J. Chem. Eng. Data 1083, 28,430-431
430
Synthesis of Some New Asymmetrical and Symmetrical 2,4,6-Triaryfpyridines Using (2-Thiophenoy lmethy lene) pyridinium Y lide Saroj Mallk and Kalpna Pandey Department of Chemistry, A.N.D.M.M. College, Kanpur -2080 72 U.P., India
Brlj RaJ and Komal C. Gupta" Department of Chemistry, D. V. (P.G.) College, Orai-28500
1 U.P., India
Scheme I
A serks of some new 2-tMenyl-4,64l(subit~1ted phenyl)pyrk#nes and 2,&dlthlenyd4-(substltuted phenyl)pytklkres have been syntherlzed by the lnteractlon of (2-thlophenoyhethylene)pyridlnlum yllde wlth substituted benzylldeneacetophenes and substttuted bensylldene-2-acetothlophenes, respectlvely, urlng ammonlum acetate In acetlc acid as a cycllzation agent. The structures of these pyrkllnes were supported by I R and HMR spectral data.
The earlier methods ( 7 - 4 ) for the synthesis of 2,4,6-triarylpyridines were not versatile because of harsh reaction conditions and poor yields of products. Moreover, these could only be used for the synthesis of symmetrical pyridines having identical substitutents at the 2- and 6-positions. However, the synthesis of symmetrical and asymmetrical pyridines having identical substituents at the 2- and 6-positions involving mild reaction conditions and good yields of products could also be applied. Prompted by Krohnke's work and following our earlier researches (5- 70) on the synthetic and mechanistic aspects of ylides of group-5 elements, we have extended the method for synthesis of symmetrical and asymmetrical 2,4,6-triarylpyridines having thiophene rings at the 2- and 6-positions and a substituted phenyl ring at the 4-position by reacting (2-thiophenoylmethylene)pyrMiniumyliie with substituted a,@-unsaturated ketones. Such pyridines are expected to possess biological activity. The (2-thiihenoylmethyl)pyridiniumbromide (1)on treatment with potassium carbonate in aqueous solution gave (2-thiophenoylmethylenebyridiniumy l i i (2).The yUde (2)reacted wlth various a,@-unsaturatedketones (3a-I) in glacial acetic acid and ammonium acetate under reflux to give 2,4,64riarylpyridines (sa-I) in 50-90% yields. The reaction seems to proceed via the intermediacy of (1,5dioxo-2-pentyl)pyridinium derivatives (4a-I), formed by the nucleophilic attack of 2 on the @-carbon of compounds 3a-I, yliies which then undergo azo cyclization in the presence of ammonium acetate in acetic acid to give the desired pyridines (sa-I) (Scheme I). All the compounds (sa-I) synthesized in the present study were new and gave satisfactory elemental analysis. The structures of the pyridines (sa-I) were evidenced by their spectral data. The I R spectra (KBr) of 5a-I showed characteristic absorption bands in the region 3000-3040 cm-', which was assigned to the C-H stretching mode of the pyridine ring. The two bands at 1800 cm-' appeared to be a general characteristic of substitutions in the pyridine nucleus. The NMR (CDCi3)spectra of 5a-I in general exhibited two pyridyl protons in the range 6 6.60-7.30 and aromatic protons at 6 6.78-8.3 1. 0021-9568/83/1728-0430$01.50/0
R'
(50- I
)
Experimental Sectlon Meitlng points were determined on a Gallenkamp apparatus and were uncorrected. I R spectra (KBr) were recorded on a Perkin-Elmer infracord spectrophotometer. NMR (CDCI3)were run by using a Varian A-60 spectrophotometer using Me$i as an intemal standard. The purity of 5a-I was checked by TLC. Pyridinium salt 1 was prepared by the reaction of bromomethyl 2-thienyl ketone with pyridine or by heating Pacetothiophene with iodine and pyridine using the procedure of King ( 7 7 ) and Krohnke (72, 73). The yliie (2)was generated by treating a cold aqueous solution of salt (1) with aqueous potassium carbonate or treating pyridinium salt (1) with sodium hydride in DMF. All the reactions were carried out by using freshly prepared pyridinium ylide (2). Preparatlon of 2,4 ,6 Trlsubstttuted Pyrldlnes (5 a -I ) General prooepkae. A mixture of yUde (2, 3 mmol), ammonium acetate (3 g), and glacial acetic acid (50 mL) was stirred at 80 O C . The cu,pUnsaturated ketone (Ba-l, 3 m d ) in glacial acetic acid (25 mL) was added dropwlse over 1 h, the temperature was raised to 120 OC, and heating was continued for an additional 6-8 h. The reaction mixture was left overnight at room temperature and ice cold water (50 mL) was added. The re-
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0 1983 Amerlcan Chemical Society
.
J. Chem. Eng. Data 1983, 28, 431-432
43 1
Table I. Physical and Spectral Data of 5a-1"
IR (KBr), cm-l
yield, compd
R2
%
mp, "C
5a b c d e
4-CH3OC,H, 4-C1C6H, 3-N02C,H, 3,4-C1,C6H, 4-FC6H,
65 55 60 65 50
93-95 111-12 160-62 104-06 125-27
recryst solvent U A ~ R' = 2-C,H3S; R3 = CHC13/n-hexade 3040 CHCl,/n-hexane 3060 C,H,N/MeOH 3040 CHCl,/n-hexane 3060 C,H,N/MeOH 3045
4-NO2C,H, 4-FC6H, C6H5 3N02C,H,
50 65 55 70
3-CH3OC,H, 3-C1C6H, 3-N02C,H,
60 70 60
f g
h i j
k 1
Huc=C
uC=N
UC=S
@C-H
C,H, 1595 1600 1592 1595 1590
1510 1540 1510 1515 1500
1175 1050 1080 1178 1165
990 1000 1010 99 5 1020
176-78 153-55 110-12 217-19
R' = 2-C,H3S; R3 = 4-C1C6H, CHCl,/n-hexane 3070 1600 1495 CHCl,/n-hexane 3060 1610 1510 C,H,N/MeOH 3065 1600 1540 C,H,N/MeOH 3040 1590 1540
1100 1160 1090 1090
1000 995 1010 995
90-92 138-40 123-25
R' = R3 = 2-C,H3S C,H,N/MeOH 3060 1600 CHCl,/n-hexane 3080 1598 CHCl,/n-hexane 3070 1620
1170 1090 1020
990 970 980
a All the compounds gave satisfactory elemental analysis for C, H, N. (out-of-plane vibrations). s = singlet; m = multiplet.
sultina solid mass was filtered, washed twice with water and methanol, dried, and then crystallized from approprlate solvents shown in Table I to give the desired pyridines (sa-I).
Acknowledgment We thank Dr.(Mrs.) H. I. Swaroop, Vice-Chancellor, Kanpur University, and Principal, A.N.D.M.M. College, Kanpur, and Principal, D.V. College, Orai, for their kind cooperation and constant encouragement.
ROggktV NO. 58, 85957-59-1; 5b, 82613-22-7; 5c, 82613-23-8; 56, 82613-25-0; 5e, 85957-60-4; 51, 85957-61-5; 5g, 85957-62-6; 5h, 73910-993 51, 85957-63-7; 51, 85957-648; 5k, 8595755-9; 51, 7444139-7.
u
1550 1535 1500
= stretching vibrations.
@
NMR data (CDCI,), 6 3.78 (s, 3 H, OCH,), 6.78-7.98 (m, 1 4 H, ArH)
7.51-8.31 (m, 1 3 H, ArH)
3.75 (s, 3 H, OCH,), 6.84-7.82 (m, 1 2 H, ArH) = bending vibrations
Llterature Cited Frank, R. L.; Rlever, E. F. J . Am. Chem. Soc.1050, 72, 4182. Tschltschlbabln, A. E. Bull. Soc. Chlm. Fr. 1038, 4 , 1826. Tschitachibabin, A. E. J . Russ. Chem. Soc. 1005, 37, 1229. Tschitschibabin, A. E. J . frakt. Chem. 1024, 707, 112. Gupta, K. C.; Srivastava, N.; Nigam. R. K. J . Organomet. Chem. 1081, 204, 55. Gupta, K. C.; Srivastava, N.; Nigam, R. K. Indkn J . Chem., Sect. B 1981, 20, 802. 923. Tewari, R. S.; Gupta, K. C. Indkn J . Chem. 1075, 73,864. Tewari, R. S.; Gupta, K. C. Indian J . Chem., Sect. B 1078, 74, 419, 829. Tewari, R. S.; Gupta, K. C.;Dube, A. K. J . Indkn Chem. SOC. 1980, 5 7 , 1135. Tewari, R. S.; Gupta, K. C.; Dube, A. K. Indian J . Chem., Sect. B 1081, 2 0 , 706. King, L. C. J . Am. Chem. Soc. 1933, 66, 894. Krohnke, F.; Zecher, W. Angew Chem., Int. Ed. €ng/. 1982, 7 , 628. Krohnke, F. Synthesis 1976, 1. Received for review Noember IO, 1982. Accepted March 25, 1983.
Synthesis of New 2-Pyridylhydrazones and 2-Quinolylhydrazones Containing 2-Thiophene or 2-Furan Groups Douglas G. Berge Department of Chemistty, University of Wisconsin-Oshkosh,
The syntheslo of 18 new 2-pyrldylhydrazone and Pqulnolylhydrazone compounds contalnlng either 2-thlophene or 2-furan functlonalliles Is descrlbed.
Contlnued interest still exists in the study of a variety of different hydrazones, particularly 2-pyridiyl- and 2-quinolylhydrazones, in addiiion to many other derivatives, for possible use as complexation reagents for transition metals ( 1-7). Because of this interest, 18 new 2-pyridylhydrazones and 2quinolylhydrazones containing either various 2-thiophene or 0021-9568/83/1720-0431$01.50/0
Oshkosh, Wisconsin 5490 1
2-furan moieties have been synthesized. The method used to prepare these new hydrazones was the standard procedure where equimolar quantities of the appropriate hydrazine and aldehyde or ketone were refluxed in ethanol, the solid hydrazone formed precipitating out of solution, filtered, and recrystallized from the appropriate solvent.
R~--NHNH~
+
o=~-R~
-
R,--NHN=~--R~
R, = 2-pyridyl or 2-quinolyl R, = H or CH, R, = 2-thiophene or 2-furan functionality
0 1983 American Chemical Society
+
H,O
