-phosphaadamantane bromide (5) were obtained in the solid state as conglomerates of enantiomorphic crystals.

Full text of DOI:10.1080/10426507.2018.1539993

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: https://www.tandfonline.com/loi/gpss20
Solvent-free N-alkylation of 1,3,5-triaza-7:
phospha-adamantane (PTA)
Antal Udvardy, Csenge Tamara Szolnoki, Ferenc Joó & Ágnes Kathó
To cite this article: Antal Udvardy, Csenge Tamara Szolnoki, Ferenc Joó & Ágnes Kathó (2019):
Solvent-free N-alkylation of 1,3,5-triaza-7: phospha-adamantane (PTA), Phosphorus, Sulfur, and
Silicon and the Related Elements, DOI: 10.1080/10426507.2018.1539993
To link to this article: https://doi.org/10.1080/10426507.2018.1539993
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PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2018.1539993
Solvent-free N-alkylation of 1,3,5-triaza-7: phospha-adamantane (PTA)
Antal Udvardya, Csenge Tamara Szolnokia, Ferenc Joóa,b, and Ágnes Kathóa
b
aDepartment of Physical Chemistry, University of Debrecen, Debrecen, Hungary; MTA-DE Redox and Homogeneous Catalytic Reaction
Mechanisms Research Group, University of Debrecen, Debrecen, Hungary
ABSTRACT
ARTICLE HISTORY
Received 6 September 2018
Accepted 11 October 2018
1,3,5-triaza-7-phosphaadamantane was alkylated under solvent-free conditions with CH3I, CH3-
(CH2)3-Br, Br-(CH2)4-Br, OH-CH2-CH2Br, and CH3CH2OOCCH2Br in a planetary ball mill with yields
over 90%. Due to spontaneous resolution, both 1-(2-ethoxy-2-oxoethyl)-3,5-diaza-1-azonia-3,5-
diaza-7-phosphaadamantane bromide (4) and (4-bromobutyl)-1-azonia-3,5-diaza-7-phosphaada-
mantane bromide (5) were obtained in the solid state as conglomerates of enantio-
morphic crystals.
KEYWORDS
PTA; N-alkylation; solvent-
free; ball-mill
GRAPHICAL ABSTRACT
Results and discussion
bromoethanol with PTA yielded the corresponding N-alky-
lated derivatives (5 and 6) by both methods. Even with an
excess of PTA only 5 was obtained despite that reactions
with 1,4-bis(chloromethyl)benzene yielded dialkylated prod-
ucts, too.[5]
Since the introduction of 1,3,5-triaza-7-phosphaadamantane
(PTA) into homogeneous catalysis[1] this ligand, its derivatives
and complexes have attracted ever-increasing interest.[2] In
acetone solution, PTA yields air-stable N-alkylated products
with alkyl halides, such as e.g. methyl iodide,[3] benzyl chlor-
ide[4,5], butyl bromide[5,6] and 2-bromoacetic acid ethyl ester.[7]
In this work, PTA was reacted with alkyl halides under
solvent-free conditions in air in a planetary ball mill (Table 1).
For comparison, some of the reactions were conducted
Molecular structures of 1 and 2 (halide salts) have been
determined already.[3,4] However, the cation of 3 was char-
acterized in the solid state only as its salt with monosulfo-
[5]
nated triphenylphosphine,
while the cation of 4 was
studied as a PF6-salt[7]. We have discovered that 4 (bromide
also in acetone. Reactions of 1,4-dibromobutane and 2- salt) can be isolated as racemic conglomerate of
Table 1. N-alkylation of 1,3,5-triaza-7-phosphaadamantane (PTA).
Products
Yields (in acetone) (%)
Solvent-free yields(%)b
1
2
3
4
5
6
663
434
805
787
43a
66a
95
95
94
91
97
91
550–600 rpm, 12 mL stainless steel grinding jar, 6 bearing balls (5 mm diameter), 4 h milling time, 0.64 mmol PTA (100 mg), nRX: nPTA
:
a2.3–2.5; b1.6–1.9.
CONTACT Antal Udvardy
udvardya@unideb.hu
Supplemental data for this article can be accessed on the publisher’s website at https://doi.org/10.1080/10426507.2018.1539993.
ß 2019 Taylor & Francis Group, LLC

2
A. UDVARDY ET AL.
Phosphaadamantane (PTA): Transition Metal Complexes and
Related Catalytic, Medicinal and Photoluminescent
enantiomorphic crystals which refers to spontaneous reso-
lution. The same is true for 5, however, such phenomenon
was not observed in case of 6, despite that it also contains a
heteroatom in the alkyl chain (see Supplemental Materials,
Figures S1–S4).
In conclusion, we have shown for the first time that N-
alkylation of 1,3,5-triaza-7-phosphaadamantane (PTA) by
alkyl halides (used to be performed in volatile organic sol-
vents under refluxing conditions) can be efficiently achieved
in a planetary ball mill without solvent, with easy product
isolation and high yields.
Applications. Coord. Chem. Rev. 2004, 248, 955–993. (b)
Bravo, J.; Bolaño, S.; Gonsalvi, L.; Peruzzini, M.
Coordination Chemistry of 1,3,5-Triaza-7-Phosphaadamantane
(PTA) and Derivatives. Part II. The Quest for Tailored
Ligands, Complexes and Related Applications. Coord. Chem.
Rev. 2010, 254, 555–607. (c) Guerriero, A.; Peruzzini, M.;
Gonsalvi, L. Coordination Chemistry of 1,3,5-Triaza-7-
Phosphatricyclo[3.3.1.1]Decane(PTA) and Derivatives. Part
III. Variations on
a Theme: NovelArchitectures, Materials
and Applications. Coord. Chem. Rev. 2018, 355, 328–361.
[3] Daigle, D. J. 1,3,5-Triaza-7-Phosphatricyclo[3.3.1.13,7]Decane
and Derivatives. Inorg Synth. 1998, 32, 40–45.
[4] Fluck, E.; Forster, J. E.; Weidlein, J.; Hadicke, E. Z. 1.3.5-
Acknowledgement
Triaza-7-Phosphaadamantan (Monophospha-Urotropin) / 1,3,5-
Triaza-7-Phosphaadamantane
Naturforsch. B: Chem. Sci. 1977, 32, 499–506.
(Monophospha-Urotropine).
The research was supported by the EU and co-financed by
the European Regional Development Fund under the proj-
ects GINOP-2.3.2-15-2016-00008 and GINOP-2.3.3-15-2016-
00004. Thanks are due to Dr. Attila Kiss-Szikszai for elem-
ental analysis.
[5] Udvardy, A.; Bényei, A. C.; Juhász, P.; Joó, F.; Kathó, Á. Two
in One: Charged Tertiary Phosphines Held Together by Ionic
or Covalent Interactions as Bidentate Phosphorus Ligands for
Synthesis of Half-Sandwich Ru(II)-Complexes. Polyhedron
2013, 60, 1–9.
[6] Kirillov, A. M.; Smoleński, P.; Haukka, M.; Guedes da Silva,
M. F. C.; Pombeiro, A. J. L. Unprecedented Metal-Free
C(sp3)–C(sp3) Bond Cleavage: Switching from N-Alkyl- to N-
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