Synthesis and Spectroscopic Characterization of Yellow monoazo Colorants for their use in Blu Ray Disc

Transcription

1 Synthesis and Spectroscopic Characterization of Yellow monoazo Colorants for their use in Blu Ray Disc SEKAR. N *, KULKARNI. B.S Dyestuff Technology Department, University Institute of Chemical Technology Matunga Mumbai , India. ABSTRACT A series of yellow monoazo dyes have been prepared using 6-amino-1, 3-dimethyluracil (8) a coupler. It has been shown that the dyes 14g, 14i and 14k, in which o-anisidine, o-nitro aniline and p-nitro aniline respectively are used as diazo components, have required absorption characteristics for possible use in Blu Ray Discs. Keywords: Yellow dyes, azo dyes, blu-ray disc dyes, optical data storage Introduction Optical data storage has proven to be a convenient means for the physical distribution of large quantities of information because of high storage capacity and relatively inexpensive media. Optical data storage is found in popular consumer products such as Compact Discs (CDs), Digital Versatile Discs (DVDs) and Mini Discs (MDs). For the storage and retrieval of data on optical storage blue-violet laser beam is essential which storage and retrieval of data on optical storage blue-violet laser beam is essential which makes it possible to focus the laser spot with greater precision. This allows data to be packed more tightly and stored in less space. This together with the change of numerical aperture to 0.85 is what enables Blu Ray Discs to hold 25GB/50GB. Colorants which absorb in the blue region is an integral part of Blue Ray Disc [1-4]. Simple monoazo colorants have been utilized as blue-absorbing medias in blu-ray optics [5-8]. Monoazo colorants constitute an important group of colorants giving absorption in the entire visible spectrum. A monoazo chromogenic system can be represented by the general structure (1) where A represents acceptor functional groups and D represents donor functional groups. The absorption characteristics of this compact monoazo chromogen is influenced by (1) The number and strength of donor groups *Address for correspondence drnsekar @yahoo.co.in, sekarnm@rediffmail.com nnsekar@udct.org (2) The number and strength of acceptor functional groups. However from the available synthetic facility in generating these chromogenic systems (using the traditional diazo-coupling reactions) it is most unlikely to have very weak donor residues in the system. This is because of the fact that, diazo-coupling reaction occurs only with highly ð excess aromatic compounds. Thus generating an ideal blue-absorbing colorant in this class becomes slightly difficult. Three approaches have been in vogue to get blueabsorbing monoazo colorants. (1) Use of diazo components having electron donor groups (2) Use of enolisable heteroaromatic couplers such as, 1-N-phenyl-3-methylpyrazole-5-one; 2, 6- dihydroxypyridone; 2-aminopyrazoles, barbituric acid and other such five or six membered heterocyclic compounds. (3) Use of donor substituted diazo components together with heterocyclic couplers. All these approaches are exemplified in structures, such as C I Disperse Yellow 3 (2), CI Disperse Yellow 5(3),CI Disperse Yellow 241(4), CI Disperse Yellow 211(5) and the greenish yellow dyes 6 and 7 [9]. 6-Amino-1, 3-dimethyluracil (8) is known to undergo diazo-coupling reaction giving monoazo dyes which can be October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4

2 further converted in to triazoles by an oxidative cyclization [10, 11]. This paper reports preparation of monoazo dyes using (8) as a coupler, and their absorption characteristics. Some dyes have promising blue absorption and are ideally suited for use in blu-ray optical data storage devices. EXPERIMENTAL Material and Methods 1, 3- Dimethylurea (9) and cyanoacetic acid (10) were obtained from Spectrochem India Ltd. Aniline (12a), o- chloroaniline(12b), p-chloroaniline(12c),o-toludine(12d),mtoludine(12e),p-toludine(12f),o-anisidine(12g), m- anisidine(12h), o-nitroaniline(12i), m-nitroaniline (12j), p- nitroaniline ( 12k) were of, commercial grade from Atul India Ltd. The inorganic reagents and solvents were obtained from S.d.fine chemicals Ltd. ph values were monitored using an Eco-Scan phmeter (Eutech, Singapore). Melting points were taken using apparatus of Sunder Industrial Products Chembur, Mumbai, India and are uncorrected. The visible absorption spectra of the dyes were recorded on a Spectronic Genesys 2 UV/ visible spectrophotometer. Elemental analyses for carbon, hydrogen and nitrogen were carried out on Herieus Rapid analyser. The NMR Spectra were recorded on Varian EM 3602 (60 MHz) spectrophotometer using tetramethylsilane as internal standard. The I.R. spectra were recorded in KBr pellets using Win-Bomem Hartmann and Brown IR Spectrophotometer. 6-Amino-1, 3-dimethyl uracil (8) was synthesized by the reported procedure [12] by the reaction between cyanoacetic acid and 1, 3-dimethyl urea. Preparation of dye (14a) Aniline (0.65,0.007mol)(12a) was diazotized using sodium nitrite(0.48g,0.007mol) and hydrochloric acid(2.6ml as30% solution) at C to get diazonium salt (13a). A solution of 8 (1.08g,0.007mol) was made by dissolving in glacial acetic acid and cooled to c under stirring to precipitate the compound in very fine form. The diazonium salt 13a was added to the above slurry of 8 at c and the mixture was stirred overnight to complete the coupling reaction. The ph of the reaction mixture was maintained at 4-5 by adding 10% NaOH solution. The dye formed was filtered, washed free of acid and dried. The crude sample was recrystallised in DMF. The yield of the crude dye: 1.24g (69 %) Melting point of recrystallised dye: c. The dyes 14b,14c,14d,14e,14f,14g,14h,14i,14j,14k were prepared analogously using the amines 12b,12c,12d,12e,12f,12g,12h,12i,12j,12k respectively. The yield and melting point and elemental analysis of all the dyes synthesized are given in Table-1 The structures of all these dyes were confirmed by infrared spectra, and NMR spectra. The infrared absorptions, NMR data are given in Table 2. UV-Visible absorption spectra The UV-Visible absorption spectra of dyes were recorded by dissolving 1 mg of the compound in DMF and diluting up to 10 ml with the same solvent; 1 ml of this solution was then further diluted to 10 ml with DMF and dilute solution so obtained was used Table 1 Structural characterization of dyes 14a-14k Substituen Elemental analysis %Found (calculated) Dye no Yield M.P 0 Molecular Molecular C ts R formula weight C H N 14a H 69% C 12 H 13 N 5 O (47.36) 3.89(3.94) 27.00(27.63) 14b o-cl 70% C 12 H 12 ClN 5 O (49.06) 4.08(4.01) 23.81(23.85) 14c p-cl 69% C 12 H 12 ClN 5 O (49.06) 4.10(4.01) 23.80(23.85) 14d o-ch 3 72% C 13 H 15 N 5 O (57.14) 5.42(5.49) 25.60(25.64) 14e m-ch 3 75% C 13 H 15 N 5 O (57.14) 5.40(5.49) 25.61(25.64) 14f p-ch 3 71% >300 C 13 H 15 N 5 O (57.14) 5.12(5.49) 25.58(25.64) 14g o-och 3 65% C 13 H 15 N 5 O (53.97) 5.10(5.19) 24.17(24.22) 14h m-och 3 73% C 13 H 15 N 5 O (53.97) 5.15(5.19) 24.19(24.22) 14i o-no 2 68% C 12 H 12 N 6 O (47.36) 3.92(3.94) 27.83(27.63) 14j m-no 2 74% C 12 H 12 N 6 O (47.36) 3.95(3.94) 27.50(27.63) 14k p-no 2 70% C 12 H 12 N 6 O (47.36) 3.90(3.94) 27.53(27.63) October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4

3 Table 2 Dye IR Spectra cm -1 (functional group) Azo Amine Carbonyl 14a , , b 3277, , c 3275, , d 3276, , e , , f 3276, , g , , h , , i , , j , , k , ,1696 NMR Spectra Chemical shift δ (multiplicity) Number of protons 2.17(s, 3H, CH 3 ), 2.49(bs, 3H, CH 3 ), 5.2 (bs, 2H, NH 2, D 2 O exchangeable), (m, 5H, ArH) 2.18(s, 3H, CH 3 ), 2.48(s, 3H, CH 3 ), 5.4 (bs, 2H, NH 2, D 2 O exchangeable), (m, 4H, ArH) 2.19(s, 3H, CH 3 ), 2.59(s, 3H, CH 3 ), 3, 5.1 (bs, 2H, NH 2, D 2 O exchangeable), 7.3(d, 2H, ArH), 7.9(d, 2H, ArH) 2.17(s, 3H, CH 3 ), 2.49(s, 3H, CH 3 ), 5.3 (bs, 2H, NH 2, D 2 O exchangeable), (m, 4H, ArH) 2.17(s,3H,CH 3 ) 3, 2.49(s,3H,CH 3 ) 3, 5.2 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), 7.3(s,H,ArH) 1, (m,ArH,3H) (s,3H,CH 3 ) 3, 2.43(s,3H,CH 3 ) (bs,nh 2 ) 2 (D 2 O exchangeable), 7.3(d,2H,ArH) 2, 7.8(d,2H,ArH) (s,3H,CH 3 ) 3, 2.47(s,3H,CH 3 ) 3, 3.81(s,3H,OCH 3 ) 3, 5.3 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), (m,4H,ArH) (s,3h,ch 3 ) 3, 2.47 (s,3h,ch 3 ) 3,3.61 (s,3h,ch 3 ) 3, 5.2 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), 7.4 (s,1h,arh) 1, (m,3h,arh) (s,3h,ch 3 ) 3, 2.48 (s,3h,ch 3 ) 5, 5.1 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), (m,4h,arh) (s,3h,ch 3 ) 3, 2.49(s,3H,CH 3 ) 3,5.3 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), (bm,3H,ArH) 3, 8.8 (s,1h,arh) (s,3h,ch 3 ) 3, 2.50(s,3H,CH 3 ) 3, 5.4 (bs,2h,nh 2 ) 2 (D 2 O exchangeable), 7.8 (d,2h,arh) 2, 8.02 (d,2h,arh) 2 October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4

4 October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4

5 October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4

6 Conclusion 6-Amino-1, 3-dimethyl uracil (8) was used as a coupling component in the preparation of a series of yellow dyes. The dyes 14g, 14i and 14k possess the required absorption maxima required for use in Blu Ray Discs. References [1] Ferrere S, Gregg BA. New J Chem 2002; 26:1155 [2] Blue-Ray Disc Founders, White Paper Blue-Ray Disc Format, August 2004 [3] Wang MM, Esener SC. Applied Optics 2000; 39:1826 [4] Blue-Ray Association, Technical Information, White Papers [5] Jsutomer U (Ricoh Co Ltd, Chemipro Kasei Ltd, Japan), Jpn Kokai Tokkyo Koho JP , Chem Abstr 2005; 143:16565v [6] Hisashi M (Fuji Photo Film) US Patent Chem Abstr 2001; 141:32645v [7] Takashi K (Mitsui Chemicals Inc), Jap Pat Chem Abstr 2003; 139:32645v [8] Hisashi M (Fuji Photo Film) Jap Pat Chem Abstr 2001; 139:28670f [9] Hunger K(Ed), Industrial Dyes: chemistry, Properties, Applications, Wiley VCH, Germany [10] Barbee RB, Tenn K, Taylor EC (Eastman Kodak Company, Rochester N Y), US Patent [11] Flechter IJ and Gngltelmo M(Ciba Geigy Research Corporation), US Patent [12] Papesch V, Schroeder EF, J Org Chem 1951; 16:1879 October - December Journal of Pharmacy and Chemistry Vol.2 Issue.4