SYNTHETIC COMMl-JNICATIONS, 30(18), 3241-3244 (2000)

SY NTHESlS OF ISOMERIC A'-PYRAZOLlNES FROM 2'-HY DROXY- 5'-CHLOROCHALCONES AND ITS DERIVATIVES.

M.M.Ali*, A.G. Doshi and P.B. Haghuwanshi, Department of Chemistry, M.1.E T., Gondia-441 614, M.S., (India)

ABSTRACT

Suitably substituted 2'-liydIoxy-5'-chlorochalcones with hydrazine hydrochloride in refluxing DhIF afforded isomeric A2-pyrazolines, which were characterized on the basis of chemical and spectral data.

Furochalcones react with hydrazine hydrate in ethanol to give isomeric

pyrazolines'. 3,5-Diaroyl-4-aroyl-l -phenylpyrazoline has been synthesised from

3-aroyltlavone in pyridine2. Recently, the reaction of chalcone with hydrazine

hydrochloride in DMF was reported to give the isomeric 3-aryl-5-(2'-

hydroxyphenyl)-A2-pyrazolines3.

In this communication we report formation of isomeric AL-pyrazolines

from substituted chalcones. The structure of compounds was established on the

basis of chemical and spectral data.

Substituted 2'-hydroxy-S'- chlorochalcones were prepared as reported4.

A mixture of 2'-hydroxy-5'-chlorochalcones (Ia) (0.01 mol., 2.58 g) and hydrazine

Copyright 8 2000 by Marcel Dekker, Inc.

3241

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3242 ALI, DOSHI, AND RAGHUWANSHI

hydrochloride (0.01 5 mol.. 1.3g) was refluxed in DMF (20 mL) for two hours.

The reaction mixture on cooling was diluted with water and product seperated

was filtered and crystallize from ethanol to obtain solid (Ha) in 65% yield, m.p.

142 "C

PROPERTIES OF (Ma)

Crystalline compound m.p. 142 "C., It gives deep coloration with neutral FeCI,

solution indicating the presence of' phenolic -OH group., A paper soaked in solution

of(l1a) in benzene was exposed to bromine vapours turned bluish and thus gave

positive Knorr's test for pyrazoline'.b It gives deep blue coloration with conc.

H,SO,, showing absence of - -CH=CH linkage'. The analytical results of the

compound (Ha) agreed with C,,H,,N,OCI, the molecular weight being 272.5 8

Elemental analysis (lla): Calculated Value (YO) - C,66.05; H,4.77; N, 10.27.

Estimated Value(%)- C,65.92; H,4.72; N, 10.12.

1R (Nujal): v = 3040 cm-' (0-H); 1670 cm-' (C=N); 2970 cm.'(N-H)

780 cm" (C-CI); 275 cm-' (C-N); 1420 cm" (C-H)

'H-NMR (CDCI,, 300 MHz)G : 3.2 (IH, dd, MX, I,,, = 16 Hz, J,,, = 10 Hz),

3.72 (IH, dd, ABX, J,,, = 16 Hz, J,Ly = lOHz), 5.53 ( lH, dd, ABX, J, = lOHz, Dow

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SYNTHESIS OF ISOMERIC A*-PYRAZOLINES 3243

TABLE 1

Sr. N o . Compounds R, R, m.p. ("C) Yield (YO) Rfvalue in chloroform

I . ; Ila H H 142 65 0.56

2. Ilb NO, H 145 62 0.60

3. Ilc Br H I49 66 0.62

4. IId H -OCH, 151 69 0.60

5. IIe NO, -OCH, 154 66 0.64

6. IIf Br -OCH, 164 68 0.66

Elemental Analysis : Ila-f Compound gaves satisfactory analytical data (C, H, N + 0.4%)

Sr No Compound YO Analysis, Calculated (Estimated) C H N

1 IIa 66.05(65.92) 4.77 (4.72) 10.27 (10.12)

2 IIb 56.69(56.48) 3.77 (3.70) 13.22 (13.36)

3 IIC 51.20(51.32) 3.41 (3.30) 7.96 (7.80)

4 IId 63.47(63.18) 4.95 (4.62) 9.25 (9.40)

5 IIe 55.25(55.20) 4.02 (4.16) 12.08 (12.25)

6 IIf 50.32(50.10) 3.66 (3.75) 7.33 (7.40)

J, ,= IOHz), 6.7-7.2(m,8H,Ar-H), 8 .8( s. lH,-NH), 9.8(s, 1H,-OH).

The compound (Ha) was identified as 3-phenyl-5-(2'-hydroxy-5'-chlorophenyl)-

A2-pyrazoline.

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3244 ALI, DOSHI, AND RAGHUWANSHI

The other compounds were prepared by the same method and tabulated in

table 1 .

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Aziz G., Nusseir M . M and Doss N.L. and Rizk A . S , J . Indian Chem

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Chincholkar M.M. and Jamode V.S., J . Indian Chem. 1979,17B(6),

622

Thakre VG. and Wadodkar, K.N. J Indian Chem., 1986, m. 610

Doshi A.G. and Ghiya B.J., Current Science, 1986,55,502.

Knorr L., Ber dt chem Ges., 1887,20, 1096.

Redford L. C. and Peteson W.S., L-0t-g. Chem., 1937,1, 544.

Paranjape M.V., Ph.D Thesis, "a-Naphthyl analogues of flavonoids in the

synthesis of Oxygen and Nitrogen Heterocyclics". Nagpur Univers;:

Nagpur, 1986

(Received in the USA 25 November 1999)

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