Synthesis of isomeric angularly annealed dinaphthoporphyrin systems: Examination of the relative positioning and orientation of ring fusion as factors influencing the porphyrin chromophore

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin

Systems: Examination of the Relative Positioning and Orientation

of Ring Fusion as Factors Influencing the Porphyrin

Chromophore^†

Jerad M. Manley, Tracy J. Roper, and Timothy D. Lash*

Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160

tdlash@ilstu.edu

Received September 24, 2004

Porphyrins built up from two naphtho[1,2-c]pyrrole subunits and two â-substituted pyrroles can

produce five isomeric dinaphthoporphyrin systems. To gain insights into the effects of ring fusion

on extended porphyrin chromophores, all five of these systems were synthesized in isomerically

pure form. In four of these syntheses, dihydronaphthopyrroles were used to introduce one or both

of the naphthalene subunits, and dehydrogenation with DDQ in refluxing toluene later produced

the fully conjugated systems. Naphthopyrroles were also prepared by reacting isocyanoacetate esters

with 1-nitronaphthalene in the presence of a phosphazene base. These compounds proved to be

less stable than their dihydronaphthopyrrolic counterparts but could still be utilized in these

synthetic studies. Three isomeric adj-dinaphthoporphyrin systems were prepared using the

MacDonald “2 + 2” condensation or by the cyclization of a,c-biladiene intermediates with copper-

(II) chloride or AgIO₃-Zn(OAc)₂. A dinaphthoporphyrin with two naphthalene units pointing toward

one another could only be obtained in low yields due to a combination of stability and steric factors,

but the other two adj-difused systems were isolated in good overall yields. However, the final

dehydrogenation step occurred in moderate yields (50-60%) and could only be performed when

the porphyrins bore propionate ester side chains that produced sufficient solubility in organic

solvents. The two related opp-dinaphthoporphyrins were synthesized by a “head-to-tail” self-

condensation of a dipyrrylmethane aldehyde, or a “3 + 1” synthesis using a tripyrrane intermediate

bearing two fused dihydronaphthalene moieties, in excellent yields. In both cases, a final

dehydrogenation step was required, but the opp-dinaphthoporphyrins were consistently formed in

virtually quantitative yields. The opp-dinaphthoporphyrin series gave UV-vis spectra with relatively

strong Soret bands at 425 nm, and the visible region was dominated by an unusually strong Q-band

III. The adj-dinaphthoporphyrins produced broader less intense Soret bands and four well-defined

Q-bands, including a relatively strong absorption at 645 nm. However, the relative orientation of

the naphthalene rings had no significant effects on these spectra. On the other hand, the dications

produced in TFA-chloroform solutions showed more discrimination between the individual porphyrin

systems, and the metallo derivatives also displayed significant variations in their electronic

absorption spectra.

Introduction

science to medicine.^1,2In some cases, ring fusion results

in highly red-shifted chromophores that could have value

in photodynamic therapy.^3,4Other structural units are

being utilized to act as bridging units in the production

of nanoscale systems, including molecular wires and

arrays.^5,6Porphyrins with fused benzene or naphthalene

rings are structurally analogous to the phthalocyanines

Porphyrins with extended chromophores are being

investigated for applications that range from material

* To whom correspondence should be addressed.

^†Porphyrins with Exocyclic Rings. 17. For part 16, see: Lash, T.

D.; Werner, T. M.; Thompson, M. L.; Manley, J. M. J. Org. Chem. 2001,

66, 3152-3159.

Published on Web 12/31/2004

874

J. Org. Chem. 2005, 70, 874-891

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

CHART 1

us to develop syntheses of porphyrins fused to other types

of aromatic rings so that we could investigate the

influence of these different ring systems on the electronic

absorption spectra.^1-3,15-17Not surprisingly, porphyrins

with two or more fused units showed larger effects, and

for the doubly fused structures substantial differences

were observed between the oppositely and adjacently di-

fused systems.^15a,c,16bTo date, little theoretical work has

been conducted on these important extended porphyrin

structures.¹⁸Phthalocyanine-type systems have been

more thoroughly studied, and the differences between

adjacent versus opposite diaromatic ring fused tetraaza-

porphyrin derivatives have been probed by synthesis,

spectroscopy, and molecular orbital calculations.¹⁹In

addition to the relative positioning of the fused rings, the

orientation of asymmetrical units can also be a factor.

To gain a better understanding of these factors, a series

of dinaphthoporphyrins related to naphthoporphyrin 3

were targeted for synthesis (Chart 2).^20-22When two

angularly annealed naphthalene rings are present, five

different structural types are possible (A-E, Chart 2).²³

Three of these dinaphthoporphyrins have adjacent ring

fusion (adj-dinaphthoporphyrins), while the other two

feature naphthalenes at the opposite positions (opp-

dinaphthoporphyrins). The synthesis of all five of these

isomeric systems proved to be a considerable challenge

that required the application of several different meth-

odologies.²⁴In this paper, the synthesis and spectroscopic

characterization of all five structural types of dinaph-

(1a) and naphthocyanines (e.g., 2), families of tetraaza-

porphyrinoids that show a wide range of industrial

applications (Chart 1). Although mono-, di-, and tetra-

benzoporphyrins 1b are presently receiving considerable

attention,^8-11far less work has been carried out on the

naphthoporphyrins.^12,13In earlier work, we reported the

first synthesis of a naphtho[1,2-b]porphyrin 3 for use as

a standard for geochemical studies.^8a,14Porphyrin 3

showed a distinctive UV-vis spectrum, but only small

bathochromic shifts were noted.¹⁴This observation led

(13) For examples of porphyrins with porphyrins with four angularly

annealed naphthalenes, see: (a) Kopranenkov, V. N.; Vorotnikov, A.

M.; Dashkevich, S. N.; Luk’yanets, E. A. J. Gen.Chem. USSR 1985,

55, 803. (b) Vorotnikov, A. M.; Krasnokut-skii, S. N.; Braude, E. V.;

Kopranenkov, V. N. Chem. Heterocyclic Comp. 1990, 26, 1314. (c) Ono,

N.; Hironaga, H.; Ono, K.; Kaneko, S.; Murashima, T.; Ueda, T.;

Tsukamura, C.; Ogawa, T. J. Chem. Soc., Perkin Trans. 1 1996, 417.

Although these porphyrins can exist in four isomeric forms, some

preparations appear to favor one specific isomer over the others.^13b,c

(14) Lash, T. D.; Denny, C. P. Tetrahedron 1995, 51, 59.

(15) (a) Lash, T. D.; Novak, B. H. Tetrahedron Lett. 1995, 36, 4381.

(b) Lash, T. D.; Novak, B. H. Angew. Chem., Int. Ed. Engl. 1995, 34,

683. (c) Novak, B. H.; Lash, T. D. J. Org. Chem. 1998, 63, 3998.

(16) (a) Chandrasekar, P.; Lash, T. D. Tetrahedron Lett. 1996, 37,

4873. (b) Lash, T. D.; Chandrasekar, P.; Osuma, A. T.; Chaney, S. T.;

Spence, J. D. J. Org. Chem. 1998, 63, 3, 8455.

(17) (a) Lash, T. D.; Wijesinghe, C.; Osuma, A. T.; Patel, J. R.

Tetrahedron Lett. 1997, 38, 2031. (b) Lash, T. D.; Werner, T. M.;

Thompson, M. L.; Manley, J. M. J. Org. Chem. 2001, 66, 3152. (c) Lash,

T. D.; Gandhi, V. J. Org. Chem. 2000, 65, 8020.

(18) Kobayashi, N.; Konami, H. J. Porphyrins Phthalocyanines 2001,

5, 233.

(19) (a) Kobayashi, N.; Miwa, H.; Nemykin, V. N. J. Am. Chem. Soc.

2002, 124, 8007. (b) Kobayashi, N.; Fukuda, T. J. Am. Chem. Soc. 2002,

124, 8021.

(20) Preliminary communication: Lash, T. D.; Roper, T. J. Tetra-

hedron Lett. 1994, 35, 7715.

(21) These results were presented, in part, at the following meet-

ings: 85th Annual Meeting of the Illinois State Academy of Science,

Springfield, IL, Oct 1992 (Roper, T. J.; Denny, C. P.; Lash, T. D. Trans.

Illinois State Acad. Sci. 1992, 85 (Suppl.), 46, Abstract No. 45); 207th

National ACS Meeting, San Diego, CA, March 1994 (Lash, T. D.; Roper,

T. J.; Novak, B. H.; Lin, Y. Book of Abstracts, ORGN 154); 34th

Midwest Regional ACS Meeting, Quincy, IL, Oct. 1999 (Manley, J. M.;

Lash, T. D. Program and Abstracts, Abstract No. 164); 219th National

ACS Meeting, San Francisco, CA, March 2000 (Manley, J. M.; Lash,

T. D. Book of Abstracts, ORGN 357).

(22) Results taken, in part, from: Manley, J. M. M.S. Thesis, Illinois

State University, 2001.

(23) Series A-E were assigned in the order that they were synthe-

sized, which also provides the most logical sequence for discussing the

syntheses of these five dinaphthoporphyrin systems.

(1) Lash, T. D. In The Porphyrin Handbook; Kadish, K. M., Smith,

K. M., Guilard, R., Eds.; Academic Press: San Diego, 2000; Vol. 2, pp

125-199.

(2) Lash, T. D. J. Porphyrins Phthalocyanines 2001, 5, 267.

(3) (a) Lash, T. D.; Chandrasekar, P. J. Am. Chem. Soc. 1996, 118,

8767. (b) Spence, J. D.; Lash, T. D. J. Org. Chem. 2000, 65, 1530.

(4) (a) Pandey, R. K.; Zheng, G. In The Porphyrin Handbook; Kadish,

K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego,

2000; Vol. 6, pp 157-230. (b) Bonnett, R. Chem. Soc. Rev. 1995, 24,

19.

(5) (a) Crossley, M. J.; Burn, P. L. J. Chem Soc., Chem. Commun.

1991, 1569. (b) Crossley, M. J.; Govenlock, L. J.; Prashar, J. K. J. Chem.

Soc., Chem. Commun. 1995, 2379. (c) Crossley, M. J.; Prashar, J. K.

Tetrahedron Lett. 1997, 38, 6751.

(6) (a) Jaquinod, L.; Siri, O.; Khoury, R. G.; Smith, K. M. Chem.

Commun. 1998, 1261. (b) Vicente, M. G. H.; Cancilla, M. T.; Lebrilla,

C. B.; Smith, K. M. Chem. Commun. 1998, 2355.

(7) Phthalocyanines: Properties and Applications; Leznoff, C. C., Ed.;

VCH Publishers: New York, 1990-1996; Vols. 1-4.

(8) (a) Lash, T. D. Energy Fuels 1993, 7, 166. (b) May, D. A., Jr.;

Lash, T. D. J. Org. Chem. 1992, 57, 4820. (c) Boggess, J. M.;

Czernuszewicz, R. S.; Lash, T. D. Org. Geochem. 2002, 33, 1111.

(9) (a) Clezy, P. S.; Fookes, C. J. R.; Mirza, A. H. Aust. J. Chem.

1977, 30, 1337. (b) Clezy, P. S.; Mirza, A. H. Aust. J. Chem. 1982, 35,

197. (c) Clezy, P. S.; Leung, C. W. F. Aust. J. Chem. 1993, 46, 1705.

(10) (a) Bonnett, R.; McManus, K. A. J. Chem. Soc., Perkin Trans.

1 1996, 2461. (b) Vicente, M. G. H.; Tome, A. C.; Walter, A.; Cavaleiro,

J. A. S. Tetrahedron Lett. 1997, 38, 3639. (c) Vicente, M. G. H.;

Jaquinod, L.; Khoury, R. G.; Madrona, A. Y.; Smith, K. M. Tetrahedron

Lett. 1999, 40, 8763. (d) Ito, S.; Ochi, N.; Murashima, T.; Uno, H.; Ono,

N. Heterocycles 2000, 52, 399.

(11) Finikova, O. S.; Cheprakov, A. V.; Beletskaya, I. P.; Carroll, P.

J.; Vinogradov, S. A. J. Org. Chem. 2004, 69, 522 and references

therein.

(12) For examples of naphtho[2,3-b]porphyrins and related linearly

annealed systems, see: (a) Kopranenkov, V. N.; Vorotnikov, A. M.;

Luk’yanets, E. A. J. Gen. Chem. USSR 1979, 49, 2467. (b) Rein, M.;

Hanack, M. Chem. Ber. 1988, 121, 1601. (c) Kobayashi, N.; Nevin, W.

A.; Mizunuma, S.; Awaji, H.; Yamaguchi, M. Chem. Phys. Lett. 1993,

205, 51. (d) Tome´, A. C.; Lacerdo, P. S. S.; Neves, M. G. P. M. S.;

Cavaleiro, J. A. S. Chem. Commun. 1997, 1199. (e) Ito, S.; Ochi, N.;

Uno, H.; Murashima, T.; Ono, N. Chem. Commun. 2000, 893. (f)

Finikova, O. S.; Cheprakov, A. V.; Carroll, P. J.; Vinogradov, S. A. J.

Org. Chem. 2003, 68, 7517.

(24) For recent reviews on porphyrin synthesis, see: (a) Smith, K.

M. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard,

R., Eds.; Academic Press: San Diego, 2000; Vol. 1, pp 1-43. (b) Smith,

K. M. J. Porphyrins Phthalocyanines 2000, 4, 319-324.

J. Org. Chem, Vol. 70, No. 3, 2005 875

Manley et al.

CHART 2. Dinaphthoporphyrins

SCHEME 1

presence of zinc acetate, gave porphyrin 8 in 44% yield.¹⁴

Alternatively, reaction of 7b with 2 equiv of pyrrole

aldehyde 10a in the presence of HBr gave a,c-biladiene

11 and subsequent cyclization with copper(II) chloride

in DMF, followed by demetalation with H₂SO₄-TFA,

gave 8 in 25% yield for the two steps combined.¹⁴

Dehydrogenation with DDQ then gave the required

naphtho[1,2-b]porphyrin 3 (Scheme 1).^14,26The success

of this strategy led us to adapt the principles used in the

synthesis of 3 to prepare the type A and type B dinaph-

thoporphyrin systems.²⁰

Synthesis of Type A Dinaphthoporphyrins. The

synthesis of the type A adj-dinaphthoporphyrin system

was accomplished by using the a,c-biladiene strategy²⁷

(Scheme 2). Although the final step of the dehydrogena-

tion strategy had been satisfactory, we also investigated

the use of naphthopyrrole intermediates as well. Dihy-

dronaphthopyrrole 4a was found to be easily dehydro-

genated with 10% Pd/C in refluxing xylenes to give

naphthopyrrole 12 in excellent yield, but this compound

proved to be too reactive to be used as an intermediate

for naphthoporphyrin synthesis. Attempts to saponify or

transesterify the ester goup for 12 led to decomposition,

while reactions with lead tetraacetate afforded complex

mixtures. However, precursor 4a is far more robust and

thoporphyrins and their nickel(II), copper(II), and zinc

metalloderivatives are reported. A preliminary com-

munication on the type A and B systems was published

some time ago,²⁰but syntheses of the type C-E systems

were accomplished more recently.^21,22

Results and Discussion

The synthesis of dinaphthoporphyrins requires the

availability of suitably substituted pyrrolic precursors

that can introduce the naphthalene units. As isoindole

structures are relatively unstable and poorly suited for

porphyrin synthesis,²⁵we initially favored the use of

dihydronaphthopyrroles rather than the fully unsatur-

ated systems (Chart 1) that might not stand up to the

reaction conditions.^14,20In addition, a fused naphthalene

unit could significantly alter the reactivity of the pyrrolic

intermediates, and this might interfere with macrocycle

formation. In the earlier synthesis of a mononaphtho-

porphyrin 3, dihydronaphthopyrrole esters 4 were used

as the key intermediates (Scheme 1).¹⁴Condensation of

diethyl aminomalonate with 2-acetyl-1-tetralone in acetic

acid gave the ethyl ester 4a, and this is transesterified

with sodium benzyloxide in benzyl alcohol to give the

benzyl ester 4b.¹⁴Further reaction with lead tetraacetate

afforded the acetoxymethyl derivative 5 and this reacted

with R-unsubstituted pyrrole 6 to give dipyrrylmethane

7a.¹⁴Cleavage of the benzyl esters with hydrogen over

palladium-charcoal gave the corresponding dicarboxylic

acid 7b, and this was taken on via two different routes

to the dihydronaphthoporphyrin 8.¹⁴Reaction of 7b with

dipyrrylmethane dialdehyde 9a in the presence of p-

toluenesulfonic acid, followed by air oxidation in the

(26) Although the dehydrogenation of tetrahydrobenzoporphyrins

to benzoporphyrins, or the related oxidation of dihydronaphthopor-

phyrins to naphthoporphyrins, using DDQ had not been noted prior

to our studies,^8adehydrogenation of a tetracyclohexenotetraazapor-

phyrin to phthalocyanine (and/or intermediary species) with DDQ in

o-dichlorobenzene had been reported many years earlier. See: Ficken,

G. E.; Linstead, R. P.; Stephen, E.; Whalley, M. J. Chem. Soc. 1958,

3879. See also: Ficken, G. E.; Linstead, R. P. J. Chem. Soc. 1952, 4846.

(27) Smith, K. M. In The Porphyrin Handbook; Kadish, K. M., Smith,

K. M., Guilard, R., Eds.; Academic Press: San Diego, 2000; Vol. 1, pp

119-148.

(25) Remy, D. E. Tetrahedron Lett. 1983, 24, 1451.

876 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

SCHEME 2

SCHEME 3

synthesis required a dehydrogenation with DDQ in a

refluxing solvent such as toluene.^8aUnfortunately, the

poor solubility of 17a in organic solvents made this

transformation difficult to accomplish, and attempts to

dehydrogenate diethylporphyrin 17a gave rise to the

formation of inseparable mixtures. However, the dipro-

pionate ester porphyrin 17b proved to be far more soluble

and this was oxidized with DDQ in refluxing toluene to

give dinaphthoporphyrin 18a in 60% yield. The porphyrin

was fully characterized and three metallo derivatives

were also prepared. Hence, 18a was reacted with nickel-

(II), copper(II), and zinc acetate in DMF to give the

corresponding metal complexes 18b-d.

Synthesis of Type B Dinaphthoporphyrins. The

second targeted dinaphthoporphyrin system could not be

synthesized by the foregoing route, but this centrosym-

metric structure is accessible via a variation on the

MacDonald “2 + 2” condensation^30,31(Scheme 3). This

requires the availability of dipyrrylmethanes 19 that can

undergo head-to-tail self-condensations.³¹The previously

synthesized acetoxymethylpyrrole 5¹⁴was reacted with

R-unsubsituted pyrrole tert-butyl esters 20 in the pres-

could be saponified and decarboxylated with sodium

hydroxide in ethylene glycol at 180 °C. The resulting

R-unsubstitued pyrrole 12 was immediately treated with

trimethyl orthoformate and TFA to generate the corre-

sponding aldehyde 14. Two equivalents of 14 was reacted

with HBr and dipyrrylmethane dicarboxylic acid 15a to

give the a,c-biladiene 16a, while reaction of 14 with 15b

afforded the related tetrapyrrole 16b. Cyclization of a,c-

biladienes 16 with copper(II) chloride in DMF at room

temperature,^28,29followed by demetalation with 15%

sulfuric acid in TFA, gave the tetrahydrodinaphthopor-

phyrins 17 in 34-38% yield. The final step in the

(28) Grigg, R.; Johnson, A. W.; Kenyon, R.; Math, V. B.; Richardson,

K. J. Chem. Soc. C 1969, 176.

(29) Smith, K. M.; Minnetian, O. M. J. Chem. Soc., Perkin Trans. 1

1986, 277.

(30) Arsenault, G. P.; Bullock, E.; MacDonald, S. F. J. Am. Chem.

Soc. 1960, 82, 4384.

(31) (a) Jackson, A. H.; Kenner, G. W.; Wass, J. J. Chem. Soc., Perkin

Trans. 1 1972, 1475. (b) Lash, T. D. Tetrahedron 1998, 54, 359.

J. Org. Chem, Vol. 70, No. 3, 2005 877

Manley et al.

ence of Montmorillonite clay in dichloromethane³²to

afford the corresponding mixed ester dipyrrylmethanes

21. These were purified by column chromatography but

could not be be induced to crystallize. This property is

commonly associated with dipyrrylmethanes having mixed

terminal tert-butyl and benzyl esters.³²However, these

compounds could be taken on in crude form and the tert-

butyl esters cleaved by treatment with TFA. Further

reaction with trimethyl orthoformate-TFA gave the

corresponding aldehydes 22 in good yields. The formyl

derivatives 22 were easily recrystallized and fully char-

acterized. Cleavage of the benzyl ester protective groups

by hydrogenolysis over 10% palladium-charcoal gave the

required carboxylic acids 19 in quantitative yields. These

underwent self-condensation with p-toluenesulfonic acid

in methanol-dichloromethane to give the porphodi-

methene intermediates 23. Subsequent addition of zinc

acetate and air oxidation afforded porphyrins 24 in 27-

36% yield. The alkyl substituted porphyrins 24a and 24b

proved to be too insoluble to take on to the fully

conjugated dinaphthoporphyrin system. However, treat-

ment of the dipropionate ester 24c with 2 equiv of DDQ

in refluxing toluene gave the opp-dinaphthoporphyrin

25a in virtually quantitative yield. The related nickel-

(II), copper(II), and zinc derivatives 25b-d were also

prepared and characterized.

SCHEME 4

Synthesis of Type C Dinaphthoporphyrins. The

isomeric opp-dinaphthoporphyrin system “type C” has a

different symmetry element and cannot be synthesized

by the procedures described for the type A or type B

systems. However, this system is readily accessible using

the “3 + 1” variant on the MacDonald condensation^33-35

(Scheme 4). Two equivalents of acetoxymethylpyrrole 5

was condensed with 3,4-diethylpyrrole under nitrogen in

refluxing acetic acid-ethanol^34,36to give the novel tripyr-

rane 26a in 73% yield.

The benzyl ester moieties were cleaved with hydrogen

over palladium-charcoal to give the related dicarboxylic

acid 26b (quantitative), and this can be reacted with

pyrrole dialdehyde 27 in TFA-dichloromethane and

oxidized with DDQ under conventional conditions³⁴to

give the tetrahydrodinaphthoporphyrin 28 in 51% yield.

This convergent route is particularly efficient and could

equally well be used in the synthesis of ring fused

porphyrin analogue systems.³⁷As was the case for the

previous opp-diannelated system, dehydrogenation of 28

with 2 equiv of DDQ in refluxing toluene occurred

smoothly to give a virtually quantitative yield of the opp-

dinaphthoporphyrin 29a. Again, the new porphyrin

system was metalated with nickel(II), copper(II) or zinc

acetate to give the related metalloporphyrins 29b-d

(Scheme 4).

Synthesis of Type D Dinaphthoporphyrins. The

“type D” adj-dinaphthoporphyrin system is the least

symmetrical of the series and requires the synthesis of

an asymmetrical dipyrrylmethane intermediate 30

(Scheme 5). This in turn could be taken on, at least in

principle, using the a,c-biladiene or MacDonald “2 + 2”

strategies. Dipyrrylmethane 30 has two naphthalene

units (one or both could be in the reduced form), but these

have different orientations relative to the pyrrole ester

groups and this means that a new naphthopyrrole

precursor is required. Although we had avoided the use

of fully unsaturated naphtho[1,2-c]pyrroles in our initial

studies, superior routes to this system were subsequently

developed.³⁸In addition, it turned out that our qualms

about the stability of these compounds were only partly

justified. In the Barton-Zard pyrrole synthesis, nitroal-

kenes react with isocyanoacetate esters in the presence

of a non-nucleophilic base to give pyrrole esters.^39,40This

method has been extended to the reaction of nitroaro-

matic compounds, such as nitrophenanthrene, with iso-

cyanoacetates to give c-annelated pyrroles.⁴¹1-Nitronaph-

thalene (31) reacted with ethyl isocyanoacetate (32a) in

(38) Lash, T. D.; Thompson, M. L.; Werner, T. M.; Spence, J. D.

Synlett 2000, 213.

(39) (a) Barton, D. H. R.; Zard, S. Z. J. Chem. Soc., Chem. Commun.

1985, 1098. (b) Barton, D. H. R.; Kervagoret, J.; Zard, S. Z. Tetrahedron

1990, 46, 7587.

(32) Jackson, A. H.; Pandey, R. K.; Rao, K. R. N.; Roberts, E.

Tetrahedron Lett. 1985, 26, 793.

(33) Lash, T. D. Chem. Eur. J. 1996, 2, 1197.

(34) (a) Lin, Y.; Lash, T. D. Tetrahedron Lett. 1995, 36, 9441. (b)

Lash, T. D. J. Porphyrins Phthalocyanines 1997, 1, 29.

(35) (a) Boudif, A.; Momenteau, M. J. Chem. Soc., Perkin Trans. 1

1996, 1235. (b) Sessler, J. L.; Genge, J. W.; Urbach, A.; Sanson, P.

Synlett 1996, 187.

(40) (a) Lash, T. D.; Bellettini, J. R.; Bastian, J. A.; Couch, K. B.

Synthesis 1994, 170. (b) Drinan, M. A.; Lash, T. D. J. Heterocycl. Chem.

1994, 31, 255. (c) Chen, S.; Lash, T. D. J. Heterocycl. Chem. 1997, 34,

273. (d) Ono, N.; Kawamura, H.; Bougauchi, M.; Maruyama, K.

Tetrahedron 1990, 46, 7483. (e) Burns, D. H.; Jabara, C. S.; Burden,

M. W. Synth. Commun. 1995, 25, 379. (f) Dumoulin, H.; Rault, S.;

Robba, M. J. Heterocycl. Chem. 1996, 33, 255. (g) Adamczyk, M.; Reddy,

R. E. Tetrahedron 1996, 52, 14689.

(36) Sessler, J. L.; Johnson, M. R.; Lynch, V. J. Org. Chem. 1987,

52, 4394.

(37) (a) Lash, T. D. Angew. Chem., Int. Ed. Engl. 1995, 34, 2533.

(b) Lash, T. D.; Chaney, S. T. Chem. Eur. J. 1996, 2, 944. (c) Lash, T.

D.; Hayes, M. J.; Spence, J. D.; Muckey, M. A.; Ferrence, G. M.;

Szczepura, L. F. J. Org. Chem. 2002, 67, 4860.

(41) (a) Lash, T. D.; Novak, B. H.; Lin, Y. Tetrahedron Lett. 1994,

35, 2493. (b) Ono, N.; Hironaga, H.; Simizu, K.; Ono, K.; Kuwano, K.;

Ogawa, T. J. Chem. Soc., Chem. Commun. 1994, 1019.

878 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

SCHEME 5

hindered protonated phosphazene is less capable of ion

pairing interactions with enolate 35, and this factor is

believed to lead to the enhanced reactivity. A similar

argument has been used to rationalize the increased

effectiveness of Verkade’s superbase in some related

chemistry.⁴³Condensation of 31 with tert-butyl isocy-

anoacetate (32b) similarly afforded the naphthopyrrole

tert-butyl ester 33b in 37% yield. However, reaction of

31 with benzyl isocyanoacetate (32c) gave poor yields

(<10%) of the related naphthopyrrole 33c, and this result

made the use of a benzyl ester protective group at this

position impractical for these studies. As the tert-butyl

ester protective group is also compatible with these

investigations, 33b was reacted with acetoxymethyldihy-

dronaphthopyrrole 5 in acetic acid with a catalytic

amount of p-toluenesulfonic acid to give the mixed ester

dipyrrylmethane 30a in 58% yield. Hydrogenolysis over

10% Pd/C cleaved the benzyl ester unit to give the

corresponding carboxylic acid 30b. Treatment of 30b with

TFA for 10 min at room temperature cleaves the tert-

butyl ester group and smoothly decarboxylates the pyr-

role carboxylic acid units to give the R-unsubstituted

dipyrrylmethane 36. Initially, this intermediate was

taken on via an a,c-biladiene type route in an attempt

to generate the required dinaphthoporphyrin. Reaction

of 36 with pyrrole aldehyde 10b in the presence of HBr,

followed by precipitation with anhydrous diethyl ether,

gave a crude a,c-biladiene dihydrobromide salt 37 in 90%

yield. Although this material was not pure by NMR

spectroscopy, this type of compound is relatively unstable

in solution and attempts at purification leads to extensive

decomposition. Attempts to cyclize 37 with copper(II)

chloride in DMF gave low yields of impure porphyrin

products. Slightly better results were obtained using

silver iodate and zinc acetate in DMF and this produced

impure zinc porphyrins. Demetalation afforded the re-

lated porphyrin 34a, but this appeared to be contami-

nated with an isomeric species. Oligopyrrolic intermedi-

ates can undergo fragmentation-recombination reactions

that result in the formation of isomers,⁴⁴but it was

unclear whether this problem arose during a,c-biladiene

formation or during the cyclization procedure. As this

approach had been unsuccessful, an alternative Mac-

Donald “2 + 2” route was selected. Dipyrrylmethane 30b

was treated with TFA, as before, to give 36 and subse-

quent acid-catalyzed condensation with diformyldipyr-

rylmethane 9b and air oxidation in the presence of zinc

acetate gave the required isomerically pure dihydrodi-

naphthoporphyrin 38a in 37% yield. Under the same

conditions, 36 was reacted with 9c to give the related

porphyrin diester in 36% yield. The dibutyl porphyrin

38a was poorly soluble and did not give satisfactory

results for the dehydrogenation step. However, the di-

ester porphyrin 38b could be dehydrogenated with DDQ

in refluxing toluene to give the dinaphthoporphyrin 39a

in 53% yield. It is notable that the dehydrogenation steps

for the two adj-dinaphthoporphyrins (type A and D) gave

relatively modest results compared to the very high yields

obtained for the opp-dinaphthoporphyrins series B and

the presence of DBU in THF to give low variable yields

of naphtho[1,2-c]pyrrole 33a.³⁸However, using the phos-

phazene base 34,⁴²31 reacted with 32a to give the

required naphthopyrrole 33a in relatively good yields.³⁸

In a preliminary investigation, 33a was obtained in 33%

yield³⁸but subsequent optimization of this procedure

afforded the pyrrolic product in 58% yield. Although

phosphazene 34 is a stronger base than DBU, this is

probably not directly responsible for the improved yields.

The base generates an enolate ion 35 from the isocy-

anoacetate and the crucial step involves subsequent

nucleophilic addition onto the aromatic ring. The more

(43) Tang, J.; Verkade, J. G. J. Org. Chem. 1994, 59, 7793.

(44) Lash, T. D.; Chaney, S. T.; Richter, D. T. J. Org. Chem. 1998,

63, 9076.

(42) Bag, N.; Chern, S.-S.; Peng, S.-M.; Chang, C. K. Tetrahedron

Lett. 1995, 36, 6409.

J. Org. Chem, Vol. 70, No. 3, 2005 879

Manley et al.

SCHEME 6

rolecarboxylic acids decarboxylate at room temperature

under acidic conditions, and it was really only necessary

to saponify the ester groupings. This was accomplished

by refluxing 40 under nitrogen with sodium hydroxide

in methanol containing a small amount of hydrazine.

Following dilution with water and neutralization with

acetic acid, the corresponding dicarboxylic acid 41 was

isolated in 81% yield. This compound proved to be

somewhat unstable and was used immediately. Attempts

to use 41 in MacDonald “2 + 2” condensations failed to

give more than a trace amounts of porphyrin products.

However, in contrast to the results for the “type D”

system, the a,c-biladiene route proved to be more suc-

cessful. The crude diacid was reacted with 2 equiv of

formylpyrrole 10b in the presence of TFA and 30% HBr

in acetic acid, and following precipitation with diethyl

ether, the a,c-biladiene dihydrochloride 42 was obtained

in 96% yield. Although the NMR spectrum for 42 showed

that it was impure, the tetrapyrrole was taken on in

crude form. The conventional cyclization procedure using

copper(II) chloride in DMF gave no more than trace

amounts of porphyrin products. However, treatment of

42 with silver iodate and zinc acetate in DMF^29,45afforded

a zinc complex and following demetalation with TFA, the

adj-dinaphthoporphyrin 43a was isolated in 6.8% yield.

The low yield may be due in part to a deleterious steric

interaction between the two naphthalene units, although

the purity of the a,c-biladiene may also be a factor. In

a,c-biladiene cyclizations, a bilatriene intermediate (i.e.,

44) is formed prior to cyclization,²⁷and this would

exacerbate the steric problems by changing the hybrid-

ization state of bridging carbon atom from sp³to sp².⁴⁶

When the central methylene group is present, the two

naphthalenes can easily twist away from one another,

but a conjugated center would force these two units into

one another. It is less clear why the MacDonald route

was unsuccessful, although the instability of dipyrryl-

methane 41 is likely to be a factor. Despite the low yields,

sufficient quantities of pure porphyrin 43a were obtained

for further study. In addition, the corresponding nickel-

(II), copper(II) and zinc(II) porphyrins 43b-d were

synthesized and spectroscopically characterized.

C. Nonetheless, these results were satisfactory, and the

related metalloderivatives 39b-d could also be gener-

ated.

Synthesis of Type E Dinaphthoporphyrins. The

synthesis of the final “type E” dinaphthoporphyrin sys-

tem proved to be the most difficult to accomplish. This

work required the availability of a symmetrical dipyr-

rylmethane 40 (Scheme 6). Naphthopyrrole 33a was

readily available from the Barton-Zard chemistry dis-

cussed above. Initially, we favored using the related

benzyl ester for these studies but 33c was obtained in

very low yields by reacting 1-nitronaphthalene with

benzyl isocyanoacetate. In addition, attempts to trans-

esterify 33a with benzyl alcohol in the presence of sodium

benzyloxide gave rise to extensive decomposition and

none of the required benzyl ester could be isolated. Due

to these difficulties, the ethyl ester was directly taken

on to the dipyrrylmethane. Reaction of 33a with di-

methoxymethane and p-toluenesulfonic acid in acetic acid

gave dipyrrylmethane 40 in 87% yield. For related

dipyrrylmethanes, the ethyl ester units could be saponi-

fied with concomitant decarboxylation by treatment with

KOH in ethylene glycol under nitrogen at 180 °C.

However, these conditions were far too harsh for 40, and

attempts to cleave the ethyl units in this way led to

decomposition. The high temperatures allow for clean

decarboxylations to occur in many cases to give the

corresponding R-unsubstituted pyrroles. However, pyr-

Spectroscopic Characterization of Dinaphtho-

porphyrins. Proton and carbon-13 NMR spectroscopy

gave spectra for the new porphyrin systems that were

consistent with the expected symmetry of the structures

and their anticipated aromatic character.⁴⁷The dinaph-

thoporphyrins were poorly soluble in CDCl₃but gave high

quality spectra in TFA-CDCl₃. Addition of TFA leads to

diprotonation of the porphyrin core to afford the corre-

sponding dications. For instance, porphyrin 29a (type C,

Figure 1) afforded the green dication 29aH₂²⁺, and this

showed the presence of three upfield resonances at -2.7

(1H), -2.5 (2H), and -1.9 ppm (1H) for the three types

of NH protons. The symmetry and aromatic character-

istics of 29aH₂²⁺is confirmed by the presence of two 2H

singlets for the meso-protons at 11.1 and 11.5 ppm. The

(45) (a) Lash, T. D.; Johnson, M. C. Tetrahedron Lett. 1989, 30, 5697.

(b) Lash, T. D.; Balasubramaniam, R. P. Tetrahedron Lett. 1990, 31,

7545.

(46) Lash, T. D. Tetrahedron Lett. 1988, 29, 6877.

(47) For a recent review on the NMR properties of porphyrins, see:

Medforth, C. J. In The Porphyrin Handbook; Kadish, K. M., Smith, K.

M., Guilard, R., Eds.; Academic Press: San Diego, 2000; Vol. 5, pp

1-80.

880 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

FIGURE 2. Downfield region of the 400 MHz proton NMR

spectra for zinc dinaphthoporphyrin 29d in CDCl₃or pyrro-

lidine-CDCl₃. (A) Proton NMR spectrum of 29d in CDCl₃

showing no sign of the aromatic resonances due to the low

solubility of this chelate. (B) This shows the same region after

the addition of one drop of pyrrolidine to the NMR tube. The

secondary amine coordinates to the zinc porphyrin and greatly

increases the solubility producing well-resolved aromatic

resonances in the resulting proton NMR spectrum.

FIGURE 1. (A) 400 MHz proton NMR spectrum of opp-

dinaphthoporphyrin 29a in TFA-CDCl₃. (B) 100 MHz carbon-

13 NMR spectrum of 29a in TFA-CDCl₃. Each of the two

peaks near 20 ppm resolve into two resonances at higher scale

expansions corresponding to the two slightly different types

of ethyl units. Two types of meso-carbons can also be seen at

97.3 and 99.2 ppm. The peaks labeled with asterisks cor-

respond to the two quartets from the TFA.

led to significantly poorer spectroscopic data. However,

addition of a drop of pyrrolidine to the NMR tube allowed

solubilization and produced well resolved proton NMR

spectra in the aromatic region (Figure 2). This is due to

coordination of the secondary amine with the zinc por-

phyrin which causes deaggregation.⁴⁸In CDCl₃, the zinc

complex 29d gave no proton NMR signals but in the

presence of pyrrolidine a well-resolved spectrum was

obtained. In this case, the meso-protons appeared as two

2H protons at 10.5 and 11.2 ppm, while the downfield

naphthalene resonance produced a 2H doublet at 10.3

ppm.

Porphyrin free base spectra show a Soret band in the

near-UV and a series of four Q-bands in the visible

region.⁴⁹For octaethylporphyrin (OEP) in benzene, the

Soret band is a strong absorption (log ꢀ 5.20) at 400 nm,

and this is followed by weaker Q-bands at 498, 532, 568,

and 622 nm.⁵⁰Mononaphthoporphyrin 3 in chloroform

showed small bathochromic shifts compared to OEP, with

naphthalene protons closest to the porphyrin macrocycle

are also deshielded giving rise to a 2H doublet at 9.95

ppm (J ) 8.4 Hz). The plane of symmetry in 29aH₂

2+

leads to an expectation that the 44 carbons will have 18

unique sp²environments and 4 sp³carbon environments.

As expected, the carbon-13 NMR spectrum of 29a in TFA-

CDCl₃shows four resonances between 17 and 21 ppm,

two peaks between 97 and 100 ppm, and 16 resonances

in the range of 119-144 ppm (Figure 1). The two

resonances at 97.3 and 99.2 ppm correspond to the typical

values observed for porphyrin meso-carbons.^34b,47The

metal complexes of the porphyrins were poorly soluble

in organic solvents and gave poor quality NMR spectra

due to aggregation. Copper(II) complexes are paramag-

netic and no NMR data can be obtained for these species,

but the diamagnetic nickel(II) complexes all gave sup-

portive proton NMR spectra. The nickel(II) complex of

the type C dinaphthoporphyrin 29b showed the retention

of a strong diatropic ring current, and the meso-protons

produced two 2H singlets at 10.1 and 10.8 ppm. The

naphthalene proton adjacent to the meso-position was

again deshielded giving a doublet at 9.8 ppm. The zinc

complexes are also diamagnetic but aggregation effects

(48) Jia, S.-L.; Jentzen, W.; Shang, M.; Song, X.-Z.; Ma, J.-G.;

Scheidt, W. R.; Shelnutt, J. A. Inorg. Chem. 1998, 37, 4402.

(49) Smith, K. M. In Porphyrins and Metalloporphyrins; Smith, K.

M., Ed.; Elsevier: New York, 1975; pp 3-28.

(50) Porphyrins and Metalloporphyrins; Smith, K. M., Ed.; Elsevi-

er: New York, 1975; pp 871-889.

J. Org. Chem, Vol. 70, No. 3, 2005 881

Manley et al.

CHART 3. Diphenanthroporphyrins

are further developed for adj- and opp-diphenanthropor-

phyrins 45 and 46, respectively (Chart 3).^15cFree base

45 gave a Soret band at 433 nm and four Q-bands at 536,

569, 594, and 652 nm (intensities III > I > IV > II). opp-

Diphenanthroporphyrin 46 showed a Soret band at 429

nm, but Q-band IV could no longer be identified and band

I was very weak showing up at λ_max647 nm. In addition,

bands II and III for this opp-diannelated system appeared

at 573 and 591 nm (III . II), values that are again only

separated by 18 nm.^15cAlthough the opp- and adj-series

of dinaphthoporphyrins have electronic absorption spec-

tra that are quite dissimilar from one another, the

individual members of the adj-series give virtually

identical UV-vis spectra. Series E, in particular, might

have been expected to show some differences due to steric

interactions, but the data do not show any significance

differences for series A, D or E. In 2% TFA-chloroform,

the related dications are generated and the UV-vis

spectra for these species were also examined. Again, the

adj-dinaphthoporphyrins gave very similar spectra with

a Soret band at 437 nm and two major Q-bands at 580

and 630 nm (Figure 4). However, the dications for opp-

series B and C were quite different from one another

(Figure 4). Porphyrin 25a (series B) in 2% TFA-

chloroform gave a split Soret band with absorptions at

427 and 449 nm and a complex series of Q-bands at 570

(infl), 585, 623, and 636 nm. Porphyrin 29a (series C)

also gave a split Soret band with absorptions at 429 and

446 nm, but the Q-band region was less complicated

showing only two major bands at 581 and 626 nm. Hence,

the orientation of the naphthalene rings in the opp-series

does have a significant impact on the UV-vis spectra for

the dications. The diphenanthroporphyrins 45 and 46

again show useful comparisons.^15cAs was the case for

the adj-dinaphthoporphyrins, 45H₂²⁺gave a single Soret

band, albeit shifted to 448 nm, and two Q-bands at 583

and 632 nm. On the other hand, opp-diphenanthropor-

FIGURE 3. UV-vis spectra of free base dinaphthoporphyrins

in 1% Et₃N-chloroform: (A) adj-dinaphthoporphyrin 39a

(series D); (B) opp-dinaphthoporphyrin 29a (series C).

the Soret band at 415 nm (log ꢀ 5.31) and Q-bands at

511, 547, 574, and 630 nm.¹⁴As anticipated, the free base

dinaphthoporphyrins in 1% triethylamine-chloroform

showed larger shifts, although the spectra fell into two

distinct classes based on the relative positions of ring

fusion (Figure 3). The three adj-dinaphthoporphyrins

gave virtually identical spectra with slightly broadened

Soret bands at 426 nm (log ꢀ 5.29-5.33) with a shoulder

near 400 nm and four defined Q-bands at 535, 567, 587,

and 645 nm (all λ_maxvalues (1 nm for series A, D, and

E). The ratio of the intensities for the Q-bands, numbered

from highest (I) to lowest wavelength (IV),⁵⁰is III > I >

II > IV. The opp-dinaphthoporphyrins gave UV-vis

spectra that differed significantly from the adj-series,

although minor differences could be seen for porphyrins

25a and 29a. Both gave much stronger Soret bands at

425 nm (log ꢀ 5.40-5.50) with a more distinct shoulder

at 405 nm. The four Q-bands for 25a were present at λ_max

values of 529, 565, 585, and 642 nm, while the corre-

sponding bands for 29a were observed at 531, 567, 584,

and 640 nm. In both cases, this region is dominated by

Q-band III, while Q-band IV is ill-defined and Q-band I

is reduced in intensity compared to the adj-series.

Overall, the relative intensities are III > II > I > IV.

Q-bands II and III are somewhat closer together for the

opp-systems, but this feature is slightly more pronounced

for 29a (∆λ 17 nm) compared to 25a (∆λ 20 nm). The

equivalent Q-band absorptions for adj-dinaphthoporphy-

rins are 25 nm apart. It is noteworthy that these trends

2+

phyrin 46H₂gave a split Soret band at λ_max438 and

2+

459 nm that was similar to the spectra for 25aH₂and

29aH₂and Q-bands at 583 and 635 nm.^15cHence, the

2+

trends exhibited for adj- vs opp-dinaphthoporphyrins

clearly apply to systems with larger ring fused units as

well. The metallo derivatives of the dinaphthoporphyrins

showed further variations, but these results were com-

plicated by aggregation processes. Although the zinc

complexes were better dissolved in solutions containing

pyrrolidine, coordination from the secondary amine ni-

trogen can also alter the spectra. As an example, the opp-

diannealed metalloporphyrins 29b-d (series C) show

increasing bathochromic shifts going across the period

table from nickel to copper to zinc. This behavior is

typical of porphyrins in general⁵⁰and is also demon-

882 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

phyrins, although minor differences between all five

series can be seen. Full details of these spectra are

provided in the Experimental Section and the Supporting

Information, and the trends and variations observed for

these compounds will be useful in developing an under-

standing of the conjugation effects in this type of ex-

tended porphyrin chromophore. However, a full discus-

sion of the metalloporphyrin electronic absorption spectra

goes beyond the scope of this paper.

Conclusions

The synthesis of five isomeric dinaphthoporphyrin

systems has been accomplished by making use of several

different versions of the MacDonald condensation and

a,c-biladiene cyclizations. In fact, a range of synthetic

options were needed to obtain this series of extended

porphyrin chromophores due to the symmetry and stabil-

ity factors that had to be taken into account. In four of

the syntheses, one or both of the naphthalene rings were

introduced in a reduced form and subsequently dehydro-

genated with DDQ in refluxing toluene. This chemistry

worked reasonably well in all four cases, but much better

results were obtained for the two opp-dinaphthoporphy-

rin systems. Good overall yields were obtained for the

type A, B, C, and D porphyrins, but the a,c-biladiene

cyclization leading to the type E dinaphthoporphyrin only

occurred in 6.8% yield. Nonetheless, all five structural

types were isolated and characterized as the free base

and diprotonated forms, and the related nickel(II), cop-

per(II), and zinc(II) complexes. The two opp-dinaphtho-

porphyrins show distinctly different UV-vis spectra from

the three adj-dinaphthoporphyrins, and more subtle

effects could also be seen in the dication and metallopor-

phyrin spectra due to differences in the relative orienta-

tions of the naphthalene rings. This work provides a

comprehensive set of matched structures that should

allow for a greater understanding of conjugation effects

in porphyrin systems.

Experimental Section

Synthesis of Dinaphthoporphyrin Type A. 4,5-Dihy-

dro-3-methylnaphtho[1,2-c]pyrrole-1-carbaldehyde (14).

Ethyl 4,5-dihydro-3-methylnaphtho[1,2-c]pyrrole-1-carboxy-

late¹⁴(4a; 2.00 g) was refluxed with sodium hydroxide (2.0 g)

in ethylene glycol (20 mL). The solution was dispersed between

hexane and water and the aqueous solution extracted with

hexane. The combined organic solutions were washed with

water and dried over sodium sulfate. After the drying agent

was filtered off, a yellow oil was obtained by evaporation of

the solvent under reduced pressure. The residue was dissolved

in trifluoroacetic acid (8 mL) and cooled to 0 °C in a salt/ice

bath. Trimethyl orthoformate (2.5 mL) was added dropwise

by syringe, maintaining the temperature at 0 °C throughout.

The salt/water bath was removed, and the mixture was

allowed to stir at room temperature for 5 min. The mixture

was poured into ice/water, and after the product had precipi-

tated out, the solid material was filtered off and washed with

water. Recrystallization from methanol gave the aldehyde

(1.507 g, 91%) as shiny off-white crystals: mp 214-215 °C;

IR (Nujol mull) ν 3248 (NH str.), 1633 cm^-1(CdO str); ¹H NMR

(CDCl₃) δ 2.32 (3H, s), 2.58 (2H, q, J ) 7 Hz), 2.88 (2H, q, J )

7 Hz), 7.21-7.30 (3H, m), 7.64 (1H, d, J ) 7.2 Hz), 9.89 (1H,

s), 9.93 (1H, br s); ¹³C NMR (CDCl₃) δ 11.5, 19.6, 30.6, 121.4,

126.4, 126.8, 127.2, 127.7, 129.0, 130.9, 131.7, 132.3, 138.0,

177.4; EI MS (70 eV) m/z (rel int) 212 (18), 211 (100, M⁺), 210

FIGURE 4. UV-vis spectra of dinaphthoporphyrin dications

2+

in 2% TFA-chloroform: (A) adj-dinaphthoporphyrin 39aH₂

(series D); (B) opp-dinaphthoporphyrin 25aH₂²⁺(series B); (C)

2+

opp-dinaphthoporphyrin 29aH₂(series C).

strated for the metallo derivatives of the other dinaph-

thoporphyrin series as well. In chloroform, the nickel(II)

complex 29b is observed at 420 nm with a minor â band

at 546 nm and a stronger R band at 591 nm. The

equivalent bands were present at 424, 550, and 596 nm

for copper(II) complex 29c, while the zinc chelate 29d

showed these absorptions at 430, 563, and 603 nm. In

2% pyrrolidine-chloroform, the zinc complexes showed

sharpened Soret bands and the absorptions were shifted

to longer wavelengths (the corresponding bands for 29d

in 2% pyrrolidine-chloroform gave λ_maxvalues at 444, 568,

and 611 nm, respectively). In general, the absorption

bands for the opp-dinaphthoporphyrins were shifted to

slightly longer wavelengths than the adj-dinaphthopor-

J. Org. Chem, Vol. 70, No. 3, 2005 883

Manley et al.

(38, [M - H]⁺), 182 (73, [M - CHO]⁺), 167 (24). Anal. Calcd

for C₁₄H₁₃NO: C, 79.59; H, 6.20; N, 6.63. Found: C, 79.32; H,

6.03; N, 6.52.

solvent was evaporated on a rotary evaporator, first under

aspirator pressure and then using a vacuum pump. The

residue was taken up in 15% sulfuic acid/trifluoroacetic acid

(121 mL) and stirred at room temperature for 45 min. The

solution was diluted with dichloromethane and washed with

5% aqueous sodium bicarbonate solution. All of organic layers

were combined and dried over sodium sulfate, and the solvent

was evaporated under reduced pressure to give a dark purple

solid. The residue was chromatographed on a grade 3 alumina

column, eluting with dichloromethane. Recrystallization from

chloroform-methanol gave the title porphyrin (329 mg, 38%)

as a purple solid: mp >300 °C; UV-vis (1% Et₃N-CHCl₃) λ_max

(log ꢀ) 412 (5.21), 511 (4.18), 548 (4.18), 578 (3.90), 633 nm

(3.74); UV-vis (1% TFA-CHCl₃) λ_max(log ꢀ) 410 (5.24), 564

Ethyl 3-Methylnaphtho[1,2-c]pyrrole-1-carboxylate (12).

Dihydronaphthopyrrole 4a¹⁴(5.00 g) and xylene (250 mL) were

placed in a round-bottom reaction flask and purged with

nitrogen. Palladium-charcoal (10%; 5.00 g) was carefully

added to the flask and washed in with an additional portion

of xylene. The mixture was refluxed for 2 h. The catalyst was

filtered off and the solvent evaporated on a rotory evaporator

using a vacuum pump. Recrystallization from 95% ethanol

gave the naphthopyrrole (3.704 g, 75%) as flaky pink crys-

tals: mp 166.5-167 °C (lit.⁵¹mp 190-191 °C); IR (Nujol mull)

ν 3280 (NH str), 1635 cm^-1(CdO str); ¹H NMR (CDCl₃) δ 1.48

(3H, t, J ) 7 Hz), 2.64 (3H, s), 4.48 (2H, q, J ) 7 Hz), 7.36

(1H, d, J ) 9.2 Hz), 7.46 (1H, d, J ) 8.8 Hz), 7.51 (1H, t), 7.58

(1H, t), 7.79 (1H, d, J ) 7.6 Hz), 9.77 (1H, d, J ) 8.4 Hz), 9.88

(1H, br s); ¹³C NMR (CDCl₃) δ 11.6, 14.9, 60.5, 112.3, 118.7,

122.4, 123.9, 125.6, 126.2, 126.4, 127.9, 128.2, 128.4, 133.3,

160.8; EI MS (70 eV) m/z (rel int) 254 (16), 253 (78, M⁺), 224

(1.6), 207 (100, [M - EtOH]⁺), 179 (48, [M - EtOH - CO]⁺).

Anal. Calcd for C₁₆H₁₅NO₂: C, 75.87; H, 5.97; N, 5.53. Found:

C, 75.92; H, 5.87; N, 5.51.

1

(4.325), 603 nm (4.01); H NMR (CDCl₃) δ -3.41 (2H, br s),

1.89 (6H, t, J ) 7.6 Hz), 3.61 (4H, t, J ) 7 Hz), 3.66 (6H, s),

4.10 (4H, q, J ) 7.6 Hz), 4.31 (4H, t, J ) 7.2 Hz), 7.52 (2H, t,

J ) 7.6 Hz), 7.72 (2H, d, J ) 7.2 Hz), 7.79 (2H, t, J ) 7.4 Hz),

9.02 (2H, d, J ) 7.6 Hz), 10.08 (1H, s), 10.20 (1H, s), 10.62

(2H, s); ¹H NMR (TFA-CDCl₃) δ -3.40 (2H, br s), -3.04 (2H,

br s), 1.73 (6H, t, J ) 7.6 Hz), 3.63 (6H, s), 3.88 (4H, t, J ) 7.4

Hz), 4.12 (4H, q, J ) 7.6 Hz), 4.25 (4H, t, J ) 7.6 Hz), 7.63

(2H, t, J ) 7.4 Hz), 7.77-7.81 (4H, m), 8.57 (2H, d, J ) 7.6

Hz), 10.58 (1H, s), 10.77 (1H, s), 10.99 (2H, s); ¹³C NMR (TFA-

CDCl₃) δ 12.0, 16.5, 20.3, 22.4, 29.7, 97.7, 100.2, 101.1, 128.7,

129.4, 129.9 (2), 130.5, 136.2, 138.3, 138.7, 139.0, 139.2, 142.0,

142.9, 143.3, 144.3; HRMS (FAB) calcd for C₄₂H₃₈N₄+ H m/z

599.3175, found 599.3177. Anal. Calcd for C₄₂H₃₈N₄.¹/₁₀-

CHCl₃: C, 82.80; H, 6.29; N, 9.17. Found: C, 82.54; H, 6.27;

N, 9.15.

13,17-Bis(2-methoxycarbonylethyl)-12,18-dimethyl-

3¹,3²,7¹,7²-tetrahydrodinaphtho[1,2-b:2,1-g]porphyrin

(17b). The porphyrin was prepared by the previous procedure

from a,c-biladiene 16b (0.25 g) and copper(II) chloride (0.55

g) in DMF (93 mL). Following demetalation with 15% sulfuric

acid/trifluoroacetic acid (23.5 mL) and extraction, the crude

product was obtained as a dark purple/metallic green solid.

This was chromatographed on grade III alumina, eluting with

dichloromethane. Recrystallization from chloroform-methanol

gave 17b (64 mg, 34%) as a purple solid: mp >300 °C; UV-

vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 412 (5.26), 512 (4.20), 548

(4.19), 579 (3.91), 635 nm (3.72); UV-vis (1% TFA-CHCl₃)

λ_max(log ꢀ) 410 (5.26), 564 (4.33), 604 nm (4.01); ¹H NMR

(CDCl₃) δ -3.49 (2H, br s), 3.30 (4H, t, J ) 7.8 Hz), 3.61 (4H,

t, J ) 7 Hz), 3.67 (12H, s), 4.29 (4H, t, J ) 7 Hz), 4.42 (4H, t,

J ) 7.6 Hz), 7.53 (2H, t, J ) 7.4 Hz), 7.72 (2H, d, J ) 7.6 Hz),

7.79 (2H, t, J ) 7.2 Hz), 8.99 (2H, d, J ) 7.2 Hz), 10.08 (1H,

s), 10.17 (1H, s), 10.60 (2H, s); ¹H NMR (TFA-CDCl₃) δ -3.62

(2H, br s), -3.16 (2H, br s), 3.14 (4H, t, J ) 7.6 Hz), 3.66 (6H,

s), 3.69 (6H, s), 3.89 (4H, t, J ) 7.6 Hz), 4.26 (4H, t, J ) 7.4

Hz), 4.50 (4H, t, J ) 7.8 Hz), 7.65 (2H, t, J ) 7.4 Hz), 7.77-

7.81 (4H, m), 8.55 (2H, d, J ) 8 Hz), 10.81 (1H, s), 10.91 (1H,

s), 11.03 (2H, s); ¹³C NMR (TFA-CDCl₃) δ 12.2, 21.8, 22.4,

29.7, 35.6, 52.8, 98.9, 100.5, 101.2, 128.8, 129.5, 129.9, 130.1,

130.3, 136.7, 139.1, 139.3, 139.5, 140.3, 142.3, 142.7, 143.1,

175.1; HRMS (FAB) calcd for C₄₆H₄₂N₄O₄+ H m/z 715.3284,

found 715.3282. Anal. Calcd for C₄₆H₄₂N₄O₄: C, 77.29; H, 5.92;

N, 7.84. Found: C, 76.86; H, 5.86; N, 7.74.

8,12-Diethyl-1,7,13,19-tetramethyl-2¹,2²,10,18¹,18²,23-

hexahydrodinaphtho[1,2-b:2,1-q]bilin Dihydrobromide

(16a). Dipyrrole 15a⁵²(0.724 g) was dissolved in trifluoroacetic

acid (4.35 mL). After the mixture was stirred for 10 min,

aldehyde 14 (0.985 g) in methanol (18 mL) was added, followed

immediately by 30% HBr-AcOH (3.5 mL). After the mixture

was stirred for 30 min, anhydrous ether (110 mL) was added

dropwise and the resulting mixture stirred for an additional

2 h. The red/brown precipitate was filtered off and washed well

with ether. Upon vacuum-drying overnight, the title compound

(1.650 g, 93%) was obtained as a red/brown powder: mp 236

°C dec; UV-vis (CHCl₃) λ_max(log ꢀ) 473 (4.31), 553 nm (5.25);

¹H NMR (CDCl₃) δ 0.71 (6H, t, J ) 7.4 Hz), 2.27 (6H, s), 2.57-

2.64 (8H, m), 2.76 (6H, s), 2.92 (4H, t, J ) 7.2 Hz), 5.28 (2H,

s), 7.34-7.41 (6H, m), 7.60 (2H, d, J ) 7.2 Hz), 7.63 (2H, s),

13.21 (2H, s), 13.60 (2H, s);¹³C NMR (CDCl₃) δ 10.2, 13.1, 14.1.

17.7, 19.2, 26.1, 30.2, 122.7, 124.6, 125.9, 127.2, 127.5, 127.7,

129.3, 129.5, 130.1, 132.9, 139.4, 141.7, 143.0, 150.5, 152.4.

Anal. Calcd for C₄₃H₄₆N₄Br₂: C, 66.33; H, 5.95; N, 7.19.

Found: C, 65.85; H, 5.94; N, 7.13.

8,12-Bis(2-methoxycarbonylethyl)-1,7,13,19-tetramethyl-

2¹,2²,10,18¹,18²,23-hexahydrodinaphtho[1,2-b:2,1-q]bilin

Dihydrobromide (16b). The a,c-biladiene was prepared by

the previous procedure from dipyrrylmethane 15b⁵²(1.03 g)

and pyrrolecarbaldehyde 14 (0.972 g). Following filtration and

vacuum-drying, the tetrapyrrole (1.60 g, 75%) was obtained

as a red/metallic green powder: mp 187-188 °C; UV-vis

(CHCl₃) λ_max(log ꢀ) 471 (4.49), 547 nm (5.26); ¹H NMR (CDCl₃)

δ 2.09 (4H, t, J ) 7.6 Hz), 2.29 (6H, s), 2.62 (4H, t, J ) 7.4

Hz), 2.77 (6H, s), 2.86-2.94 (8H, m), 3.46 (6H, s), 5.34 (2H, s),

7.36-7.40 (6H, m), 7.59 (2H, d, J ) 6.8 Hz), 7.64 (2H, s), 13.30

(2H, s), 13.68 (2H, s); ¹³C NMR (CDCl₃) δ 10.4, 13.1, 19.2, 19.8,

25.9, 30.2, 34.1, 51.6, 123.3, 125.1, 126.0, 127.0, 127.8, 127.9,

128.9, 129.6, 129.9, 139.4, 142.2, 143.4, 149.5, 153.6, 173.0.

Anal. Calcd for C₄₇H₅₀N₄O₄Br₂‚H₂O: C, 61.85; H, 5.74; N, 6.14.

Found: C, 61.34; H, 5.60; N, 6.12.

13,17-Bis(2-methoxycarbonylethyl)-12,18-dimethyl-

dinaphtho[1,2-b:2,1-g]porphyrin (18a). Porphyrin 17b (25

mg) was refluxed with DDQ (21. 2 mg) in toluene (10 mL) for

40 min. The solvent was evaporated under reduced pressure

and the residue chromatographed on silica eluting initially

with dichloromethane and then with chloroform. Recrystalli-

zation from chloroform-methanol gave the dinaphthoporphy-

rin (15 mg, 60%) as a purple solid: mp >300 °C; UV-vis (1%

Et₃N-CHCl₃) λ_max(log ꢀ) 426 (5.33), 535 (4.11), 567 (4.57), 587

(4.13), 645 nm (4.25); UV-vis (5% TFA-CHCl₃) λ_max(log ꢀ)

437 (5.38), 581 (4.23), 630 nm (4.62); ¹H NMR (CDCl₃) δ -5.04

(2H, br s), 3.23 (4H, t, J ) 8 Hz), 3.38 (6H, s), 3.71 (6H, s),

4.26 (4H, t, J ) 8 Hz), 7.91 (2H, t, J ) 7.2 Hz), 8.90 (2H, t, J

) 7.2 Hz), 8.25 (2H, d, J ) 7.6 Hz), 8.38 (2H, d, J ) 8 Hz),

13,17-Diethyl-12,18-dimethyl-3¹,3²,7¹,7²-tetrahydrodi-

naphtho[1,2-b:2,1-g]porphyrin (17a). a,c-Biladiene 16a

(1.119 g) was added to a stirred solution of copper(II) chloride

(2.91 g) in DMF (485 mL). The flask was covered with foil and

the solution stirred at room temperature for 2 h. The solution

was diluted with dichloromethane (135 mL) and washed with

water (3 × 125 mL), and each of the aqueous layers was back-

extracted with dichloromethane. The organic layers were

combined, dried over sodium sulfate, and filtered, and the

(51) Mataka, S.; Takahashi, K.; Tsuda, Y.; Tashiro, M. Synthesis

1982, 157.

(52) Lash, T. D.; Armiger, Y. L. S.-T. J. Heterocycl. Chem. 1991, 28,

965.

884 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

8.70 (2H, br d), 9.27 (1H, br s), 9.66 (2H, d, J ) 7.2 Hz), 9.74

(1H, s), 10.15 (2H, s); ¹H NMR (TFA-CDCl₃) δ -2.40 (4H, two

overlapping broad singlets), 3.14 (4H, t, J ) 7.5 Hz), 3.65 (6H,

s), 3.74 (6H, s), 4.49 (4H, t, J ) 7.5 Hz), 8.11 (2H, t, J ) 7.4

Hz), 8.37 (2H, t, J ) 7.6 Hz), 8.58 (2H, d, J ) 8.4 Hz), 8.91

(2H, d, J ) 8.4 Hz), 9.67 (2H, d, J ) 8.8 Hz), 9.98 (2H, d, J )

8.4 Hz), 10.95 (1H, s), 11.47 (2H, s), 11.50 (1H, s); ¹³C NMR

(TFA-CDCl₃) δ 12.2, 21.8, 35.7, 53.1, 94.5, 100, 100.7, 119.9,

125.6, 128.9, 129.1, 130.4, 131.0, 134.2, 135.9, 137, 139.8,

140.2, 140.8, 142.7, 175.6; HRMS (FAB) calcd for C₄₆H₃₈N₄O₄

+ H m/z 711.2971, found 711.2969. Anal. Calcd for C₄₂H₃₈N₄.¹/

₁₀CHCl₃: C, 76.61; H, 5.31; N, 7.75. Found: C, 76.87; H, 5.36;

N, 7.70.

Nickel(II) Complex 18b. Porphyrin 18a (7.5 mg) and

nickel(II) acetate tetrahydrate (27 mg) were heated for 2 h

under reflux in DMF (10 mL). The solution was diluted with

chloroform, washed with water, and evaporated to dryness

under reduced pressure. Recrystallization from chloroform-

methanol gave the nickel(II) complex (6 mg, 80%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 419 (5.21),

546 (4.01), 588 nm (4.70); UV-vis (2% pyrrolidine-CHCl₃) λ_max

(log ꢀ) 422 (4.91), 449 (5.26), 570 (4.22), 592 (4.39), 603 nm

(4.42); HRMS (FAB) calcd for C₄₆H₃₆N₄O₄Ni m/z 766.2090,

found 766.2090.

Copper(II) Complex (18c). Porphyrin 18a (7 mg) and

copper(II) acetate monohydrate (25 mg) were heated for 2 h

under reflux in DMF (10 mL). The solution was diluted with

chloroform, washed with water, and evaporated to dryness on

a rotary evaporator. Recrystallization from chloroform-

methanol gave the copper(II) complex (6 mg, 80%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 421 (5.26),

552 (3.96), 594 nm (4.52); UV-vis (2% pyrrolidine-CHCl₃) λ_max

(log ꢀ) 421 (5.17), 442 (sh, 4.79), 555 (3.98), 595 nm (4.50);

HRMS (FAB) calcd for C₄₆H₃₆N₄O₄Cu m/z 771.2032, found

771.2033.

salt bath. Trimethyl orthoformate (3.60 mL) was added drop-

wise keeping the temperature at 0 °C. The mixture was stirred

for 5 min at room temperature and then poured into ice/water

and allowed to stand for 1-2 h. The precipitate was filtered,

washed with water, and recrystallized from 95% ethanol to

give the aldehyde (1.051 g, 55%) as off-white crystals: mp

201-202 °C; IR (Nujol mull) ν 3289 (NH str), 1712 (ester Cd

O str), 1611 cm^-1(CHdO str); ¹H NMR (CDCl₃) δ 1.07 (3H, t,

J ) 7.5 Hz), 2.18 (3H, s), 2.49 (2H, q, J ) 7.5 Hz), 2.71 (2H, t,

J ) 7 Hz), 2.90 (2H, t, J ) 7 Hz), 3.97 (2H, s), 5.27 (2H, s),

7.03 (1H, t, J ) 7.4 Hz), 7.11-7.25 (5H, m), 7.28 (2H, d, J )

8 Hz), 8.47 (1H, d, J ) 8 Hz), 9.22 (1H, s), 11.04 (1H, br s),

11.56 (1H, br s); ¹³C NMR (CDCl₃) δ 9.1, 15.5, 17.3, 20.5, 22.6,

31.3, 66.0, 116.4, 120.9, 125.4, 126.7, 126.9, 127.5, 127.7, 127.9,

128.0, 128.1, 128.2, 128.5, 128.8, 131.2, 134.2, 136.3, 137.4,

137.6, 160.9, 176.7. Anal. Calcd for C₂₉H₂₈N₂O₃: C, 76.97; H,

6.24; N, 6.19. Found: C, 76.83; H, 6.44; N, 6.36.

Benzyl 3-(5-Formyl-3,4-dimethylpyrrolylmethyl)-4,5-

dihydronaphtho[2,1-c]pyrrole-1-carboxylate (22b). Ben-

zyl 3-(5-tert-butyloxycarbonyl-3,4-dimethylpyrrolylmethyl)-3,4-

dihydronaphtho[2,1-c]pyrrole-1-carboxylate (21b) was prepared

by the foregoing procedure from 5¹⁴(1.343 g) and tert-butyl

3,4-methylpyrrole-2-carboxylate³⁹(20b; 0.87 g). Following

chromatography, as described for 22a, the product 21b (1.562

g, 86%) was isolated as a yellow gum that could not be induced

to crystallize: ¹H NMR (CDCl₃) δ 1.53 (9H, s), 1.93 (3H, s),

2.22 (3H, s), 2.55 (2H, t, J ) 7 Hz), 2.84 (2H, t, J ) 7 Hz), 3.89

(2H, s), 5.31 (2H, s), 7.14-7.40 (8H, m), 8.36-8.39 (1H, m),

8.64 (1H, br s), 8.91 (1H, br s). The formyl derivative was

prepared by the previous procedure by reacting 21b (1.917 g)

with TFA-CH(OMe)₃. Recrystallization from 95% ethanol gave

the dipyrrylmethane aldehyde (1.101 g, 67%) as an off-white

powder: mp 222.5-223.5 °C; IR (Nujol mull) ν 3288 (NH str),

1691 (ester CdO str), 1620 cm^-1(CdO str); ¹H NMR (CDCl₃)

δ 2.02 (3H, s), 2.14 (3H, s), 2.71 (2H, t, J ) 7 Hz), 2.89 (2H, t,

J ) 7 Hz), 3.96 (2H, s), 5.28 (2H, s), 7.07 (1H, t, J ) 7.6 Hz),

7.14-7.23 (5H, m), 7.28 (2H, d, J ) 7.6 Hz), 8.45 (1H, d, J )

7.2 Hz), 9.21 (1H, s), 10.99 (1H, br s), 11.52 (1H, br s); ¹³C

NMR (CDCl₃) δ 8.8, 9.3, 20.6, 22.8, 31.3, 65.9, 116.3, 118.7,

121.0, 126.7, 126.9, 127.5, 127.7, 127.9, 128.0, 128.1, 128.2,

128.5, 128.6, 131.2, 134.8, 136.3, 137.4, 138.0, 160.9, 176.6.

Anal. Calcd for C₂₈H₂₆N₂O₃: C, 76.69; H, 5.97; N, 6.39.

Found: C, 76.53; H, 5.88; N, 6.23.

Zinc Complex (18d). Porphyrin 18a (7.0 mg) and zinc

acetate dihydrate (27 mg) were heated for 2 h under reflux in

DMF (10 mL). The solution was diluted with chloroform,

washed with water, and evaporated under reduced pressure.

Recrystallization from chloroform-methanol gave the zinc

chelate (7 mg, 92%) as purple crystals: mp >300 °C; UV-vis

(CHCl₃) λ_max(rel int) 407 (infl, 0.216), 433 (1.00), 561 (0.057),

601 (0.170); UV-vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 417

1

(4.73), 441 (5.57), 568 (4.27), 608 nm (4.64); H NMR (pyrro-

Benzyl

3-(5-Formyl-3(2-methoxycarbonylethyl)-4-

lidine-CDCl₃; downfield region only) δ 7.83 (2H, t, J ) 7.4

Hz), 8.13 (2H, t, J ) 7.4 Hz), 8.39 (2H, d, J ) 8 Hz), 8.46 (2H,

d, J ) 8 Hz), 9.54 (2H, d, J ) 8 Hz), 10.03 (1H, s), 10.20 (2H,

d, J ) 8 Hz), 10.78 (1H, br s), 11.06 (2H, s); HRMS (FAB) calcd

for C₄₆H₃₆N₄O₄Zn m/z 772.2028, found 772.2025.

methylpyrrolylmethyl)-4,5-dihydronaphtho[2,1-c]pyrrole-

1-carboxylate (22c). Benzyl 3-(5-tert-butyloxycarbonyl-3(2-

methoxycarbonylethyl)-4-methylpyrrolylmethyl)-3,4-dihy-

dronaphtho[2,1-c]pyrrole-1-carboxylate (21c) was prepared by

the foregoing procedure from 5¹⁴(3.80 g) and tert-butyl 3-(2-

methoxycarbonylethyl)-4-methylpyrrole-2-carboxylate³⁹(20c;

2.85 g). Following chromatography on silica, eluting with 5%

ethyl acetate-toluene, the dipyrrylmethane (5.60 g, 95%) was

isolated as a reddish gum that could not be induced to

crystallize: ¹H NMR (CDCl₃) δ 1.52 (9H, s), 2.24 (3H, s), 2.47

(2H, t, J ) 7.0 Hz), 2.62 (2H, t, J ) 7 Hz), 2.73 (2H, t, J ) 7.0

Hz), 2.88 (2H, t, J ) 7 Hz), 3.53 (3H, s), 3.98 (2H, s), 5.31 (2H,

s), 7.16-7.40 (8H, m), 8.38-8.41 (1H, m), 8.59 (1H, br s), 9.46

(1H, br s). The title aldehyde was prepared from 21c (2.44 g)

by the previous procedure. Recrystallization from 95% ethanol

gave the product (1.45 g, 68%) as pale brown crystals: mp

181-181.5 °C; IR (Nujol mull) ν 3259 (NH str), 1730 (propi-

onate CdO str), 1694 (pyrrole ester CdO str), 1613 cm^-1(CHd

Synthesis of Dinaphthoporphyrin Type B. Benzyl 3-(3-

Ethyl-5-formyl-4-pyrrolylmethyl)-4,5-dihydronaphtho-

[1,2-c]pyrrole-1-carboxylate (22a). Montmorillonite clay

(K10, 5.5 g) was added to a solution of benzyl 2-acetoxymethyl-

3,4-dihydronaphtho[2,1-c]pyrrole-1-carboxylate¹⁴(5; 1.388 g)

and tert-butyl 4-ethyl-3-methylpyrrole-2-carboxylate³⁹(20a;

0.90 g) in dichloromethane (84 mL) and the mixture stirred

vigorously overnight. The mixture was filtered, the clay

washed with dichloromethane, and the solvent evaporated

under reduced pressure. The residual oil was chromatographed

on silica, eluting initially with 2% ethyl acetate-toluene and

then gradually increasing the polarity to 15% ethyl acetate-

toluene. Benzyl 3-(5-tert-butyloxycarbonyl-3-ethyl-4-meth-

ylpyrrolylmethyl)-3,4-dihydronaphtho[2,1-c]pyrrole-1-carbox-

ylate (1.650 g, 85%) was isolated in crude form as a gum that

could not be induced to crystallize: IR (Nujol mull) ν 3330 (NH

str), 1696, 1643 cm^-1(CdO str); ¹H NMR (CDCl₃) δ 1.01 (3H,

t, J ) 7.6 Hz), 1.53 (9H, s), 2.25 (3H, s), 2.39 (2H, q, J ) 7.6

Hz), 2.55 (2H, t, J ) 7 Hz), 2.85 (2H, t, J ) 7 Hz), 3.90 (2H, s),

5.30 (2H, s), 7.14-7.40 (8H, m), 8.36-8.39 (1H, m), 8.71 (1H,

br s), 8.94 (1H, br s). The tert-butyl ester 21a (2.197 g) was

dissolved in trifluoroacetic acid (11.5 mL), stirred at room

temperature for 15 min, and then cooled to 0 °C using an ice/

1

O str); H NMR (CDCl₃) δ 2.19 (3H, s), 2.44 (2H, t, J ) 7.6

Hz), 2.68 (2H, t, J ) 7 Hz), 2.78 (2H, t, J ) 7.6 Hz), 2.88 (2H,

t, J ) 7 Hz), 3.64 (3H, s), 4.01 (2H, s), 5.27 (2H, s), 7.11 (1H,

t, J ) 7 Hz), 7.12-7.24 (5H, m), 7.30 (2H, d, J ) 7.2 Hz), 8.42

(1H, dd, J ) 2.0, 7.2 Hz), 9.29 (1H, s), 10.61 (1H, br s), 10.91

(1H, br s); ¹³C NMR (CDCl₃) δ 9.1, 19.3, 20.5, 22.8, 31.2, 34.7,

51.9, 66.1, 116.5, 121.3, 121.5, 126.7, 127.0, 127.2, 127.7, 127.9,

128.0, 128.2, 128.3, 128.6, 128.9, 131.0, 133.5, 136.3, 137.2,

137.4, 160.9, 173.5, 176.9. Anal. Calcd for C₃₁H₃₀N₂O₅: C,

72.92; H, 5.92; N, 5.49. Found: C, 72.62; H, 5.87; N, 5.58.

J. Org. Chem, Vol. 70, No. 3, 2005 885

Manley et al.

3-(3-Ethyl-5-formyl-4-methyl-2-pyrrolylmethyl)-4,5-di-

hydronaphtho[1,2-c]pyrrole-1-carboxylic Acid (19a). Ben-

zyl 3-(3-ethyl-5-formyl-4-pyrrolylmethyl)-4,5-dihydronaphtho-

[1,2-c]pyrrole-1-carboxylate (22a; 253 mg), methanol (150 mL),

and 6 drops of triethylamine were placed in a hydrogenation

vessel and purged with nitrogen. Palladium-charcoal (10%;

100 mg) was added and the mixture shaken under an

atmosphere of hydrogen (45 psi) at room temperature over-

night. After filtering off the catalyst, the solvent was removed

under reduced pressure keeping the water bath below 40 °C.

This residue was taken up in 5% aqueous ammonia, trans-

ferred to an Erlenmeyer flask, and cooled to 0 °C using an

ice/salt bath. The mixture was neutralized to litmus by adding

glacial acetic acid dropwise while maintaining the temperature

below 5 °C. The solution was stirred for 1 h and the resulting

precipitate filtered and washed thoroughly with water to

remove all traces of acid. Following vacuum-drying overnight,

the carboxylic acid (178 mg, 88%) was obtained as a pink

C₄₂H₃₈N₄+ H m/z 599.3175, found 599.3177. Anal. Calcd for

C₄₂H₃₈N₄‚³/₄CHCl₃: C, 74.60; H, 5.67; N, 8.14. Found: C, 74.64;

H, 5.63; N, 8.03.

7,8,17,18-Tetramethyl-3¹,3²,13¹,13²-tetrahydrodinaph-

tho[1,2-b:1,2-l]porphyrin (24b). The title porphyrin was

prepared from 19b (169 mg) by the previous procedure.

Recrystallization from chloroform-methanol gave 24b (38 mg,

27%) as a purple solid: mp >300 °C; UV-vis (1% Et₃N-

CHCl₃) λ_max(log ꢀ) 396 (5.03), 405 (infl., 5.01), 510 (3.93), 554

(4.15), 582 (3.91), 640 nm (3.72); UV-vis (1% TFA-CHCl₃)

λ_max(log ꢀ) 409 (5.12), 563 (4.15), 602 (4.16), 613 nm (4.18); ¹H

NMR (TFA-CDCl₃) δ -3.59 (2H, br s), -2.96 (2H, br s), 3.63

(6H, s), 3.64 (6H, s), 3.88 (4H, t, J ) 7.6 Hz), 4.25 (4H, t, J )

7.6 Hz), 7.63 (2H, t, J ) 7.4 Hz), 7.76-7.80 (4H, m), 8.54 (2H,

d, J ) 7.6 Hz), 10.68 (2H, s), 10.99 (2H, s); ¹³C NMR (TFA-

CDCl₃): δ 12.2, 12.3, 22.4, 29.7, 99.6, 100.3, 128.7, 129.5, 129.9,

130.0, 130.4, 136.5, 138.6, 138.9, 139.3, 141.8, 142.9, 143.3;

HRMS (FAB) calcd for C₄₀H₃₄N₄+ H m/z 571.2862, found

571.2864.

1

powder: mp 170 °C dec; H NMR (CDCl₃-DMSO-d₆) δ 0.96

(3H, t, J ) 7.6 Hz), 2.17 (3H, s), 2.38 (2H, q, J ) 7.6 Hz), 2.56

(2H, t, J ) 7 Hz), 2.77 (2H, t, J ) 7 Hz), 3.80 (2H, s), 7.03 (1H,

t, J ) 7.2 Hz), 7.10-7.15 (2H, m), 8.42 (1H, d, J ) 7.6 Hz),

9.40 (1H, s), 10.90 (1H, br s), 11.24 (1H, br s). Anal. Calcd for

C₂₂H₂₂N₂O₃: C, 72.91; H, 6.12; N, 7.73. Found: C, 73.05; H,

6.17; N, 7.56.

7,17-Bis(2-methoxycarbonylethyl)-8,18-dimethyl-

3¹,3²,13¹,13²-tetrahydrodinaphtho[1,2-b:1,2-l]porphyrin (24c).

Porphyrin 24c was prepared from 19c (275 mg) by the

previous procedure. Recrystallization from chloroform-

methanol gave the porphyrin (72 mg, 31%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 398

(5.24), 411 (infl, 5.21), 510 (4.20), 549 (4.30), 580 (3.99),

638 nm (3.95); UV-vis (1% TFA-CHCl₃) λ_max(log ꢀ) 409

(5.35), 564 (4.34), 604 (4.36), 612 nm (infl, 4.21); ¹H NMR

(TFA-CDCl₃) δ -3.52 (2H, br s), -2.94 (2H, br s), 3.18

(4H, t, J ) 8 Hz), 3.67 (6H, s), 3.72 (6H, s), 3.89 (4H,

t, J ) 7.8 Hz), 4.27 (4H, t, J ) 7.4 Hz), 4.53 (4H, t,

J ) 8 Hz), 7.64 (2H, t, J ) 7.4 Hz), 7.75-7.81 (4H, m),

8.50 (2H, d, J ) 7.6 Hz), 10.82 (2H, s), 11.01 (2H, s);

¹³C NMR (TFA-CDCl₃) δ 12.2, 21.9, 22.2, 29.6, 35.7, 53.0,

99.9, 100.5, 128.7, 129.6, 129.9, 130.1, 130.3, 136.8, 139.2,

139.4, 139.7, 140.1, 142.0, 142.4, 143.0, 175.1; HRMS (FAB)

calcd for C₄₆H₄₂N₄O₄+ H 715.3284, found 715.3282. Anal.

Calcd for C₄₆H₄₂N₄O₄‚¹/₁₀CHCl₃: C, 76.18; H, 5.84; N, 7.71.

Found: C, 76.08; H, 5.81; N, 7.66.

7,17-Bis(2-methoxycarbonylethyl)-8,18-dimethyldi-

naphtho[1,2-b:1,2-l]porphyrin (25a). Porphyrin 24c (25 mg)

was refluxed with DDQ (21. 2 mg) in toluene (10 mL) for 40

min. The solvent was evaporated under reduced pressure and

the residue chromatographed on grade 3 alumina, eluting

initially with dichloromethane and then with chloroform.

Recrystallization from chloroform-methanol gave the dinaph-

thoporphyrin (25 mg, quantitative) as purple crystals: mp

>300 °C; UV-vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 405 (infl, 5.04),

426 (5.40), 529 (3.94), 565 (4.75), 585 (4.26), 642 nm (4.00);

UV-vis (5% TFA-CHCl₃) λ_max(log ꢀ) 427 (5.16), 449 (5.28),

570 (infl, 3.97), 585 (4.16), 623 (4.53), 636 nm (4.30); ¹H NMR

(TFA-CDCl₃) δ -2.35 (2H, br s), -2.15 (2H, br s), 3.24 (4H, t,

J ) 7 Hz), 3.65 (6H, s), 3.76 (6H, s), 4.53 (4H, t, J ) 7 Hz),

8.09 (2H, t, J ) 7.5 Hz), 8.35 (2H, t, J ) 7.6 Hz), 8.57 (2H, d,

J ) 8 Hz), 8.89 (2H, d, J ) 8.5 Hz), 9.69 (2H, d, J ) 8.5 Hz),

9.94 (2H, d, J ) 8.1 Hz), 11.24 (2H, s), 11.49 (2H, s); ¹³C NMR

(TFA-CDCl₃) δ 12.4, 22.0, 35.8, 52.8, 97.5, 99.9, 120.1, 125.7,

128.5, 128.6, 129.1, 130.2, 130.9, 134.0, 134.6, 135.8, 138.4,

138.8, 139.4, 139.8, 142.2, 142.7, 174.7; HRMS (FAB) calcd

for C₄₆H₄₀N₄O₄+ H m/z 711.2971, found 711.2969. Anal. Calcd

for C₄₆H₃₈N₄O₄: C, 77.73; H, 5.39; N, 7.88. Found: C, 77.52;

H, 5.80; N, 7.36.

3-(5-Formyl-3,4-methyl-2-pyrrolylmethyl)-4,5-dihy-

dronaphtho[1,2-c]pyrrole-1-carboxylic Acid (19b). The

carboxylic acid was prepared from 22b (250 mg) as described

above. The product (0.178 mg, 90%) was isolated as a pink

1

powder: mp 172 °C dec; H NMR (DMSO-d₆) δ 1.97 (3H, s),

2.19 (3H, s), 2.61 (2H, t, J ) 7 Hz), 2.81 (2H, t, J ) 7 Hz), 3.85

(2H, s), 7.07 (1H, t, J ) 7.2 Hz), 7.13-7.18 (2H, m), 8.44 (1H,

d, J ) 7.2 Hz), 9.47 (1H, s), 11.17 (1H, br s), 11.41 (1H, br s).

Anal. Calcd for C₂₁H₂₀N₂O₃: C, 72.40; H, 5.78; N, 8.04.

Found: C, 72.58; H, 6.16; N, 8.22.

3-(5-Formyl-3-(2-methoxycarbonylethyl)-4-methylpyr-

rolylmethyl)-4,5-dihydronaphtho[2,1-c]pyrrole-1-carbox-

ylic Acid (19c). The dipyrrylmethane carboxylic acid was

prepared from 22c (500 mg) by the foregoing procedure. The

carboxylic acid (365 mg, 89%) was isolated as an off-white

powder: mp 150 °C dec, darkens at 120 °C; ¹H NMR (DMSO-

d₆) δ 2.16 (3H, s), 2.21 (2H, t, J ) 7.8 Hz), 2.44 (2H, t, J ) 6.8

Hz), 2.59 (2H, t, J ) 7.8 Hz), 2.69 (2H, t, J ) 6.8 Hz), 3.53

(3H, s), 3.88 (2H, s), 7.07 (1H, t, J ) 7.4 Hz), 7.13-7.19 (2H,

m), 8.40 (1H, d, J ) 7.6 Hz), 9.47 (1H, s), 11.32 (1H, s), 11.55

(1H, s), 12.39 (1H, v br s). Anal. Calcd for C₂₄H₂₄N₂O₅: C,

68.56; H, 5.75; N, 6.66. Found: C, 68.41; H, 5.70; N, 6.43.

7,17-Diethyl-8,18-dimethyl-3¹,3²,13¹,13²-tetrahydrodi-

naphtho[1,2-b:1,2-l]porphyrin (24a). A solution of p-tolu-

enesulfonic acid (125 mg) in methanol (2.2 mL) was added to

a solution of dipyrrylmethane monoaldehyde 19a (176 mg) in

dichloromethane (22 mL) and methanol (2.2 mL) and the

resulting mixture stirred in the dark at room temperature

overnight. A saturated solution of zinc acetate in methanol

(2.7 mL) was added and the resulting solution stirred open to

the air overnight. The solution was washed with water, 5%

hydrochloric acid (2×), 5% aqueous ammonia, and water. The

solvent was evaporated under reduced pressure, and the

resulting residue was chromatographed on grade 3 alumina,

eluting with dichloromethane. Recrystallization from chloro-

form-methanol gave the porphyrin (52 mg, 36%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 397 (infl.,

5.00), 413 (5.17), 511 (3.86), 553 (4.12), 590 (4.24), 639 nm

(3.47); UV-vis (1% TFA-CHCl₃) λ_max(log ꢀ) 409 (5.18), 563

(4.20), 602 (4.23), 612 nm (4.20); ¹H NMR (TFA-CDCl₃) δ

-3.66 (2H, br s), -3.15 (2H, br s), 1.77 (6H, t, J ) 7.8 Hz),

3.65 (6H, s), 3.89 (4H, t, J ) 7.5 Hz), 4.13 (4H, q, J ) 7.6 Hz),

4.25 (4H, t, J ) 7.5 Hz), 7.64 (2H, t, J ) 7.4 Hz), 7.76-7.80

(4H, m), 8.54 (2H, d, J ) 7.2 Hz), 10.69 (2H, s), 11.01 (2H, s);

¹³C NMR (TFA-CDCl₃) δ 12.1, 16.5, 20.3, 22.4, 29.7, 99.4,

100.3, 128.7, 129.5, 129.9, 130.0, 130.4, 136.6, 138.2, 138.9,

139.3, 141.9, 142.1, 143.3, 144.7; HRMS (FAB) calcd for

Nickel(II) Complex 25b. Porphyrin 25a (9 mg) and nickel-

(II) acetate tetrahydrate (29 mg) were heated for 2 h under

reflux in DMF (10 mL). The solution was diluted with

chloroform, washed with water, and evaporated to dryness

under reduced pressure. Recrystallization from chloroform-

methanol gave the nickel(II) complex (9 mg, 93%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 421 (5.20),

547 (4.02), 590 (4.80); UV-vis (2% pyrrolidine-CHCl₃) λ_max

(log ꢀ) 420 (4.86), 444 (5.24), 451 (5.29), 567 (4.22), 592 (4.43),

609 nm (4.58); ¹H NMR (CDCl₃) δ 2.97 (4H, t, J ) 7.4 Hz),

886 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

3.23 (6H, s), 3.66 (6H, s), 4.05 (4H, t, J ) 7.4 Hz), 7.91 (2H, t,

J ) 7.4 Hz), 8.16 (2H, t, J ) 7.4 Hz), 8.38-8.44 (4H, m), 9.17

(2H, d, J ) 8 Hz), 9.62 (2H, d, J ) 8 Hz), 9.67 (2H, s), 10.12

(2H, s); HRMS (FAB) calcd for C₄₆H₃₆N₄O₄Ni m/z 766.2090,

found 766.2092.

Copper(II) Complex 25c. Porphyrin 25a (7.8 mg) and

copper(II) acetate monohydrate (27.8 mg) were heated for 2 h

under reflux in DMF (10 mL). The solution was diluted with

chloroform, washed with water, and evaporated to dryness on

a rotary evaporator. Recrystallization from chloroform-

methanol gave the copper(II) complex (8.0 mg, 94%) as purple

crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 410 (infl,

4.92), 425 (5.04), 553 (3.77), 596 (4.31); HRMS (FAB) calcd for

C₄₆H₃₆N₄O₄Cu m/z 771.2032, found 771.2030.

Zinc Complex 25d. Porphyrin 25a (7 mg) and zinc acetate

dihydrate (27 mg) were heated for 2 h under reflux in DMF

(10 mL). The solution was diluted with chloroform, washed

with water, and evaporated in vacuo. Recrystallization from

chloroform-methanol gave the zinc chelate (7 mg, 92%) as

purple crystals: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 437

(5.36), 567 (3.84), 609 (4.34); UV-vis (2% pyrrolidine-CHCl₃)

λ_max(log ꢀ) 419 (4.64), 423 (infl, 5.29), 444 (5.48), 568 (4.20),

610 nm (4.71); ¹H NMR (pyrrolidine-CDCl₃; downfield region

only) δ 7.84 (2H, t, J ) 7.4 Hz), 8.15 (2H, t, J ) 7.6 Hz), 8.41

(2H, d, J ) 8 Hz), 8.48 (2H, d, J ) 8 Hz), 9.55 (2H, d, J ) 8

Hz), 10.22 (2H, d, J ) 8 Hz), 10.42 (2H, s), 11.06 (2H, s); HRMS

(FAB) calcd for C₄₆H₃₆N₄O₄Zn + H m/z 773.2106, found

773.2016.

crude dicarboxylic acid 26b (0.375 g, 99%) was obtained as a

pink powder and was used without further purification.

The foregoing dicarboxylic acid (0.230 g) was dissolved in

trifluoroacetic acid (1.8 mL) under an atmosphere of nitrogen

at room temperature for 10 min. The mixture was diluted with

dichloromethane (35 mL), followed immediately by the addi-

tion of 3,4-diethylpyrrole-2,5-dicarbaldehyde^34b,54(27; 72 mg),

and the resulting solution was stirred at room temperature

for 2 h under a nitrogen atmosphere. The mixture was

neutralized by the dropwise addition of triethylamine, DDQ

(193.2 mg; 2.10 equiv) was added, and the mixture was allowed

to stir for an additional 1 h at room temperature. The solution

was washed with water and the solvent evaporated under

reduced pressure to give a dark purple residue. The residue

was chromatographed on grade III alumina eluting with

dichloromethane. The fractions containing the porphyrin were

combined, evaporated under reduced pressure, and recrystal-

lized from chloroform-methanol to give the desired tetrahy-

drodinaphthoporphyrin (128 mg, 51%) as purple crystals: mp

>300 °C; UV-vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 401 (5.26), 512

(4.14), 555 (4.32), 575 (4.02), 640 nm (3.77); UV-vis (2% TFA-

1

(CHCl₃) λ_max(log ꢀ) 410 (5.29), 565 (4.31), 615 nm (4.20); H

NMR (TFA-CDCl₃) δ -2.95 (3H, br s), -2.29 (1H, br s), 1.74

(6H, t, J ) 7.6 Hz), 1.80 (6H, t, J ) 7.6 Hz), 3.90 (4H, t, J )

7.4 Hz), 4.08-4.17 (8H, m), 4.23 (4H, t, J ) 7.4 Hz), 7.63 (2H,

t, J ) 7.4 Hz), 7.78-7.81 (4H, m), 8.55 (2H, d, J ) 7.6 Hz),

10.62 (2H, s), 10.96 (2H, s); ¹³C NMR (TFA-CDCl₃) δ 18.6,

18.7, 21.2, 21.3, 23.4, 30.8, 100.2, 100.7, 129.4, 130.3, 130.5,

130.6, 131.4, 136.7, 139.8, 140.0, 140.1, 142.0, 142.8, 143.6,

144.1, 144.3; HRMS (FAB) calcd for C₄₄H₄₂N₄+ H m/z

627.3487, found 627.3488. Anal. Calcd for C₄₄H₄₂N₄‚H₂O: C,

81.95; H, 6.88; N, 8.69. Found: C, 82.31; H, 6.59; N, 8.73.

Synthesis of Dinaphthoporphyrin Type C. Bis-2,5-(3-

benzyloxycarbonyl-4,5-dihydro-1-naphtho[1,2-c]pyrro-

lylmethyl)-3,4-diethylpyrrole (26a). 3,4-Diethylpyrrole⁵³

(0.324 g) and benzyl 3-acetoxymethyl-4,5-dihydronaphtho[1,2-

c]pyrrole-1-carboxylate (5; 1.99 g) were dissolved in ethanol

(20 mL) and glacial acetic acid (1.3 mL). The resulting solution

was allowed to reflux under a nitrogen atmosphere for 16 h.

The mixture was then allowed to cool to room temperature

and further cooled with an ice bath to precipitate out the

product. The precipitate was collected by suction filtration,

washed with cold ethanol, and dried in vacuo overnight to give

the tripyrrane dibenzyl ester (1.45 g, 73%) as an off white

7,8,17,18-Tetraethyldinaphtho[1,2-b:2,1-l]porphyrin

(29a). Dihydronaphthoporphyrin 28 (71 mg) and DDQ (53.2

mg; 2.0 equiv) were refluxed in toluene (30 mL) for 1 h. The

reaction flask was allowed to cool to room temperature and

then diluted with chloroform and washed with water. The

organic extracts were evaporated under reduced pressure, and

the residue was recrystallized from chloroform-methanol to

give the fully conjugated dinaphthoporphyrin (68 mg, 97%) as

dark purple sheets: mp >300 °C; UV-vis (1% Et₃N-CHCl₃)

λ_max(log ꢀ) 404 (sh, 4.91), 425 (5.50), 531 (3.83), 567 (4.86),

584 (4.44), 640 nm (3.96); UV-vis (2% TFA-CHCl₃) λ_max(log

ꢀ) 429 (sh, 5.27), 446 (5.45), 581 (4.26), 626 nm (4.70); ¹H NMR

(TFA-CDCl₃) δ -2.73 (1H, br s), -2.53 (2H, br s), -1.95 (1H,

br s), 1.78 (6H, t, J ) 7.8 Hz) 1.83 (6H, t, J ) 7.6 Hz), 4.22

(8H, q, J ) 7.5 Hz), 8.10 (2H, t, J ) 7.4 Hz), 8.36 (2H, t, J )

7.8 Hz), 8.57 (2H, d, J ) 8.0 Hz), 8.88 (2H, d, J ) 8.4 Hz),

9.60 (2H, d, J ) 8.8 Hz), 9.95 (2H, d, J ) 8.4 Hz), 11.07 (2H,

s), 11.46 (2H, s); ¹³C NMR (TFA-CDCl₃) δ 17.4, 17.5, 20.2,

20.3, 97.3, 99.2, 119.8, 125.7, 128.4, 128.6, 129.1, 130.3, 130.9,

134.1, 134.5, 135.7, 138.0, 139.8, 141.9, 142.8, 143.4, 143.6;

HRMS (FAB) calcd for C₄₄H₃₈N₄m/z 622.3097, found 622.3096.

Anal. Calcd for C₄₄H₃₈N₄‚¹/₂H₂O: C, 83.64; H, 6.06; N, 8.87.

Found: C, 84.13; H, 5.93; N, 8.91.

1

powder: mp 194 °C dec; H NMR (CDCl₃) δ 1.04 (6H, t, J )

7.2 Hz), 2.40 (4H, q, J ) 7 Hz), 2.54 (4H, br m), 2.74 (4H, t, J

) 6.6 Hz), 3.84 (4H, s), 4.53 (4H, br s), 6.73 (2H, br t), 6.87

(4H, br d), 7.07-7.10 (6H, m), 7.16-7.19 (4H, m), 8.07 (2H,

d), 8.94 (1H, br s), 11.01 (2H, br s); ¹³C NMR (CDCl₃) δ 16.9,

17.9, 20.5, 22.4, 31.4, 67.3, 115.8, 119.5, 120.9, 122.4, 126.5,

126.7, 127.0, 127.9 (2), 128.2, 128.6, 128.8, 131.3, 131.5, 135.3,

137.3, 162.9. Anal. Calcd for C₅₀H₄₇N₃O₄: C, 78.65; H, 6.28;

N, 5.57. Found: C, 78.42; H, 6.08; N, 5.65.

7,8,17,18-Tetraethyl-3¹,3²,12¹,12²-tetrahydrodinaphtho-

[1,2-b:2,1-l]porphyrin (28). Tripyrrane benzyl ester 26a

(0.500 g) was placed in a hydrogenation vessel along with

anhydrous THF (62 mL). Methanol (21 mL) and triethylamine

(8 drops) were added to the vessel, and the resulting solution

was purged under nitrogen for several minutes. Palladium on

activated carbon (10%; 100 mg) was added and the vessel

placed on the Parr hydrogenator. The mixture was shaken at

45 psi under a hydrogen atmosphere at room temperature for

16 h. The catalyst was removed by suction filtration and the

vessel washed with small portions of ethanol. The filtrate was

evaporated under reduced pressure to give a pink residue,

which was taken up in a 3% aqueous ammonia solution. The

aqueous solution was cooled to 5 °C with an ice/salt bath and

neutralized to litmus endpoint with glacial acetic acid, main-

taining the temperature between 0 and 5 °C. The resulting

mixture was allowed to stand and 0 °C for 1 h and the

precipitate collected by suction filtration and washed repeat-

edly with water to remove all traces of acetic acid. The

tripyrrane dicarboxylic acid was dried overnight in vacuo. The

Nickel(II) Complex 29b. Dinaphthoporphyrin 29a (10.1

mg) and nickel(II) acetate tetrahydrate (25 mg) were stirred

in DMF (10 mL) under reflux conditions for 2 h. The solution

was then cooled to room temperature, diluted with chloroform,

and washed with three 200 mL portions of water. The organic

layers were evaporated under reduced pressure, and the

resulting residue was recrystallized from chloroform-metha-

nol to give the nickel complex (10.2 mg, 93%) as deep purple

sheets: mp >300 °C. UV-vis (CHCl₃) λ_max(log ꢀ) 420 (5.27),

546 (4.04), 591 (4.87); UV-vis (2% pyrrolidine-CHCl₃) λ_max

(log ꢀ) 422 (sh, 5.03), 444 (sh, 5.12), 451 (5.14), 554 (4.08), 593

1

(4.61), 610 nm (sh, 4.51); H NMR (CDCl₃) δ 1.86 (6H, t, J )

7.6 Hz), 1.92 (6H, t, J ) 7.6 Hz), 3.95-4.07 (8H, m), 7.86 (2H,

t, J ) 7.2 Hz), 8.13 (2H, t, J ) 7.6 Hz), 8.38-8.42 (4H, m),

(53) Sessler, J. L.; Mozaffari, A.; Johnson, M. R. Org. Synth. 1991,

70, 68.

(54) Tardieux, C.; Bolze, F.; Gros, C. P.; Guilard, R. Synthesis 1998,

267.

J. Org. Chem, Vol. 70, No. 3, 2005 887

Manley et al.

9.32 (2H, d, J ) 8.4 Hz), 9.83 (2H, d, J ) 8.4 Hz), 10.12 (2H,

s), 10.78 (2H, s); HRMS (EI) calcd for C₄₄H₃₆N₄Ni m/z 678.2293,

found 678.2293.

J ) 3.4 Hz), 8.00 (1H, d, J ) 9.2 Hz), 8.15 (1H, d, J ) 7.9 Hz),

10.2 (1H, br s); ¹³C NMR (CDCl₃) δ 30.0, 82.5, 115.6, 116.2,

121.2, 123.4, 123.7, 125.6, 126.1, 127.7, 127.9, 129.1, 129.7,

131.6, 162.8; EI MS (70 eV) m/z 267 (9.5, M⁺), 239 (2.1), 211

(55), 193 (100), 167 (91), 139 (59). Anal. Calcd for C₁₇H₁₇NO₂:

C, 76.38; H, 6.41; N, 5.24. Found: C, 75.98; H, 6.32; N, 5.24.

Copper(II) Complex 29c. Dinaphthoporphyrin 29a (10.0

mg) and copper(II) acetate monohydrate (25 mg) were stirred

in DMF (10 mL) under reflux conditions for 2 h. The solution

was then cooled to room temperature, diluted with chloroform,

and washed with water. The organic layer was evaporated

under reduced pressure and the resulting residue recrystal-

lized from chloroform-methanol to give the copper complex

(8.1 mg, 74%) as deep green sheets: mp >300 °C; UV-vis

(CHCl₃) λ_max(log ꢀ) 397 (sh, 4.53), 424 (5.13), 550 (4.07), 596

nm (4.52); UV-vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 397 (sh)

(4.50), 424 (5.10), 551 (4.06), 596 (4.50), 633 (sh) (4.03); HRMS

(EI) calcd for C₄₄H₃₆N₄Cu m/z 683.2236, found 683.2246.

Zinc(II) Complex 29d. Dinaphthoporphyrin 29a (10.0 mg)

and zinc acetate dihydrate (25 mg) were stirred in DMF (10

mL) under reflux conditions for 2 h. The solution was then

cooled to room temperature, diluted with chloroform, and

washed with water. The organic layer was evaporated under

reduced pressure and the resulting residue recrystallized from

chloroform-methanol to give the zinc complex (10.2 mg, 93%)

as deep green sheets: mp >300 °C; UV-vis (CHCl₃) λ_max(rel

int) 430 (1.00), 563 (0.08), 603 nm (0.24); UV-vis (2% pyrro-

lidine-CHCl₃) λ_max(log ꢀ) 419 (4.64), 422 (sh, 5.48), 444 (5.62),

568 (4.34), 611 nm (4.85); ¹H NMR (pyrrolidine-CDCl₃) δ 2.02

(6H, t, J ) 7.6 Hz), 2.09 (6H, t, J ) 7.6 Hz), 4.23 (4H, q, J )

7.6 Hz), 4.32 (4H, q, J ) 7.6 Hz), 7.87 (2H, t, J ) 7.2 Hz), 8.20

(2H, t, J ) 7.6 Hz), 8.44 (2H, d, J ) 7.6 Hz), 8.51 (2H, d, J )

8.8 Hz), 9.62 (2H, d, J ) 8.4 Hz), 10.30 (2H, d, J ) 8.4 Hz),

10.55 (2H, s), 11.22 (2H, s); HRMS (EI) calcd for C₄₄H₃₆N₄Zn

m/z 684.2231, found 684.2213.

tert-Butyl 1-(1-Benzyloxycarbonyl-4,5-dihydronaph-

tho[1,2-c]pyrrolylmethyl)naphtho[1,2-c]pyrrole-3-car-

boxylate (30a). Acetoxymethylpyrrole 5¹⁴(0.308 g) and tert-

butyl ester 33b (0.192 g) were dissolved in acetic acid (5.0 mL)

containing p-toluenesulfonic acid (10.3 mg). The resulting

mixture was stirred at room temperature under a nitrogen

atmosphere for 2 h. The solution was then diluted with

chloroform and washed successively with water, 10% sodium

bicarbonate solution, and water, back-extracting with chloro-

form at each stage. The combined organic extracts were

evaporated under reduced pressure to give a brown residue.

Recrystallization from chloroform-hexanes gave the desired

dipyrrole (0.244 g, 58%) as off-white needles: mp 230-231 °C;

¹H NMR (CDCl₃) δ 1.63 (9H, s), 2.62 (2H, t, J ) 6.8 Hz), 2.91

(2H, t, J ) 6.8 Hz), 4.68 (2H, s), 5.26 (2H, s), 7.19-7.31 (8H,

m), 7.44-7.54 (3H, m), 7.84 (1H, d, J ) 7.6 Hz), 7.98 (1H, d,

J ) 9.2 Hz), 8.11 (1H, d, J ) 8.0 Hz), 8.42 (1H, d, J ) 6 Hz),

8.92 (1H, br s), 9.61 (1H, br s); ¹³C NMR (CDCl₃) δ 20.3, 26.8,

28.8, 31.1, 66.4, 81.5, 113.4, 116.7, 118.3, 120.5, 122.3, 123.0,

125.0, 125.5, 126.8, 127.1, 127.3, 127.6, 128.0, 128.2, 128.4,

128.6, 128.7, 128.8, 129.3, 130.7, 131.4, 136.0, 137.5, 160.6.

Anal. Calcd for C₃₈H₃₄N₂O₄‚¹/₂H₂O: C, 77.14; H, 5.79; N, 4.73.

Found: C, 77.10; H, 5.90; N, 4.78.

13,17-Dibutyl-12,18-dimethyl-3¹,3²-dihydrodinaphtho-

[1,2-b:1,2-g]porphyrin (38a). Dipyrrylmethane 30a (0.310 g)

was placed in a hydrogenation vessel and dissolved in anhy-

drous THF (50 mL). The solution was then diluted with

methanol (17 mL), and triethylamine (7 drops) was added. The

solution was purged with nitrogen for several minutes, and

10% palladium on activated carbon (100 mg) was added. The

resulting mixture was shaken under a hydrogen atmosphere

at 40 psi for 16 h at room temperature on a Parr hydrogenator.

The palladium catalyst was then removed by suction filtration

and the solvent evaporated under reduced pressure giving a

light blue residue. The residue was taken up in 3% aqueous

ammonia solution and cooled to 0 °C using an ice/salt bath.

The solution was then neutralized to a litmus endpoint with

glacial acetic acid, maintaining the temperature below 5 °C.

The mixture was allowed to stand at 0 °C for 1 h. The

precipitate was filtered under suction, washed with copious

amounts of water, and dried overnight in vacuo to give the

carboxylic acid 30b as a pink powder (0.249 g, 95%): ¹H NMR

(CDCl₃) 1.54 (9H, s), 2.74 (2H, br t), 2.90 (2H, br t, J ) 6 Hz),

2.98-3.06 (4H, m), 4.75 (2H, s), 7.12 (1H, t, J ) 7.2 Hz), 7.17-

7.22 (2H, m), 7.43 (1H, t, J ) 7.4 Hz), 7.48 (1H, d, J ) 9 Hz),

7.54 (1H, t, J ) 7.4 Hz), 7.80 (1H, d, J ) 7.6 Hz), 7.95 (1H, d,

J ) 9 Hz), 8.36 (1H, d, J ) 8 Hz), 8.57 (1H, d, J ) 7.6 Hz),

10.94 (2H, 2 broad overlapping singlets). Dipyrrylmethane 30b

(0.200 g) was treated with trifluoroacetic acid (2 mL) under a

nitrogen atmosphere for 10 min and then diluted with chlo-

roform and washed successively with water, 10% sodium

bicarbonate solution, and water. The organic phase was dried

over sodium sulfate and evaporated to dryness under reduced

pressure to give a dark purple residue. The residue and

dialdehyde 9b^31b(0.145 g) were dissolved in a mixture of

dichloromethane (45 mL) and methanol (5 mL), and the

resulting solution was placed in a 100 mL pressure equalized

addition funnel. The solution was then added dropwise over a

2 h period to a 100 mL round-bottom flask containing a stirred

mixture of p-toluenesulfonic acid (260 mg), methanol (5 mL)

and dichloromethane (45 mL) under a nitrogen atmosphere.

The deep purple solution was allowed to stir at room temper-

ature for 16 h under nitrogen. A saturated solution of Zn(OAc)₂

in methanol (10 mL) was then added and the mixture stirred

for an additional 2 days open to the air. The organic solution

was monitored every 8 h using a UV-vis spectrophotometer

Synthesis of Dinaphthoporphyrin Type D. Ethyl Naph-

tho[1,2-c]pyrrole-3-carboxylate (33a). A mixture of 1-ni-

tronaphthalene (2.005 g) and ethyl isocyanoacetate⁵⁵(1.611

g) in anhydrous THF (24.0 mL) was stirred for several

minutes, and a phosphazene base, P-t-Bu-tris-(tetramethylene)

34 (4.04 g), was then added. The solution was refluxed

overnight under anhydrous conditions. The solution was cooled

to room temperature, diluted with chloroform, and washed

with three portions of water (200 mL). The organic solutions

were combined and evaporated under reduced pressure to give

a brownish-orange oil. The residue was purified by column

chromatography on a silica gel column eluting with dichlo-

romethane. Recrystallization from 95% ethanol gave the

desired naphthopyrrole (1.60 g, 58%) as off-white crystals: mp

1

199-201 °C (lit.³⁸mp 200-202 °C); H NMR (CDCl₃) δ 1.49

(3H, t, J ) 7.2 Hz), 4.48 (2H, q, J ) 7.2 Hz), 7.47 (1H, t, J )

7.6 Hz), 7.53-7.57 (2H, m), 7.82 (1H, d, J ) 7.6 Hz), 7.87 (1H,

d, J ) 3.2 Hz), 8.03 (1H, d, J ) 9.2 Hz), 8.15 (1H, d, J ) 7.6

Hz), 9.93 (1H, br s); ¹³C NMR (CDCl₃) δ 14.9, 60.5, 114.4, 114.8,

120.2, 122.8, 122.9, 125.5, 127.0, 127.5, 128.3, 129.0, 130.0,

131.0, 162.0; EI MS (70 eV) m/z 239 (57, M⁺), 193 (100), 165

(54), 139 (36).

tert-Butyl Naphtho[1,2-c]pyrrole-3-carboxylate (33b).

A mixture of 1-nitronaphthalene (1.50 g) and tert-butyl

isocyanoacetate^15c(1.20 g) in anhydrous THF (18 mL) was

stirred until of the all reactants were dissolved. To the yellow

solution was added phosphazene base P-t-Bu-tris-(tetrameth-

ylene) 34 (3.03 g) and the mixture allowed to reflux overnight

under anhydrous conditions. The solution was cooled to room

temperature and diluted with chloroform. The chloroform

solution was then washed with water (3 × 200 mL), and the

organic solutions were combined and evaporated to give a

brownish-orange oil. The resulting crude product was purified

by column chromatography on silica gel, eluting with dichlo-

romethane. Recrystallization with 95% ethanol gave the

desired pyrrole (1.23 g, 54%) as off-white crystals: mp 169-

1

171 °C; H NMR (CDCl₃) δ 1.72 (9H, s), 7.46 (1H, t, J ) 7.5

Hz), 7.51-7.56 (3H, m), 7.82 (1H, d, J ) 7.9 Hz), 7.84 (1H, d,

(55) Hartman, G. D.; Weinstock, L. M. Org. Synth. 1979, 59, 183.

888 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

a brown residue. The residue was chromatographed twice on

to detect the emergence of a Soret band at 424 nm. The organic

mixture was then diluted further with dichloromethane and

washed successively with water, aqueous sodium bicarbonate

solution, and water, back-extracting with chloroform at each

step. The organic layers were combined and evaporated down

under reduced pressure to give a dark purple residue. The

residue was columned on grade III alumina eluting with

dichloromethane to remove tarry impurities. A second column

was performed on grade III alumina, eluting with dichlo-

romethane, and the fractions containing pure porphyrin by

TLC were combined, evaporated under reduced pressure, and

recrystallized from chloroform-methanol to give the desired

dinaphthoporphyrin (110 mg, 41%) as reddish purple fibers:

mp >300 °C; UV-vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 424 (5.34),

517 (4.16), 552 (4.45), 583 (3.99), 640 nm (4.13); UV-vis (2%

TFA-CHCl₃) λ_max(log ꢀ) 431 (5.33), 561 (sh, 4.10), 572 (4.29),

611 (4.18), 624 nm (4.26); ¹H NMR (CDCl₃) δ -3.96 (2H, br s),

1.11-1.18 (6H, 2 overlapping triplets), 1.70-1.85 (4H, m),

2.20-2.29 (4H, m), 3.50 (3H, s), 3.55 (3H, s), 3.61 (2H, t, J )

7.2 Hz), 3.92 (2H, t, J ) 7.6 Hz), 4.01 (2H, t, J ) 7.8 Hz), 4.23

(2H, t, J ) 7.2 Hz), 7.59 (1H, t, J ) 7.2 Hz), 7.76 (1H, d, J )

7.6 Hz), 7.80-7.87 (2H, m), 8.07 (1H, t, J ) 7.6 Hz), 8.34 (2H,

d, J ) 7 Hz), 9.03 (1H, d, J ) 7.6 Hz), 9.18 (1H, d, J ) 8.0 Hz),

9.84-9.85 (2H, overlapping singlet and doublet), 10.04 (1H,

s), 10.44 (1H, s), 10.69 (1H, s); ¹H NMR (TFA-CDCl₃) δ -2.97

(1H, br s), -2.81 (1H, br s), -2.62 (2H, br s), 1.05-1.12 (6H,

2 overlapping triplets), 1.60-1.73 (4H, m), 2.04-2.18 (4H, m),

3.64 (3H, s), 3.70 (3H, s), 3.97 (2H, t, J ) 7.2 Hz), 4.07-4.15

(4H, m), 4.32 (2H, t, J ) 7.4 Hz), 7.64 (1H, t, J ) 7.2 Hz),

7.77-7.82 (2H, m), 8.10 (1H, t, J ) 7.2 Hz), 8.37 (1H, t, J )

7.6 Hz), 8.56 (2H, t, J ) 7.4 Hz), 8.88 (1H, d, J ) 8.8 Hz), 9.61

(1H, d, J ) 8.8 Hz), 10.03 (1H, d, J ) 8.4 Hz), 10.58 (1H, s),

11.02 (1H, s), 11.04 (1H, s), 11.55 (1H, s); ¹³C NMR (TFA-

CDCl₃) δ 12.1, 12.2, 14.0 (2), 22.5, 23.2 (2), 26.7, 26.8, 29.8,

34.4, 34.5, 96.1, 99.1, 100.3, 101.3, 119.9, 125.7, 128.7, 128.9,

129.1, 129.6, 129.9 (2), 130.2, 130.5, 130.9, 134.0, 134.6, 135.8,

136.3, 137.7, 138.2, 138.3, 139.3 (2), 139.8, 139.9, 140.8, 142.0,

142.1, 142.2, 142.7, 143.8, 144.0; HRMS (FAB) calcd for

C₄₆H₄₄N₄+ H m/z 653.3644, found 653.3645. Anal. Calcd for

C₄₆H₄₄N₄‚¹/₂H₂O: C, 83.47; H, 6.70; N, 8.46. Found: C, 83.58;

H, 6.61; N, 8.48.

grade 3 alumina eluting with dichloromethane. The fractions

containing the porphyrin were combined, evaporated under

reduced pressure, and recrystallized from chloroform-metha-

nol to give the desired dinaphthoporphyrin (166 mg, 38%) as

reddish purple fibers: mp >300 °C; UV-vis (1% Et₃N-CHCl₃)

λ_max(log ꢀ) 424 (5.34), 513 (4.18), 552 (4.46), 584 (3.98), 641

nm (4.12); UV-vis (2% TFA-CHCl₃) λ_max(log ꢀ) 430 (5.33),

1

559 (sh, 4.10), 573 (4.30), 611 (4.19), 624 nm (4.21); H NMR

(CDCl₃) δ -3.92 (2H, br s), 3.25-3.31 (4H, 2 overlapping

triplets), 3.54 (3H, s), 3.64 (5H, overlapping singlet and triplet),

3.67 (3H, s), 3.71 (3H, s), 4.25-4.34 (4H, 2 overlapping

triplets), 4.44 (2H, t, J ) 7.8 Hz), 7.60 (1H, t, J ) 7.4 Hz),

7.77 (1H, d, J ) 7.2 Hz), 7.83-7.88 (2H, m), 8.11 (1H, t, J )

7.2 Hz), 8.40 (2H, t, J ) 8.6 Hz), 9.03 (1H, d, J ) 7.2 Hz), 9.25

(1H, d, J ) 8.4 Hz), 9.89 (1H, d, J ) 8.8 Hz), 9.95 (1H, s),

10.15 (1H, s), 10.49 (1H, s), 10.76 (1H, s); ¹H NMR (TFA-

CDCl₃) δ -2.84 (1H, br s), -2.68 (1H, br s), -2.59 (2H, br s),

3.13 (2H, t, J ) 7.6 Hz), 3.19 (2H, t, J ) 7.6 Hz), 3.65 (6H, s),

3.67 (3H, s), 3.73 (3H, s), 3.97 (2H, t, J ) 7.4 Hz), 4.32 (2H, t,

J ) 7.6 Hz), 4.45-4.53 (4H, 2 overlapping triplets), 7.65 (1H,

t, J ) 7.6 Hz), 7.78 (2H, m), 8.11 (1H, t, J ) 7.6 Hz), 8.38 (1H,

t, J ) 7.6 Hz), 8.54 (1H, d, J ) 7.6 Hz), 8.58 (1H, d, J ) 7.6

Hz), 8.90 (1H, d, J ) 9.2 Hz), 9.61 (1H, d, J ) 8.8 Hz), 10.02

(1H, d, J ) 8.8 Hz), 10.93 (1H, s), 11.03 (1H, s), 11.04 (1H, s),

11.55 (1H, s); ¹³C NMR (TFA-CDCl₃) δ 12.0, 12.1, 21.6, 21.7,

22.4, 29.6, 35.6, 35.7, 53.2, 96.4, 99.6, 100.5, 101.6, 119.8, 125.6,

128.8, 129.0 (2), 129.1, 129.6, 130.0, 130.1, 130.4, 130.5, 131.0,

134.6, 134.9, 136.0, 137.2, 138.3, 138.9, 139.3 (2), 139.6, 139.8,

140.4, 140.5, 141.0, 141.3, 141.4, 141.9, 143.6, 176.1; HRMS

(FAB) calcd for C₄₆H₄₀N₄O₄+ H m/z 713.3128, found 713.3131.

Anal. Calcd for C₄₆H₄₀N₄O₄: C, 77.51; H, 5.66; N, 7.89.

Found: C, 77.03; H, 5.64; N, 7.78.

13,17-Bis(2-methoxycarbonylethyl)-12,18-dimethyl-

dinaphtho[1,2-b:1,2-g]porphyrin (39a). Dihydrodinaphtho-

porphyrin 38a (50.0 mg) was refluxed with DDQ (17.0 mg, 1

equiv) in toluene (19 mL) for 15 min. The solvent was

evaporated under reduced pressure and the residue washed

with copious amounts of methanol. The residue was then

purified by chromatography on a silica gel column eluting with

dichloromethane. The fractions containing pure porphyrin

were combined and recrystallized from chloroform-methanol

to give 39a (26.7 mg, 53%) as dark purple crystals: mp >300

°C; UV-vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 402 (sh, 4.91), 426

(5.32), 535 (4.07), 567 (4.55), 587 (4.07), 645 nm (4.23); UV-

vis (2% TFA-CHCl₃) λ_max(log ꢀ) 438 (5.43), 581 (4.22), 630

nm (4.64); ¹H NMR (TFA-CDCl₃) δ -2.72 (1H, br s), -2.35 (1H,

br s), -2.25 (1H, v br), -1.84 (1H, v br), 3.11-3.18 (4H, 2

overlapping triplets), 3.65 (3H, s), 3.66 (3H, s), 3.72 (3H, s),

3.74 (3H, s), 4.48-4.52 (4H, m), 8.09-8.14 (2H, m), 8.35-8.43

(2H, m), 8.59 (2H, d, J ) 8.6 Hz), 8.92 (2H, d, J ) 9.2 Hz),

9.61 (1H, d, J ) 8.8 Hz), 9.68 (1H, d, J ) 8.8 Hz), 9.98 (1H, d,

J ) 8.4 Hz), 10.08 (1H, d, J ) 8.4 Hz), 10.93 (1H, s), 11.06

(1H, s), 11.48 (1H, s), 11.91 (1H, s); ¹³C NMR (TFA-CDCl₃) δ

12.1, 12.3, 21.8, 35.7 (2), 52.8, 96.9, 97.5, 99.7, 100.8, 119.8,

119.9, 125.7, 125.8, 128.1, 128.6, 128.8, 128.9, 129.1, 129.2,

130.4 (2), 131.0, 134.1, 134.2, 134.5, 135.0, 135.8, 135.9, 137.7,

137.8, 138.3, 140.3, 140.4 (2), 140.7, 141.6, 142.4, 143.0, 175.1;

HRMS (EI) calcd for C₄₆H₃₈N₄O₄m/z 711.2971, found 711.2972.

Anal. Calcd for C₄₆H₃₈N₄O₄‚¹/₂H₂O: C, 76.75; H, 5.32; N, 7.78.

Found: C, 76.34; H, 5.35; N, 7.69.

13,17-Bis(2-methoxycarbonylethyl)-12,18-dimethyl-3¹,3²-

dihydrodinaphtho[1,2-b:1,2-g]porphyrin (38b). Dipyrryl-

methane 54 (0.300 g) was treated with trifluoroacetic acid (2

mL) for 10 min under a nitrogen atmosphere. The acidic

solution was then diluted with chloroform and washed suc-

cessively with water, 10% sodium carbonate solution, and

water. The organic solutions were combined, dried over sodium

sulfate, and evaporated to dryness under reduced pressure to

give a brown residue. The residue was then combined in a

solution of dichloromethane (63 mL) and methanol (6 mL) with

dialdehyde 9c⁵⁶(0.247 g) and the resulting mixture placed in

a 100 mL pressure-equalized addition funnel. The solution was

then added dropwise under a nitrogen atmosphere over a 2 h

period to a stirred solution of p-toluenesulfonic acid (390 mg)

in methanol (6 mL) and dichloromethane (63 mL). The

resulting solution was allowed to stir at room temperature for

16 h under nitrogen. A saturated solution of zinc acetate in

methanol (10 mL) was then added and the mixture stirred for

an additional 2 days open to the air. The solution was then

diluted with dichloromethane and washed successively with

water, sodium bicarbonate, and water. The organic layer was

evaporated under reduced pressure to give a dark purple

residue. The residue was dissolved in 5% sulfuric acid/

methanol (30 mL) and allowed to stir for 24 h. The resulting

mixture was partitioned between chloroform and water, and

the chloroform layer was carried through a sequence of washes

with water, 5% sodium bicarbonate solution, and water, back-

extracting with chloroform at each step. The organic solutions

were combined and evaporated under reduced pressure to give

Nickel(II) Complex 39b. Dinaphthoporphyrin 39a (7.3

mg) and nickel(II) acetate tetrahydrate (33.4 mg) were stirred

in DMF (10 mL) under reflux conditions for 2 h. The solution

was then cooled to room temperature, diluted with chloroform,

and washed with three 200 mL portions of water. The organic

layers were evaporated under reduced pressure, and the

resulting residue was recrystallized from chloroform-metha-

nol to give the nickel complex (6.4 mg, 81%) as purple sheets:

mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 419 (5.21), 546 (4.02),

588 nm (4.77); UV-vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 423

(4.84), 449 (5.32), 569 (4.23), 590 (sh, 4.39), 604 nm (4.48); ¹H

(56) Clezy, P. S.; Fookes, C. J. R.; Liepa, A. J. Aust. J. Chem. 1972,

25, 1979.

J. Org. Chem, Vol. 70, No. 3, 2005 889

Manley et al.

NMR (CDCl₃) δ 2.98-3.05 (4H, m), 3.06 (3H, s), 3.13 (3H, s),

3.70 (3H, s), 3.71 (3H, s), 3.93-3.99 (4H, m), 7.81-7.86 (2H,

m), 7.95-8.00 (2H, m), 8.06 (1H, d, J ) 8.4 Hz), 8.21 (1H, d,

J ) 8.0 Hz), 8.29 (1H, d, J ) 8 Hz), 8.33 (1H, d, J ) 8 Hz),

8.42 (1H, d, J ) 8 Hz), 8.77 (1H, d, J ) 8.0 Hz), 9.07 (1H, d,

J ) 8.0 Hz), 9.16-9.20 (3H, m), 9.61 (1H, s), 9.66 (1H, s);

HRMS (FAB) calcd for C₄₆H₃₆N₄O₄Ni m/z 766.2089, found

766.2090.

Copper(II) Complex 39c. Dinaphthoporphyrin 39a (6.0

mg) and copper(II) acetate monohydrate (33.2 mg) were stirred

in DMF (10 mL) under reflux conditions for 2 h. The solution

was then cooled to room temperature, diluted with chloroform,

and washed with water. The organic layers were evaporated

under reduced pressure, and the resulting residue was recrys-

tallized from chloroform-methanol to give the copper complex

(5.6 mg, 86%) as dark green sheets: mp >300 °C; UV-vis

(CHCl₃) λ_max(log ꢀ) 422 (5.39), 553 (4.00), 594 nm (4.68); UV-

vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 422 (5.37), 553 (4.02),

594 nm (4.67); HRMS (FAB) calcd for C₄₆H₃₆N₄O₄Cu m/z

771.2030, found 771.2032.

Zinc(II) Complex 39d. Dinaphthoporphyrin 39a (7.2 mg)

and zinc(II) acetate dihydrate (33.7 mg) were stirred in DMF

(10 mL) under reflux conditions for 2 h. The solution was then

cooled to room temperature, diluted with chloroform, and

washed with water. The organic solution was evaporated under

reduced pressure and the resulting residue recrystallized from

chloroform-methanol to give the zinc complex (6.4 mg, 82%)

as deep green sheets: mp >300 °C; UV-vis (CHCl₃) λ_max(log

ꢀ) 411 (sh, 4.82), 433 (5.38), 562 (4.11), 602 nm (4.66); UV-vis

(2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 417 (sh, 4.68), 442 (5.57),

568 (4.24), 608 nm (4.67); ¹H NMR (pyrrolidine-CDCl₃,

downfield region only) δ 7.85-7.90 (2H, m), 8.15-8.24 (2H,

m), 8.41-8.45 (2H, m), 8.50 (2H, t, J ) 9.4 Hz), 9.55 (1H, d, J

) 8.8 Hz), 9.64 (1H, d, J ) 8.4 Hz), 10.04 (1H, s), 10.24 (1H,

d, J ) 8.8 Hz), 10.35 (1H, d, J ) 8.8 Hz), 10.46 (1H, s), 11.10

(1H, s), 11.46 (1H, s); HR (FAB) calcd for C₄₆H₃₆N₄O₄Zn m/z

772.2030, found 772.2028.

Synthesis of Dinaphthoporphyrin Type E. Diethyl

Bis(1-naphtho[1,2-c]pyrrolylmethane)-3,3′-dicarboxy-

late (40). A mixture of naphthopyrrole ethyl ester 33a (0.500

g), dimethoxymethane (0.159 g), p-toluenesulfonic acid mono-

hydrate (62 mg), and glacial acetic acid (31 mL) was allowed

to stir at room temperature under a nitrogen atmosphere for

3 days. The resulting greenish-blue, colloidal suspension was

poured into ice-water (250 mL) and was allowed to stand for

2 h at room temperature. The resulting precipitate was suction

filtered and washed with copious amounts of water. The crude

pale blue solid was heated with ethanol on a warm water bath

to dissolve any impurities and then suction filtered and dried

overnight in vacuo to give the desired dipyrrole (0.472 g, 92%)

as a pale blue powder: mp 240 °C dec; ¹H NMR (CDCl₃) δ

0.93 (6H, t, J ) 7.2 Hz), 3.39 (4H, br q), 5.44 (2H, s), 7.46-

7.56 (4H, m), 7.58 (2H, d, J ) 9 Hz), 7.82 (2H, d, J ) 8.8 Hz),

7.90 (2H, d, J ) 7.2 Hz), 8.28 (2H, d, J ) 8.0 Hz), 11.32 (2H,

br s); ¹³C NMR (CDCl₃) δ 14.1, 29.8, 60.5, 112.8, 119.1, 120.9,

123.2, 125.0, 126.4, 126.6, 127.1, 127.4, 129.0, 129.3, 131.7,

162.4. Anal. Calcd for C₃₁H₂₆N₂O₄: C, 75.90; H, 5.34; N, 5.71.

Found: C, 75.52; H, 5.33; N, 5.65.

mediately in the following reaction. Dicarboxylic acid 41 (220

mg) was dissolved in trifluoroacetic acid (1.0 mL) in a pear-

shaped flask and stirred under a nitrogen atmosphere for 10

min. A solution of monoaldehyde 9b^57,58(182 mg) in methanol

(4 mL) was added, followed immediately by the addition of 30%

HBr-AcOH (0.784 mL). The resulting mixture was allowed

to stir at room temperature under nitrogen for 30 min.

Anhydrous diethyl ether (20 mL) was then added dropwise to

give a dark red solution, which was allowed to stir under

nitrogen for an additional 2 h. The reaction mixture was

stirred in an ice-water bath for the second hour to further

induce precipitation. After this time, the precipitate was

suction filtered, washed with cold anhydrous diethyl ether, and

dried in vacuo overnight. The crude a,c-biladiene dihydrobro-

mide salt 42 (402 mg, 96%), which was obtained as dark green

crystals (mp >300 °C), was taken on without further purifica-

1

tion. H NMR (CDCl₃, downfield region only) δ 5.61 (2H, s),

7.27-7.35 (4H, m), 7.57 (2H, s), 7.65-7.83 (6H, m), 8.16 (2H,

d, J ) 8 Hz), 13.52 (2H, s), 14.40 (2H, s). Biladiene 42 (524

mg) was added to DMF (153 mL) containing zinc acetate (2.03

g) and silver iodate (2.60 g) and the mixture heated with

stirring at 160 °C for 40 min under a nitrogen atmosphere.

The mixture was then cooled to room temperature, diluted

with dichloromethane (250 mL), and suction filtered through

Celite. The filtrate was washed with water (2 × 300 mL) and

dried over anhydrous sodium sulfate. The organic solution was

then evaporated under reduced pressure to yield a green

residue, which was dissolved in trifluoroacetic acid (3.0 mL)

and stirred under nitrogen for 10 min. The acidic solution was

then diluted with dichloromethane (150 mL), washed succes-

sively with water, 5% sodium bicarbonate, and water, and

dried over anhydrous sodium sulfate. The solvent was removed

under reduced pressure and the purple residue chromato-

graphed on grade III alumina eluting with dichloromethane

to remove tarry byproducts. A second column was then

performed on grade III alumina eluting with 5% hexanes in

dichloromethane. The fractions containing pure porphyrin

were combined, evaporated under reduced pressure, and

recrystallized from chloroform-methanol. The title porphyrin

(28 mg, 6.8%) was obtained as purple crystals: mp >300 °C;

UV-vis (1% Et₃N-CHCl₃) λ_max(log ꢀ) 400 (sh, 4.92), 427 (5.29),

535 (4.16), 568 (4.62), 588 (4.15), 646 nm (4.31); UV-vis (2%

TFA-CHCl₃) λ_max(log ꢀ) 436 (5.45), 579 (4.26), 629 nm (4.61);

¹H NMR (CDCl₃) δ -3.51 (2H, br s), 1.15 (6H, t, J ) 7.4 Hz),

1.76-1.84 (4H, m), 2.26-2.32 (4H, m), 3.65 (6H, s) 4.04 (4H,

t, J ) 7.6 Hz), 7.94 (2H, t, J ) 7.4 Hz), 8.25 (2H, t, J ) 7.4

Hz), 8.47 (2H, d, J ) 8.0 Hz), 8.54 (2H, d, J ) 8.4 Hz), 9.49

(2H, d, J ) 8.4 Hz), 10.00 (1H, s), 10.22 (2H, d, J ) 8.8 Hz),

10.41 (2H, s), 11.91 (1H, s); ¹H NMR (TFA-CDCl₃) δ -2.98 (2H,

br s), -2.0 (2H, v br), 1.08 (6H, t, J ) 7.2 Hz), 1.61-1.70 (4H,

m), 2.06-2.15 (4H, m), 3.70 (6H, s), 4.12 (4H, t, J ) 7.8 Hz),

8.13 (2H, t, J ) 7.6 Hz), 8.39 (2H, t, J ) 7.6 Hz), 8.62 (2H, d,

J ) 8.4 Hz), 8.95 (2H, d, J ) 8.4 Hz), 9.65 (2H, d, J ) 8.4 Hz),

10.04 (2H, d, J ) 8.0 Hz), 10.70 (1H, s), 11.17 (2H, s), 12.49

(1H, s); ¹³C NMR (TFA-CDCl₃) δ 12.1, 13.9, 23.2, 26.7, 34.5,

97.4, 99.2, 100.3, 119.9, 125.6, 128.0, 128.6, 129.1, 130.6, 131.1,

134.6, 135.0, 135.9, 137.4, 138.5, 140.7, 141.5, 142.8, 143.9;

HRMS (FAB) calcd for C₄₆H₄₂N₄+ H m/z 651.3489, found

651.3488. Anal. Calcd for C₄₆H₄₂N₄‚¹/₂H₂O: C, 83.73; H, 6.42;

N, 8.42. Found: C, 83.24; H, 6.24; N, 8.47.

13,17-Dibutyl-12,18-dimethyldinaphtho[2,1-b:1,2-g]por-

phyrin (43a). Sodium hydroxide (1.10 g) in water (5 mL) was

added to dipyrrole 40 (250 mg) in methanol (13 mL) and

hydrazine (25 drops) and the resulting mixture refluxed under

a nitrogen atmosphere for 24 h. The mixture was cooled to

room temperature and diluted with water (60 mL). The

resulting cloudy solution was then cooled to 0 °C with the aid

of an ice-salt bath and the aqueous mixture neutralized to

litmus endpoint with glacial acetic acid, maintaining the

temperature between 0 and 5 °C. The resulting precipitate was

then suction filtered, washed with copious amounts of water,

and dried overnight in vacuo to yield dicarboxylic acid 41 (189

mg, 85%) as a light purple powder. Crude 41 proved to be

rather unstable when exposed to air and was used im-

Nickel(II) Complex 43b. Dinaphthoporphyrin 43a (6.4

mg) and nickel(II) tetrahydrate (33 mg) were stirred in DMF

(10 mL) under reflux conditions overnight. The solution was

then cooled to room temperature, diluted with chloroform, and

washed with three 200 mL portions of water. The organic

layers were evaporated under reduced pressure, and the

resulting residue was recrystallized from chloroform-metha-

nol to give the nickel complex (5.1 mg, 73%) as dark purple

sheets: mp >300 °C; UV-vis (CHCl₃) λ_max(log ꢀ) 418 (5.14),

(57) Lash, T. D.; Mani, U. N.; Drinan, M. A.; Hall, T.; Zhen, C.;

Jones, M. A. J. Org. Chem. 1999, 64, 464.

(58) Fischer, H.; Bertl, M. Z. Physiol. Chem. 1934, 229, 37.

890 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of Isomeric Angularly Annealed Dinaphthoporphyrin Systems

547 (3.96), 590 nm (4.67); UV-vis (2% pyrroldine-CHCl₃) λ_max

(log ꢀ) 419 (5.02), 448 (4.82), 548 (sh, 3.90), 591 nm (4.55); ¹H

NMR (CDCl₃) δ 1.10 (6H, t, J ) 7.4 Hz), 1.64-1.72 (4H, br

m), 2.02-2.10 (4H, br m), 3.25 (6H, s), 3.60-3.66 (4H, br m),

7.85 (2H, t, J ) 7.0 Hz), 8.06 (2H, t, J ) 7.2 Hz), 8.25 (2H, d,

J ) 8.4 Hz), 8.34 (2H, d, J ) 8 Hz), 8.95 (2H, br), 9.20 (1H, br

s), 9.52 (4H, br m), 10.91 (1H, br s); HRMS (FAB) calcd for

C₄₆H₄₀N₄Ni m/z 706.2606, found 706.2606.

Copper(II) Complex 43c. Dinaphthoporphyrin 43a (6.1

mg) and copper(II) acetate monohydrate (32 mg) were stirred

in DMF (10 mL) under reflux conditions overnight. The

solution was then cooled to room temperature, diluted with

chloroform, and washed with water. The organic solution was

evaporated under reduced pressure and the residue recrystal-

lized from chloroform-methanol to give the copper complex

(5.4 mg, 81%) as dark green sheets: mp >300 °C; UV-vis

(CHCl₃) λ_max(log ꢀ) 398 (sh, 4.67), 422 (5.30), 553 (3.97), 597

nm (4.56); UV-vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 397 (sh,

4.65), 422 (5.28), 554 (3.97), 597 nm (4.57); HRMS (FAB) calcd

for C₄₆H₄₀N₄Cu m/z 711.2549, found 711.2549.

reduced pressure and the residue recrystallized from chloroform-

methanol to give the zinc complex (7.2 mg, 79%) as greenish-

blue sheets: mp >300 °C; UV-vis (CHCl₃) λ_max440, 567, 603,

610 nm (sh); UV-vis (2% pyrrolidine-CHCl₃) λ_max(log ꢀ) 417

(sh, 4.74), 442 (5.56), 568 (4.30), 603 (4.63), 612 nm (sh, 4.68);

¹H NMR (pyrrolidine-CDCl₃, downfield region only) δ 7.91

(2H, t, J ) 7.6 Hz), 8.28 (2H, t, J ) 7.4 Hz), 8.47 (2H, d, J )

7.6 Hz), 8.53 (2H, d, J ) 8.0 Hz), 9.64 (2H, d, J ) 8.4 Hz),

10.08 (1H, s), 10.54 (4H, d), 10.55 (2H, s), 12.33 (1H, s); HRMS

(EI) calcd for C₄₆H₄₀N₄Zn m/z 712.2541, found 712.2544.

Acknowledgment. This work was supported by the

National Science Foundation under Grant No. CHE-

0134472 and the Petroleum Research Fund, adminis-

tered by the American Chemical Society. J.M.M. also

acknowledges a summer fellowship from Abbott Labo-

ratories.

1

Supporting Information Available: UV-vis, H NMR,

Zinc(II) Complex 43d. Dinaphthoporphyrin 43a (8.3 mg)

and zinc(II) acetate dihydrate (32 mg) were stirred in DMF

(10 mL) under reflux conditions for 2.5 h. The solution was

then cooled to room temperature, diluted with chloroform, and

washed with water. The organic solution was evaporated under

¹³C NMR, and mass spectra for selected compounds are

provided. This material is available free of charge via the

Internet at http://pubs.acs.org.

JO040269R

J. Org. Chem, Vol. 70, No. 3, 2005 891

Article Doi

Synthesis of isomeric angularly annealed dinaphthoporphyrin systems: Examination of the relative positioning and orientation of ring fusion as factors influencing the porphyrin chromophore

DOI: 10.1021/jo040269r

Source and publish data:

Authors:

Article abstract of DOI:10.1021/jo040269r

Full text of DOI:10.1021/jo040269r

Products guided by the article

R&D Labs maybe for 845784-96-5

Relevant to this article

Hot Product