PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
5
(Table 2, entries 12 and 13) akin to earlier observation. It is yield under operationally convenient conditions are some of
pertinent to mention that in case of simple aldehydes 4 the the noteworthy features of the presented methodology which
reaction proceeded through the initial formation of makes this methodology a better and alternative compared
Knoevenagel product which was further activated by the to many reported protocols.
lithium ion and water molecule to react with trialkylphos-
phite to deliver the desired b-malonophosphonates (7a-h)
through pospha-Michael reaction. However, in case of o-
Acknowledgement
hydroxysalicyldehydes 8 the selective formation of diethyl V.K. thanks the Head, School of Biotechnology, SMVDU for providing
the facilities for the conduct of summer training. The contribution of
(
2-amino-3-cyano-4H-chromen-4-yl)phosphonates (9a-e) is
SAIF Chandigarh, IIM Jammu and the Department of Chemistry at
University of Jammu for providing instrumentation facilities is also
acknowledged.
believed to be takes place through the initial formation of
cyanoolefin via Knoevenagel condensation. The cyanoolefin
then undergoes ring-closer through intramolecular Pinner
reaction to form iminocoumarin which lastly undergoes
phospha-Michael reaction to generate the desired products
Disclosure statement
(9a) instead of b-malonophosphonates (Scheme 2). The
No potential conflict of interest was reported by the authors.
structures of the products were confirmed on the basis of
1
13
31
physical and NMR ( H, C and P NMR) data.
ORCID
Anil Kumar
Plausible mechanism
[
15]
Based on a literature precedent,
mechanism for the synthesis of diethyl (2-amino-3-cyano-
H-chromen-4-yl)phosphonate, 9a is depicted in Scheme 2.
a proposed reaction
References
4
[1] (a) Zhu, J.; Bienayme, H. (Eds.), Multi-component Reactions,
Wiley-VCH, 2005. (b) Domling, A.; Wang, W.; Wang, K.
Chemistry and Biology of Multicomponent Reactions. Chem.
Rev. 2012, 112, 3083–3135. (c) Zhu, J.; Wang, Q.; Wang, M.
Initially, salicyldehyde 8a and malononitrile 5a underwent
Knoevenagel condensation in the presence of LiBr to form
intermediate III which subsequently undergoes ring-closure
to form imino-coumarin intermediate IV. Next, intermediate
IV undergoes phospha-Michael reaction via nucleophilic
attack of triethylphosphite 6a that leads to the formation of
intermediate V which finally provides anticipated prod-
uct, 9a.
(
Eds), Multi-component Reactions in Organic Synthesis, Wiley-
VCH, 2014. (d) Herrera, R. P.; Marques-Lopez, E. Multi-compo-
nent Reactions: Concepts and Applications for Design and
Synthesis, Wiley-VCH, 2015. (e) Wang, Q.; Wang, D-X.; Wang,
M-X.; Zhu, J. Still Unconquered: Enantioselective Passerini and
ꢀ
[2] (a) Toure, B. B.; Hall, D. G. Natural Product Synthesis using
Multicomponent reaction Strategies. Chem. Rev. 2009, 109,
Experimental
4
439–4486. (b) Godineau, E.; Landais, Y. Radical and
General procedure
1
Wang, X. One-pot synthesis of 1-Aryl-1H,3H-thiazolo[3,4-
a]benzimidazoles using Magnetite-linked Sulfonic acid as
The mixture of aromatic aldehyde (1 mmol), malononitrile/
ethyl cyanoacetate (1 mmol) and alkylphosphite (1 mmol)
were heated under reflux in water (1 mL). The reaction pro-
gress was monitored by silica gel coated thin layer chroma-
tography till appropriate time as summarized in Table 2.
Subsequently, the reaction mixture was cooled and solid was
precipitated which was filtered followed by washing with
water. The product was further subjected to silica gel col-
umn chromatography using hexane-ethyl acetate mixture
;
Patel, M. P.; Patel, R. G. One-Pot, Multicomponent
Condensation Reaction in Neutral conditions: Synthesis,
Characterization, and Biological studies of Fused Thiazolo[2,3-
(e) Ghandi, M.; Ghomi, A.-T.; Kubicki, M. Synthesis of
Cyclopentadiene-fused
Chromanones
via
One-pot
(2:8 to 4:6) to afford the pure products. The desired prod-
ucts have been unambiguously analyzed by spectroscopic
[
3] (a) Bienayme, H.; Hulme, C.; Oddon, G.; Schmitt, P.
1
and physical data. The Supplemental Materials contains H,
Maximizing
Transformations lead the way. Chem. Eur. J. 2000, 6,
321–3329. (b) Mobinikhaledi, A.; Foroughifar, N.; Mosleh, T.;
Synthetic
Efficiency:
Multi-Component
1
3
31
C and P NMR spectra for 7a – 7h and 9a – 9e
Figures S1–S39).
3
(
Hamta, A. Synthesis of New Pyrimidine, Quinazoline and
Diazatricyclo Derivatives by Multicomponent Reaction and
Conclusion
4] (a) Hosseinian, A.; Shaterian, H. R. NaHSO
Multicomponent Synthesis of 1-(Benzothiazolylamino) Methyl-
-Naphthols under Solvent-free Conditions. Phosphorus Sulphur
To summarize, we have developed an efficient and conveni-
ent LiBr-catalyzed three-component domino Knoevenagel-
phospha-Michael route for the synthesis of b-phosphono-
malonates under aqueous conditions. The avoidance of toxic
solvents and catalyst, use of water and good to excellent
[
4 2
.H O Catalyzed
2
Silicon Relat. Elem. 2012, 187, 1056–1063. (b) Pal, S.;
Choudhury, L. H.; Parvin, T. One-Pot Multicomponent