Sulfamic acid as a reusable and green catalyst for efficient and simple synthesis of 2-substituted-2

Available online at www.sciencedirect.comCHINESEScienceDirectC HEMICALL .ETTERSEI SEVIERChinese Chemical Letters 22 (2011) 1317-1320www.elsevier.com/locate/ccletSulfamic acid as a reusable and green catalyst for efficient andsimple synthesis of 2-substituted-2,3-dihydroquinazolin-4(1H)-onesin water or methanolAmin Rostami *, Ashkan TavakoliDepartment of Chemistry, Faculty of Science, University of Kurdistan, Sanandaj 6617715143, lranReceived 19 April 2011Available online 29 July 2011AbstractA series of 2.3-dihydroquinazolin 4(1H)-ones have been synthesized in good to excellent yields through direct cyclocondensa-tion of anthranilamide and aryl aldehydes or ketones in water or methanol under mild conditions. The reaction was efficientlypromoted by 10 mol% sulfamic acid (SA, H2NSOzH) and the catalyst could be recovered easily after the reactions and reusedwithout evident loss of reactivity.O 2011 Amin Rostami. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.Keywords: Sulfamic acid; Catalyst; Anthranilamide; Aldehyde; Ketone; 2.3-Dibydroquinazolin 4(1H)-oncs2,3-Dihydroquinazolinones are a class of heterocycles that atracted much attention because they have beenreported to possess a wide range of pharmaceutical activities including antifertility, antibacterial, antitumor,antifungal, and mono amine oxidase inhibition [1]. In addition, these compounds can easily be oxidized to theirquinazolin-4(3H)- one analogues [2], which also include important pharmacologically active compounds [3]. Severalmethods have been reported for the synthesis of 2,3-dihydroquinazolinones [4- -20]. The typical procedure for thesynthesis of 2,3-dihydroquinazolin 4(1H)-ones involves the condensation reaction of anthranilamide with aldehyde orketone using acids as a catalyst under various conditions [4,8,10,14 -20]. However, some of these methodologies havelimitations such as harsh reaction conditions, use of expensive acid catalysts in organic solvents, long reaction timeand tedious work up. Hence, the development of simple, efficient, clean, high-yielding, and environmentally benignprotocols using green catalysts for the synthesis of these important compounds is still desirable and is in demand.The use of water as a solvent has many advantages in organic synthesis from both economic and environmentalpoints of view [21]. Also, water has become an attractive medium for many organic reactions, not only as one canavoid using drying reactants and expensive catalysts and solvents, but also rendering unique reactivity and selectivity[22]. In recent years, the use of solid acidic catalysts has offered important advantages in organic synthesis, some ofthese advantages are: operational simplicity, environmental compatibility, non-toxicity, reusability, low cost, and easeof isolation [23]. Sulfamic acid (SA, H2NSOzH) is a common inorganic acid with a mild acidity that is nonvoltile,* Corresponding author.中国煤化工E-mail address: a srostami372@yahoo.com (A. Rostami),MHCNMHG1001-8417/S - see front matter◎2011 Amin Rostami. Published by EIlsevier B.V. on behalf of Chinese Chemical Society, All rights reserved.doi:10.1016j.ce.2011.06.0081318A. Rostami, A. Tavakoli/Chinese Chemical Letters 22 (2011) 1317-1320NH2NH2SOzH (Cat)H2O, 700C-R2or MeOH, rtH R;2aq3aqR, R2= Aryl, Alkyl, HScheme 1.noncorrosive, stable, low-cost, and commercially available reagent. More important, its water resistance makes it anoutstanding alternative to metal catalysts, in different areas of organic synthesis, as an efficient and greenheterogeneous catalyst [24 -26].In continuation of our efforts to develop more versatile methodologies in organic synthesis [27,28], herein, wereport a simple and straightforward method for the preparation of 2-substituted-2,3-dihydroquinazolin-4(1H)-onesfrom direct cyclocondensation of anthranilamide with aldehydes and ketones in the presence of catalytic amounts ofSA as a green catalyst in water at 70。C or in methanol at room temperature (Scheme 1).At the onset of the research, in order to optimize the reaction conditions, we investigated the modelcyclocondensation reaction between anthranilamide (1 mmol) and benzaldehyde (1 mmol) in the presence of SA(10 mol%) under various reaction conditions. The results are ilustrated in Table 1. The reaction in methanol is the best(entry 1). However, the reaction time in water proceeded similar to that in methanol (entry 6). We have improved ourreaction to an environmentally friendly one. We then examined the generality of the reaction in methanol and water.The results from the reactions of anthranilamide and various aldehydes and ketones in both MeOH and H2O areshown in Table 2. As shown in entries 1-14, various aromatic aldehydes bearing either electron-donating or electron-withdrawing groups on aromatic ring and terephthaldehyde aldehyde were investigated. The substitution groups on thearomatic ring have no obvious effect on the yields and reaction time under the above optimal conditions. However,aldehydes with strongly electron-withdrawing groups on aromatic ring gave the products with good yield in a longreaction time (Table 2, entries 10 and 11). It is noteworthy that this synthetic method is efficient for the preparation ofbis- 2-substituted-2,3-dihydroquinazolin-4(1H)-ones (Table 2, entry 14).Most of the aldehydes gave almost the same results in MeOH and H2O, whereas in some cases, the yields of theproducts in water tend to be decreased probably due to the lower solubility of starting material or intermediate in thesolvent. To expand the scope further investigations were carried out for condensation of ketones with anthranilamideand the results were summarized in Table 2 (entries 15- -17). In all cases, it was found that ketones can react well withanthranilamide in good yields.In order to shown activity of sulfamic acid in this transformation, we subject the condensation of 2-nitrobenzaldehyde with anthranilamide in the absence of catalyst, the reaction did not occur even after prolongedreaction time. Interestingly, the catalyst is recycled at least three times (in the case of benzaldehyde) withoutconsiderable loss in its activity (Table 2, entry 1).Finally, to investigation the feasibility of applying this method on a preparative scale, we performed the synthesis of2-phenyl-2,3- dihydroquinazolin-4(1H)-one on a 50 mmol scale. As expected, the reaction proceeded, similar to thecase in a smaller scale (Table 2, entry 1).Table 1Synthesis of 23-dihydroquinazolin4(1H)-ones under different reaction conditions.EntryReaction conditionsTIme (min)Conversion (%)MeOH, rt20100EtOH, refux中国煤化工CH2CN, refuxCH2C2, refuxMYHCNMHG.n-Hexane, refux150H2O, 70°C30A. Rostamil, A. Tavakoli/Chinese Chemical Letters 22 (2011) 1317-13201319Table 2Synthesis of 23-dihydroquinazolin 4(1H) -ones in the presence catalytic amount of SA under aqueous' or methanol.EntryAldehyde or KetoneProductTime (min)Yielde (%)Mp (°C) (Ref,)WaterMethanolC&HyCHO3a302092, 86, 80d89, 83, 78'218- -219 [15]4CH3 CHLCHO3t134233- 234 [15]4-CHzOC&H.CHO3c401:85192- -193 [15]2,4-(CHjO)2CH4 CHO3d4:80186-187 [15]3,4-(CH:O)2CH2CHO3e3(2:592212-214 [12]4(CH3) N CHCHO3:4(39228 -229 [15]4-Br CJH4 CHO3y70197-199 [19]4FC.H4 CHO3h3589199 -200 [15]4-C1 C&Hs CHO395205- -206 [20]02-NO2 CH4 CHO3}9086193-194 [15]3-NO2 C6H4 CHO3l60778216- 217 [15]240H-C&H4 CHO)1278- -280 [15]132-Naphthaldehyde3m4536)3225- 22714Terephthaldehyde3x15°77°243 -245 [10]15Acetophenone180120s5'227- -228 [20]16Cyclobexanone3p5081224 -226 [8]Acetone9183-184 [20]●Reaction conditions: anthranilamide (1 mmol), aldehyde or ketone (1 mmol), and SA (10 mol%, 10 mg), 70 °C.b Reaction conditions: anthranilamide (1 mmol), aldehyde or ketone (1 mmol), and SA (10 mol%, 10 mg), rnt.. Isolated yield."Catalyst was reused for 3 times.Reaction conditions: in order to preparation of bis-2,3- dihydroquinazolin-4(1H)- one, anthranilamide (2 mmol), terephthaldehyde (1 mmol), andSA (20 mol%, 20 mg).Reaction in methanol were run under reflux condition.To show merit of the present work in comparison with reported results in the literature, we compared our results onthe reaction of anthranilamide and benzaldehyde with data from the literature (Table 3). As shown in Table 3, thepreviously reported procedures suffer from one or more disadvantages such as elevated reaction temperatures[8,15,16,19], longer reaction times [19], using transition metal and expensive catalyst [14 -16], special efforts for thepreparation of catalyst [8, 14], and the need of organic solvents [15,16,18]. Therefore, we believe the present method tobe an improvement with respect to other procedures.In summary, a very simple, efficient, cost- effective, and eco-friendly synthesis of 2,3-dihydroquinazolin-4(1H)-ones through direct cyclocondensation of anthranilamide and aryl aldehydes or ketones in the presence catalyticamount of sulfamic acid with good to high yields in water or methanol has been devised. In addition, this method areused for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones in both small and large scale.General procedure for the synthesis of 2.,3-dihydroquinazolin 4(1H)-ones under aqueous conditions. In a roundbottomed fask, sulfamic acid (0.1 mmol, 0.010 g) was added to a mixture of anthranilamide (1 mmol, 0.136 g) andaldehyde or ketone (1 mmol) in water (2 mL), and then the mixture was sirred at 70 °C for the appropriate time (Table 2).Table 3Comparison of the activity of various catalysts in the reaction of anthranilamide and benzaldehyde.CatalystConditionYield (%)Ref.Ga(OTf)3 (1 mol%)EtOH, 70°C4Sc(OTf)3 (5 mol%)EIOH, 70°C[16]NH4Cl (5 mol%)EtOH, t中国煤化工[18]Bu,NBr (40 mol%)Soleanfree, 100°C[19]PPA- SiO2 (1.25 mol%)Solvent-frce, 70 °CYHCNMHG[8]HsPW:2O4o (0.1 mol%)H20, rtSA (10 mol%)H2O, 70°CThis workMeOH, rt1320A. Rostami, A. Tavakoli/Chinese Chemical Ltters 22 (2011) 1317-1320After completion of the reaction which confirmed by TLC (eluent: n-hexane/ethyl acetate: 2/1), the crude product wasfiltered off and recrystallized from ethanol to give pure product in good to high yields.General procedure for the synthesis of 2,3-dihydroquinazolin-4(lH)-ones in methanol. In a round bottomed fask,sulfamic acid (0.1 mmol, 0.010 g) was added to a mixture of anthranilamide (1 mmol, 0.136 g) and aldehyde or ketone(1 mmol) in methanol (2 mL), and then the mixture was stirred at room temperature for the appropriate time (Table 2).After cormpletion of the reaction which confirned by TLC (eluent: n-hexane/ethyl acetate: 2/1), the crude product wasfiltered off and recrystallized from ethanol to give products in good to high yields.All of the obtained 2,3-dibydroquinazolin-4(1H)-ones are known compounds (expect product 3|) and their physicaldata, IR and lH NMR spectra were essentially identical with those of authentic samples. Compound 3l, which is new,was characterized by IR, 'H NMR, BC NMR, and MS spetroscopy and elemental analysis.2-(2-Naphy)-2,3-dihydroquinazolin 4(1H)-one (Table 2, entry 13): white solid; mp: 225- -227 °C; IR (film) Vmx(cm-): 3282m, 3188w, 3065w, 2926w, 1649vs, 161 lm, 1512m, 1486w, 1441w, 1390m, 1315m, 1158w, 825m, 747m.'H NMR (DMSO-d6, 250 MHz): 8 5.90 (s, 1H, CH), 6.6 -8.2 (m, 12H, NH+Ar- H), 8.4 (s, 1H, NH).13C NMR(DMSO-ds, 62.9 MHz): 8 67.41, 114.85, 115.38, 117.58, 125.28, 126.35, 126.70, 126.78, 127.82, 127.97, 128.37,128.51, 132.91, 133.45, 133.70, 139.22, 148.33, 164.16; MS (EI, 70 eV, m/z): 275.1(M+H)*, 274.1(M*), 273.1(M-1)*, 147, 120, 92; Anal. Calcd. for C1gH4N2O: C 78.81, H 5.14, N 10.21; found, C 78.82, H5.12, N 10. 25.References. [1] M. Hour, L. Huang, s. Kuo, et al. J. Med. Chem.43 (2000) 4479.[2] RJ. Abdel-Jalil, W. Volter, M. Saeed, Tetrahedron Lelt. 45 (2004) 3475.[3] JF Liu, J. Lee, A.M. Dalton, et al. Tetrahedron Lett. 46 (2005) 1241.[4] JA. Moore, GJ. Sutherland, R. Sowerby, et al. J. Org. Chem. 34 (1969) 887.[5] W.K. Su, B. Yang, Aust. J. Chem. 55 (2002) 695.[6] D.Q. Shi, L.C. Rong, J.X. Wang, et al. Tetrahedron Lett. 44 (2003) 3199.[7] YS. Sadanandam, K.R.M. Reddy, A.B. Rao, Eur. J. Org. Chem. 22 (1987) 169.[8] HR. Shaterian, A.R. Oveisi, Chin. J. Chem. 27 (2009) 2418.[9] C.L. Yoo, J.C. Fettinger, M.J. Kurth, J. Org. Chem. 70 (2005) 6941.[10] M. Bagbanzadeh, P. Salehi, M. Dabir, et al. Syntbesis (2006) 344.[11] P. Salchi, M. Dabiri, MA. Zolfigol, et al. Synlett (2005) 155[12] M. Dabin, P. Salchi, s. Otokesh, et al. Tetrabedron Lett. 46 (2005) 6123.[13] P. Salchi, M. Dabiri, M. Baghbanzadeh, et al. Synth. Commun. 36 (2006) 2287.[14] Y.X. Zong, Y. Zhao, W.C. Luo, et al. Chin. Chem. Lett. 21 (2010) 778.[15] J.X. Chen, D. Wu, F. He, et al. Tetrahedron Lett. 49 (2008) 3814.[16] JX. Chen, H.Y. Wu, W.K. Su, Chin. Chem. Lett. 18 (200) 536.[17] JX. Chen, W.K. Su, HY. Wu, et al. Green Chem. 9 (2007) 972.[18] A. Shaabani, A. Maleki, H Mofakham, Synth. Commun. 38 (2008) 3751.[19] A. Davoodnia, S. Allameh, A.R. Fakhari, et al. Chin. Chem. Let. 21 (2010) 550.[20] R.Z. Qiao, B.L. Xu, YH. Wang, Chin Chem. Lelt. 18 (2007) 656.[21] CJ. Li, Chem. Rev. 105 (2005) 3095.[22] L.R. Pratt, A. Polrille, Chem. Rev. 102 (2002) 2671.[23] R.S. Varma, Green Chem.1 (1999) 43.[24] M.M. Heravi, B. Baghermejad, H.A. Oskooie, Cur. Org. Chem. 13 (2009) 1002 (References therein).[25] M.M. Heravi, H. Alinejhad, K Bakhtiar, et al. Mol. Divers. 14 (2010) 621.[26] J.P. Li, JK. Qiu, HJ. Li, et al. Chin. J. Chem. 29 (2011) 511.[27] A. Rostami, J. Akradi, Tetrahedron Lett. 51 (2010) 3501. .[28] A. Rostami, F. Ahmad-Jangi, M.R. Zarebin, et al. Synth. Commun.40 (2010) 1500.中国煤化工MYHCNMHG