摘要:
Investigation of a 'reverse' approach to extended porphyrin systems. Synthesis of a 2,3=diaminoporphyrinand its reactions with a-diones Maxwell J. Crossley,* Lionel G. King, Ian A. Newsom and Craig S. Sheehan School of Chemistry, The University of Sydney, IV S. W 2006, Australia A 2,3-diaminoporphyrin has been synthesised for the first time and its reaction with a-diones has been examined. Two regioselectiveroutes to the precursor 2-amino-3-nitroporphyrins have been established. 2-Aminoporphyrins are directly nitrated on the porphyrin ring in the 3-position while 2-nitroporphyrins react with acylamide ions regioselectivelyat the 3-position and can be converted to the required 2-amino-3-nitroporphyrins by hydrolysis of the amide bond. 2,3-Diamino-5,10,15,2O-tetraarylporphyrinsare prepared by transfer hydrogenation of the corresponding 2-amino-3-nitroporphyrins but are relatively unstable.Electrochemical measurements show that 2,3-diaminoporphyrins are easily oxidised and this probably accounts for their instability. Condensation of the 2,3-diarninoporphyrin 29 with the a-diones benzil and cyclohexane-1,2-dione occurs readily and in good yield to give the ring annulated systems 31 and 32, respectively. Reaction with o-benzoquinone, however, causes decomposition of the diaminoporphyrin 29 making 'reverse' synthesis of quinoxalinoporphyrins and related polyporphyrin systems much less attractive than the alternate approach involving condensation of a porphyrin-2,3-dione with o-phenylenediamine and related diamines.A synthetic route to extended porphyrin systems (e.g., the quinoxalinoporphyrin 3) involves the condensation of a porphyrin-2,3-dione 1 with an o-diaminoarene 2 [Scheme 1, enhanced if the positions of the o-diamino and a-dione func-tionalities could also be interchanged in the starting materials. In this way, extended porphyrin systems such as the quinoxali-noporphyrin 3 could also be accessed by condensation of a 2,3-+ 1 Path (a)1 diaminoporphyrin 4 and an o-quinone 5 [Scheme 1, path (b)]. 2,3-Diaminoporphyrins 4 have not been reported previously. We envisaged two approaches to such compounds (Scheme 2). Nitration of a metallo-2-aminoporphyrin 7,which can beH2NxxRH2N R obtained from the corresponding nitro compound 6 by reduc-tion,' might afford the 2-amino-3-nitroporphyrin 8, and sub-2 sequent reduction would afford 2,3-diaminoporphyrin 4 [Scheme2, path (ci)].This sequence requires the amino group to direct nitration to the adjacent P-pyrrolic position. We antici-pated that this might be a highly regioselectiveprocess given the fact that 2-aminoporphyrins form Troger's base analogues in very good yield in a process that clearly requires the reaction to be directed in such a way.' The second approach [Scheme 2, path (b)]involves nucleophilic substitution of hydrogen by an Path (b) (Scheme 2). We have found that both pathways of Scheme 2 afford 2- amino-3-ni troporphyrins in reasonable yield. We now report these investigations and we also report the conversion of a zinc(ri) 2-amino-3-nitroporphyrin 16 into the corresponding ,N-M-N"/ NH2 + O0 n R 2,3-diaminoporphyrin 29 and its subsequent reaction a-diones.ONH2 with acyl amide ion at the P-pyrrolic position adjacent to a nitro N R group.There is a good analogy for this process in the reaction with oxy-anions with 2-nitroporphyrin~.~,'In the present case the resultant 2-amido-3-nitroporphyrin 9 should then be able to be converted into 2-amino-3-nitroporphyrin 8 and thence to3 2,3-diaminoporphyrin 4 by hydrolysis followed by reductionI Ar -Ar 5 4 Scheme I path (cr)],' and has been extended to the synthesis of doubly annulated porphyrins by condensation of porphyrin-2,3,12,13-and -2,3,7,8-tetraones with o-diaminoarenes and 1,2,4,5-ben~enetetramine.~While this is an efficient entry into such extended systems, the versatility of the approach would be Results and discussion Preparation of 2-amino-3-nitroporphyrins Both routes to 2,3-diarninoporphyrins outlined in Scheme 2 require the initial synthesis of the corresponding 2-amino-3-nitroporphyrins. The first route to 2-amino-3-nitroporphyrins involves the nitration of 2-aminoporphyrins [Scheme 2, path (ct)].The required metallo-2-aminoporphyri11s, 1S15, were readily available by reduction of the corresponding zinc(ll), copper(1i) and palladium(l1) 2-nitroporphyrins, 10-12 respect-J Cliern. SOC.,Perkin Trans. I, I996 2675 Path (b) H2N-C-R-base 6 9 HydrolysisPath (a)I Reduction &NH.,N-M-N NO; &NH2,N-M-N I I NO2 Ar*Ar ArWLU 7 8 ReductionI 4 Scheme 2 ively, by a hydrogen transfer process using NaBH, in the pres- ence of 10% palladium on carbon catalyst (Scheme 3), the met- allonitroporphyrins being prepared by metallation of 2-nitro- 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin. These metalloporphyrins were chosen to span a range of metal ion electronegativities (Pauling electronegativities Zn 1.65,Cu 1.90 and Pd 2.20) as the nature of the chelated metal has been shown to be a determining factor in the regiochemical outcome of nitrations of other metallotetraarylporphyrins.' 2-Amino-porphyrins are photolabile and somewhat prone to oxidation and so compounds 13-15 were used immediately.Each aminoporphyrin 1S15 was treated with a solution of nitrogen dioxide in CH,CI, until TLC analysis showed that no starting material remained (between 1.8and 2.1 equiv. of nitro- gen dioxide was req uired).9 The reaction product was fraction- ated on silica gel. A single aminonitroporphyrin regioisomer, the 2-amino-3-nitroporphyrin,was obtained in each case along with products resulting from N-nitrosation of the amino group. The reaction of the zinc(rr) 2-aminoporphyrin 13 with nitrogen dioxide at -78 "C gave the zinc(i1) 2-amino-3-nitroporphyrin 16 in 50% yield for the two steps from zinc(1r) 2- nitroporphyrin 10, while the reaction at 25 "C gave 16 in 42% overall yield. In the latter reaction zinc(1r) porphyrin 20 (12% yield) and several highly coloured non-polar bands, each in very low yield, and a major, unstable and relatively polar by-product (about 30% yield) were also isolated by chromatography over silica. The 'HNMR spectrum of 16 showed resonances of six pro- tons in the p-pyrrolic region.Two AX systems (6 8.58and 8.87, J 4.7 Hz,and S 8.93 and 9.07, J 4.8 Hz)and an AB quartet (S 8.83 and 8.86,JAB4.6 Hz)were observed. This pattern of signals is only consistent with vicinal substitution on a p,p'-pyrrolic position on the porphyrin periphery. The 1R spectrum of 16 showed absorbances consistent with the presence of a 2676 J Cliem. SOC.,Perkin Trans. I, 1996 primary amine (\~m;lx 3475and 3341 cm-') and a nitro (vmnX 1534 cm-') group. Examination of the crude reaction mixture by 'H NMR spec- troscopy in a separate experiment showed the presence of only two products before chromatography.The 2-amino-3-nitroporphyrin 16 (cu. 55'X) and a compound we tentatively assigned as the porphyrin diazonium salt 19 (c'u.45%))because of a strong absorbance (vn,ilx2130 cm-') in the IR spectrum consistent with the presence of a diazonium group"." and the nature of decomposition products, including the deamiiiated porphyrin 20, resulting from chromatography. It is known that primary amines are diazotised by treatment with dinitrogen tetroxide,".'4 by reaction with the equilibrium amounts of nitrosonium nitrate present. Although the use of a solution of nitrogen dioxide in light petroleum has been referred to throughout this work, the predominant species in these solutions is dinitrogen tetroxide.Is Porphyrin diazonium salts have been prepared previously by treatment of an ami- noporphyrin with sodium nitrite in tetrafluoroboric acid at -5 "C," or with sodium nitrite and sulfuric acid in a tetra- hydrofuran-methanol mixture." Interestingly, neither zinc(1i) 2-nitroporphyrin 10 nor the corresponding nitroporphyrin diazonium salt was formed, indicating both that the porphyrin diazonium salt 19 is deactivated toward nitration compared to the aminoporphyrin 13, and that the 2-amino-3-nitroporphyrin 16 is less reactive at the amino group toward nitrosation than is the 2-aminoporphyrin 13. Under the same nitration conditions as above at 25 "C, both the copper(r1) and palladium(rr) 2-amino-3-nitro-porphyrins 17 and 18 were obtained in 22% yield from their .NH2 1 Ar WAr Ar WAr 10 M = ZnI' 13 M = Zn" 11 M = Cu" 14 M = Cu" 12 M = Pd" 15 M = Pd" i/ J + 16 M = Zn" 19 M = Zn" 17 M = Cu" 18 M = Pd" J Bu' Bu' 20 M = Zn" Scheme 3 Reugenrs urztl cont1iriolz.s: i, NaBH,, 10% Pd-C in CH,CI,-MeOH (4: I); ii, NO,-light petroleum,CH,CI, corresponding metallo-2-aminoporphyrins, 14 and 15 respect-ively.The IR spectra of products 17 and 18 indicated the pres- ence of both amine and nitro groups and the 'H NMR spec- trum of the diamagnetic palladium(1l) compound 18 was only consistent with vicinal substitution of one pyrrolic ring. The major by-product in the latter reaction is putatively assigned as the corresponding palladium(ii) porphyrin diazonium salt (I],,,, 2 130 cni-I).The absence of 2-amino-.~-nitroporphyrinregioisomers of the corresponding 2-amino-3-nitroporphyrin in each case- these would result from nitration elsewhere on the 2-aminoporphyrin ring-shows that the amino group exerts a powerful directing effect. This effect of the amino group may be contrasted with that of the methyl group, which has only a small influence on the nitration reaction. Indeed, all seven pos- sible copper(11) 2-methyl-x-nitro-5,10,15,20-tetraphenylpor-phyrin regioisomers are obtained from the nitration of cop- per(ir) 2-methyl-5,10,15,2O-tetraphenylp0rphyrin.~The nitro group directs nitration away from the adjacent site, so that the other five possible copper(ii) 2,s-dinitro-5,10,15,20-tetra-arylporphyrins are obtained but not the 2,3-dinitro isomer from nitration of either copper(r1) 2-nitro-5,10,15,20-tetraphenyl-porphyrin 22 or the corresponding octa-tert-butylated deriv- ative 11.'*' Interestingly, the nitration of zinc(rr) aminoporphyrin 13 gave a higher yield (at least 42-50%) of the nitrated analogue 16 than did the corresponding nitration of zinc(rr) porphyrin 20, which gave zinc(ii) nitroporphyrin 10 in 13%~yield along with ring- opened compounds.In both cases, the mechanism of nitration involves the initial oxidation of the metalloporphyrin by nitro- gen dioxide to a porphyrin n-cation radical, followed by a rad- ical combination with further nitrogen dioxide and proton 10~s.~ The rr-cation radical of zinc(r1) porphyrin is likely to have a highest occupied orbital of u2" symmetry which results in pre-dominant meso-reactions and subsequent ring opening.' Intro- duction of the amine group destabilises the orbital of ulUsym-metry, which becomes the highest occupied orbital and causes predominant P-pyrrolic reactions under the cation-radical conditions.'* 2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butyl-pheny1)porphyrin 21 was prepared by the demetallation of either zinc(r1) 2-amino-3-nitroporphyrin 16 or copper(ri) 2-amino-3-ni troporphyrin 17 (Scheme 4). Demetallation of zinc(i1) 2-amino-3-nitroporphyrin 16 by shaking with hydro- chloric acid gave 21 in 87% yield. Similarly, demetallation of 17 with a mixture of sulfuric acid and trifluoroacetic acid gave 21 in 78% yield.The demetallation of copper(1i) 2-amino-3-nitro- porphyrin 17 provided additional evidence for the proposed structure of this compound. Free-base 2-amino-3-nitroporphyrin 21 could be easily met- allated by normal procedures. For example, treatment of free- base 2-amino-3-nitroporphyrin21 with excess palladium(r1) chloride in an acetic acid-chloroform mixture heated at reflux gave palladium(ri) 2-amino-3-nitroporphyrin18 in 90% yield. The other route [Scheme 2, path (b)] to 2-amino-3-nitroporphyrins requires regiospecific amination of a metallo- 2-nitroporphyrin. Sodamide was the first nitrogen nucleophile investigated.Treatment of (2-nitro-5,IO,15,20-tetraphenyl-porphyrinato)copper( I I) 22 in N,N-dimethyl formamide with 2-12 equiv. of sodamide over 18 h did not yield any (2- amino-3-nitro-5,10,15,20-tetraphenylporphyrinato)copper(11). The major product was (2-formamido-3-nitro-5,10,15,20-tetraphenylporphyrinato)copper(ri) 23 in yields of 63-68'%1 (Scheme 5). The formamide product presumably arose from the initial reaction of sodamide with the solvent. In this event, transami- dation by attack of amide ion on N,N-dimethylformamide would afford formamide. Deprotonation of the formamide by the liberated dimethylamide ion, or by the amide ion, would then form the nucleophile to attack the nitroporphyrin 22. NH2 'NO2 17 li 21 18 Ar= $aBy'Bu' Scheme 4 Reuprscmdconrlitiuas: i, H2S04(I 8 mol dm-'), CF,CO,H; ii, HCI (7 mol dm-3), Et,O; iii, PdCl?, NaOAc.AcOH-CHCI, (2: I), reflux, 16 h Independent evidence for the role of formamide ion as the nucleophile in this reaction was sought. (2-Nitr0-5,10,15,20- tetraphenylporphyrinato)copper(rr) 22 was therefore treated with formamide ion (5 equiv.), which had been generated in Me,SO. This reaction again afforded (2-formamido-3-nitro- 5,10,15,20-tetraphenylporphyrinato)copper(11) 23, in 57% yield, supporting the assumed formation of the formamide ion in the N,N-dimethylformamide reaction. The reactivity of (2-nitro-5,10,15,20-tetraphenylpor-phyrinato)copper(ir) 22 toward acylamide ions was further evident by its reaction with the sodium salt of acetamide.Thus, stirring a Me,SO solution of the sodium salt of aceta- mide (5 equiv.) with (2-nitro-5,10,15,2O-tetraphenyl-porphyrinato)copper(11) 22 overnight afforded (2-acetamido-3- nitro-5,10,15,20-tetraphenylporphyrinato)copper(11)24 in 43% yield. The reaction of amide nucleophiles with (2-nitr0-5,10,15,20- tetraphenylporphyrinato)copper( 11) 22 clearly parallels that of the hydroxide ion.$ The site of nucleophilic attack for these nitrogen nucleophiles is at the vicinal P-pyrrolic carbon to that bearing the nitro group. Furthermore, there is no indication of a chlorin product from a second attack of an amide nucleophile at the P-pyrrolic carbon. Demetallation of the copper(1i) 2-amido-3-nitroporphyrins 23 and 24, in the standard procedure using concentrated sul-furic acid, afforded high yields of the free-base porphyrins, 2-formamido-3-nitro-5,10,15,20-tetraphenylporphyrin25 (91%) and 2-acetamido-3-nitro-5,1O,I5,20-tetraphenylporphyrin26 (8 7%).The structures of the 2-amido-3-ni troporphyrins 23-26 were evident from the spectra of these compounds. The IR spectra indicated the presence of nitro and amide carbonyl groups in each case. The visible spectra confirmed the porphyrin rather than chlorin structures.8.'" The 400 MHz 'HNMR spectrum of the free-base 2-acetamido-3-nitro-5,10,15,20-tetraphenyl-porphyrin 26 also supported the assigned structure, showing six P-pyrrolic protons as three AB quartets, a broad one-proton J. Cliein. Soc., Perkin Trclizs.I, I996 2677 1 __t 'N-C-H Hg Ph 11 iii ' NAc 'N-C-H H H 110 24 25 iii 1 1J + 26 27 V m25 28 Scheme 5 Reugents utnd conditions: i, DMF, N,, sodamide, 18 h; ii, NaH, Me2S0. N?, 65°C 45 niin. then stirred overnight; iii, CH2CI2, H2S04( 18 mol dm-'1, 4 min; iv. pyridine, acetic anhydride. reflux, 1 h; v, THF, KOH (lO'%), reflux, 18 h singlet corresponding to an amide proton (d 7.42) and a three- proton singlet for the acetamide methyl group (6 1.72). The 'H N M R spectrum of the free-base 2-formamido-3-nitro- 5,10,15,20-tetraphenylporphyrin25 was not consistent with a single structure. Investigation by variable temperature 'HNM R experiments revealed this compound to be a 1 :1 mixture of cis-and trans-amide isomers.The mass spectra of porphyrins 23-26 showed a clear molecular ion only in the case of (2-formamido- 3-nitro-5,10,15,20-tetraphenylporphyrinato)copper(11)23 but were consistent with the assigned structures. As was observed for (2-hydroxy-3-nitro-5,10,15,20-tetraphenylporphyrinato)-copper(i1) and the al koxy-3-nitroporphyrins, the mass spectra of these 2-amido-3-nitroporphyrins each showed a major frag- 2678 J Ckem. SOC.,Perkin Trans. I, 1996 ment 45 mass units less than the expected parent ion, due to hydrogenation of the 2,3-P-pyrrolic bond of the parent porphy- rin in the inlet system of the mass spectrometer and subsequent elimination of nitrous acid.s The structure of 2-formamido-3-nitro-5,10,I5,20-tetra-phenylporphyrin 25 was further established by acylation.Treatment of 25 with a 1 :1 mixture of acetic anhydride and pyridine at reflux for 1 h afforded 2-acetamido-3-nitro-tetraphenylporphyrin 26 (~OXI), together with the mixed diacylimide 2-(N-formylacetamido)-3-nitro-5,10,15,20-tetra-phenylporphyrin 27 (59'%1)(Scheme 5). The structure of this imide 27 was supported by the IR spectrum, which showed two carbonyl stretches [v,,,, 1725 and 1700cm-'I, the porphyrin-like visible spectrum and the 'HNMR spectrum, which showed six P-pyrrolic protons and resonances corresponding to the acet- amide methyl group (62.33) and the formyl proton (d 9.08). Base-catalysed hydrolysis of 2-formamido-3-nitroporphyrin 25 afforded 2-amino-3-nitroporphyrin 28 in 72'Ml yield.Reduction of 2-amino-3-nitroporphyrins to 2,s diaminoporphy rins Reduction of zinc(1i) 2-amino-3-nitroporphyrin 16 and of pal- ladium(11) 2-amino-3-ni troporphyrin 18 by hydrogen transfer from sodium borohydride in the presence of a 10% palladium on carbon catalyst gave the corresponding metaIlo-2,3-diaminoporp hyri ns (Scheme 6). The me tallo-2,3-diami no- . 16 M=Zn" 18 M =Pd" li ii ___c 31 29 M =Zn" 30 M =Pd" iv 1 32 Ar BU' 33 Scheme 6 Rrugents nrd conditions: i, NaBH,, lo'%,Pd-C in CH2C12-MeOH (4 : 1); ii, PhCOCOPh, CH,CI,; iii, cyclohexane-1 ,Zdione, CH,CII; iv, o-benzoquinone, CH2C12 Table 1 Electrochemical half-wave potentials vs. FcIFc' for metallated complexesin CH,C12-0.1 mol dni-' Bu4NBF," EflniV Porphyrin Oxidation 1 Oxidation 2 20 294 584 34 445 785 566 103035 13 190 476 14 250 580 15 302 696 29 --227h 362 C.d 30 --201 460'." ('All measurements made at room temperature. Solutions were purged by bubbling with argon. Quasi-reversible. ' Irreversible. ''E2 Esti-mated from differential pulse voltammogram (DPV) potential byadding 25 mV to the DPV experimental value. porphyrins were bright red and were slightly more polar than the corresponding 2-amino-3-nitroporphyrins when chromato- graphed on silica gel. Zinc( ii) 2,3-diaminoporphyrin 29 and palladium(ii) 2,3-diaminoporphyrin 30 proved to be unstable both as a solid and in solution, and a 'H NMR spectrum of these materials free from impurities could not be obtained.An attempt to similarly reduce 2-amino-3-nitro-5,10,15,20-tetraphenylporphyrin 28 led to an extremely air-sensitive prod- uct, presumably the diaminoporphyrin, which could not be isolated. Electrochemistry of metalloaminoporphyrins and metallodiaminoporphy rins In other work which investigated how valence orbital levels of metalloporphyrins were modulated by substituents at the p-pyrrolic positions, electrochemical measurements showed that copper(i1) 2-amin0-5,10,15,20-tetraphenylporphyrin was oxi-dised at a potential 207 mV lower than copper(i1) 5,10,15,20- tetraphenylporphyrin." We expect that 2,3-diaminoporphyrins would be even easier to oxidise. In order to quantify the effect of successive amino substitution, we examined the electro- chemistry of zinc(1i) 5,10,15,20-tetrakis(3,5-di-tert-butyl-pheny1)porphyrin 20, copper(i~)5,10,15,20-tetrakis(3,5-di-tert-butylpheny1)porphyrin 34, palladium(rr) 5,10,15,20-tetra-kis(3,5-di-tert-butylphenyl)porphyrin 35, the correspondingly metallated 2-aminoporphyrins 13-1 5 and the freshly prepared zinc(ri) and palladium(r1) 2,3-diaminoporphyrins 29 and 30.Ar= $GBu' Bu' 34 M = Cu" 35 M = Pd" Electrochemical half-wave potentials of these compounds are collected in Table 1. The cyclic voltammogram of each metalloaminoporphyrin 13-1 5 showed two reversible one-electron oxidation processes with peak separations (AE,,)in the range of 57-78 mV, which were substantially independent of the sweep rate (11 = 50-500 mV s-I), while the peak currents i,, and i, increased linearly with 417.At sweep rates 1' 2 1 V s-I, the two oxidations of zinc(11) aminoporphyrin 13 were quasi-reversible.No reductions were observed within the solvent window. The cyclic voltammogram showed that the first oxidation of each meiallodiaminoporphyrin 29 and 30 was quasi-reversible with peak separations in the range of 94-105 mV at low scan rates (v = 50-100 mV s-I). The first oxidation became more irreversible (i.e. larger peak separation) as the scan rate was increased. Peak currents ip, and i,,, increased linearly with dv. The second oxidation of each metallodiaminoporphyrin was found to be irreversible. It can be seen that zinc(ii) porphyrins are easier to oxidise than the corresponding copper(r1) compounds, which are in turn easier to oxidise than the corresponding palladium( 11) compounds.This trend is a common feature of metal-loporphyrin electrochemistry and reflects the fact that the more electronegative the chelated metal ion, the harder it is to oxidise the metalloporphyrin."'." Addition of an electron-donating amino group to the por- phyrin periphery lowers the oxidation potential by 100-260 mV. One-electron oxidation of unsubstituted zinc(ri), copper(i1) and palladium(i1) porphyrins yields the metalloporphyrin n-cation radical, and a second oxidation is known to afford a porphyrin .rc-dication."'." The first and second oxidation potentials of the 2-aminoporphyrins 13-15 parallel those of the unsubstituted porphyrins 20, 34 and 35, strongly suggesting that the oxid- ations are occurring at the porphyrin n-system rather than at the metal centre or the amino group.This is the same behaviour as was seen with the corresponding copper(1r) tetraphenylpor- phyrins,18 the half-cell potentials being nearly the same as those in the present case when corrected for reference electrode poten- tial. Copper(i1) 2-amino-5,lO,I5,20-tetraphenylporphyrinwas shown to be oxidised at the lilt,porphyrin n-level orbital.18 Oxidation of the 2,3-diaminoporphyrins 29 and 30 occur at even lower potential, as expected. The palladium(1r) 2,3- diaminoporphyrin 30 is easier to oxidise by 760 mV than the palladium(ii) porphyrin 35 and the corresponding zinc(r1) 2,3- diaminoporphyrin 29 has a lower first oxidation potential than zinc(rr) porphyrin 20 by 621 mV.In these 2,3-diaminoporphyrin cases, we have not established the site of oxidation but we note that oxidants as weak as atmospheric oxygen can oxidise both the metallo-2,3-diaminoporphyrins 29 and 30. We expect the same to be true of the corresponding nietallo-2,3-dianiino- 5,10,15,20-tetraphenylporphyrins.The ease of oxidation thus accounts for the instability in air of the 2,3-diaminoporphyrins. Investigation of the reaction of 2,3-diaminoporphyrin 29 with a-diones Despite the instability of zinc(1r) 2,3-diaminoporphyrin 29, it could be used for the preparation of extended systems by treating it with an appropriate dione.Treatment of freshly prepared zinc(ir) 2,3-diaminoporphyrin 29 with benzil or cyclo- hexane-1J-dione gave the corresponding adducts, zinc( 11) diphenylpyrazinoporphyrin 31 and zinc(11) 2',23,24,2'-tetrahydroquinoxalinoporphyrin 32, in 64 and 70% yield for the two steps from zinc(i1) 2-amino-3-nitroporphyrin 16. By contrast, treatment of freshly prepared zinc(ii) 2,3-diaminoporphyrin 29 with o-benzoquinone gave only a 4% yield of the expected condensation product, zinc(ir) quinoxali- noporphyrin 33. The low yield of zinc( 11) quinoxalinoporphyrin 33 may be due to oxidation of zinc(l1) 2,3-diaminoporphyrin 29 catal ysed by o-benzoq uinone. Conclusions Two routes to 2-amino-3-nitroporphyrins have been developed, both of which are highly regioselective.Nitration of zinc(il), copper(i1) and palladium(ii) 2-amin0-5,10,15,20-tetrakis(3,5-di-tcrr-butylpheny1)porphyrins 13-15, respectively, afford the cor- responding 2-amino-3-nitroporphyrins 16-18 regioselectively. The second approach involves regioselective nucleophilic substitution. Thus, 2-amido-3-nitroporphyrins are formed by treatment of the copper(i1) 2-nitro-5,10,15,20-tetra-J Chenz. SOC.,Perkin Trans. 1, 1996 2679 phenylporphyrin 22 with acylamide ion. Demetallation and subsequent base hydrolysis converts copper( 11) 2-formamido-3-nitro-5,10,15,2O-tetraphenylporphyrin23 into the correspond- ing 2-amino-3-nitroporphyrin 28in good overall yield. 2,3-Diaminoporphyrins can be prepared by reduction of 2- amino-3-nitroporphyrins as expected, but are prone to oxid- ation.This behaviour is similar to that of o-diaminobenzene derivatives and related hydroquinones and as such the 2,3- diaminoporphyrins can be considered as ring-expanded aro- matic analogues of the o-disubstituted benzenes. Reaction with o-benzoquinone causes decomposition of the diaminoporphyrin 29 making this 'reverse' synthesis [Scheme I, path (b)]of quinoxalinoporphyrins and related polyporphyrin systems much less attractive than the alternate approach involv- ing reaction of a porphyrin-2,3-dione with o-phenylenediamine and related diamines [Scheme 1, path (a)].Less redox active a-diones, however, react smoothly with the diaminoporphyrin 29 to give ring annulated porphyrins.The new porphyrin transformations reported above further illustrate the versatility of 2-nitroporphyrins as starting materials for the introduction of new functionality to P-pyrrolic positions of the porphyrin rit~g.~.~ 8*")*32 '' Experimental General procedures Melting points were recorded on a Reichert melting point stage and are uncorrected. Microanalyses were performed by the Microanalytical Unit, The University of New South Wales, or by the Australian Mineral Development Laboratory, Mel- bourne. Infrared spectra of chloroform solutions were collected with a Perkin-Elmer Series I600 FTI R spectrometer. Electronic spectra were collected in chloroform solutions on a Hitachi 150-20 spectrophotometer. 'H NMR spectra were recorded on a Bruker AMXBOO (400 MHz) spectrometer.Deuteriochloro- form was used as the solvent with tetramethylsilane as an internal standard unless otherwise stated. Electron impact (EI) mass spectra were recorded on an AEI MS902 spectrometer. Chemical ionisation (CI) mass spectra were recorded on a Triple Stage Quadrapole FINNIGAN MAT spectrometer. Matrix- assisted laser desorption ionisation time-of-flight (MALDI- TOF) mass spectra were recorded on a VG Tofspec spectro- meter. Mass spectra recorded using this instrument are obtained as an envelope of the isotope peaks of the molecular ion. The mass corresponding to the envelope's maxima is reported and was compared with the maxima of a simulated spectrum. The MALDI-TOF mass spectra were accurate to +I a.m.u.(ca. 0.10%). Column chromatography was performed using Merck silica gel 60 Type 9385 (40-60 pm). Analytical thin layer chroma- tography (TLC) was run on Merck silica gel 60 FZs4 precoated sheets (0.2 mm). Where solvent mixtures are used, proportions are given by volume. Light petroleum refers to the fraction of bp 60-80 "C. Ether refers to diethyl ether. Dichloromethane and light petroleum were routinely redistilled prior to use. Ether was distilled over crushed calcium chloride and stored over sodium wire. Merck AR grade methanol was used. Electrochemistry was performed using a BAS lOOB Electro- chemical Analyser. All measurements were made at room temperature on 1 .O mmol dm-' solutions in dichloromethane-0.1 mol dm-3 tetrabutylammonium tetrafluoroborate by using a Teflon-shrouded gold disk working electrode, plat- inum wire auxiliary electrode, and a Ag/AgCI/KCI (sat.) reference electrode.The working electrode was polished with diamond paste prior to use and polished with alumina prior to each measurement. The internal standard was the ferrocenium/ferrocene couple which had an oxidation at Ef 541 mV under these conditions. Tetrabutylammonium tetrafluoroborate was purified by recrystallisation from cold 2680 J Chem. SOC.,Perkin Tsans. I, 1996 ethyl acetate-ether three times and dried under high vacuum over P,O, for 2 days. Solutions were prepared under argon and a positive pressure of argon maintained in the sample cell. All glassware was oven dried overnight prior to use.Dichloromethane for electrochemistry was purified by heating at reflux over P305 under nitrogen for 2 days followed by distillation from P,Os under nitrogen. Samples of metalloaminoporphyrins and metallodi-aminoporphyrins for electrochemistry were prepared by the following procedure: a mixture of the appropriate metal-lonitroporphyrin or metalloaminonitroporphyrin and a lo'%, palladium on carbon catalyst (850 mg mmol-') was suspended in a dichloromethane-methanol (4: 1) mixture (120 cm3 mmol-') and purged with nitrogen. Sodium borohydride (25 equiv.) was added in portions over 10 min and the mixture stirred in the dark under nitrogen for 30 min. The mixture was evaporated to dryness under reduced pressure.The remainder of the workup was performed in a glove bag under nitrogen. The residue was dissolved in dichloromethane and filtered through a plug of silica (Type 7736, dichloromethane) and the filtrate evaporated to dryness to give the reduced product which was stored under nitrogen and used without further purification. (2-Nitro-5,lOJ5,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinatolzinc(l1)10 Method 1. A mixture of 2-nitro-5,10, 15,20-tetrakis(3,5-di- tert-butylpheny1)porphyrin (702 mg, 0.633 mmol), zinc(1i) acetate dihydrate (474 mg, 2.16 mmol), dichloromethane (40 cm') and methanol (4 cm3) was heated at reflux for 30 min, allowed to cool, and evaporated to dryness. The residue was dissolved in dichloromethane and filtered through a plug of silica (Type 9385, dichloromethane).The filtrate was evapor- ated to dryness and the residue was purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :2). The major green band was collected and evaporated to give [2- nitr0-5,10,15,20-tetrukis(3,5-di-tert-butylpl~cnyl)porpl~yrinuro]-zinc.(ir) 10 (695 mg, 94%) as a purple amorphous powder. A sample for analysis, recrystallised from a dichloromethane- methanol mixture, had mp =. 300 "C (Found: C, 77.6; H, 7.95; N, 5.9. C,6H,,N,01Zn requires C, 77.9; H, 7.8; N, 6.0%); vn,,,(CHCl,)lcm-' 15 16 (NO?)and 1336 (NO?);iL,,,(CHCl,)lnm 309 (log c 4.29), 431 (5.37), 526sh (3.61), 563 (4.16) and 608 (4.06); S,(400 MHz, CDCI') 1 S1-1.53 (72 H, m, tert-butyl H), 7.76 (1 H, t, J 1.8, aryl HJ, 7.79 (2 H, t, J 1.8, aryl H,J, 7.81 (1 H, t, J 1.8, aryl H,,), 8.02 (2 H, d, J 1.8, aryl H,,), 8.04 (2 H, d, J 1.8, aryl H,,), 8.05-8.06 (4 H, m, aryl H,,), 8.93-8.97 (5 H, m, p-pyrrolic H), 9.02 (1 H, d, J 4.8, P-pyrrolic H) and 9.22 (1 H, ZS, H-3); I~ (CI) 1170 (M + H, loo'%,).Method 2.A solution of [5,10,15,20-tetrakis(3,5-di-rcrr-butylphenyl)porphyrinato]zinc(rl) 20 (1 01 mg, 0.089 mmol) in dichloromethane (6 cm3) was treated with aliquots of a solution of nitrogen dioxide in light petroleum (0.1mol dm-', 0.035 cm') every 5 min until TLC analysis showed that no zinc(ir) porphy- rin 20 remained. The mixture was evaporated to dryness and the residue purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :2). The major green band was collected and evaporated to dryness to give [2-nitro- 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrinato]-zinc(rr) 10 (14 mg, 13%) as a purple amorphous powder which co-eluted with, and had an identical 'HNMR spectrum to, a sample prepared by Method 1.~2-Nitro-5,10,15,20-tetrakis(3,5-di-terf-butyIphenyl)-porphyrinatolpalladium(1r) 12 A mixture of 2-nitro-5,10, I5,20-tetrakis(3,5-di-rcrt-butyl-pheny1)porphyrin (406 mg, 0.37 mmol) and sodium acetate (121 mg, 1.47 mmol) was dissolved in an acetic acid-chloroform mixture (2:1, 120 cm') and heated. Just before reflux, pal- ladium(rr) chloride (132 mg, 0.75 mmol) was added and the mixture heated at reflux for 16 h.The mixture was allowed to cool and ether (80 cm') was added. The organic phase was washed with water (4 x 80 cm'), aqueous sodium carbonate (5'%),80 cm3) and brine (80 cm'), dried over anhydrous sodium sulfate and filtered. The filtrate was evaporated to dryness and the residue purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :3). The major red band was collected and evaporated to dryness to give [2-nitr.u- 5,10,15,20-tetrukis( 3,5-ili-tert-b~r~ylp/zcn~~)purpiz~rin~~o]-pulludiuni(ir) 12 (438 mg, 96%) as a red amorphous powder, mp > 300 "C (Found: C, 75.1; H, 7.8; N, 5.5. C7,H,,NSO2Pd requires C, 75.25; H, 7.6; N, 5.8%); v,,,(CHCl,)/cm-' 1522 (NO,) and 1347 (NO,); iL,,,,(CHCl,)/nm 295 (log c 4.19), 386sh (4.47).429 (5.26), 532 (4.27) and 572 (4.03); 6,(400 MHz, CDCl,) 1.50-1.51 (72 H, m, tert-butyl H), 7.74 (1 H, t, J 1.8, aryl HJ, 7.78-7.79 (2 H, m, aryl HJ, 7.80 (1 H, t, J 1.8, aryl H,J, 7.97-8.00 (8 H, m, aryl H,,), 8.77 (I H, d, J 5.0, P-pyrrolic H), 8.79-8.83 (4 H, m, P-pyrrolic H), 8.80 (1 H, d, J 5.0, P-pyrrolic H) and 9.12 (1 H, s, H-3); in/=(MALDI-TOF) 1212 (M + H requires 1213). (2-Arnino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinatolzinc(l1) 16 Method 1. [2-Nitro-5,10,15,20-tetrakis(3,5-di-tert-butyl-phenyl)porphyrinato]zinc(~r)10(200 mg, 0.17 1 mmol) and 10% palladium on carbon catalyst (148 mg) were suspended in a dichloromethane-methanol mixture (4: 1, 40 cm') and purged with nitrogen.Sodium borohydride (162 mg, 4.29 nimol) was added in small portions over a 10 min period and the mixture stirred in the dark under nitrogen for 45 min. The mixture was evaporated to dryness, taken up in dichloromethane, filtered through a plug of silica (Type 9385), and evaporated to dryness. The residue was dissolved in dichloromethane (40 cm') and treated with aliquots of nitrogen dioxide in light petroleum solution (0.1 mol dm-', 0.10 cm') every 5 min until TLC analy- sis showed that none of the starting material remained. Metha- nol (10 cm') was added and the mixture evaporated to dryness. The residue was purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 : 1) and the major green band collected and evaporated to dryness to give [2-urnino-3-nitro-5,10,15,20-tetrukis(3,5-&- tert-buty1phenyl)- porp/~~rinuto]=inc(ii)16 (81 mg, 40%)) as a purple amorphous powder.A sample for analysis, recrystallised from a dichloromethane-methanol mixture, had mp > 300 "C (Found: C, 77.2; H, 8.1; N, 6.7. C,,H,,N,O,Zn requires C,76.8; H, 7.9; N,7.1%); v,,,,(CHCl,)/cm-' 3481 (NH,), 3353 (N H,), 1604 and 1534 (NO?);&,,,,(CHCl,)/nm 318 (log e 4.33), 349sh (4.33), 445 (5.24), 518 (3.81), 567 (4.20) and 607 (4.01); SH(400 MHz, CDC13)1 SO-1.53 (72 H, m, terz-butyl H), 6.45 (2H, br s, NH,), 7.65 (1 H, t, J 1.8, aryl H/J, 7.76-7.79 (2 H, m, aryl HJ, 7.90 (1 H, t, J 1.8,aryl H,,), 7.97 (2 H, d, J 1.9, aryl H,,),8.02-8.05 (4 H, m, aryl H,,), 8.09 (2H,d, J 1.7, aryl H,,),8.58 and 8.87 (2 H, AX, over silica (Type 9385, dichloromethane-light petroleum; 1 : 1 changing to ether when the major green band had been col- lected).The bands less polar than the major green band were collected and evaporated to dryness to give a dark purple amorphous powder (1 14 mg) which was further purified as described later. The major green band was collected and evapor- ated to dryness to give [2-amino-3-nitro-5,1O,I5,20-tetrakis(3,5-di-tcrt-butylphenyl)porphyrinato]zinc(11) 16(433 mg, 42'%1) as a purple amorphous powder which co-eluted with, and had an identical 'H NMR spectrum to, an authentic sample. The materials which were less polar than 16 were purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :4).The major purple band was collected and evaporated to dryness to give zinc(ii) porphyrin 20 (42 mg, 4%) as a purple amorphous powder. The remaining bands were col-lected and evaporated to dryness to give a dark purple amorph- ous powder (55.3 mg) (85')/0mass recovery of the non-polar fraction). The bands more polar than the major green band were col- lected and evaporated to dryness to give an impure dark purple amorphous powder (41 3 mg), vnlC,,(CHCl,)lcm-' 2130. This material was rechromatographed over silica (Type 9385, dichloromethane-light petroleum, I :4, changing to ether after the less polar bands had eluted). The major non-polar purple band was collected and evaporated to dryness to give further [5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrinato]-zinc(ir) 20 (76 mg, 8'%, combined 12% overall from 10) which co-eluted with, and had an identical 'H NMR spectrum to, an authentic sample.The bands which were more polar than zinc(i1) porphyrin 20 were collected and evaporated to dryness to give a dark purple amorphous powder (296 mg) (90'X) mass recovery of the polar fraction). ~2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-revt-butylphenyl)-porphyrina tolcopper( I I) 17 [2-Nitro-5,10,15,20-tetrakis(3,5-di-tcrt-butylphenyl)porphyriii-ato]copper(ii) 11 (404 mg, 0.346 mmol) was reduced with sodium borohydride (325 mg, 8.59 mmol) in the presence of 10% palladium on carbon catalyst (285 mg) and thence treated with nitrogen dioxide following similar procedures to the preparation of [2-amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrinato]zinc(11) 16.The residue was purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 2:5, increasing to 1 : 1 when the major non-polar bands had eluted) and the major green band collected and evaporated to dryness to give [2-umino-3- nitro-5,IO,l5,20-tetruh-is(3,5-~~-tert-butylp/lento]-copper(rr) 17 (88 mg, 22%) as a purple amorphous powder. A sample for analysis, recrystallised from a dichloromethane- methanol mixture, had mp > 300 "C (Found: C, 76.8; H, 7.95; N, 7.0. C,,H,JhN,02 requires C, 77.0; H, 7.8; N, 7.1%); J4.7, P-pyrrolic H), 8.83 and 8.86 (2H, AB, J4.6, P-pyrrolic H), v,,,,(CHCl,)/cm-' 3482 (NH,), 3355 (NH,), 1611 and 1541 8.93 and 9.07 (2 H, AX, J 4.8, P-pyrrolic H); id2 (CI) 1185 (NO,); iL,,,,,(CHCl,)/nm 309 (log E 4.29), 404sh (4.76), 419sh (M + H, 100'%).(4.91), 442 (5.16), 560 (4.10).604 (3.94) and 660 (3.23); m/z Method 2. [2-Amino-3-nitro-5,IO,15,20-tetrakis(3,5-di-ter~-(MALDI-TOF) 1184 (M + H requires 1185). butylphenyl)porphyrinato]zinc( 11) 16 (94 mg, 50%) was pre- pared from [2-nitro-5,10,15,20-tetrakis(3,5-di-tert-butyl-phenyl)porphyrinato]zinc(~r)10(1 87 mg, 0.160 mmol) following the previous method except that the nitration with a solution of nitrogen dioxide in light petroleum was performed at -78 "C under an atmosphere of nitrogen. The product, a purple amorphous powder, co-eluted with, and had an identical 'H NMR spectrum to, an authentic sample.Method 3. [2-Nitro-5,10,15,20-tetrakis(3,5-di-tert-butyl-phenyl)porphyrinato]zinc(lr) 10 (1.08 g, 0.86 mmol) was reduced with sodium borohydride (799 mg, 21.1 mmol) in the presence of lo'%, palladium on carbon catalyst (757 mg) and thence treated with nitrogen dioxide following similar pro- cedure to Method 1 above. The crude product, [vn,..,(CHCI3)/ cm-' 3481m, 3353m, 2130~1was purified by chromatography 12-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-terf-butyIphenyl)-porphyrina to] pa Iladium( II) 18 Method 1. 2-Amino-3-nitro-5,10,15,2O-tetrakis(3,5-di-tert-butylpheny1)porphyrin 21 (89.4 mg, 0.080mmol) and sodium acetate (23.8 mg, 0.290 mmol) were dissolved in an acetic acid-chloroform mixture (2 : 1, 30 cm') and heated. Just before reflux, palladium(i1) chloride (36.3 mg, 0.205 mmol) was added and the mixture heated at reflux until the reaction had gone to completion as determined by TLC analysis.After allowing the mixture to cool, ether (20 cm') was added and the organic phase washed successively with water (4 x 20 cm'), aqueous sodium carbonate (5'%),20 cm') and brine (20 cm')), and then dried over anhydrous sodium sulfate and filtered. The filtrate was evaporated to dryness and the residue was J Clieiv. Soc., Perkin Trans. I, I996 2681 purified by chromatography over silica (Type 9385, and filtered. The filtrate was evaporated to dryness and the dichloromethane-light petroleum, 2: 3) and the major red residue purified by chromatography over silica (Type 9385, band collected and evaporated to dryness to give [2-umino-3- dichloromethane-light petroleum, 1 :2).The major brown band 3,5-cli-tert-biit~vlphenyoporpl?l?ril2porp1zyrinuto]-was collected and evaporated to dryness to give 2-amino-3- nitr0-5,10,15,20-teirukis( pul!udiiii?i(rr) I8 (88 mg, 90%) as a red amorphous powder. A sample for analysis, recrystallised from a dichloromethane-methanol mixture, had mp > 300 "C (Found: C, 74.1; H, 7.8; N, 6.7. C,,N,,N,O,Pd requires C, 74.3; H, 7.55; N, 6.85%); v,,,,(CHCl,)lcm-' 3481 (NH,), 3352 (NH?), 1612 and 1541 (NO,); iinl~,,(CHCl~)lnm323sh (log c 4.26), 353sh (4.32), 374sh (4.62), 444 (5.13, 509 (3.72), 546 (4.27) and 587 (4.12); SH(400 MHz, CDCI,) 1.49 (18 H, s, tert-butyl H), 1.50-1.52 (54 H, m, tert-butyl H), 6.51 (2 H, br s, NH,), 7.64 (1 H, t, J 1.8, aryl H,,), 7.75-7.78 (2 H, m, aryl H/,), 7.89 (I H, t, J 1.8, aryl Hp), 7.94 (2 H, d, J 1.8, aryl H,,), 7.97-7.99 (4 H, m, aryl H,,), 8.05 (2 H, d, J 1.8, aryl H,,), 8.45 (1 H, d, J4.9, P-pyrrolic H), 8.70 (1 H, d, J 4.9, P-pyrrolic H), 8.74--8.78 (3 H, m, P-pyrrolic H) and 8.90 (1 H, d, J 5.0, P-pyrrolic H); idz (MALDI-TOF) 1228 (M + H requires 1227).Method 2. [2-Nitr0-5,10,15,20-tetrakis(3,5-di-tert-butyl-phenyl)porphyrinato]palladium(~i) 12 (200 mg, 0.165 mmol) was reduced using sodium borohydride in the presence of 10%) palladium on carbon catalyst and thence treated with nitrogen dioxide following similar procedures to that used for the preparation of [2-amino-3-ni tro-5,10,15,20-tetrakis(3,5-di-rert-butylphenyl)porphyrinato]zinc(ir) 16.The crude product was purified by chromatography over silica (Type 9385, dichloro- methane-light petroleum, 1 :2) and the major red band col- lected and evaporated to dryness to give [2-amino-3-nitro- 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrinato]-palladium(1r) 18 (45 mg, 22%)) as a red amorphous powder which co-eluted with, and had an identical 'H NMR spectrum to, a sample prepared by Method 1. 2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butyIphenyl)-porphyrin 21 nitro-5, IO,15,20-tetrakis(3,5-di-ter~-butylphenyl)porphyrin 21 (98 mg, 87%) as a purple amorphous powder which co-eluted with, and had identical 'H NMR spectrum to a sample pre- pared by Method 1.(2-Formamido-3-ni troJ,lO, 15,20-tetraphenylporphyrinato)-copper(i1) 23 Method 1. A solution of (2-nitro-5,10,15,20-tetra-phenylporphyrinato)copper(Ii) 22 (267 mg, 0.371 mmol) in dry, distilled N,N-dimethylformamide (60 cm') was stirred under nitrogen with sodamide(NaNH,) (50'%~suspension in benzene, 70 mg, 0.90 mmol) for 18 h. The mixture was then diluted with dichloromethane (150 cm'), washed with water (6 x 200 cm-'), dried over anhydrous sodium sulfate, filtered and evaporated to dryness. The residue was chromatographed over silica (Type 9385) eluting with dichloromethane. The major, polar, brown- green band was collected to yield (2-Jbriiiuinido-3-nitro-5,10,15,20-tetrup/~enylporp1zyrinuto)c.opper(1~)23 (1 77 mg, 63%) which was recrystallised from dichloromethane-hexane to yield a fine dark purple powder, mp 331 -333 "C (Found: C, 70.8; H, 3.8; N, 10.6.C4,H,RCuN,0, requires C, 70.7; H, 3.7; N, 1 1 .O'%I); v,,,(Nujol)/cm-' 3350br (NH), 1700 (C=O), 1570 (NO?), 1510 and 1330 (NO,); ~,,,,(CHCl,)nm 390sh (log c 4.57), 425 (5.28), 551 (4.1 1) and 594(3.95); 1dz 763 (M', 12'%,), 733 (12), 732 (1 1). 731 (16), 721 (19), 720 (36), 719 (39), 718 (M + 2H -HNO,, 70), 717(18),716(16),706(10),705(21),704(31),703 (61),702 (70), 701 (M + 2H -HNO, -OH, loo), 700 (51), 699 (44), 698 (13), 694 (14), 693 (18), 692 (29), 691 (31), 690 (43), 689 (21) and 688 (30). Method 2. A solution of sodium methylsulfinylmethanide was prepared by stirring sodium hydride (50% suspension in oil, 90 mg, 1.9 mmol) with dry, distilled Me,SO (60 cm') under Method 1.[2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-nitrogen at 65 "C for 45 min. On cooling to room temperature, butylphenyl)porphyrinato]copper(~i) 17 (47 mg, 0.039 mmol) was moistened with trifluoroacetic acid, concentrated sulfuric acid (0.25 cm') was added, and the mixture stirred for 15 min and poured onto ice (20 g). Ether (20 cm') was added and the organic phase washed successively with water (2 x 15 cm-'), aqueous sodium carbonate (5%, 15 cm') and brine (15 cm'), and then dried over anhydrous sodium sulfate, filtered and the filtrate evaporated to dryness. The residue was purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :2) and the major brown band collected and evaporated to dryness to give 2-ai?iino-3-nitr0-5,10,15,20-tetrukis(3,5-di-tert-biitylplrenyl)porpliyrin21 (35 mg, 78%) as a purple amorphous powder.A sample for analysis, recrystallised from a dichloromethane-methanol mixture, had mp > 300 "C (Found: C, 81.1; H, 8.3; N, 7.3. C76H94Nh02 requires C, 81.2; H, 8.4; N, 7.5%);vnlL,,(CHCI3)/cm-' 3475 (NH,), 3341 (NH,), 1608 and 1534 (NO?); iL,,,,(CHCl,)/nm 317 (log c 4.30), 392sh (4.65), 439 (5.14), 535 (4.15), 575 (3.92), 607 (3.80) and 668 (3.51); 6,(400 MHz, CDCI,) -2.52 (1 H, br s, inner NH), -2.28 (1 H, br s, inner NH), 1.51 (18 H, s, tert-butyl H), 1.53 (36 H, s, tcrt-butyl H), 1.54 (1 8 H, s, tcrt-butyl H), 6.72 (2 H, br s, NH,), 7.67 (1 H, t, J 1.8, aryl H,,), 7.77-7.80 (2 H, my aryl H,,), 7.92 (1 H, t, J 1.8, aryl HI,), 8.02-8.06 (6 H, m, aryl H,,), 8.21 (2 H, d, J 1.8, aryl H,,), 8.63 (I H, d, J 5.0, P-pyrrolic H), 8.66 and 8.69 (2 H, AB, J 4.6, P-pyrrolic H), 8.82-8.87 (2 H, m, P-pyrrolic H) and 9.06 (1 H, d, J 5.0, P-pyrrolic H); idz (MALDI-TOF) I125 (M + H requires 1124). formamide (0.10 cm', 2.5 mmol) was added and the mixture was stirred for 15 min.(2-Nitr0-5,10,15,20-tetraphenyl-porphyrinato)copper(ii) 22 (297 mg, 0.41 3 mmol) was added and the mixture was stirred overnight. The mixture was then diluted with dichloromethane (100 cm'), washed with water (6 x 100 cm'), dried over anhydrous sodium sulfate, filtered and evaporated to dryness. The residue was chromatographed over silica (Type 9385) eluting with dichloromethane and the major, polar band was collected to yield (2-formamido-3-nitro- 5,10,15,20-tetraphenylporphyrinato)copper(i1) 23 (1 79 mg, 57'%), identical in all respects to the sample prepared by Method 1.(2-Acetamido-3-nitro-5,I0,15,2O-tetraphenylporphyrinato)-copper(r1) 24 A solution of sodium methylsulfinylmethanide was prepared by stirring sodium hydride (50% suspension in oil, 85 mg, 1.8 mmol) with dry, distilled Me,SO (60 cm') under nitrogen at 65 "C for 45 min. On cooling, acetamide (1 13 mg, 1.92 mmol) was added and the mixture was stirred for 20 min. (2-Nitro- 5,10,15,20-tetraphenylporphyrinato)copper(i1) 22 (272 mg, 0.378 mmol) was added and the mixture was stirred overnight.The residue was chromatographed over silica (Type 9385) eluting with dichloromethane to yield (2-c~c.etui~iillo-3-izitro-5,10,15,20-te~rcrpl~c.nylporp/iyrin~~t~)c.oppcr(1r)24 (1 27 mg, 43%). An analytical sample was recrystallised from dichloromethane-hexane to give a purple solid, mp 301 -303 "C Method 2. [2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-(Found: C, 70.7; H, 3.8; N, 10.7. C46H30C~N,03 requires C, butylphenyl)porphyrinato]zinc(~i) 16 (1 20 mg, 0.101 mmol) was dissolved in ether (25 cm') and shaken with hydrochloric acid (7 mol dm-3, 25 cm-') for 5 min. The organic phase was separated and washed with aqueous sodium carbonate (5%, 25 cm') and brine (25 cm'), dried over anhydrous sodium sulfate 2682 J: Chem.SOC.,Perkin Trans. I, 1996 71.0; H, 3.9; N, 10.8%)); vnli,x(Nujol)/cm-' 1700br (C=O), 1570w (NO,) and 1520; i,,,,,(CHCl,)/nm 427 (log c 5.28), 551 (4.12) and 593 (3.93); nil: 735 (25'%)), 734 (56), 733 (44), 732 (M + 2H -HNO?, loo), 690 (1 3), 689 (1 l), 688 (14), 677 (1 2), 676 (10) and 675 (18). 25 dichloromethane (80 cm3) was added and the mixture was2-Formamido-3-nitro-5,10,15,20-tetraphenylporphyrin A solution of (2-formamido-3-nitro-5,10,15,20-tetra-washed with hydrochloric acid (3 mol dm-', 3 x 100 cm'), water phenylporphyrinato)copper(lr) 23 (1 38 mg, 0.181 mmol) in dichloromethane (20 cm') was poured into rapidly-stirred con- centrated sulfuric acid (1 5 cm') and the mixture was stirred for 4 min.The mixture was then poured onto ice (150 g) and extracted with dichloromethane (100 cm', 50 cm')). The com- bined organic extracts were washed with water (3 x 150 cmj), dried over anhydrous sodium sulfate and evaporated to dryness. The residue was chromatographed over silica (Type 9385) elut- ing with dichloromethane to yield a major, polar band of 2- Jor1numido-3-nitro-5,10,15,20-tetruplienylporpliyrin25 ( 116 mg, 91%) as purple crystals. A sample for analysis, recrystallised from a dichloromethane-methanol mixture, had mp 302- 304 "C (Found: C, 76.4; H, 4.3; N, 12.0. C45H30N603 requires C, 76.9; H, 4.3; N, 12.0%); v,,,,,(Nujol)/cm-' 1690, 1575 (NO,) and 1510; A,,,,,(CHCl,)/nm 434 (log c 5.24), 532 (4.11), 602 (3.56) and 677 (3.85); SH(400MHz, CD,C12) -2.56 (2 H, br s, inner NH), 7.12 (0.5 H, br s, cis-CHONH), 7.29 (0.5 H, br s, truns-CHONH), 7.66-7.92 (12 H, m, Ph H,,, and H,,), 8.16-8.23 (6 H, m, Ph H,,), 8.25-8.30 (2 H, m, Ph H,,), 8.38 (0.5 H, br s, truns-CHOHN), 8.67 (2 H, s, P-pyrrolic H), 8.84-8.92 (3 H, m, P-pyrrolic H) and 8.98 (1 H, br s, P-pyrrolic H); m/z 720 (1 3%), 719 (15), 718 (M + 6'C~+ 2H -HNO,, 25),t 705 (ll), 704 (13), 703 (27), 702 (37), 701 (M + 6'C~+ 2H -HNO, -OH, 40), 700 (25), 699 (25), 693 (1 I), 692 (16), 691 (24), 690 (41), 689 (27), 688 (45), 659 (16), 658 (19), 657 (M + 2H -HNO?, IOO), 656 (37), 655 (19), 644 (16), 643 (19,642 (24), 641 (50),640 (91), 639 (43), 638 (1 l), 631 (13), 630 (23), 629 (32), 628 (35), 627 (21)and 612 (12).2-Acetamido-3-nitro-5,10,15,20-tetraphenylporphyrin26 (100 cm'), aqueous sodium hydrogen carbonate (5%, 50 cm') and water (100 cm'), dried over anhydrous sodium sulfate, fil-tered and evaporated to dryness. The residue was chromato- graphed over silica (Type 9385) eluting with dichloromethane to yield a front running, brown band of 2-(N-Jbrri?yl~~~.er~i?7~~fo)-3-nitro-5,10,15,2O-tctruplter1~lporp~1~~rin27 (38 rng, 59%). A sample for analysis, recrystallised from a dichloromethane-hexane mixture, had mp 277-278 "C (Found: C, 75.8; H, 4.0; N, 11.2. C47H32N604 requires C, 75.8; H, 4.3; N, 11.3'%); v,,,,,(Nujol)/cm-' 3330w, 1725 (C=O), 1700 (C=O), 1510wbr, 1360 and 1340; ;I,,,(CHCl,)/nm 430 (log e 5.15), 531 (3.95), 608 (3.39) and 671 (3.76); 6',(400 MHz, CDCI,) -2.64 (2 H, br s, inner NH), 2.33 (3 H, br s, COMe), 7.66-7.83 (12 H, m, Ph H,,, and H,,), 7.95-8.06 (2 H, m, Ph H,,), 8.10-8.33 (6 H, br m, Ph HI,),8.68 (2 H, s, 12- and 13-H), 8.68 and 8.81 (2 H, ABq, JAB 5.0, P-pyrrolic H), 8.87 and 8.96 (2 H, ABq, JAB 5.0, P-pyrrolic H) and 9.08 (1 H, br s, CHO); nik 734 (1 3'%1), 733 (1 6), 732 (M + WU+ 2H -CO -HN02, 27), 730 (12), 688 (12), 687 (22), 673 (15), 672 (55), 671 (M +2H -CO -HNO,, loo), 670 (45), 669 (72), 659 (1 I), 657 (11), 656 (22), 645 (12), 644 (19), 641 (lo), 640 (17), 633 (15), 632 (31), 631 (15), 630 (27), 629 (20), 628 (27), 615 (12), 614 (21), 613 (16) and 612 (27).Further elution with ethyl acetate-dichloromethane (1 :9) yielded a more polar, brown band of 2-acetamido-3-nitro- 5,10,15,20-tetraphenylporphyrin26 (25 mg, 40%).This prod- uct was identical with authentic material by TLC and NMR comparison. 2-Amino-3-nitr0-5,10,15,20-tetraphenylporphyrin28 2-Formamido-3-nitro-5,10,15,20-tetraphenylporphyrin25 (237 A solution of (2-acetamido-3-nitro-5,10,15,20-tetraphenyl-porphyrinato)copper(11) 24 ( 125 mg, 0.16 1 mmol) in dichlo- romethane (30 cm') was poured into rapidly-stirred concen-trated sulfuric acid (20 cm') and the mixture was stirred for 4 min then poured onto ice (1 50 g). The organic layer was separ- ated and the aqueous phase was extracted with dichlorometh- ane (3 x 50 cm'). The combined organic layers were washed with water (2 x 200 cm'), dried over anhydrous sodium sulfate, filtered and evaporated to dryness.The residue was chromato- graphed over silica (Type 9385) eluting with dichloromethane to yield a major polar brown band which afforded on evapor- ation 2-~~~ctumido-3-nitro-5,lO,l5,20-~etrapl1mylporpliyrin26 (100 mg, 87%). A sample for analysis, recrystallised from a dichloromethane-hexane mixture, had mp 308-309 "C (Found: C, 76.5; H, 4.2; N, 11.3. C46H32Nh03 requires C, 77.1; H, 4.5; N, 11.7%); v,,li,x(Nujol)/cm-' 3350br (NH), 1690br (C=O) and 1520 (NO2); &,,,(CHCl,)/nm 436 (log E 5.22), 532 (4.10), 607 (3.53) and 675 (3.81); SH(400 MHz, CDCI,) -2.49 (2 H, s, inner NH), 1.72 (3 H, s, CH,), 7.42 (I H, br s, NHCOCH'), 7.68-7.89 (12 H, m, Ph H,,, and H,,), 8.17-8.32 (8 H, m, Ph H,,), 8.61 (2 H, s, 12-and I3-H), 8.76 (2 H, br s, P-pyrrolic H), 8.78 and 8.91 (2 H, ABq, JAB 5.0, P-pyrrolic H); in/z 735 (lo%), 734 (23), 733 (1 8), 732 (M + "CU + 2H -HNO,, 41), 730 (1 6), 688 (1 5), 687 (27), 673 (16), 672 (56), 671 (M + 2H -HNO,, loo), 670 (18), 669 (28), 659 (14), 656 (14), 644 (18), 633 (1 6), 632 (30), 631 (1 l), 630 (1 6), 629 (1 5), 628 (1 9), 614 (14), 61 3 (I 9) and 61 2 (27).2-(N-Formylacetamido)-3-nitro-5,10,15,2O-tetraphenylporphyrin A solution of 2-formamido-3-nitro-5,10,15,20-tetraphenyl-porphyrin 25 (61 mg, 0.087 mmol) in a mixture of pyridine (1 8 cm3) and acetic anhydride ( 18cm3) was heated under reflux for 1 h. On cooling, water (5 cm-') was carefully added dropwise over 30 min. The mixture was allowed to stand for 20 min then t Mass spectra of these free base porphyrins contain peaks due to sequestering of copper(ii) ions from the copper tubes of the spectrometer.mg, 0.337 mmol) was dissolved in tetrahydrofuran (250 cm'), aqueous potassium hydroxide (lo'%), 100 cm') was added and the two-phase system was stirred while heated at reflux for 18 h. The reaction mixture was separated and the organic phase washed with brine ( 100 cm'), dried over anhydrous sodium sul-fate, filtered and the solvent removed to yield a purple solid (384 mg). The crude product was purified by column chroma- tography over silica (Type 9385) with dichloromethane as the eluent to yield a purple solid (1 63 mg, 72%). The product was recrystallised from dichloromethane-methanol to give 2-utnino-3-nitro-5,10,15,20-t~truplic.n~~lpo~pli~vrin28 as purple crystals, mp 305-308 "C (dec.) (Found: C, 78.I; H, 4.3; N, 12.35. C,,H,,,N60, requires C, 78.3; H, 4.5; N, 12.5%); v,,lx(CHCl,)/ cm-' 3485w, 3346w, 3007w, 161 Is, 1598m, 1550m, 1536m, 1507m, 1475m, 1443m, 1420s, 1369m, 1348m, 1300m, 1282m, 1138m, 11 1 lm, 1074m, 1032m, 1002m and 965m; hl,,,,,(CHCI,)/ nm 264sh (log E 4.20), 31 1 (4.26), 329sh (4.24), 439 (5.19), 493sh (3.63), 535 (4.18), 559 (3.80), 574sh (3.89), 594sh (3.63), 610 (3.78), 649sh (3.03) and 671 (3.39); ni/z 629 (M -NO,, 1OO(%). Attempted reduction of (2-amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrinatolpalladium(~~)18 [2-Amino-3-nitr0-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinato]palladium(rr) 18 (73.1 mg, 0.060 mmol) and lo'%, palladium on carbon (52.4 mg) were suspended in a dichloromethane-methanol mixture (4: 1, 8 cm') and purged with nitrogen.Sodium borohydride (56.3 mg, 1.49 mmol) was added in small portions over a 10 min period and the mixture stirred in the dark under nitrogen for 30 min. The mixture was evaporated to dryness, taken up in dichloromethane and filtered through a plug of silica (Type 7734). TLC analysis of the filtrate showed a red band slightly more polar than the starting material. Allowing the solution to stand over air for several rnin caused the solution to change from a red to a green colour. The formation of a red band, which was more polar than the start- ing material, was observed by TLC analysis.The mixture was evaporated to dryness. TLC analysis of the solid after it had J: Chem Soc., Perkin Trans. I, 1996 2683 been allowed to stand overnight showed a large number of bands, all more polar than the starting material. 15,10,15,20-Tetrakis(3,5-di-tevt-b~tyIpheny1)-2~,2~-diphenyl-pyrazinol2,3-b)porphyrinatolzinc(11)31 [2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinato]zinc(~r) 16 (72.8 mg, 0.061 mmol) and lo'%, palladium on carbon (65.6 mg) were suspended in a dichloromethane-methanol mixture (4: I, 8 cm') and purged with nitrogen. Sodium borohydride (67.7 nig, 1.79 mmol) was added in small portions over a 10 min period and the mixture stirred in the dark under nitrogen for 45 min.The mixture was evaporated to dryness, taken up in dichloromethane, filtered through silica (Type 9385) and evaporated to dryness. A mix- ture of the residue and benzil (18.9 mg, 0.090 mmol) was dis- solved in dichloromethane (4 cm') and stirred at room temper- ature in the dark for 20 h. The mixture was evaporated to dry- ness and the residue purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 1 :4). The major red band was collected and evaporated to dryness to give [5,10,15,20-tetrukis(3,5-di-tert-b~rtvlp/ienyl)-2',2~-diplien~vl-pyru~i~~o[2,3-blporp/iyrin~lto]=inc.(lr)31 (52 mg, 64%) as a red amorphous powder, mp > 300 "C (Found: C, 79.1; H, 7.75; N, 5.9.C,,HItr,N,Zn + 0.5CH2Cl, requires C, 79.15; H, 7.4; N, 6.1(!A); v,,,,,(Nujol)/cm-' 1592, 1344, 1297, 1247, 1224, 1 174, 1067, 1002, 937, 926 and 899; iLn,,,(CHCl,)/nm 334 (log c 4.38), 388 (4.51), 439 (5.29), 487 (3.88), 512 (3.85), 559 (4.39) and 595 (3.76); SH(400 MHz, CDCI,) 1.39 (36 H, s, tert-butyl H), 1.53 (36 H, s, tert-butyl H), 7.21-7.33 (6 H, m, Ph H), 7.36-7.40 (4 H, m, Ph H), 7.79 (2 H, t, J 1.8, aryl H,,), 7.85 (2 H, t, J 1.8, aryl H,J, 8.00 (4 H, d, J 1.8, aryl H,,), 8.10 (4 H, d, J 1.8, aryl H,,), 8.95 (2 H, s, 12- and 13-H), 8.97 and 9.01 (4 H, AA'XX', J4.7, 7-, 8-, 17-and 18-H); nik (MALDI-TOF) 1331 (M + H requires 1330). ~5,10,15,20-Tetrakis(3,5-di-tevt-b~tyIpheny1)-2~,2~,2~,2~-tetra-hydroquinoxalino~2,3b~porphyrinato~zinc(11)32 [ZAmino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinato]zinc(~r)16 (81 mg, 0.068 mmol) was reduced with sodium borohydride in the presence of a 10% palladium on carbon catalyst following a similar procedure to that described above.A solution of the crude product and cyclohexane-l,2- dione (26 mg, 0.238 mmol) in dichloromethane (6 cm') was stirred in the dark for 3.5 h and evaporated to dryness. The residue was purified by chromatography over silica (Type 9385, dichloromethane-ligh t petroleum, 1 :2). The major purple-red band collected and evaporated to dryness to give [5,10,15,20- carbon catalyst following a similar procedure to that described above. A suspension of the crude product and o-benzoquinone (1 5 mg, 0.139 mmol) in dichloromethane (5 cm') was stirred for 3 days.The crude product was evaporated to dryness and the residue purified by chromatography over silica (Type 9385, dichloromethane-light petroleum, 2 : 1). The first green band was collected and evaporated to dryness to give { 5,10,15,20-tetrakis(3,5-di-tcrt-butylphenyl)quino~a~ino~~,3-b~porphy~ii-ato).zinc(II)33 (3.6 mg, 4%) as a purple amorphous powder which co-eluted with, and had an identical 'H NMR spectrum to, an authentic sample." Acknowledgements This research was funded by an Australian Research Council research grant to M. J. C. We thank the Australian Government for the award of a Post-graduate research scholarship to L. G. K. and C. S. S. References 1 M.J. Crossley and I? L. Burn, J Cheni. Soc.. Cheni. Cuniniun., 1987, 39. 2 M. J. Crossley and P. L. Burn, J. Clzeiti. Soc., Cheni. Coliiniun., 1991, 1569. 3 M. J. Crossley, P. L. Burn, S. J. Langford and J. K. Prashar. J Chmn. Soc., Chein. Coniiiiwi.. 1995, 192 1. 4 M. J. Crossley, L. J. Govenlock and J. K. Prashar, J Chem Suc., Chem. Cumnirm., 1995, 2379. 5 J. E. Baldwin, M. J. Crossley and J. DeBernardis, Tetruheilrun,1982, 38, 685. 6 M. J. Crossley, T. W. Hambley, L. G. Mackay, A. C. Try and R. Walton, J Chein. Suc., Cheiii. Conimm., 1995, 1077. 7 M. M. Catalano, M. J. Crossley and L. G. King, J Cheni. Suc., Cheiii. Coiiiiiiun., 1984, 1537. 8 M. J. Crossley and L. G. King, J. Chan. Suc., Perkir? Truns. f, 1996, 1251. 9 M.M. Catalano, M. J. Crossley, M. M. Harding and L. G. King, J Cheiii. Suc., Chenz. Cuiiiiwiz., 1984, 1535. 10 M. J. Crossley and L. G. King, J Chm. Suc., Cheni. Cunimitn., 1984.920. 1 1 L. J. Bellamy, The Infru-red Sp~ctruof Cunzples Mukecules, 3rd edn., Chapman and Hall, London, 1975. p. 294. 12 D. A. Ben-Efraim, in The Cheitzistry of Diiizuniuni tiizcl Dim) Gruups. ed. S. Patai, Wiley, Chichester, 1978, p. 149. 13 B. Houston and T. B. Johnson, J Am. Chcm. Soc.. 1925, 47, 301 1. 14 A. Aziz, M. Hoharum and M. I. Khalil, J. Cli~ii.SOL..,Fiirrrcluy Truns. I. 198I, 77. 1737. 15 T. F. Redmond and B. B. Wayland, J Php. Chcni., 1968, 72, 1626. 16 J.-H. Fuhrhop, in The Purphjlrins, ed. D. Dolphin. Academic Press, New York. 1978, vol. 11, p. 131./ino[2,3-blporp/i~rinncrto]=inL.(lr)32 (59 mg, 70%) as a purple-red amorphous powder. A sample for analysis, recrystallised from a dichloromethane-methanol mixture, had mp > 300 "C (Found: C, 80.1; H, 8.2; N, 6.5. C,,H,,N,Zn requires C, 79.9; H, 8.0; N, 6.8%); vn,,,,(CHCl,)lcm-' 2964, 2863, 1680, 1593, 1477, 1462, 1427, 1393, 1363, 1340, 1323, 1296, 1248, 1147, 1075, 1041, 1002, 938, 908, 882, and 820; iL,,,(CHCl,)lnm 296 (log e 4.23), 310sh (4.23), 378 (4.20), 41 1 (4.65), 430 (5.56), 489 (3.50), 516 (3.65), 554 (4.28) and 591 (3.82); S,(400 MHz, CDCI,) 1.40 (36 H, s, trzrt-butyl H), 1.45 (36 H, s, tert-butyl H), 1.87-1.93 (4 H, m,CH,),2.78-2.83 (4 H, m, CH,), 7.71 (2 H, t, J 1.8, aryl H,,), 7.73 (2 H, t, J 1.8, aryl H,,), 7.83 (4 H, d, J 1.8, aryl H,,), 8.02 (4 H, d, J 1.8, aryl H,,), 8.87 (2 H, s, 12- and 13-H), 8.93 and 8.95 (4 H, ABq, J4.7,7-, 8-, 17- and 18-H); id1 (MALDI-TOF) 1232 (M + H requires 1233). I5,10,15,20-Tetrakis(3,5-di-tert-butylphenyl)quinoxalino[2,3-b[-porphyrinatolzinc(1 I)33 [2-Amino-3-nitro-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinato]zinc(~r)16 (81 mg, 0.068 mmol) was reduced with sodium borohydride in the presence of a lO'% palladium on 2684 J Chetn. SOC.,Perkin Trans. I, 1996 tc.trukis( 3,5-d- tert-butylphenyl)-2',2' ,24,25-tetru/i~~~royzlino,~u-17 H. K. Hombrecher, V. M. Gherdan, S. Ohm, J. A. S. Cavaleiro, M. P. M. S. Neves and M. F. Condesso, Terralietlrun,1993,49, 8569. 18 R. A. Binstead, M. J. Crossley and N. S. Hush, Iizorg Clic~ii~,1991, 30, 1259. 19 K. M. Smith, Purphyrins arzti Metallo/70rpl~~lrii~.~, Elsevier, Amster- dam, 1975, p. 3. 20 K.H. Felton, in The Purpliyr~in.~,ed. D. Dolphin, Academic Press, New York, 1978, vol. V, p. 53. 21 D. G. Davis, in The Pur.phjv+zs, ed. D. Dolphin, Academic Press. New York, 1978, vol. V, p. 127. 22 M. J. Crossley, L. G. King and S. M. Pyke, Tcrrulii~clruiz.1987, 43. 4569. 23 M. J. Crossley. J. J. Gosper and L. G. King, Tetrdzerlroii LCII.,1988. 29, 1597. 24 M. J. Crossley, P. L. Burn, S. J. Langford, S. M. Pyke and A. G. Stark. J Cheni. Suc., Chayi. Conimuii., 1991, 1567. 25 M. J. Crossley and L. G. King, J Org Cheni., 1993, 58, 4370. 26 M. J. Crossley, M. M. Harding and C. W. Tansey. J. 0i.g. Ctieitz., 1994,59,4433. 27 M. J. Crossley, P. L. Burn, S. S. Chew, E B. Cuttance and I. A. Newsom, J Cheiiz. Suc., Clieiii. Coiiuiiwz.. 1991. 1564. hrper 6/04245G Received 1 7th Jim 1996 Accepted 9th Aiigirst 1996
ISSN:1472-7781
DOI:10.1039/P19960002675
出版商:RSC
年代:1996
数据来源: RSC