Naidu, M S R

Naidu, R Ravi

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IndianJournalofChemistryVol.36B, January1997, pp.99-100I Synthesis, structural and antimicrobialstudies of some novel 1-(aroyl )-1-(arylsulphonyll- 2-[4-oxo-4 H-l-benzopyran- 3-yl]ethenesM S R Naidu*& RRaviNaiduDepartmentofChemistry,SriVenkateswaraUniversity,Tirupati517 502, IndiaReceived14 February1996; accepted5 June 1996A series of new unsaturated ketosulphones,1-(aroyl)-1-(arylsulphonyl)-2- [4-oxo-4H-l-benzopy-ran-3-yljethenes 3, have been prepared by the con-densation of pheacyl aryl sulphones with 3-formylch-rornones. The geometry of these compounds havebeen assigned by IR, J H NMR and mass spectral data.Their antimicrobial activity has also been studied.In search of new antimicrobial agents, we haveundertaken the synthesis of a series of new unsa-turated ketosulphones 1. As benzopyrans are ofconsiderable biological importance, the introduc-tion of benzopyran unit into a, ~-unsaturated ket-osulphones may stimulate the biological activity ofthe resultant compounds 3. In connection withour current investigation on aroyl(cyclopropyl)sulphones with benzopyran moiety, we were alsointerested in preparing a series of unsaturatedketo suiphones 3 as intermediates. The condensa-tion of phenacyl aryl sulphones 2 with substituted3-formylchromones 1 in acetic anhydride/gl. acet-ic acid in the presence of benzyl amine as catalyst,yielded 1-(aroyl)-I-( arylsulphonyl)- 2-[4-oxo-4 H-l-benzopyran-Svyljethenes 3. The physical andspectral data of these compounds are given inTable I.The IH NMR spectra of 3 showed a signal inthe region b 7.80-8.00 (IH, s) for a vinylic pro-ton. It is reported? that when the proton is cis toa sulphonyl group the chemical shift for vinylic~IlR~CHOo1Noteproton occurs in the range b 7.40-8.15. For simi-lar type of compounds Uma ' also re-ported the chemical shifts of the vinylic protonsin the region 7.97-8.86. From this it may be in-ferred that in these compounds the vinylic pro-tons may lie cis to sulphonyl group as shown instructure 3. Baliah and Natarajan" assigned thesame coinfiguration for similar type of com-pounds by dipole moment studies. The IH NMRspectra of 3 showed sharp singlets integrating forone proton in the region [) 8.00-8.69 characteris-tic of 2"'-H of chromone moiety. The chemicalshift values of 2"'-H corroborate with the chemi-cal shift values (8.20-9.00) reported' for 2-H ofchromones in various chromone derivatives.The mass spectrum of 30 did not show anymolecular ion (M +). The major fragmentation ofthe molecular ion showed the loss of chloroben-zenesulphonyl radical [C6H4ClS04] with the for-mation of the cation, CI9HJ2CIO:, at mlz 339(68%). This cation on further loss of neutralmolecules, Cl2Hg03 and CO, successively, gavethe ions at mlz 139 (94%) [CIC6H4CO]+ and 111(100%) [C6H4CW, respectively.Experimental SectionMelting points reported are uncorrected .. IRspectra were recorded as KEr discs on a Perkin-Elmer Infrared 683 spectrometer, IH NMRspectra on a Bruker WH 300 or a Varian FT 80A(200 MHz, 80 MHz) instrument in CDCl/CDCl3 + d6-DMSO using TMS as internal stand-ard, and mass spectra on a CEC, 21-110B unit at70 eY. Elemental analyses were performed at theUniversity of Poona, Pune. 2'-Hydroxyacetophe-nones were prepared according to the procedureof Norris". Benzopyrancarboxyaldehydes 1 wereprepared by subjecting various o-hydroxyace-tophenones to Vilsmeier-Haack reaction". Phena-~2111 __JI~I6 UI 0 I CO---&-RhI. IIR 2 SO ~R"o H 2 ~3100 INDIAN J. CHEM. SEC B, JANUARY 1997Table 1-1-(aroyl)-I-(arylsulphonyl)-2-[4-oxo- 4H-1-benzopyran-3-yl]ethenes 3Compd* R R' R" Yield m.p. lHNMR,o(ppm)(%) (0C) >C=CH-3a H H H 42 181-83 7.963b H N02 Br 18 234-363c H Cl Cl 58 175-76 7.983d H CH) Cl 41 138-40 7.953e Br H Cl 59 230-313f Br Cl Cl 23 206-08 7.923g Br CH) Cl 60 231-33 7.953h Br N02 Cl 42 260-61 8.003i Cl H Br 20 216-173j Cl H Cl 58 221-223k Cl Cl Cl 20 204-06 7.8131 CI N02 Cl 68 236-38 7.803m Cl N02 CH) 38 250-51 8.003n CH)O H CI 40 184-85 7.9830 CHP Cl CI 31 195-96 7.923p CH) H H 41 204-06 7.983q CH) H Br 20 193-953r CH) CI Br 37 205-06 7.933s CH) N02 Br 20 236-373t CH) CH) CI 27 202-03 7.993u CH) N02 CH) 21 285-86*Satisfactory chemical analyses were obtained: C ± 0.25; H ± 0.30.cyl aryl sulpbones" were prepared by the reactionof aryl sulphinates with phenacyl bromides.1- (4-Chlorobenzoyl) -1- (4-chlorophenylsul-phonyl) -2- [6-methoxy-4-oxo-4H-benzopyran-3-yllethane 30 (Table I). A mixture of o-methoxy-4-oxo-4H-1-benzopyran-3-carboxaldehyde (2.05g, 0.01 mole), 4-chlorophenacyl-4-chlorophenyl-sulphone (4.93 g, 0.01 mole) and benzylamine(0.2 mL) in acetic anhyride (25 mL) was heatedon a water bath for 8 hr. The progress of thereaction was monitored by TLC. The product thatseparated on treatment of the reaction mixturewith 50 mL of dry ether was recrystallised twicefrom gl. acetic acid, yielding 1.5 g (31%) of 30 ascolourless crystals, m.p. 195-97°.This typical procedure was used for the prepar-ation of other compounds 3a-u (Table I).Antimicrobial activity. The unsaturated keto sul-phones 3a, c-j, l.n-r and t were tested for theirantibacterial activity in vitro against S. aureus, B.subtillus (gram + ve), P. aeruginosa, E. coli (gram- ve) and antifungal activity against C lunata, F.oxysporum following the minimum inhibitoryconcentration? and Horsfall and Rich 10 methods,respectively, with slight modification. Compounds3a, d, f, g, h, j and I showed activity only aga-inst B. subtillus and E. coli while other com-pounds were inactive. As expected, chloro andbromo substituents on aromatic rings enhancedthe antibacterial activity, and in general the com-pounds were more effective against B. subtil/uscompared to E. coli. However, all these unsaturat-ed compounds potent antifungal activity.AcknowledgementThe authors are grateful to Prof. R S Mali, Uni-versity of Poona for elemental analyses and Prof.M V Subba Rao, Dr T Venkata Reddy, Prof. T KK Reddy and Dr A Rajasekhar for their assist-ance in biological screening.References1 Nirmala V, Ph.D. thesis, S.Y. University, Tirupati, India(1982).2 Friedman ARK & Graber D R, J Org Chern, 37, 1972,1902.3 Uma K, Ph.D. thesis, s.v. University, Tirupati, India(1993).4 Baliah V & Natarajan C, Indian J Chern, 5, 1970,694.5 Nohara A, Ukawa K & Sanno Y, Tetrahedron, 30, 1974,3563.6 Norris J F, JAm Chern Soc, 91,1969,1413.7 Nohara A, Umetani T & Sanno Y, Tetrahedron, 30,1974,3553.8 Troger J & Beck W, J Prakt Chern, 1, 1913,295,297.9 Krwickshank R, Duguid J P, Marmion B P & Swain R HA, Medical microbiology, Vol. II (Churchill Livingstone,London), 1975, pp. 191.10 Horsfall J C & Rich S, Indian Phytopathol; 6, 1953, 1.

Synthesis, structural and antimicrobial studies of some novel 1-(aroyl)-1-(arylsulphonyl)-2-[4-oxo-4H-1-benzopyran-3-yl]ethenes

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Synthesis, structural and antimicrobial studies of some novel 1-(aroyl)-1-(arylsulphonyl)-2-[4-oxo-4H-1-benzopyran-3-yl]ethenes

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