FORM-2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (Section 10 and Rule 13)
1. TITLE OF THE INVENTION: - A process for microwave assisted green synthesis of 1, 3-diketones ((3-diketones) from 2-aryloxy acetophenone using Cadmium oxide nanoparticles as a catalyst.
2. ADDRESS OF THE APPLICANT:-

(a) NAME: -Dr. M. M. V. Ramana
(b) NATIONALITY: INDIAN
(c) ADDRESS: Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai- 400 098.
India.
3. PREAMBLE TO THE DESCRIPTION: - COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

4.DESCRIPTION:-
Title:-
A process for microwave assisted green synthesis of 1, 3-diketones (p-diketones) from 2-aryloxy acetophenone using Cadmium oxide nanoparticles as a catalyst.
Abstract of invention:-
The present invention relates to the solid state microwave assisted synthesis of 1, 3-diketones (P-diketones) from 2-aryloxy acetophenone derivatives using Cadmium oxide nanoparticles as catalyst via Baker-Venkataraman rearrangement. Along with the high yields, significance of using solid state microwave synthesis is short reaction time, ease of separation of product and the process is environmentally benign.
Background of invention and Prior art:-
1, 3-diketone is a key subunit related to diversified biological activities (US 4065502 A, US 5475145 A, US 7820209 B2,), furthermore as an organic intermediate for the synthesis of different flavonoid molecules ( KR 2009092859 A). These flavonoid molecules have wide range of pharmaceutical applications (KR 2013127802A, CN 103191157A, CN 103181414A, US 20130030045A1). Due to such essential applications, a variety of methods have been developed for the construction of 1, 3-diketone motif (US 2214117 A, US 2418173 A, US 2621212 A, US 2864850 A). Baker-Venkataraman rearrangement is the most widely used route for synthesis of p-diketones (Scheme 1). (Sharma D, Kumar S, Makrandi JK, Green chemistry letters and reviews, 2009,
2, 53). In this reaction, base-induced transfer of the ester acyl group in an o-acylated phenol ester, which leads to a P-diketone. The reaction proceeds through the formation of an enolate, followed by intramolecular acyl transfer.

Scheme 1: Baker-Venkataraman Rearrangement.
Application of catalyst in synthetic protocol reduces the reaction time along with the high yields many a times (WO 2014134733 Al, WO 2014120585 Al, CN 103936536 A). Nanostructured metal oxides have been extensively investigated for their synthesis, fundamental properties and applications in the field of chemistry (US 20130089739 Al, JP 2008049280 A, WO 2007074437 A2). In past decade, various metal oxide nanoparticles were applied as catalyst to carry out organic transformations (Pugazhenthi I, Shaik M. G., Bae J. S., Kim J. P., Khan N., Rahman F., Duck J. E., Hyuk C. E., Yadavalli S., Dasarath C. RSC Advances, 2015, Ahead of print, DOI: 10.1039/C4RA13045F; Hattori M., Einaga H., Diao T., Tsuji M. Journal of Material Chemistry A: Materials for Energy and Sustainability, 2015, Ahead of print, DOI: 10.1039/C4TA06988A). Cadmium oxide (CdO) nanoparticles also served as catalyst for one pot synthesis of a-aminophosphonates (Sara S, Falatooni M.Z., Moones H. RSC Advances, 2014, 4, 30)
Microwave irradiated organic synthesis has demonstrated itself to be superior in many instances when compared to conventional heating. Along with the high yields, short reaction lime is major outcome using microwave heating. (Shimizu Y.; Morimoto H.; Zhang M.; Ohshima T. Angew. Chem. Int. Ed. 2012, 51; Yuvaraj P.; Manivannan K.; Reddy B. S. R. Tetrahedron Letters, 2015, 56)

The present invention describes microwave assisted solid phase synthesis of P-diketones from 2-aryloxy acetophenones using cadmium oxide (CdO) nanoparticles as a reusable catalyst.
Description of the invention:-
The main objective of the present invention is to synthesize compounds 2a-2h via microwave assisted green synthesis of 1, 3-diketones from 2-aryloxy acetophenone using Cadmium oxide nanoparticles as a catalyst
Synthesis of compounds 2a-2h:-
Compounds 2a-2h were synthesized as per the Scheme 2

Entry Compounds R
1 2a H
2 2b 2-CH3
3 2c 3-C1
4 2d 4-C1
5 2e 4-CH3
6 2f 4-F
7 2g 4-OCH3
8 2h 4-NO2

Synthesis and characterization of Cadmium oxide nanopartides:
In a clean dry beaker, 50.0 ml solution of Cadmium nitrate hexahydrate (1.5M) was prepared in distilled water. Similarly 50.0 ml solution of Urea (3M) was prepared in distilled water separately. Cadmium nitrate solution was slowly heated to 70°C with constant stirring of 500 RPM. After attaining the temperature, urea solution was added dropwise within total time 2.0 hours. The addition of the urea solution should be very slow to obtain nanoparticles. After the total addition, formed precipitate was centrifuged and repeatedly washed with distilled water. Residue then dried at 120°C for 1 hour in oven followed by heating at 500°C for 5.0 hours in a muffle furnace. XRD diffraction pattern of the synthesized CdO nanoparticles (Fig.2) are in good agreement with International Centre for Diffraction Data Powder Diffraction file (PDF-00-005-0640)
Fig.2 XRD pattern of Cadmium oxide nanoparticles
Particle size of the CdO nanoparticles were calculated from XRD diffraction pattern using Scherrer's equation
t=Kλ/βcosθ
t = mean particle size of the ordered domains

K = dimensionless shape factor, with a value close to unity. The shape factor has a typical value of about 0.9
λ = X-ray wavelength
β = line broadening at half the maximum intensity (FWHM)
θ =Bragg angle
Particle size of Cadmium oxide nanoparticles calculated from above equation by using XRD diffraction pattern.
t = 54.70 nm
Example 1:- Synthesis of l-(2-hydroxyphenyl)-3-phenylpropane-l, 3-dione (2a)
2-Acetyl phenyl benzoate (la) (1 mmol) was mixed with cadmium oxide (CdO) nanoparticles (0.1 g) in round bottom flask. Reaction mixture was mixed well by gentle shaking. Reaction mixture then irradiated with microwaves for 1.0 minute at 100 watts. After the completion of reaction (TLC), 20.0 ml ethyl acetate was added to reaction mixture and CdO nanoparticles were recovered by filtration using Whatman filter paper No. 1. Ethyl acetate was removed under reduced pressure to obtain compound (2a). H NMR and IR spectra of compounds 2a were consistent with the data reported in literature
Yield:-85%, Melting Point: - Observed- 118°C Literature- 118-119°C (Sharma D, Kumar S, Makrandi JK, Green chemistry letters and reviews, 2009, 2, 53)
Example 2:- Synthesis of l-(2-hydroxyphenyl)-3-(o-tolyl) propane-1, 3-dione (2b)
Compound (2b) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-2-methyl benzoate in place of 2-acetyl phenyl benzoate. lH NMR and IR spectra of compounds 2b were consistent with the data reported in literature

Yield:-80% Melting Point: - Observed- 96°C Literature- 96-97°C. (Cramer, Friedrich D.; Elschnig, Gert H, Chemische Berichte, 1956, 89, 1)
Example 3:- Synthesis of l-(3-chlorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2c)
Compound (2c) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-3-chlorobenzoate in place of 2-acetyl phenyl benzoate. H NMR and IR spectra of compounds 2c were consistent with the data reported in literature
Yield:-80% Melting Point: - Observed- 118°C Literature- 116-118°C. (Bapna M, Nema RK, Asian journal of chemistry, 2009, 21, 1244)
Example 4:- Synthesis of l-(4-chlorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2d)
Compound (2d) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-4-chlorobenzoate in place of 2-acetyl phenyl benzoate. ]H NMR and IR spectra of compounds 2d were consistent with the data reported in literature
Yield:-82% Melting Point: - Observed- 110°C Literature- 108-110°C. (Bapna M, Nema RK, Asian journal of chemistry, 2009, 21, 1244)
Example 5:- Synthesis of l-(2-hydroxyphenyl)-3-(p-tolyl) propane-1, 3-dione (2e)
Compound (2e) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-4-methyl benzoate in place of 2-acetyl phenyl benzoate. *H NMR and IR spectra of compounds 2e were consistent with the data reported in literature
Yield:-84% Melting Point: - Observed- 110°C Literature- 109-110°C. (Cramer, Friedrich D.; Elschnig, Gert H, Chemische Berichte, 1956, 89, 1)

Example 6:- Synthesis of l-(4-fluorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2f)
Compound (2f) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-4-fluorobenzoate in place of 2-acetyl phenyl benzoate. lH NMR and IR spectra of compounds 2f were consistent with the data reported in literature
Yield:-88% Melting Point: - Observed- 134°C Literature- 133-135°C. (Bapna M, Nema RK, Asian journal of chemistry, 2009, 21, 1244)
Example 7:- Synthesis of l-(2-hydroxyphnyl)-3-(4-methoxyphenyl) propane-1, 3-dione (2g)
Compound (2g) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-4-methoxybenzoate in place of 2-acetyl phenyl benzoate. *H NMR and IR spectra of compounds 2g were consistent with the data reported in literature
Yield:-85% Melting Point: - Observed- 110°C Literature- 110°C. (Sharma D, Kumar S, Makrandi JK, Green chemistry letters and reviews, 2009, 2, 53)
Example 8:- Synthesis of l-(2-hydroxyphenyl)-3-(4-nitrophenyl) propane-1, 3-dione (2h)
Compound (2h) was synthesized by procedure as described in Example 1 using 2-acetylphenyl-4-nitro benzoate in place of 2-acetyl phenyl benzoate. [H NMR and IR spectra of compounds 2h were consistent with the data reported in literature
Yield:-80% Melting Point: - Observed- 204°C Literature- 203-204°C. (Rama Rao, A. V.; Telang, S. A.; Nair, P. Madhavan, Indian /. Chem., 1964, 2, 431)
Cadmium oxide nanoparticles recovery and reuse:-
Encouraged by these results, we decided to examine the catalytic activity of the recycled cadmium oxide nanoparticles. The catalyst was recovered by simple filtration, washed with ethyl acetate and dried at 120°C for 2 hours. Catalyst again

used for the synthesis of 2a and 2e, successively three times without significantly affecting its activity as delineated in Table.
Table: - Synthesis of β-diketones 2a and 2e with recycled CdO nanoparticles catalyst.

Entry Product Yield Recycle


1 2 3
1 2a 85% 85% 82% 82%
2 2e 84% 84% 82% 82%

5. CLAIMS:
We claim: -
(1) Microwave assisted solid state synthesis of l-(2-hydroxyphenyl)-3-
phenylpropane-1, 3-dione (2a) by Baker-Venkataraman rearrangement of 2-acetyl
phenyl benzoate using reusable catalyst cadmium oxide nanoparticles as described
in Example 1.
(2) Microwave assisted solid state synthesis of l-(2-hydroxyphenyl)-3-(0-tolyl)
propane-1, 3-dione (2b) by Baker-Venkataraman rearrangement of 2-acetylphenyl-
2-methyl benzoate using reusable catalyst cadmium oxide nanoparticles as
described in Example 2.
(3) Microwave assisted solid state synthesis of l-(3-chlorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2c) by Baker-Venkataraman rearrangement of 2-acetylphenyl-3-chlorobenzoate using reusable catalyst cadmium oxide nanoparticles as described in Example 3.
(4) Microwave assisted solid state synthesis of l-(4-chlorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2d) by Baker-Venkataraman rearrangement of 2-acetylphenyl-4-chlorobenzoate using reusable catalyst cadmium oxide nanoparticles as described in Example 4.
(5) Microwave assisted solid state synthesis of l-(2-hydroxyphenyl)-3-(p-tolyl)
propane-1, 3-dione (2e) by Baker-Venkataraman rearrangement of 2-acetylphenyl-
4-methyl benzoate using reusable catalyst cadmium oxide nanoparticles as
described in Example 5.
(6) Microwave assisted solid state synthesis of l-(4-fluorophenyl)-3-(2-hydroxyphenyl) propane-1, 3-dione (2f) by Baker-Venkataraman rearrangement of 2-acetylphenyl-4-fluorobenzoate using reusable catalyst cadmium oxide nanoparticles as described in Example 6.
(7) Microwave assisted solid state synthesis of l-(2-hydroxyphnyl)-3-(4-methoxyphenyl) propane-1, 3-dione (2g) by Baker-Venkataraman rearrangement of 2-acetylphenyl-4-methoxybenzoate using reusable catalyst cadmium oxide nanoparticles as described in Example 7.

(8) Microwave assisted solid state synthesis of l-(2-hydroxyphenyl)-3-(4-nitrophenyl) propane-1, 3-dione (2h) by Baker-Venkataraman rearrangement of 2-acetylphenyl-4-nitro benzoate using reusable catalyst cadmium oxide nanoparticles as described in Example 8.