Proximate, "Parallel-In-Plane" Preoriented Bis(diazenes) - In-Plane Delocalized Bis(homoconjugated) 4N/5(6)e Anions

FULL PAPER

Proximate, ‘‘Parallel-In-Plane’’ Preoriented Bis(diazenes) ؊ In-Plane

Delocalized Bis(homoconjugated) 4N/5(6)e Anions

Eberhard Beckmann,*^[a]Nicolaus Bahr,^[a]Oliver Cullmann,^[a]Fushun Yang,^[a]

Markus Kegel,^[a]Markus Vögtle,^[a]Kai Exner,^[a]Manfred Keller,^[a]Lothar Knothe,^[a]and

Horst Prinzbach^[a]

Keywords: Azo compounds / Cyclic voltammetry / Density functional calculations / Homoconjugation

˚

Synthetic details are presented for a series of more or less

enes) (d_N=N/N=Nca. 3.3 A; ω 142−146°) provide more insight

rigid, ‘‘parallel-in-plane’’ preoriented bis(diazenes), with N= into the structural prerequisites for bis(homoconjugative) in-

˚

N/N=N distances (d) of 3.3−2.9 A and interorbital angles (ω)

of 142−164° (X-ray crystal structures). DFT calculations

plane electron delocalization in 4N/5e radical anions and 4N/

6e dianions.

(B3LYP/6−31G*) and one-/two-electron reduction experi- ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,

ments with the two least preoriented, most ‘‘distant’’ bis(diaz-

Germany, 2003)

Introduction

Bis(diazenes) of type AϪD (Figure 1) had provided the

playing ground for our partly long-lasting^[1,2]attempts to

effect photochemical NϭN/NϭN ([2ϩ2]) cycloaddition^[3]

as a route to the still unknown^[4]tetrazetidines. Judged by

the degree of preorientation between the NϭN/NϭN chro-

mophores Ϫ as defined by NϭN/NϭN distance (d) and

π-orbital alignment (ω), originally calculated by force-field

(MMX)^[5]and semiempirical (AM1) techniques^[6]and re-

cently by DFT methods (B3LYP/6Ϫ31G*, Figure 1)^[7]

Ϫ

cycloaddition seemed to have a good chance. After all, for

the geometrically closely related CϭC/CϭC^[8]and NϭN/

CϭC^[9]systems, [2ϩ2] cycloaddition had been established

as highly efficient if not exclusive photochemical pathway.

In the end, though, in no case was NϭN/NϭN photocy-

cloaddition observed. Arguments have been put forward for

why cycloaddition could not compete with more or less ra-

pid N₂elimination even in the most promising, near to per-

fectly syn-periplanar, A-systems.^[10,11]One such argument

was based on the fact that exothermic metathetical iso-

merization into the B-type isomers, via the respective tetra-

zetidine N-Oxides as vibrationally excited transients,^[12]

might become a highly competitive process after N-oxi-

dation of A-type bis(diazenes).^[1,13]In contrast, various

B-,^[13]C-,^[14]and D-type N-Oxides,^[15]in which metathesisis

significantly endothermic, underwent only standard photo-

processes (deoxygenation, oxaziridine formation).^[2cϪ2e]

[a]

Chemisches Laboratorium der Universität Freiburg i.Br.,

Institut für Organische Chemie und Biochemie,

Albertstraße 21, 79104 Freiburg i. Br., Germany

Fax: (internat.) ϩ49-(0)761-2036048

Figure 1. Calculated (B3LYP/6Ϫ31G*) NϭN/NϭN-distances (d,

˚

A) and interorbital angles (ω,°) of bis(diazenes) AϪE (for R ϭ H,

E-mail:hprinz@orgmail.chemie.uni-freiburg.de

m ϭ n ϭ 1)

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DOI: 10.1002/ejoc.200300298

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Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

The bis(diazenes) AϪD experienced a much acclaimed

comeback with the discovery Ϫ initiated by the one-/two-

electron oxidation of similarly preoriented CϭC/CϭC sub-

strates (‘‘pagodadienes") to highly persistent, in-plane delo-

calized σ-bis(homoconjugated) cations [4C/3(2)e]^[16]Ϫ that

one-/two-electron reduction provides access to in-plane σ-

bis(homoconjugated) radical anions (4N/5e) and σ-bis(ho-

moaromatic) dianions (4N/6e) with theoretically novel

bonding.^[17Ϫ19]Tetra N-Oxides were subsequently shown to

undergo one-/two-electron oxidation to equally intriguing

cations [4N/3(2?)e, cubic 4O4N/11(10)e?].^[20]

In this paper we present an updated, full account of our

activities directed towards the synthesis of B-, C-, and D-

type bis(diazenes), which in the greater part have already

been employed in photochemical and electron-transfer

studies. In addition, recent electron-transfer experiments

with two B-type bis(diazenes) featuring NϭN/NϭN dis-

tances close to the van der Waals limit and performed in the

hope of gaining more insight into the structure/persistence

relationship of the 4N/5(6)e bonding motifs are also re-

ported.

In this last context, bridging α to the NϭN double bonds

as in, for example, the hexacyclic skeleton E, has been pur-

sued as a means through which to prohibit diazene Ǟ hy-

drazone tautomerization and to enforce closer ‘‘proximity’’.

From calculations,^[21]E-type bis(diazenes), optimally ‘‘pre-

oriented’’ with appreciable exothermicity for their meta-

thetical isomerization, had emerged as first choice targets

for the demonstration of photo[2ϩ2] cycloadditions.^[2b,2e]

Most regrettably, though, numerous attempts to construct

such E-type skeletons had met with failure.^[2cϪ2e]

Results and Discussion

Scheme 1. a) CH₃Li/CeCl₃, THF, room temp., 2 h; 85 (50Ϫ70)%;

b) PCC, K₂CO₃, room temp., 10 h, 77%; c) N₂H₄·H₂O, ethanol,

room temp., 10 h, 100%; d) N₂H₄·H₂O, ethanol, room temp. Ǟ 80

°C, 4 d; ca. 75(50); e) C₆H₅CH₂Br, DMSO, K₂CO₃, room temp. Ǟ

40 °C, 10 h, 41%; f) C₆H₅SO₂Cl, pyridine, 12 h, 90%; g) CH₃OH,

1. Syntheses

B-Type Bis(diazenes) 4b؊f (Scheme 1):^[22]The synthesis

of bis(diazene) 4a, the parent B structure, from bicyclic di- room. temp. Ǟ 40 °C, 85%; h) Br₂, CH₂Cl₂, room. temp., 2.5 h,

enedione 1a and hydrazine hydrate has been described in

75%

detail in the context of our attempts to use NϭN/NϭN

complexation as a way to enforce closer proximity.^[23]To

recap, after a smooth double Michael addition of hydrazine

to 1a, cyclization [cf. bis(pyrazolidine) 6], and dehydration, had after 10 h changed into a single product (TLC). After

vigorous ‘‘one-pot’’ conditions (80 °C, sealed ampoule, evaporation, the air-sensitive 3b was isolated nearly quanti-

10 d^[2i]) were necessary to effect the isomerization of the, tatively and, being highly air-sensitive, was used without

thermodynamically less stable bis(pyrazoline) [bis(hydraz- further purification. Obviously, the Michael additions had

one)] 3a to 4a. The poor yield (40Ϫ50% of 4a, together with occurred in an α-specific manner and the subsequent con-

polymers) had been attributed to the lack of stereocontrol densations only in intercyclic fashion, bridging C4/C2 and

in the Michael addition steps and to the loss of highly C8/C6 (rather than C4C/6 and C8/C2). On standing, 3b

strained 3a through polymerization. The 10,11-and 1,6-di- slowly equilibrated to a ca. 9:1 mixture with 4b, CH₃/CH₃

methyl-bis(diazenes) 4b and 4c were approached anal- steric strain in the more rigid 4b being the probable cause

ogously from the 1,5-dimethyl- and 4,6-diene-2,6-diones 1b for this thermodynamic situation.^[25]Under forcing ‘‘one-

and 1c. For the reaction between 1b (from butane-2,3-dione pot’’ conditions, the 9:1 equilibrium mixture of 3b and 4b

and dimethyl 2-oxomalonate)^[24]and hydrazine, steric pro- was produced in ca. 75% yield with bis(pyrazolidine) 6 as a

tection of the convex side (α) by the methyl groups prom- ¹H NMR spectroscopically identifiable intermediate. Still,

ised higher selectivity in the Michael addition steps. In fact, selective solubility Ϫ extraction with water (3b) or CH₂Cl₂

when 1b was added very slowly to an excess of N₂H₄·H₂O (4b) Ϫ provided a convenient means of separation and, by

(ethanol) at room temperature, a complex reaction mixture repeated equilibration, the tedious acquisition of 4b.

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Access to dienedione 1c as precursor of 4c was first at- mide 10 and Schwesinger’s P₂F base,^[33]β-elimination pro-

tempted through a double Michael addition of a methyl ved straightforward, the strongly bent^[34]ene/bis(diazene)

cuprate to 1a and dehydrogenation.^[26]The α,α-dimethyl di- 11 being, as might be expected,^[35]very prone to polymeriz-

ketone 7 was formed highly selectively by addition of Me_2-ation.

CuLi to 1a, but no means to effect the dehydrogenation

could be found. ‘‘Alkylative 1,3-carbonyl transposition’’^[27]

(1a Ǟ 2 Ǟ1c) provided the solution. Whilst 1a instan-

taneously polymerized upon contact with CH₃Li or

[28]

CH₃MgBr, it selectively added the reagent CH₃Li/CeCl₃

from the convex (α) side to give the C₂-symmetrical 2β,6β-

bis(carbinol) 2 (85%) via the spectroscopically identified in-

termediate 5. For the subsequent double rearrangement/

oxidation sequence to provide the air- and acid-sensitive 1c,

a serviceable result (77%) was achieved with pyridinium

chlorochromate/K₂CO₃. Bis(diazene) 4c was produced in

ca. 50% yield from the reaction between 1c and N₂H₄ϫ

H₂O under ‘‘one-pot’’ conditions, together with polymers

(cf. 4a). As also demonstrated with 1b, in the reaction per-

formed at room temperature, after 12 h intermediate 3c had

been formed in nearly quantitative yield and being, like 3b,

air-sensitive, was directly used. With 3c now readily to

hand, a convenient route to the 1,4,6,9-tetramethylbis(di-

The complex looking B-type bis(diazene) 20 (Scheme 2),

azene) 4d was attainable. A two-step sequence of double N- featuring an unusual oxapentaaza-cyclodecadiene subunit,

sulfonylation (3e) and double S_N2Ј substitutive alkylation was discovered fortuitously.^[36]Treatment of tetraacetyl-

of 3e with CH₃Li/CeCl₃provided 4d in an overall yield of cyclohexene 14^[37]with hydrazine had been part of a pro-

50Ϫ70%. For comparison, the total yield of the first elabor- ject^[9]to construct allylically peralkylated syn-periplanar

ated sequence Ϫ N-benzylation (3d), CH₃-addition (CH₃Li/ bis(diazenes) (kinetically stabilized tetrazetidines) via bis-

CeCl₃)/hydrazide interception (8a), hydrogenolytic depro- (isopyrazoles) such as 12 or bis(dihydropyrazines) such as

tection (8b), oxidation Ϫ was never better than ca. 10%.

13.^[38]In practice, treatment of 14 with hydrazine under

As part of our efforts directed towards the E-type skel- highly varied conditions had generally produced multi-com-

etons (Figure 1), activated bis(pyrazolines) such as 3e and ponent reaction mixtures. To avoid some of the compli-

bridgehead-halogenated bis(diazenes) such as the tetra- cations involved, anhydrous hydrazine and aprotic solvents

bromo compound 4f had figured as key intermediates. In were used. In experiments performed with an excess of re-

explorative experiments, 3e added methanol to give 4e, for- agent at 0 °C (CH₃CN), the air-sensitive hydrazone/acetal

mally a S_N2Ј substitutive methoxylation, and treatment of 15 was formed quantitatively, presumably only formally

4a with bromine afforded 4f (75%), presumably through nu- through readdition of the evolving water. Upon warming to

cleophilic addition to the corresponding hydrazones.

room temperature, 15 slowly lost water, while upon being

Like parent bis(diazene) 4a, compound 4b and the allyl- heated (60 °C) in high vacuum, dehydration, presumably to

ically substituted derivatives 4cϪf proved thermally stable 16, as a highly unstable solid material, was total. When

enough to be sublimed under reduced pressure (60Ϫ100 °C, freshly prepared 16 was treated at 0 °C with LiClO₄as a

10^Ϫ3Torr), but decomposed near their melting points. They weak Lewis acid with careful exclusion of moisture, the

could be stored at room temperature with exclusion of light thermally labile spiro(isopyrazole) 17 became the major

and air. Their preference for rather ‘‘closed’’ conformations product (60%). With 17 seemingly half way to the targeted

in solution (B, Figure 1) was manifested in, inter alia, the dispiro(isopyrazole) 12, the conditions of the condensation

degree of deshielding exerted by the NϭN double bonds on 14 Ǟ 15 were applied, first with one equivalent of hydra-

the syn-methylene protons [e.g. ∆(δ_5(12)-HϪ δ_5(12)-Ha) ϭ zine. In a very complex mixture including some oxygen-sen-

s

0.98 ppm for 4c, 1.44 ppm for 4d; cf. 1.04 ppm for 4a^[3a]]. sitive components, no individual product could be ident-

The n Ǟ π* transitions in 4b (CH₃CN, 343 nm), 4c ified. The picture was simplified by use of an increased ex-

(339 nm), and 4d (343 nm) hardly differed from that in 4a cess of reagent. When a solution of 17 and ca. four equiva-

(339 nm), but that in 4f (CH₃OH, 330 nm) was significantly lents of hydrazine in CH₃CN was stirred at 0 °C under O₂

blue-shifted.

and with exclusion of light, three (at least, by TLC) new

In the context of our longstanding interest in fulvalene- components were slowly replaced by one, C_s(or C₂) sym-

type hydrocarbons,^[29]more recently revitalized by the po- metrical (¹H, ¹³C NMR), species. This C₁₆H₂₄N₆O com-

lyunsaturated dodecahedranes (C₂₀fullerene),^[30]allylically pound (MS) was isolated in good yield (80%) in the form

brominated 4a and 4b (e.g., 4f) became of interest as poten- of pale yellowish, light-sensitive crystals, and was spectro-

tial precursors of 9a and 9b, the tetraaza analogues of the scopically identified as allylically permethylated bis(diaz-

‘‘classical’’^[31]C₁₂H₆tetraquinene and tetracyclic C₁₂H₈ene) 20. Sublimation at 160 °C/10^Ϫ6Torr was unproblem-

[10]annulene.^[32]In exploratory experiments with monobro- atic, and decomposition started only well above the melting

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in the NMR spectra of 20 (likewise 17) attested to the flexi-

bility of the cyclohexene ring.

In relation to the n Ǟ π* absorption of 4a(b) [339 (343)

nm], the longest-wavelength UV/Vis absorption of 20

[λ_max(CH₃CN) ϭ 394 nm, ε ϭ 245] was remarkably red-

shifted, raising speculations that the n-electron pairs of the

two ‘‘bridge’’ heteroatoms might extend the NϭN/NϭN

chromophore through homoconjugation. Irradiation with

monochromatic light (254 nm) only produced polymers, but

use of a sensitizer (acetone) and n Ǟ π*-excitation selec-

tively gave the ‘‘reluctant’’ monodiazene 22 (Scheme 3). As

pointed out previously,^[1a]a geometrically very similar

˚

model diene (d ϭ 3.10 A, ω ϭ 153.3°) efficiently underwent

CϭC/CϭC photocycloaddition.^[11]The relatively rigid,

nearly in-plane orientation of the NH₂group and the proxi-

˚

mate NϭN double bonds (distances of ca. 2.9 A) suggested

a route to the all-cis-persubstituted pentazolidine 24

through bis(homoconjugate) [2ϩ2ϩ2] cycloaddition in the

corresponding aminonitrene 23.^[40]Like tetrazetidines,

pentazolidines are a still elusive family of all-nitrogen hetero-

cycles.^[41]Oxidation of 20 with [Pb(OAc)₄] furnished a yel-

low, crystalline compound of the correct composition in

high yield [C₁₆H₂₂N₆O, 80Ϫ90%, λ_max(CH₃CN) ϭ 394 nm,

ε ϭ 245]: the tris(diazene) 25, a persubstituted oxa-hexa-

aza-cycloundecatriene with three homoconjugated NϭN

bonds, resulting from β-migration in 23. Upon n Ǟ π* exci-

tation, 25 lost two N₂units to give 26 (39%) together with

polymers.

Scheme 2. a) anhydr. N₂H₄, CH₃CN, O °C, 12 (5)h, 100(80)%, b)

10^Ϫ3Torr, room temp. Ǟ 60 °C; c) LiClO₄, CH₂Cl₂, 0 °C, 30 h,

60%; d) anhydr. N₂H₄, CH₃CN, O₂, O °C, 5 h, 80%; e) C₆H₅CHO,

p-toluenesulfonic acid, benzene, room temp., 2.5 h, 73%

point of 210 °C. The O-bridged bis(pyrazoline) 18 and the

oxygen-sensitive tris(hydrazine) 19 are plausible intermedi-

ates en route to 20. Particularly for comparison of the pho-

tochemical behavior, the Schiff base 21 was prepared. It was

possible to perform an X-ray crystal structure analysis on

crystals of 20 obtained from CH₃CN (Figure 2).^[39]With

˚

d

_avϭ 2.97 A and ω ϭ 154.3°, the proximity parameters are

significantly better than those given in Figure 1 for the par-

Scheme 3. a) 800-W daylight lamp, Solidex filter, CH₃CN, Ϫ40 °C,

ent tetramethyl-B structure.^[36]The C_ssymmetry manifested 74(39)%; b) [Pb(OAc)₄], K₂CO₃, CH₂Cl₂, room temp., 1 h, 80%

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˚

Figure 2. X-ray crystal structures of bis(diazenes) 20, 34a, 34d and bispyrazoline 33d; NϭN/NϭN distances (d, A) and interorbital

angles (ω,°)

C-Type Bis(diazenes) 34a؊f (Scheme 4): The bis(diaz- malonate, ‘‘Meerwein ester’’)^[43]Ǟ 27 Ǟ 28 Ǟ 30 Ǟ 31a

enes) 34a, 1,6-dimethyl-substituted 34b and 1,4,6,9-tetra- was developed. In the case of 31b a proven, but somewhat

methyl-substituted 34c were constructed in analogy to the modified, three-step procedure starting with formaldehyde

B-type analogues 4aϪc (Scheme 1) and in line with the and acetylacetone^[42d]was followed. Still, with 31a ex-

pioneering study of Mellor et al.^{[14,42aϪ42c]}For 34a and 34b, peditiously available, the two-step sequence worked out for

the dienediones 31a and 31b served as starting materials. 1c became an alternative. In practice, the highly side-selec-

For the preparation of 31a, the sequence from bicyclo[3.3.1]- tive (α) addition of MeLi/CeCl₃to 31a and oxidative trans-

nonane-2,6-dione (from paraformaldehyde and dimethyl position of bis(carbinol) 32 furnished 31b in up to 60%

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two-step procedure 33b Ǟ 33e Ǟ 34c (overall ca. 50%) re-

placed the preparatively unserviceable five-step route 31b Ǟ

33b Ǟ 33d (X-ray structure, Figure 2)^[39]Ǟ 35a Ǟ (35b) Ǟ

34c (ca. 10% overall^[3c,3d]).

As noted for the skeletons 4, all efforts to bridge the al-

lylic positions in 34a (C1/C4;C6/C9, cf. E, Figure 1) re-

mained without success. In this context, inter alia, the di-

methyl-dimethoxy compound 34d (see: Figure 2)^[39]and the

bridgehead-halogenated 34e and 34f were prepared.

The bis(diazenes) 34aϪf are, in common with the series

4aϪf, thermally persistent up to their melting points and

storable at room temperature in the absence of light and

oxygen. The spectral trends cited for 4aϪf as characteristics

of ‘‘proximate’’, closed conformations influenced by the

buttressing bridgehead substituents are similarly notable.

Thus, the shift differences ∆[δ_5(13)HϪ δ_5(13)Ha] increase

s

from 34a (δ ϭ1.19 ppm), to 34b (δ ϭ1.33 ppm), to 34c (δ ϭ

1.44 ppm) and the n Ǟ π* transitions are, if only very

slightly, bathochromically shifted (333 nm for 34a, 334 nm

for 34b, 335 nm for 34c). The X-ray structural analyses^[39]

˚

for 34a [d(av.) ϭ 3.04 A, calculated 3.15 A, ω ϭ 156.3°,

Figure 1] and 34d underline these trends (Table 1).

D-Type Bis(diazenes) 46: (Scheme 5)^[15]At the planning

stage, bicyclo[3.3.2]decadienedione 38^[44]had been targeted

as a precursor for the parent bis(diazene) D (Figure 1). This

approach, however, came to an early end when no way to

transform bicyclo[3.3.2]decatriene 37^[45]into 38 could be

found. Recourse was therefore made to the 9,10-benzoanel-

lated derivative 46, for which the calculated d/ω parameters

(MMX) hardly differed from those of parent D and for

which the starting material was readily accessible in the

form of benzocyclooctene-3,7-dione 39.^[46]However, the

seemingly trivial transformation 39 Ǟ 41 proved tricky. Ul-

timately, the Fetizon procedure^[47]was once more^[48]found

to be of practical use, superior to various procedures that

had been severely hampered by side reactions (primarily

bridging in the eight-membered ring^[49]).

Scheme 4. a) C₅H₅NBr₃, THF, Ϫ78 °C Ǟ room temp., 2 h, 87%;

b) CH₃ONa, DMSO, 80 °C, 2 h, 81%; c) CH₃ONa, DMSO, 90 °Ǟ

120 °C, 4 h, 68%; d) acetone, sulfosalicylic acid, 40 °C, 6 h, 90%;

e) CH₃Li/CeCl₃, THF, diethyl ether, room temp.2(10)h; 82(71)%; f)

PCC, K₂CO₃, room temp., 10 h, 77%; g) N₂H₄·H₂O, ethanol, room

temp. 15 h; 100%. h) N₂H₄·H₂O, ethanol, K₂CO₃, reflux, 7 h, 60%;

i) C₆H₅CH₂Br, DMF, K₂CO₃, 80 °C, 16 h, 60(70)%; k) C₆H₅SO₂Cl,

pyridine, room temp.,12 h, 72%; l) CH₃OH, room. temp. Ǟ 40 °C,

80%; m) Br₂, CH₂Cl₂, Ϫ78 °C Ǟ room. temp., 82(84)%; n) NCS,

CHCl₃, room temp., 4 h, 92%

The intermediate bis(enolate) provided effective charge

separation and thus a moderately selective formation of the

C₂-symmetrical bis(enol) ester 40 (66%). Hydrogenolysis of

this to give the diene 41, though, turned out to be somewhat

erratic (60Ϫ90%), primarily due to the difficulty in con-

yield. From the controlled reactions of 31a and 31b with trolling overreduction. In exceptional cases, the yield could

N₂H₄·H₂O the bis(pyrazolines) 33a and 33b were produced drop to ca. 30%. The reagent of choice for the twofold

nearly quantitatively and, being less torsionally strained but epoxidation of waxy solid 41 was dimethyldioxirane

still air-sensitive, were used directly after evaporation of the (DMDO) α,α-diepoxide 42 accounted for ca. 80% of the

reaction solutions. Under conditions somewhat less forcing quantitatively produced mixture with the α,β isomer. After

than the ‘‘one-pot’’ operations with 1a or 1c, the yields this mixture had been exposed to standard conditions for

achieved for 34a and 34b were higher (60 and 80%). For the epoxide Ǟ allylic alcohol rearrangement (LDA/THF), only

synthesis of the tetramethyl compound 34c, as for 4d, the the major 2α,6α-diol 43 was isolated after chromatographic

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chemistry formulated in 42 and 43 was not unequivocally

1

corroborated by the H NMR spectroscopic data but was

highly plausible in view of the established α-additions to the

carbonyl groups of 39. When 44a was added slowly to a

vast excess of N₂H₄·H₂O at room temperature, C₂-sym-

metrical bis(pyrazoline) 45a was the rapidly and quantitat-

ively generated product, which was derivatized as the bis-

(acetamide) 45b. Bis(diazene) 46 was expected to be

thermodynamically less stable than 45a; and indeed, under

‘‘one-pot’’ conditions, not even traces of 46 were produced.

A detour through reduction of 45a to the bis(hydrazine)

47 (with NaBH₃CN^[51]rather than LiAlH₄/AlCl₃^[52]) and

immediate oxidation (CuCl₂) was straightforward. During

chromatography of the crude material on base-treated silica

gel, however, 46 (60Ϫ75% isolated) was partly isomerized

back to 45a. The isomerization was rapid and total upon

addition of acetic acid to a solution of 46 in ethanol. H,H

Coupling

constants

[J_{1,13(4,13)(6,10)(9,10)}

ϭ

11.0,

J_{1,14s(4,5s)(5s,6)(9,14s)}ϭ 5.4, J_{1,14a(4,5a)(5a,6)(9,14a)}ϭ 3.0 Hz] and

n Ǟ π* absorption (CH₃OH, 336 nm) fitted with expec-

tations based on the rather ‘‘closed’’ structure calculated for

parent D-bis(diazene).

2. Electron Transfer to the Bis(diazenes) 4a and 4d

Ϫ

For the reported M^ϩ4N/5e·

and 2M^ϩ4N/6e^2Ϫion

pairs,^[17Ϫ19]the calculated differences in NϭN/NϭN pre-

orientation (counter-ion-free d: 2.7Ϫ3.0 A, ω: 179Ϫ163°;

˚

Ϫ

˚

d: 2.6Ϫ2.7 A, ω: 180Ϫ175°) in ion pairing and kinetic pro-

tection were manifested in their greatly differing lifetimes.

Thus, the green radical anions (λ_maxϭ 700Ϫ900 nm) gener-

ated through short contact of the A- (A_12,A₂₂), C- (34a,

34c), and D-type (46) bis(diazenes) to Li, K, or Cs either

persisted at room temperature for days or even months

(A₁₂, A₂₂, 34c), or decayed within minutes if not seconds

(34a, 46). Nevertheless, all five radical anions could be ana-

lyzed spectroscopically by ESR, and the three most persist-

ent ones (Li^ϩA₁₂· ^Ϫ, Li^ϩA₂₂· ^Ϫ, Li^ϩ34c· ^Ϫ) allowed smooth

reduction to the golden yellow (red at NMR concen-

trations) 2Li^ϩA₁₂^2Ϫ, 2Li^ϩA₂₂^2Ϫ, and 2Li^ϩ34c^2Ϫdianions

(λ_maxϭ 360Ϫ430 nm), the absorbance remaining constant

for weeks. Thermodynamically meaningful information be-

came available when the first and second reduction poten-

tials (E_1/2ca. Ϫ2.4; Ϫ2.9 V) were recorded by cyclic voltam-

metry for the most proximate A₁₂and A₂₂bis(diazenes),

together with the first reduction potential (E_1/2ϭ Ϫ2.72 V)

for the more ‘‘distant’’ 34c.

Scheme 5. a) (CH₃)₂CHLi, THF, Ϫ78 °C Ǟ room temp., TMEDA,

diethyl chlorophosphate, room temp., 66%; b) Li, NH₃, Ϫ78 °C,

tBuOH, 96%; c) DMDO, acetone, room temp., 10 h, 100%, d)

(CH₃)₂CHLi, THF, Ϫ78 °C Ǟ room temp., 72%; e) pyridinium

dichromate, CH₂Cl₂, 2 h, 45Ϫ60%; f) N₂H₄ϫH₂O, methanol, room

temp. 10 h; 100%. g) NaCNBH₃, methanol, room temp., 48 h,

CuCl₂, NH_3,, 60Ϫ75%. h) CH₃CO₂H, ethanol

In Figure 1, the B₁₁-bis(diazenes) (4a, 4d) possess the

largest NϭN distances, close to the limiting van der Waals

distance, and the smallest interorbital angles. These skel-

etons also display the highest mobility and so adjust more

easily to the geometrical changes necessitated by the re-

spective, ‘‘tighter’’ 4N/5(6) anions, but could also avoid the

workup (72%), and this was oxidized to give the crystalline imposed concentration of charge by changing into more

diene-2,6-dione 44a, if only in modest yield (45Ϫ60%, λ_max‘‘extended’’ conformations. From the B3LYP/6Ϫ31G* cal-

(MeOH) ϭ 363, 236 nm; cf. λ_max(EtOH) ϭ 314, 230 nm culations,^[7]the counter-ion-free anions derived from 4a and

for cycloocten-2-one^[50]). It should be added that the stereo- 4d emerged as cyclically in-plane delocalized 4N/5(6)e·^Ϫ

4254

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Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

species (Scheme 6). Extended localized conformations (e.g.,

In UV-monitored reduction experiments with 4a (Li,

NϭN· ^Ϫ/NϭN· ^Ϫ; NϭN/NϭN^2Ϫ) were significantly higher carefully degassed and dried THF) under various con-

in energy.^[53]The changes in NϭN/NϭN distances (d), Nϭ ditions (Ϫ60 up to ϩ20 °C), rapid decomposition without

N bond lengths (dЈ), and interorbital angles (ω) on going evolution of color was noted. In the case of 4d, the color of

Ϫ

from neutral 4d to radical anion 4d·

[∆d(dЈ)

ϭ

the THF solutions changed to green, then to golden yellow

Ϫ0.34(ϩ0.056) A, ∆ω ϭ ϩ12.9°] to dianion 4d^2Ϫ[∆d(dЈ) ϭ (15Ϫ20 min, λ_maxϭ 400 nm, tailing to ca. 580 nm); this

Ϫ0.21(ϩ0.062) A, ∆ω ϭ ϩ7.4°] Ϫ as consequences of color, though, was clearly less brilliant than that seen in the

˚

homoconjugational/homoaromatic interaction Ϫ are even reduction of 34c. When such a sample was exposed to air

larger than seen for the structurally closest reductions 34c after one hour, instantaneous decoloration occurred, with-

Ϫ

2Ϫ

˚

Ǟ 34c· (∆d ϭ Ϫ0.26 A, ∆ω ϭ ϩ8.7°) Ǟ 34c (∆d ϭ out the green color of the intermediate radical anion being

Ϫ0.17 A, ∆ω ϭ ϩ5.6°). Still, with d ϭ 2.95 A (ω ϭ 158.9°) discernible,^[18a,18b]]and 4d was recovered nearly quantitat-

˚

for 4d· ^Ϫand d ϭ 2.74 A (ω ϭ 166.3°) for 4d^2Ϫ, the homo- ively. The H NMR spectra (500 MHz) of homogeneous,

l

˚

conjugate distances are longer, the interorbital angles more concentrated (ca. 4 ϫ 10^Ϫ2, brownish-red) [D₈]THF

smaller.

solutions, recorded ca. 1 hour after exposure to Li (room

temperature), proved surprisingly complex. In addition to

broad absorptions with sharp singlet signals between δ ϭ

2.1 and 1.1 ppm, presumably due to higher aggregated di-

anions, very weak signals (5Ϫ8% of total integrated inten-

sity) were recorded for, in all probability, 2Li^ϩ4d^2Ϫ, doublet

signals with δ ϭ 3.05 and 2.25 ppm (J ϭ 14.9 Hz) for 5(12)-

H_sand 5(12)-H_a, dia- and paramagnetically, respectively,

displaced versus δ ϭ 3.28/2.02 ppm for neutral 4d. The shift

differences of ∆δ ϭ ϩ0.23/Ϫ0.23 ppm, to be compared with

∆δ ϭ ϩ0.14/Ϫ0.35 for 34c Ǟ 2Li^ϩ34c^2Ϫ(2.55 Ǟ 2.41;

1.52^[54]Ǟ 1.87 δ), reflect a good in-plane alignment with

the N₄-ring for the syn-hydrogen atoms. After ca. 2 h, ad-

ditional signals appeared at δ ϭ 4.8 and 5.4 ppm and in-

creased slowly at the expense of the doublet signals of

2Li^ϩ4d^2Ϫ, disclosing the latter’s decomposition to olefinic

products. Practically total twofold reduction of a sample

after ca. 1 hour exposure to Li was confirmed when ad-

dition of deoxygenated H₂O to the brownish-red THF solu-

tion furnished the extremely oxygen-sensitive diazene/di-

hydrodiazene 48 nearly quantitatively (traces of 4d). As in

the protonation of 2Li^ϩ34c^2Ϫ, but differently from that of

the A-type dianions, homoconjugate addition (here to give

tetrazane 50) did not occur. When water was added to

samples kept much longer in contact with the metal

(50Ϫ70 h), besides mainly 4d (50Ϫ60%, oxidation of 48), a

small amount (5Ϫ10%, roughly corresponding with the

NMR proportion for 2Li^ϩ4d^2Ϫ) of a mixture of highly vol-

atile C₁₂H₁₈hydrocarbons (inter alia, isomers 49) was sepa-

rated chromatographically, but was found to be too com-

plex for individual assignments (specifically, triasterane 51,

known as a product of the direct irradiation (λ Ͼ 280 nm)

of 4d,^[2g,55]was not a major component). As before,^[18a]it

can only be speculated about the sequence of events im-

2Ϫ

plying the formal extrusion of two Li^ϩN₂· ^Ϫ(N₂/2Li^ϩN₂

?) units. Because of the very complex product composition,

neither ¹³C NMR spectroscopic data for 2Li^ϩ4d^2Ϫnor ESR

data for the radical anion (Li^ϩ4d· ^Ϫ) could be secured.

Conclusions

˚

Scheme 6. Calculated (B3LYP/6Ϫ31G*) NϭN/Nϭdistances (d, A),

˚

NϭN bond lengths (dЈ, A) and interorbital angles (ω,°) for the

The discovery of novel bonding motifs has developed

into a major reward for the enormous investment that had

gone into the synthesis of the AϪD-type bis(diazenes). It

counter-ion-free, in-plane delocalized (‘‘closed") 4d, 4d· ^Ϫand 4d^2Ϫ

.

a) 4d, Li, [D₈]THF, room temp., 1 h, H₂O; b) 4d, Li, [D₈]THF,

room temp., 50Ϫ70 h, H₂O

Eur. J. Org. Chem. 2003, 4248Ϫ4264

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4255

E. Beckmann et al.

FULL PAPER

2α,6α-Dimethylbicyclo[3.3.0]octa-3,7-diene-2β,6β-diol (2):

CeCl₃·H₂O was dehydrated at 160 °C/0.1 Torr for 8 h, and was then

flame-dried until the pink powder became grayish. Dry THF (Na/

benzophenone, 110 mL), then followed at Ϫ78 °C by MeLi

(28.0 mL, 1.6  solution in diethyl ether, 44.8 mmol), were added

dropwise to anhydrous CeCl₃(11.1 g, 44.8 mmol). After this system

had been stirred for 60 minutes, the solution of 1a (2.00 g,

14.9 mmol) in anhydrous THF (50 mL) was slowly added at room

temperature. After total conversion (3 h), the mixture was hy-

drolyzed (satd. aqueous NH₄Cl) and concentrated in vacuo. The

needs no further comment that these bis(diazenes), thanks

to the fixed cis arrangement of four nitrogen substituents

on more or less rigid carbon skeletons, are also valuable

building blocks in synthesis. A forthcoming paper will be

devoted to their use for the construction of cage structures

as potential hosts for the so far unknown bonding motifs

with seven and six electrons cyclically delocalized in the

plane made up of two parallel hydrazine units [4N/7(6)e

cations].^[56]Sound calculated and experimentally obtained

evidence is provided that Li-mediated one-/two-electron residue was extracted with diethyl ether (5 ϫ 50 mL) and the dried

organic phase (MgSO₄) was concentrated in vacuo. The solid resi-

due was flash chromatographed (silica gel, cyclohexane/ethyl acet-

ate, 1:1), the main fraction R_f(2) ϭ 0.30 was concentrated, and

colorless crystals (2.10 g, 85%) were isolated; m.p. 108 °C (cyclo-

transfer even to the comparably ‘‘distant’’ bis(diazene) 4d

Ϫ

enforces the formation of bis(homoconjugated) Li^ϩ4d·

and 2Li^ϩ4d^2Ϫion pairs, if only as minor, comparably short-

lived components of very complex ion clusters. It is reason-

able to relate the decrease in stability (persistence) of these

ion pairs, at least in part, to their geometries, with the so

far longest documented homoconjugate NϭN/NϭN dis-

tances (d) and poorest orbital alignments (ω). As stated pre-

viously,^[18a]a more quantitative assessment of the degree

1

hexane). IR (KBr): ν˜ ϭ 3350 cm^Ϫ1(OH), 1620 (CϭC). H NMR:

δ ϭ 5.85 (d, 4-,8-H), 5.61 (d, 3-,7-H), 3.08 (s, 1-,5-H), 2.17 (s, 2

OH), 1.38 (s, 2 CH₃) ppm; J_3,4ϭ 6.0 Hz. ¹³C NMR: δ ϭ 139.0 (C-

4,-8), 130.7 (C-3,-7), 82.9 (C-2,-6), 58.8 (C-1,-5), 28.2 (CH₃) ppm.

C₁₀H₁₄O₂(166.2): calcd. C 72.26, H 8.51; found C 72.60, H 8.91.

Occasionally a small amount (up to 5%) of 6β-Hydroxy-6α-methyl-

of thermodynamic stabilization [‘‘σ-bis(homoaromaticity)’’, bicyclo[3.3.0]octa-3,7-diene-2-one (5) (R_fϭ 0.14) was separated.

Colorless crystals, m.p. 64 °C (cyclohexane). IR (KBr): ν˜ ϭ 3444

ring current] in the 4N/6e dianions has to await the out-

come of ongoing calculations.

1

cm^Ϫ1(OH), 1684 (CϭO). H NMR: δ ϭ 7.68 (d, 4-H), 5.99 (d, 3-

H), 5.74 (d, 6-H)*, 5.56 (7-H)*, 3.32 (s, 1-,5-H), 2.21 (s, OH), 1.46

(s, CH₃) ppm; J_3,4ϭ 6.0 Hz. ¹³C NMR: δ ϭ 210.3 (C-2), 164.1

(C-4), 138.9 (C-6), 131.9 (C-3)*, 129.1 (C-7)*, 82.2 (C-8), 56.9

(C-1)**, 54.5 (C-5)**, 29.6 (CH₃). C₁₀H₁₄O₂(150.2) ppm.

Experimental Section

General Remarks: Melting points were determined with a Mono-

skop IV (Fa. Bock) instrument and are uncorrected. Elemental

analyses were performed by the Analytische Abteilung des Chem-

ischen Laboratoriums Freiburg i. Br. IR spectra were measured

with a PerkinϪElmer 457 or a Phillips PU 9706 machine, ¹H NMR

spectra with a Bruker AC 250 or AM 400 instrument, and ¹³C

NMR spectra with a Bruker AM 400. When necessary, assignments

were confirmed by homo- and heteronuclear decoupling and by

H,H and H,X correlation experiments. Chemical shifts are given

relative to TMS (δ ϭ 0 ppm), coupling constants in Hz; if not speci-

fied otherwise, the 250 MHz (¹H) and 100.6 MHz (¹³C) spectra re-

corded in CDCl₃are given; values marked with an asterisk are

interchangeable. Mass spectra were run with a Finnigan MAT 44S

spectrometer (EI, 70 eV, if not specified differently). All reactions

with metallorganic reagents were performed with careful exclusion

of air, the condensation reactions with hydrazine hydrate generally

in deoxygenated solutions (p.a. grade solvents). For TLC, silica gel

plates 60 F₂₅₄(Merck, Darmstadt) were used. The silica gel used

for column chromatography was purchased from Merck

10,11-Dimethyl-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodeca-

1,6-diene (3b): A solution of 1b (325 mg, 2.0 mmol) in ethanol

(25 mL) was slowly added (30 min) at room temperature to a solu-

tion of hydrazine hydrate (250 mg, 5.0 mmol) in ethanol (5 mL).

After stirring until total conversion (TLC, ca. 10 h) and concen-

tration in vacuo, the yellowish, water-soluble solid residue consisted

of practically pure, highly air-sensitive 3b (380 mg, ca. 100%), m.p.

155 °C (dec.) and was used as such. IR (KBr): ν˜ ϭ 1656 cm^Ϫ1(Cϭ

N). ¹H NMR (D₂O): δ ϭ 3.28 (d, 4-,29-H_s), 2.81 (dd, 5-,12-H_s),

2.45 (d, 5-,12-H_a), 0.92 (s, 2 CH₃) ppm; J_4,5a(9,12a)ϭ 6.0,

J_{5a,5s(12a,12s)}ϭ 18.5 Hz. ¹³C NMR (D₂O): δ ϭ 164.5 (C-1,-6), 63.8

(C-4,-9), 58.4 (C-10,-11), 32.2 (C-5,-12), 14.8 (CH₃) ppm. HRMS:

calcd. for C₁₀H₁₄N₄190.1219; found 190.1210. A sample of 3b

equilibrated after 7 days at room temp. to a ca. 9:1 mixture with 4b.

4,9-Dimethyl-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodeca-1,6-

diene (3c): See 3b. Hydrazine hydrate (400 mg, 8.0 mmol)/ethanol

(5 mL)/1c (325 mg, 2.0 mmol)/ethanol (25 mL)/30 min. After stir-

ring for ca. 12 h and concentration in vacuo, the yellowish solid

residue (380 mg) consisted of nearly pure, air-sensitive 3c, m.p. 97

°C (dec.), and was used as such. IR (film): ν˜ ϭ 1592 cm^Ϫ1(CϭN).

¹H NMR (500 MHz, CD₃OD): δ ϭ 3.27 (d, 5-,12-H_s), 2.46 (s,

(0.040Ϫ0.063 mm)

or

ICN,

Biomedicals

GmbH

(0.032Ϫ0.063 mm). The conditions for the reduction experiments

were generally those of the preceding study.^[18a]

10-,11-H), 2.39 (d, 5-,12-H_a), 1.38 (s, 2 CH₃) ppm; J_{5a,5s(12a,12s)}

ϭ

4,8-Dimethylbicyclo[3.3.0]octa-3,7-diene-2,6-dione (1c): K₂CO₃

(708 mg, 5.12 mmol) was dried at 110 °C for 4 h. After addition of

pyridinium chlorochromate (3.32 g, 15.4 mmol) and CH₂Cl₂

(35 mL) and stirring for 30 minutes, a solution of 2 (850 mg,

15.0 Hz. ¹³C NMR (CD₃OD): δ ϭ 125.9 (C-1,-6), 57.3 (C-10,-11),

45.4 (C-5,-12), 23.9 (CH₃) ppm. C₁₀H₁₄N₄(190.3): calcd. C 63.13,

H 7.42, N 29.45; found C 63.47, H 7.48, N 28.97.

5.1 mmol) in CH₂Cl₂(50 mL) was added dropwise (2 h). After the 3,8-Dibenzyl-4,9-dimethyl-2,3,7,8-tetraazatetracyclo-

mixture had been stirred for 10 h, filtered, and concentrated in

vacuo, the solid residue was chromatographed [silica gel, cyclohex-

ane/ethyl acetate, 1:1, R_f(1c) ϭ 0.28] to provide colorless crystals

[7.2.1.0^4,11.0^6,10]dodeca-1,6-diene (3d): K₂CO₃(5.46 g, 40.0 mmol)

and benzyl bromide (1.71 g, 10.0 mmol) were added to a solution

of 3c, prepared from hydrazine hydrate (800 mg, 16.0 mmol) and

1c (650 mg, 4.0 mmol) in anhydrous DMF (65 mL). After the mix-

(635 mg, 77%); m.p. 107 °C (cyclohexane). IR (KBr): ν˜ ϭ 1678

1

cm^Ϫ1(CϭO), 1604 (CϭC). H NMR: δ ϭ 5.70 (s, 3-,7-H), 3.50 (s, ture had been stirred for ca. 10 h, warmed to 40 °C for 4 h (total

l-,5-H), 2.25 (s, 2 CH₃) ppm. ¹³C NMR: δ ϭ 202.5 (C-2,-6), 174.6 conversion, TLC), and evaporated in vacuo, the solid residue was

(C-4,-8), 127.9 (C-3,-7), 57.8 (C-1,-5), 18.1 (CH₃) ppm. C₁₀H₁₀O₂

(162.2): calcd. C 74.04, H 6.23; found C 73.67, H 6.07.

dissolved in CH₂Cl₂(50 mL) and washed with phosphate buffer

(pH 7). After concentration of the dried (MgSO₄) organic phase,

4256

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Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

the solid residue (ca. 900 mg) was flash chromatographed (silica

gel, cyclohexane/ethyl acetate, 2:1), to afford oily, air-sensitive 3d

H_s), 2.53 (dd, 10-,11-H), 2.29 (dd, 5-,12-H_a), 1.32 (s, 2 CH₃) ppm;

J_4,5aϭ 8.3, J_4,5sϽ 1, J_5a,5sϭ 15.1, J_4,10ϭ 2.9, J_4,11ϭ 4.7 Hz. ¹³C

(608 mg, 41%). This, sensitive even to base-treated silica gel, was NMR: δ ϭ 102.6 (C-1,-6), 95.9 (C-4,-9), 53.7 (C-10,-11), 39.0 (C-

partly lost during its separation. IR (KBr): ν˜ ϭ 1662 cm^Ϫ1, 1489

5,-12), 22.7 (CH₃) ppm. MS (CI, isobutane): m/z (%) ϭ 191 (100)

(CϭC). ¹H NMR: δ ϭ 7.30 (m, 10-H), 4.25 (1-H) 3.81 (d, 2-H) [M ϩ H]^ϩ. C₁₀H₁₄N₄(190.3): calcd. C 63.11, H 7.43, N 29.45;

3.70 (s, 10-,11-H), 3.05 (d, 5-,12-H_s), 2.01 (d, 5-,12-H_a), 1.59 (s, 2 found C 62.65, H 7.03 N 29.14.

CH₃) ppm; J_C,Hϭ 14.0, J_{5a,5s(12a,12s)}ϭ 9 Hz. ¹³C NMR: δ ϭ 164.3

1,4,6,9-Tetramethyl-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]-

dodeca-2,7-diene (4d): See 2. From 3e: A solution of freshly pre-

pared, crude 3e (900 mg, ca. 800 mg 3e, ca. 1.8 mmol) in anhydrous

THF (80 mL) was slowly added (60 min) to a suspension of the

MeLi/CeCl₃reagent (dry CeCl₃, 1.05 g, 4.3 mmol, THF, 75 mL;

MeLi, 3.6 mL, 1.6  in diethyl ether, 5.8 mmol). The brownish sus-

pension was stirred for 12 h, and then hydrolyzed (satd. aqueous

NH₄Cl, 50 mL). After extraction with tert-butyl methyl ether (5 ϫ

60 mL), the dried (MgSO₄) organic phase was concentrated in va-

cuo and the solid residue was filtered through silica gel (CHCl₃/

MeOH, 1:1). After standard workup and crystallization (diethyl

ether), colorless crystals (195Ϫ270 mg, 50Ϫ70%) were isolated;

they remained unchanged during sublimation at 70 °C/10^Ϫ3Torr.

M.p. 167 °C (dec., N₂elimination). UV (CH₃CN): λ_max(ε) ϭ

343 nm (470). IR (KBr): ν˜ ϭ 1547 cm^Ϫ1(NϭN). ¹H NMR: δ ϭ

3.48 (d, 5-,12-H_s), 2.19 (s, 10-,11-H), 2.04 (d, 5-,12-H_a), 1.35 (s, 4

CH₃) ppm; , J_{5s,5a(12s,12a)}ϭ 15.1 Hz. ¹H NMR ([D₈]THF): δ ϭ 3.28

(d, 5-,12-H_s), 2.18 (s, 10-,11-H), 2.02 (d, 5-,12-H_a), 1.26 (s, 4 CH₃)

ppm; J_{5s,5a(12s,12a)}ϭ 14.9 Hz. ¹³C NMR: δ ϭ 102.6 (C-1,-4,-6,-9),

59.5 (C-10,-11), 46.2 (C-5,-12), 24.1 (CH₃) ppm. MS (CI, isobutane,

200 eV), m/z (%) ϭ 219 (100) [M ϩ H]^ϩ. C₁₂H₁₈N₄(218.3): calcd.

C 66.02, H 8.31, N 25.67; found C 65.87, H 8.43, N 25.76. From

8a: A solution of crude 8a (ca. 500 mg, 0.75 mmol) in ethanol/

ethyl acetate (100 mL, 1:2) was vigorously stirred over Pd/C (10%,

300 mg) under H₂(1 bar). After total conversion (5 h, 8b), a satu-

rated aqueous CuCl₂solution (3 mL) was added and stirring was

continued for 1 h. Aqueous NH₃was added until the blue color

persisted. After standard workup (diethyl ether), concentration in

vacuo, and chromatography (silica gel, cyclohexane/ethyl acetate,

1:5), 4d (65 mg, 40%) was isolated.

(C-1,-6), 139.7, ²128.4, 128.3, 126.9 (10 C), 81.5 (C-4,-9), 62.4 (C-

10,-11), 53.8 (C-1Ј), 33.2 (C-5,-12), 25.2 (CH₃) ppm. MS: m/z (%) ϭ

370 (17) [M^ϩ], 279 (28) [M ϪCH₂C₆H₅^ϩ], 185 (50), 91 (100)

[CH₂C₆H₅].

4,9-Dimethyl-3,8-di(phenylsulfonyl)-2,3,7,8-tetraazatetracyclo-

[7.2.1.0^4,11.0^6,10]dodeca-1,6-diene (3e): See 3c. Benzenesulfonyl chlo-

ride (915 mg, 5.2 mmol) was added to a solution of 3c, prepared

from hydrazine hydrate (400 mg, 8.0 mmol) and 1c (325 mg,

2.0 mmol) in anhydrous pyridine (7 mL). After the deep red solu-

tion had been stirred for ca. 12 h and concentrated in vacuo, the

brownish-red, rapidly decomposing solid material (ca. 90% 3e) was

used as such. For analytical purposes, a small amount of material

was separated, with substantial loss, by flash chromatography (sil-

ica gel, CHCl₃/MeOH, 10:1). ¹H NMR: δ ϭ 8.78 (m, 2 H), 8.01

(m, 4 H), 7.55Ϫ7.45 (m, 4 H), 3.51 (d, 5-,12-H_s), 2.63 (s, 10-,11-

H), 2.51 (s, 5-,12-H_a), 1.50 (s, 2 CH₃) ppm; J_{5a,5s(12a,12s)}ϭ 14.7 Hz.

C₂₂H₂₂N₄O₄S₂(470.7).

2,3,7,8-Tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodeca-2,7-diene

(4a):

This compound was prepared on gram-scale as described,^[23a]ex-

cept for the more simple use of a sealed round-bottomed flask and

a shorter reaction time (3 d).

10,11-Dimethyl-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodeca-

2,7-diene (4b): See 4a (‘‘one-pot’’ reaction conditions).^[23]A solu-

tion of 1b (330 mg, 2.0 mmol) in ethanol (30 mL) was slowly added

(2 h) at room temperature to a stirred solution of hydrazine hydrate

(400 mg, 8.0 mmol) in anhydrous ethanol (30 mL). After the mix-

ture had been kept at 80 °C for 3 days and concentrated in vacuo,

the brownish, oily residue contained a ca. 9:1 mixture of 3b and 4b

l

(270Ϫ290 mg, 77Ϫ79%, H NMR). Dissolved in CH₂Cl₂/acetone

1,6-Dimethoxy-4,9-dimethyl-2,3,7,8-tetraazatetracyclo-

[7.2.1.0^4,11.0^6,10]dodeca-2,7-diene (4e): After a solution of crude 3e

(80 mg, ca. 70 mg 3e, 0.15 mmol) had been stirred in anhydrous

methanol (5 mL) for 2 days, two products were identified (ca. 1:2

mixture of monoadduct and 4e, TLC, ¹H NMR,); after this had

been kept at 40 °C for 6 h, only 4e was present. After concentration

in vacuo and filtration through silica gel (CHCl₃/MeOH, 10:1) oily

4e (32 mg, 85%) was isolated. IR (KBr): ν˜ ϭ 1557 cm^Ϫ1(NϭN).

¹H NMR (400 MHz): δ ϭ 3.56 (d, 5-,12-H_s), 3.46 (s, 2 OCH₃), 2.42

(s, 10-,11-H), 2.39 (d, 5-,12-H_a), 1.42 (s, 2 CH₃) ppm; J_{5a,5s(12a,12s)}ϭ

14.8 Hz. ¹³C NMR: δ ϭ 129.4 (C-1,-6), 100.8 (C-4,-9), 54.7 (2

OCH₃), 53.9 (C-10,-11), 42.3 (C-5,-12), 23.7 (CH₃) ppm. MS (CI,

isobutane), m/z (%) ϭ 252 (15), 251 (100) [M ϩ H]^ϩ, 223 (3), 220

(2) [M ϩ H Ϫ OCH₃]·^ϩ, 194 (4), 179 (4), 137 (2). C₁₂H₁₈N₄O₂

(250.3).

(20:1), the mixture was filtered through silica gel [R_f(acetone/

CH₂Cl₂/ethyl acetate, 1:1:1) ϭ 0.40]. Only 4b (30 mg, 8%) was

eluted; colorless crystals; m.p. 140 °C (toluene, dec., N₂elimin-

ation). UV (CH₃CN): λ_max(ε) ϭ 343 nm (770). IR (KBr): ν˜ ϭ 1540

1

cm^Ϫ1(NϭN). H NMR: δ ϭ 4.58 (d, 1-,4-,6-,9-H), 3.48 (d, 5-,12-

H_s), 2.50 (dt, 5-,12-H_a), 1.18 (s, 2 CH₃) ppm; J_{1,12a(4,5a)(6,5a)(9,12a)}ϭ

8.0, J_{5a,5s(12a,12s)}ϭ 15.0 Hz. ¹H NMR (D₂O): δ ϭ 4.71 (d,

1-,4-,6-,9-H), 3.22 (d, 5-,12-H_s), 2.67 (dt, 5-,12-H_a), 1.18 (s, 2 CH₃)

ppm. J_{1,12a(4,5a)(6,5a)(9,12a)}ϭ 8.5, J_{5a,5s(12a,12s)}ϭ 16.0 Hz. MS (CI,

NH₃): m/z (%) ϭ 208 (10) [M ϩ NH₄]^ϩ, 191 (3) [M ϩ H]^ϩ. HRMS:

calcd. for C₁₀H₁₄N₄190.1219; found 190.1201. For convenient sep-

aration, the 9:1 mixture was extracted either with water (3b) or

CH₂Cl₂(4b). Pure 4b after 7 days at room temp. had equilibrated

with 3b, ratio ca. 1:9.

1,6-Dimethyl-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodeca-2,7-

1,4,6,9-Tetrabromo-2,3,7,8-tetraazatetracyclo[7.2.1.0^4,11.0^6,10]-

diene (4c): See 4a. Hydrazine hydrate (400 mg, 8.0 mmol)/ethanol

dodeca-2,7-diene (4f): A solution of Br₂(2.70 mL, 15.0 mmol) in

(2.5 mL)/1c (300 mg, 1.85 mmol)/ethanol (30 mL)/4 h. After the CH₂Cl₂(50 mL) was slowly added (2 h) at Ϫ78 °C to a solution of

mixture had been heated at 80 °C for 10 days and concentrated

in vacuo, the solid residue (ca. 50% 4c and polymers) was flash

chromatographed on silica gel. The residue of the fraction with R_f

(acetone/CHCl₃, 5:1) ϭ 0.41 was crystallized from THF, providing

colorless crystals (90 mg, 51%); m.p. 147 °C (dec., N₂elimination).

The crystals survived sublimation (60 °C, 10^Ϫ3Torr) unchanged.

4a (160 mg, 1.0 mmol) in CH₂Cl₂(5 mL). After the mixture had

been stirred at room temp. for 2.5 h, concentrated in vacuo, and

filtered through silica gel (CH₂Cl₂), the solid residue was crys-

tallized from CH₂Cl₂. Colorless crystals (358 mg, 75%) were iso-

lated, and these started to eliminate N₂at ca. 190 °C. UV

(CH₃OH): λ_max(ε) ϭ 330 nm (20). IR (KBr): ν˜ ϭ 1517 cm^Ϫ1(Nϭ

1

IR (KBr): ν˜ ϭ 1538 (CϭN). UV (CH₃CN): λ_max(ε) ϭ 339 nm N). H NMR: δ ϭ 4.12 (d, 5-,12-H_s)*, 3.57 (s, 10-,11-H), 3.39 (d,

1

(501), 198 (906). H NMR: δ ϭ 4.94 (ddd, 4-,9-H), 3.48 (d, 5-,12-

5-,12-H_a)* ppm; J_{5s,5a(12s,12a)}ϭ 15.8 Hz. ¹³C NMR: δ ϭ 96.9

Eur. J. Org. Chem. 2003, 4248Ϫ4264

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4257

E. Beckmann et al.

FULL PAPER

(C-1,-4,-6,-9), 63.4 (C-10,-11), 51.4 (C-5,-12) ppm. MS (CI, NH₃):

solution of 17 (126 mg, 0.46 mmol) and anhydrous hydrazine

m/z (%) ϭ 496 (6) [M ϩ NH₄^ϩ], 291 (25), 264 (27), 262 (56), 198 (0.06 mL, 1.82 mmol) in CH₃CN (6 mL) was stirred at 0 °C under

(18), 181 (40), 170 (100). HRMS: calcd. for C₈H₆⁷⁹Br₄N₄473.7326; exclusion of light under O₂until only one product was observed

found 473.7305.

(5 h, TLC). After removal of the volatiles in vacuo (10^Ϫ3Torr),

the solid residue was chromatographed on silica gel (CH₂Cl₂/ethyl

acetate, 5:1). Only the yellowish 20 was eluted (115 mg, 80%), and

this remained unchanged upon sublimation at 160 °C/10^Ϫ3Torr.

Just before melting at 210 °C, elimination of N₂occurred. Crystals

obtained from CH₃CN proved suitable for X-ray structural analy-

sis. UV (CH₃CN): λ_max(ε) ϭ 394 nm (245), 364 (300), 251 (sh,

1155), 221 (2015). IR (KBr): ν˜ ϭ 3400 cm^Ϫ1(NϪH), 1735, 1570

(NϭN). ¹H NMR (400 MHz): δ ϭ 1.87 (d, 11-,14-H), 1.82 (d,

11Ј-,14Ј-H), 1.78 (s, 12-,13-CH₃), 1.42 (s, 1-,9-CH₃)*, 1.38 (s, 4-,6-

CH₃)* ppm; J_{11,11Ј(14,14Ј)}ϭ 14.0 Hz. ¹³C NMR: δ ϭ 126.6 (C-12,-

13), 123.6 (C-4,-6), 112.45 (C-1,-9), 58.4 (C-10,-15), 31.1 (C-11,-

14), 19.2 (12-,13-CH₃), 19.0 (1-,9-CH₃)*, 17.7 (4-,6-CH₃)* ppm.

MS: m/z (%) ϭ 288 (6) [M Ϫ N₂]·^ϩ, 245 (12) [(M Ϫ COCH₃]^ϩ, 217

(18) [M Ϫ N₂Ϫ COCH₃]^ϩ, 43 (100) [COCH₃]. C₁₆H₂₄N₆O (316.4):

calcd. C 60.74, H 7.65, N 26.56; found C 60.82, H 7.52, N 26.89.

3,8-Dibenzyl-2,7-bis(benzyloxycarbonyl)-1,4,6,9-tetramethyl-2,3,7,8-

tetraazatetracyclo[7.2.1.0^4,11.0^6,10]dodecane (8a): See 2. A solution

of 3d (200 mg, 0.54 mmol) in THF (9 mL) was added dropwise

(45 min) to a suspension of the MeLi/CeCl₃reagent prepared at

Ϫ78 °C in THF (10 mL) (MeLi, 1.35 mL, 1.6  in diethyl ether,

2.16 mmol; anhydr. CeCl_3,534 mg, 2.16 mmol). After the mixture

had been warmed slowly (3 h) to Ϫ5 °C, benzyloxycarbonyl chlo-

ride (740 mg, 4.3 mmol) was added. After the mixture had been

stirred for 6 h it was hydrolyzed (15 mL H₂O). After standard

workup, the oily residue, consisting of at least three components,

was chromatographed (silica gel, cyclohexane/ethyl acetate, 3:1)

and the major fraction (R_fϭ 0.20) was concentrated in vacuo. The

ca. 90% pure, waxy 8a (180Ϫ190 mg, ca. 50%) was used as such.

^lH NMR: δ

؍

7.4Ϫ7.2 (m, 20 H), 5.04 (d, CH₂), 4.96 (d, CH₂),

4.12 (d, CH₂), 3.88 (d, CH₂), 2.91 (d, 10-,11-H), 2.43 (d, 5-,12-HЈ),

16-Benzylidenamino-1,4,6,9,12,13-hexamethyl-5-oxa-2,3,7,8,16-

pentaazapentacyclo[7.6.1.0^4,15.0^6,10.0^10,15]hexadeca-2,7,12-triene

(21): A solution of 20 (60 mg, 0.21 mmol), benzaldehyde (53 mg,

0.50 mmol), and p-toluenesulfonic acid (1 mg) in benzene (2 mL)

was stirred at room temperature until total conversion (2.5 h,

TLC). After concentration in vacuo, chromatographic separation

(silica gel, CH₂Cl₂/ethyl acetate, 20:1), and crystallization (diethyl

ether), yellowish crystals (60 mg, 73%) were isolated. m.p. 173 °C.

UV (CH₃CN): λ_max(ε) ϭ 410 nm (165), 310 (1055), 225 (665). IR

2.12 (d, 5-,12-H), 1.68 (s, 2 CH₃), 1.16 (s, 2 CH₃) ppm; J_C,H

ϭ

2

12.5, J_C,Hϭ 14.0, J_5a,s(l3a,3s)ϭ 15.3 Hz.

2

1-Acetyl-6-(1Ј-hydrazonoethyl)-7,9-dihydroxy-3,4,7,9-tetramethyl-8-

oxabicyclo[4.3.0]non-3-ene (15): Anhydrous hydrazine (0.15 mL,

4.96 mmol) was added to a solution of 14 (150 mg, 0.54 mmol) in

CH₃CN (3 mL). After the mixture had been stirred at 0 °C for 12

h, conversion was total (TLC). Concentration in vacuo at 0 °C

afforded a crystalline solid, which was thoroughly washed with di-

ethyl ether; 157 mg (100%) were recovered and used as such; m.p.

128Ϫ130 °C (dec.). UV (CH₃CN): λ_max(ε) ϭ 272 nm (sh, 85), 226

(2180). IR (KBr): ν˜ ϭ 3296 cm^Ϫ1(N-H), 1699 (CϭO), 1622 (Cϭ

C). ¹H NMR (400 MHz): δ ϭ 2.55 (d, 2-H)*, 2.34 (s, CH₃CO),

2.21 (d, 5-H)*, 1.90 (d, 5-HЈ)*, 1.81 (s, CH₃CN), 1.79 (d, 2Ј-H)*,

1.68 (s, 4-CH₃)**, 1.64 (s, 7-CH₃)***, 1.62 (s, 3-CH₃)**, 1.30 (s,

9-CH₃)*** ppm; J_2,2Ј(5,5Ј)ഠ 17.0 Hz. ¹³C NMR: δ ϭ 206.2 (CϭO),

159.7 (CϭN), 124.3, 120.3 (C-3,-4), 103.6, 101.9 (C-7,-9), 62.3, 61.6

(C-1,-6), 34.8, 31.6 (C-2,-5), 27.7 (CH₃CO), 23.7, 21.6 (3-,4-CH₃),

18.8, 18.4 (7-,9-CH₃), 15.9 (CH₃CN) ppm. MS: m/z (%) ϭ 311 (32)

[M ϩ H]^ϩ, 293 (30) [M ϩ H Ϫ H₂O]^ϩ, 275 (12) [M ϩ H Ϫ 2H₂O]^ϩ,

234 (18), 233 (100) [M Ϫ OH Ϫ NH₃Ϫ CH₃CO]·^ϩ, 189 (78)[M Ϫ

H₂O Ϫ NH₃Ϫ 2COCH₃]·^ϩ. Upon warming to room temp., 15

slowly lost water; after 2 h at 60 °C in high vacuum (10^Ϫ4Torr),

dehydration to a rapidly decomposing solid (presumably 16) was

total. C₁₆H₂₄N₂O₃(292.4): calcd. C 65.73, H 8.27 N 9.58; found

66.01, H 8.36, N 10.12.

1

(KBr): ν˜ ϭ 1564 cm^Ϫ1(NϭN). H NMR (400 MHz): δ ϭ 8.88 (s,

NϭCϪH), 7.73 (m, 2-H), 7.38 (m-, 2-H), 7.34 (m, 1-H), 2.02 (d,

11-,14-H), 1.92 (d, 11-,14-HЈ), 1.82 (s, 12-,13-CH₃), 1.66 (s, 1-,9-

CH₃)*, 1.45 (s, 4-,6-CH₃)* ppm; J_{11,11(14,14Ј)}ϭ 14.0 Hz. ¹³C NMR:

δ ϭ 145.4 (CϭN), 135.6 (1 C), 129.2 (1 C), 128.5 (2 C), 126.9 (2

C), 126.8 (C-12,-13), 123.5 (C-4,-6), 112.2 (C-1,-9), 59.4 (C-10,-15),

31.3 (C-11,-14), 19.3 (4-,6-CH₃), 19.2 (12-,13-CH₃), 17.6 (1-,9-CH₃)

ppm. HRMS: calcd. for C₂₃H₂₈N₆O 404.2325; found 404.2314.

14-Amino-1,4,5,8,9,11-hexamethyl-10-oxa-12,13,14-triazapenta-

cyclo[6.5.1.0^2,7.0^2,11.0^7,9]tetradeca-4,12-diene (22): A degassed solu-

tion of 20 (32 mg, 0.10 mmol) in CH₃CN (20 mL), kept at Ϫ40 °C

in a Solidex vessel, was irradiated with a 800-W daylight lamp until

total conversion (TLC monitoring). After concentration in vacuo,

the brownish, solid residue, consisting of one monomeric compo-

nent and polymers (TLC), was filtered through silica gel (ethyl acet-

ate). The eluted solid crystallized from diethyl ether to provide col-

orless crystals (21 mg, 74%); m.p. 130 °C (dec.; loss of N₂). UV

(CH₃CN): λ_max(ε) ϭ 360 nm (120), 307 (sh, 250), 222 (1900). IR

Spiro Compound 17: A suspension of a freshly prepared sample

obtained by dehydration of 15 (16, 160 mg, 0.55 mmol) and LiClO₄

(10 mg) in CH₂Cl₂(5 mL) was stirred for 30 h. After filtration and

concentration in vacuo, the solid residue was chromatographed (sil-

ica gel, acetone). Concentration of the major fraction (R_fϭ 0.29)

provided a yellowish, air-and heat-sensitive, highly viscous oil

(90 mg, 60%, decomposition above 60 °C), which was used as such.

UV (CH₃CN): λ_max(ε) ϭ 227 nm (3470). IR (KBr): ν˜ ϭ 1719 cm^Ϫ1

(CϭN), 1688 (CϭO). ¹H NMR: δ ϭ 2.63 (3-H)*, 2.24 (s, 6-H)*,

2.19 (s, COCH₃), 2.07 (s, 3Ј-,5Ј-CH₃), 1.77 (s, 5-CH₃)**, 1.69 (s, 4-

CH₃)** ppm. ¹³C NMR: δ ϭ 202.6 (CϭO), 178.0 (C-3Ј,-5Ј), 122.8

(C-4)*, 121.8 (C-5)*, 66.6 (C-1)**, 65.9 (C-2)**, 35.8 (C-6)***, 33.4

(C-3)***, 28.1 (COCH₃), 18.9 (5-CH₃)****, 18.5 (4-CH₃)****, 16.2

(3Ј-,5Ј-CH₃) ppm. C₁₆H₂₂N₂O₂(274.4): calcd. C 70.04, H 7.66, N

10.33; found C 69.46, H 8.08, N 10.21.

1

(KBr): ν˜ ϭ 1540 cm^Ϫ1(NϭN). H NMR (400 MHz): δ ϭ 1.92 (d,

3-H)*, 1.78 (d, 6-H)**, 1.73 (d, 6-HЈ)**, 1.70 (s, CH₃), 1.68 (s,

CH₃), 1.66 (s, CH₃), 1.59 (s, CH₃), 1.53 (d, 3-HЈ)*, 1.30 (s, CH₃),

1.12 (s, CH₃) ppm; J_3,3Јϭ 16.0, J_6,6Јϭ 15.0 Hz. ¹³C NMR: δ ϭ

127.0 (C-4)*, 127.6 (C-5)*, 125.3 (C-11), 111.9 (C-1), 80.6 (C-9),

65.6 (C-8), 64.1 (C-2), 38.4 (C-7), 30.4 (C-3), 25.8 (C-6), 20.8

(CH₃), 19.4 (2 CH₃), 18.3 (CH₃), 14.7 (CH₃), 13.3 (CH₃) ppm. MS:

m/z (%) ϭ 288 (20) [M·^ϩ], 245 (21) [(M Ϫ COCH₃]^ϩ, 217 (100) [M

Ϫ N₂Ϫ COCH₃]^ϩ, 200(36), 189 (48), 43 (99) [COCH₃]. HRMS:

calcd. for C₁₆H₂₄N₄O 288.1959; found 288.1901.

1,4,7,10,13,14-Hexamethyl-2,3,5,6,8,9-hexaaza-17-oxapentacyclo-

[8.6.1.0^4,16.0^7,11.0^11,16]heptadeca-2,5,8,13-tetraene (25): K₂CO₃

(150 mg), followed by [Pb(OAc)₄] (78 mg, 0.20 mmol), were added

to a solution of 20 (64 mg, 0.20 mmol) in CH₂Cl₂(10 mL). After

16-Amino-1,4,6,9,12,13-hexamethyl-5-oxa-2,3,7,8,16-penta- the mixture had been stirred at room temp. until total conversion

azapentacyclo[7.6.1.0^4,15.0^6,10.0^10,15]hexadeca-2,7,12-triene (20): A

(TLC, 1 h), filtered, and evaporated in vacuo, the solid residue was

4258

 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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Eur. J. Org. Chem. 2003, 4248Ϫ4264

Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

chromatographed (silica gel, ethyl acetate). From the main fraction

(R_fϭ 0.59), yellowish crystals (50Ϫ57 mg, 80Ϫ90%) were obtained,

water (200 mL). The aqueous phase was saturated with NaCl and

extracted with diethyl ether (5 ϫ 50 mL). The combined organic

phases were washed with brine (20 mL) and dried (Na₂SO₄). After

m.p. 125 °C (dec.). UV (CH₃CN): λ_max(ε) ϭ 365 nm (305), 345

1

(sh, 235), 225 (2030). IR (KBr): ν˜ ϭ 1542 cm^Ϫ1(NϭN). H NMR concentration in vacuo and crystallization (cyclohexane), colorless

(400 MHz): δ ϭ 1.92 (d, 12-,15-H), 1.76 (s, 13-, 14-CH₃), 1.68 (s, 1- needles (4.6 g, 81%) were obtained, m.p. 157 °C, R_f(CH₂Cl₂) ϭ

1

,l0-CH₃), 1.58 (d, 12-,15-HЈ), 1.47 (s, 4-,7-CH₃) ppm; J_{12,12Ј(15,15Ј)}ϭ 0.18. IR (KBr): ν˜ ϭ 1644 cm^Ϫ1(CϭC). H NMR: δ ϭ 6.08 (dd,

15.5 Hz. ¹³C NMR: δ ϭ 125.9 (C-13,-14), 124.1 (C-1,-10), 100.4 4-H), 5.72 (d, 3-H), 4.71 (dd, 7-H), 4.3Ϫ3.8 (m, 4 OCH₂), 2.56

(C-4,-7), 50.5 (C-11,-16), 27.5 (C-12,-15), 19.8 (13-,14-CH₃), 19.2

(ddt, 9-H), 2.44 (m, 5-H), 2.2Ϫ2.0 (m, 1-,8-H, 8-,9-HЈ) ppm; J_3,4ϭ

(1-,10-CH₃), 11.1 (4-,7-CH₃) ppm. MS (CI, NH₃): m/z (%) ϭ 305 10.5, J_4,5ϭ 6.3, J_7,8ϭ 12.3, J_7Ј,8,ϭ 5.3, J_9,9Јϭ 12.9 Hz. ¹³C NMR:

(20), 304 (100) [M ϩ NH₄Ϫ N₂]^ϩ, 288 (18) [M ϩ 2H Ϫ N₂]^ϩ, 287 δ ϭ 133.5 (C-4), 131.4 (C-3), 108.5 (C-6)*, 105.6 (C-2)*, 66.4

(18) [M ϩ H Ϫ N₂]^ϩ. HRMS: calcd. for C₁₆H₂₂N₆O 314.1855; (OCH₂), 65.7 (OCH₂), 65.0 (OCH₂),64.3 (OCH₂), 53.7 (C-7), 40.3

found 314.1848.

(C-5)**, 39.4 (C-1)**, 36.0 (C-8), 29.3 (C-9) ppm. MS: m/z (%) ϭ

318 (25), 316 (25) [M·^ϩ], 237 (100) [M Ϫ Br]^ϩ, 99 (83), 55 (92).

HRMS: calcd. for C₁₃H₁₇⁷⁹BrO₄316.0310; found 316.0300.

2-Acetyl-1,4,5,8,11-pentamethy1Ϫ9,10-diazatetracyclo-

[5.3.1.0^2,7.0^1,11]undeca-4,8-diene (26): A degassed solution of 25

(35 mg, 0.11 mmol) in CH₃CN (20 mL), kept at Ϫ40 °C, was ir-

radiated with a daylight lamp (800 W, solidex vessel) until total

Bicyclo[3.3.1]nona-3,7-diene-2,6-dione Diethylene Acetal (30): See

29. Compound 28 (32.5 g, 82.0 mmol)/NaOCH₃(26.4 g,

conversion (TLC, only one product besides polymers). After con- 490 mmol)/DMSO (150 mL). The mixture was stirred at 90 °C for

centration in vacuo, the brownish oily residue was filtered through

2 h, then for 2 h at 120 °C (TLC monitoring). After workup and

silica gel (ethyl acetate); a highly viscous oil (11 mg, 39%) was iso-

lated. UV (CH₃CN): λ_max(ε) ϭ 297 nm (sh, 190), 225 (2000). H isolated; m.p. 76Ϫ78 °C, R_f(CH₂Cl₂) ϭ 0.10. IR (KBr): ν˜ ϭ 1639

NMR (400 MHz): δ ϭ 2.52 (m, 3-H)*, 2.42 (m, 6-H)*, 2.35 (m, 3-

HЈ)**, 2.01 (s, CH₃CO), 1.92 (m, 6-HЈ)**, 1.89 (s, 1-CH₃)***, 1.74 3.95Ϫ3.60 (m, 4 OCH₂), 2.21 (m, 1-,5-H), 1.98 (t, 9-H) ppm;

crystallization (cyclohexane), colorless crystals (13.3 g, 68%) were

1

cm^Ϫ1(CϭC). ¹H NMR: δ ϭ 5.79 (dd, 4-,8-H), 5.28 (d, 3-,7-H),

(s, 4-CH₃)***, 1.70 (s, 5-CH₃)***, 1.55 (s, 11-CH₃)***, 1.09 (s, 8-

CH₃) ppm; J_3,3Јϭ 16.5, J_6,6Јϭ 17.0 Hz. ¹³C NMR: δ ϭ 213.5 (Cϭ

0), 179.0 (C-8), 124.9 (C-4)*, 122.8 (C-5)*, 68.3 (C-1)**, 65.3 (C-

J_3,4(7,8)ϭ 10.2, J_4,5(8.₉₎

ϭ 5.9, J_5,9ϭ 2.9 Hz. ¹³C NMR: δ ϭ 132.6

(C-4,-8), 126.9 (C-3,-7), 107.4(C-2,-6), 65.0 (2 OCH₂), 64.4 (2

OCH₂), 38.1 (C-1,-5), 28.5 (C-9) ppm. MS: m/z (%) ϭ 236 (6)

11)**, 58.9 (C-2)**, 55.1 (C-7)**, 34.0 (C-6)***, 30.1 (COCH₃), [M··^ϩ], 170 (100), 91 (98). C₁₃H₁₆O₄(236.3): calcd. C 66.07, H 6.84;

27.8 (C-3)***, 20.0 (4-CH₃)****, 19.6 (5-CH₃)****, 14.7 (1-

CH₃)****, 11.2 (11-CH₃)****, 8.61 (8-CH₃) ppm. MS (70 eV, CI,

NH₃): m/z (%) ϭ 259 (8) [M ϩ 1]^ϩ, 219 (6), 213 (16), 191 (10),

187 (7), 88 (14), 78 (22). HRMS: calcd. for C₁₆H₂₂N₂O 258.1732;

found 258.1726.

found C 66.47, H 6.54.

Bicyclo[3.3.1]nona-3,7-diene-2,6-dione (31a):

A solution of 30

(13.3 g, 56.0 mmol) and sulfosalicylic acid·2H₂O (0.50 g, 2.0 mmol)

in acetone (150 mL) was stirred at 40 °C until total conversion

(TLC, 6 h). After standard workup and crystallization (cyclohex-

ane), colorless needles (7.5 g, 90%) were obtained; m.p. 78Ϫ80 °C.

IR (KBr): ν˜ ϭ 1673 cm^Ϫ1(CϭO), 1601 (CϭC). ¹H NMR: δ ϭ

7.00 (dd, 4-,8-H), 5.87 (d, 3-,7-H), 3.33 (dt, 1-,5-H), 2.77 (t, 9-H)

ppm; J_1,8(4,5)ϭ 6.8, J_1,9ϭ 3.0, J_3,4(7,8)ϭ 10.5 Hz. ¹³C NMR: δ ϭ

193.5 (C-2,-6), 146.4 (C-4,-8), 126.1 (C-3,-7), 45.8 (C-1,-5), 34.4 (C-

9) ppm. MS: m/z (%) ϭ 148 (32) [M·^ϩ], 120 (45) [M Ϫ CO]·^ϩ,

Bicyclo[3.3.1]nonane-2,6-dione Diethylene Acetal (27): A solution of

bicyclo[3.3.1]nonane-2,6-dione^[46](19.2 g, 126.0 mmol), ethane-1,2-

diol (17 mL, 332 mmol), and p-toluenesulfonic acid ϫ H₂O (0.3 g)

in benzene (150 mL) was heated at reflux for 24 h with azeotropic

removal of water. After standard workup (diethyl ether) and subli-

mation of the solid residue, colorless needles (22.6 g, 75%) were

1

isolated; m.p. 68Ϫ73 °C. H NMR: δ ϭ 4.0Ϫ3.8 (m, 8 H, OCH₂), 91 (100). C₉H₈O₂(148.2): calcd. C 72.94, H 5.45; found C 73.01,

2.0Ϫ1.85 (m, 4 H, 1-,5-H, 9-H), 1.8Ϫ1.6 (m, 8 H, 3-,4-,7-8-H). H 5.67.

Ϫ¹³C NMR: δ ϭ 110.7 (C-2,-6), 64.4 (OCH₂), 64.2 (OCH₂), 36.0

4,8-Dimethylbicyclo[3.3.1]nona-3,7-diene-2,6-dione (31b). (a) Modi-

(C-4,-8), 31.6 (C-3,-7), 29.4 (C-1,-5), 23.7 (C-9). MS: m/z (%) ϭ

fied Original Procedure:^[42d]A suspension of paraformaldehyde

240(24)[M·^ϩ], 99(100).

(1.5 g, 17 mmol) in acetylacetone (10.0 g, 100.0 mmol) and triethyl-

(3β,7β)-Dibromobicyclo[3.3.1]nonane-2,6-dione Diethylene Acetal amine (0.5 mL) was homogenized by heating to 60 °C. The solution

(28): Pyridinium tribromide (65.8 g, 206 mmol) was added to a was stirred at room temperature for 5 days, triethylamine (0.5 mL)

solution of 27 (22.6 g, 94 mmol) in THF (200 mL), kept at Ϫ78 °C.

The red suspension was stirred for 1 hour and then warmed to

room temperature over 2 h. The suspension was poured into vigor-

ously stirred ice-water (700 mL), and the uniform (TLC) precipitate

was filtered off and crystallized from methanol (100 mL) to provide

the compound (32.5 g, 87%); m.p. 202 °C. ¹H NMR: δ ϭ 4.44 (dd,

3-,7-H), 4.21 (m, 2 OCH₂), 3.97 (m, 2 OCH₂), 2.45Ϫ2.55 (m, 4 H,

being added daily. After concentration in vacuo, the yellowish, oily

residue was dissolved in benzene (30 mL) and, together with p-

toluenesulfonic acid monohydrate (600 mg, 3.0 mmol), was heated

at reflux in a DeanϪStark apparatus; after 3 days ca. 2 mL of water

had been collected. After standard workup (CHCl₃, 80 mL), the

solid residue was purified by flash chromatography (silica gel,

cyclohexane/ethyl acetate 3:1) and crystallized from cyclohexane to

afford yellow needles (3.6 g, 41%). M.p. 125 °C (cyclohexane),

4-,8-H, 9-H), 2.12 (m, 4-,8-HЈ), 2.02 (m, 1-,5-H) ppm; J_1,9(5,9)

ϭ

3.0 Hz. ¹³C NMR: δ ϭ 108.7 (C-2,-6), 66.5 (OCH₂), 65.8 (OCH₂), R_f(cyclohexane/ethyl acetate, 1:1) ϭ 0.30. (b) From 32: See 2 Ǟ 1c:

54.3 (C-3,-7), 41.6 (C-1,-5), 33.8 (C-4,-8), 27.9 (C-9) ppm. Dry K₂CO₃(350 mg, 2.5 mmol), pyridinium chlorochromate

C₁₃H₁₈Br₂O₄(398.1): calcd. C 39.22, H 4.57; found C 39.10, H

4.60.

(1.60 g, 7.5 mmol), CH₂Cl₂(20 mL), 32 (450 mg, 2.5 mmol),

CH₂Cl₂(30 mL). After stirring at room temperature for 8 h , fil-

tration, workup, chromatography (silica gel, cyclohexane/ethyl acet-

ate, 1:1) and crystallization (cyclohexane), 310 mg (70%) were ob-

tained.

7β-Bromobicyclo[3.3.1]non-3-ene-2,6-dione Diethylene Acetal (29):

Compound 28 (7.0 g, 18.0 mmol) was added to a suspension of

freshly prepared NaOCH₃(1.35 g, 25.0 mmol) in dry DMSO

(40 mL). After having been heated at 80 °C for 2 h, the brownish

mixture was cooled to room temperature and poured onto ice-

4β,8β-Dimethylbicyclo[3.3.1]nona-2,6-diene-4α,8α-diol (32): MeLi

(9.4 mL, 1.6  solution in diethyl ether, 15.0 mmol) was added

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E. Beckmann et al.

FULL PAPER

dropwise at Ϫ40 °C, over 60 minutes, to a solution of 31a (1.00 g,

lated; m.p.176Ϫ177 °C. IR (KBr): ν˜ ϭ 1621 cm^Ϫ1, 1489 (CϭC).

6.8 mmol) in anhydrous THF (25 mL). After having been slowly ¹H NMR: δ ϭ 7.45Ϫ7.2 (m, 10 H), 4.55 (d, CH₂), 3.95 (d, CH₂),

warmed up (12 h) and then heated at reflux (2 h), the mixture was

hydrolyzed (satd. aqueous NH₄Cl, pH 7). After the bulk of the

THF had been distilled, the residue was extracted with CH₂Cl₂(5

ϫ 30 mL). After standard workup, the colorless solid was purified

by flash chromatography (silica gel, CH₂Cl₂/cyclohexane, 1:1, R_f

(32) ϭ 0.11) and crystallized (CH₂Cl₂/cyclohexane, 1:1). 1.00 g

(82%) of colorless crystals were isolated; m.p. 151 °C. IR (KBr):

3.02 (10-,12-H), 3.00 (d, 5-,13-H_s), 2.01 (ddd, 5-,13-H_a), 1.90 (t, 11-

H), 1.48 (s, 2 CH₃) ppm; J_{5,5Ј(13,13Ј)}ϭ 14.0, J_10,11(11,12)ϭ 3.1 Hz.

¹³C NMR (400 MHz): δ ϭ 159.4 (C-1,-6), 140.2, 128.4, 128.3,

126.8, 80.7 (C-4,-9), 52.3 (2 CH₂), 51.6 (C-10,-12), 30.7 (C-5,-13),

24.1 (CH₃), 17.6 (C-11) ppm. MS: m/z (%) ϭ 384 (15) [M·^ϩ], 293

[M Ϫ C₆H₅CH₂]^ϩ, 199 (88), 91 (100). C₂₅H₂₈N₄(384.5): calcd. C

78.09, H 7.34, N 14.57, found C 77.61, H 7.15, N 14.13.

1

ν˜ ϭ 3350 cm^Ϫ1(OH), 1640 (CϭC). H NMR: δ ϭ 5.82 (dd, 2-,6-

4,9-Dimethyl-3,8-bis(phenylsulfonyl)-2,3,7,8-tetraazatetracyclo-

[7.3.1.0^4,12.0^6,10]trideca-1,6-diene (33e): See 3e. A solution of freshly

prepared 33b (590 mg, 3.0 mmol) and benzenesulfonyl chloride

(1.5 mL, 11.8 mmol) in pyridine (5 mL) was stirred, under ex-

clusion of air, at room temp. for 12 h. After standard workup and

crystallization (methanol), colorless crystals (1.05 g, 72%) were ob-

tained; m.p. 222 °C R_f(CHCl₃/MeOH, 10:1) ϭ 0.38. IR (KBr): ν˜ ϭ

H), 5.60 (d, 3-,7-H), 2.31 (dt, l-,5-H), 1.91 (t, 2 H, 9-H), 1.64 (s,

OH), 1.36 (s, 2 CH₃) ppm; J_1,2(5,6)ϭ 6.0, J_1,9ϭ 3.1, J_2,3(6,7)

ϭ

9.8 Hz. ¹³C NMR: δ ϭ 135.8 (C-2,-6), 128.3 (C-3,-7), 74.3 (C-4,-

8), 40.4 (C-1,-5), 29.5 (C-9), 27.7 (CH₃) ppm. CI MS (isobutane):

m/z (%) ϭ 163 (10) [M ϩ H Ϫ H₂O]^ϩ, 145 (100) [M ϩ H Ϫ

2H₂O]^ϩ. C₁₁H₁₆O₂(180.3): calcd. C 73.27, H 8.96; found C 73.89,

H 9.01. An occasional by-product was identified as separately pre-

pared 36.

1

1622 cm^Ϫ1, 1471, 1446, 1339. H NMR: δ ϭ 8.02Ϫ7.98 (m, 4 H),

7.59Ϫ7.49 (m, 6 H), 3.05 (d, 5-,13-H_s), 2.92 (t, 10-,12-H), 2.21 (d,

5-,13-H_a), 1.89 (t, 11-H), 1.88 (s, 2 CH₃) ppm; J_{5,5Ј(13,13Ј)}ϭ 14.3,

J_10,11(11,12)ϭ 2.7 Hz. ¹³C NMR(400 MHz): δ ϭ 163.9 (C-1,-6),

2,3,7,8-Tetraazatetracyclo[7.3.1.0^4,12.0^6,10]trideca-1,6-diene (33a):

See 3b. A solution of 31a (148 mg, 1.0 mmol) in ethanol (30 mL)

was added dropwise over 3 h to a solution of hydrazine hydrate 140.7 (C-15,-13), 24.2 (2 CH₃), 15.2 (C-11) ppm. FAB-MS: m/z

(100 mg, 2.0 mmol) in ethanol (2 mL). This system was stirred for

12 h and heated at reflux until total conversion (3 h, TLC). After

concentration in vacuo the solid residue was practically pure, air-

sensitive 33a [175 mg, 100%, R_f(CHCl₃/CH₃OH, 12:1) ϭ 0.11]

(%) ϭ 485 (66) [M·^ϩ], 343 (40 [M Ϫ PH_sO₂]^ϩ, 307 (40), 154 (100),

136 (80). C₂₃H₂₄N₄O₄S₂(484.6).

2,3,7,8-Tetraazatetracyclo[7.3.1.0^4,12.0^6,10]trideca-2,7-diene (34a):

See 4b. Hydrazine hydrate (850 mg, 17.0 mmol)/ethanol (5 mL)/31a

(1.00 g, 6.8 mmol)/ethanol (100 mL), room temperature. After

complete formation of 33a (TLC) and addition of K₂CO₃(2.35 g,

17.0 mmol), the mixture was heated at reflux until total conversion

(TLC, 5Ϫ7 h). After standard workup (CH₂Cl₂), chromatography

(silica gel, CH₂Cl₂/acetone, 10:1), and concentration of the major

fraction, the residue was crystallized from CH₃CN to afford color-

less prisms (720 mg, 60%) ; m.p. 175 °C (dec., N₂elimination). UV

(CH₃CN): λ_max(ε) ϭ 333 nm (790), 201 (845). IR (KBr): ν˜ ϭ 1550

1

which was used as such. H NMR (CD₃OD): δ ϭ 4.14 (t, 4-,9-H),

3.25 (m, 10-,12-H), 2.61 (ddd, 5-,13-H_s), 2.34 (d, 5-,13-H_a),2.21 (t,

11-H) ppm; J_4,5(9,13)ϭ 5.7, J_4,12(9,10)ϭ 6.0, J_5,5Јϭ 13.5, J_5,12(10,13)ϭ

1.5, J_10,11(11,12)ϭ 3.0 Hz. ¹³C NMR(CD₃OD): δ ϭ 163.6 (C-1,-6),

69.1 (C-4, Ϫ9), 46.1 (C-10,-12), 32.7 (C-5,-13), 17.9 (C-11) ppm.

HRMS: calcd. for C₉H₁₂N₄176.1062; found 176.1054.

4,9-Dimethyl-2,3,7,8-tetraazatetracyclo[7.3.1.0^4,12.0^6,10]trideca-1,6-

diene (33b): See 33a. Hydrazine hydrate (355 mg, 7.1 mmol)/ethanol

(10 mL)/31b (500 mg, 2.84 mmol)/ethanol (150 mL)/3(12) h. After cm^Ϫ1(NϭN). ¹H NMR: δ ϭ 4.92 (ddd,1-,4-,6-,9-H), 3.07 (dt,

concentration in vacuo, the solid residue was practically pure, air-

5-,13-H_s), 2.35 (tt, 10-,12-H), 1.88 (dt, 5-,13-H_a), 1.57 (t, 11-H)

1

sensitive 33b (590 mg, 100%) and was used as such. H NMR: δ ϭ ppm; J_{1(4),12:6(9),10)}ϭ 10.5, J_{1,13Ј(13Ј,9;6,5Ј;5Ј,4)}ϭ 1.5, J_{1,13(13,9;6,5;5,4)}ϭ

5.35 (br., 2 NH), 2.89 (t, 10-,12-H), 2.45 (d, 5-,13-H_s), 2.33 (d, 6.9,, J_{5,5Ј(13,13Ј)}ϭ 16.2, J_10,11ϭ 3.0 Hz. ¹³C NMR: δ ϭ 85.2

5-,13-H_a), 1.92 (t, 11-H), 1.48 (s, 2 CH₃) ppm; J_10,11(11,12)ϭ 3.1,

J_{5,5Ј(12,12Ј)}ϭ 13.4 Hz.

(C-1,-4,-6,-9), 23.7 (C-10,-12), 18.5 (C-5,-13), 15.6 (C-11) ppm. MS:

m/z ϭ 176 (14) [M·^ϩ], 79 (100). C₉H₁₂N₄(176.3): calcd. C 61.31,

H 6.87, N 31.79; found C 60.98, H 6.71, N 31.91.

3,8-Dibenzyl-2,3,7,8-tetraazatetracyclo[7.3.1.0^4,12.0^6,10]trideca-1,6-

diene (33c): A solution of freshly prepared 33a (600 mg, 3.4 mmol)

and benzyl bromide (1.71 g, 10 mmol) was heated at 80 °C for 16

1,6-Dimethyl-2,3,7,8-tetraazatetracyclo[7.3.1.0^4,12.0^6,10]trideca-2,7-

diene (34b): See 34a. Hydrazine hydrate (794 mg, 14.2 mmol/etha-

h in the presence of K₂CO₃(500 mg). After standard workup and nol (5 mL)/31b (1.00 g, 5.7 mmol)/ethanol (100 mL)/K₂CO₃

flash chromatography (silica gel, ethyl acetate/cyclohexane, 2:1), the

major fraction (R_fϭ 0.34) was concentrated in vacuo and the yel-

lowish residue was crystallized (diethyl ether) to afford colorless

crystals (850 mg, 70%); m.p.125 °C. IR (KBr): ν˜ ϭ 1609 cm^Ϫ1(Cϭ

(1.97 g, 14.2 mmol)/reflux, 5Ϫ7 h. Colorless needles (930 mg, 80%)

were recovered; m.p. 158 °C (CH₃CN) (dec., N₂elimination),

R_f(CH₂Cl₂/ethyl acetate, 1:1) ϭ 0.27. IR (KBr): ν˜ ϭ 1563 cm^Ϫ1

(NϭN). UV (CH₃CN): λ_max(ε) ϭ 334 nm (408), 196 (970). ¹H

N), 1488 (CϭC). ¹H NMR: δ ϭ 7.50Ϫ7.11 (m, 10 H), 4.68 (d, NMR: δ ϭ 4.97 (ddd, 4-,9-H), 2.89 (dd, 5-,13-H_s), 1.70 (dt, 10-,12-

CH₂), 4.24 (d, CH₂), 4.07 (t, 4-,9-H), 3.28 (m, 10-,12-H), 3.0 (d, H), 1.56 (dd, 5-,13-H_a), 1.50 (t, 11-H), 1.36 (s, 2 CH₃) ppm;

5-, 13-H_s), 2.02 (ddd, 5-,13-H_a), 2.00 (t, 11-H) ppm; J_4,5(9,13)

J_4,12(9,10)ϭ 6.0, J_{5,5Ј(13,13Ј)}ϭ 14.2, J_5,12(10,13)ϭ 1.4, J_10,11(11,12)

ϭ

J_4,12(9,10)ϭ 10.5, J_{4,5Ј(9,13Ј)}ϭ 1.5, J_4,5(9,13)ϭ 7.4, J_10,11(11,12)ϭ 3.1,

J_{5,5Ј(13,13Ј)}ϭ 15.8 Hz. ¹³C NMR: δ ϭ 89.8 (C-1,-6), 87.0 (C-4,-9),

31.1 (C-10,-12), 28.0 (CH₃), 26.1 (C-5,-13), 16.9 (C-11) ppm.

ϭ

3.0 Hz. ¹³C NMR (400 MHz): δ ϭ 160.2 (C-1,-6), 138.7, 128.7,

128.5, 127.1 (12 C), 71.9 (C-4,-9), 53.8 (2 CH₂), 45.7 (C-10,-12), C₁₁H₁₆N₄(204.3): calcd. 64.68 H 7.89 N 27.43; found C 64.49, H

24.2 (C-5,-13), 18.1 (C-11) ppm. MS: m/z (%) ϭ 356 (18) [M^ϩ], 91 7.99, N 27.12.

(100). HRMS: calcd. for C₂₃H₂₄N₄356.2000; found 356.2010.

1,4,6,9-Tetramethyl-2,3,7,8-tetraazatetracyclo[7.3.1.0^4,12.0^6,10]-

3,8-Dibenzyl-4,9-dimethyl-2,3,7,8-tetraazatetracyclo- trideca-2,7-diene (34c): See 4d. A solution of 33e (1.82 g, 3.8 mmol)

[7.3.1.0^4,12.0^6,10]trideca-1,6-diene (33d): See 33c. Freshly prepared

33b (ca. 600 mg, 2.8 mmol), benzyl bromide (1.7 g, 10 mmol)/

K₂CO₃(500 mg)/80 °C/16 h. After standard workup, flash chroma-

tography (silica gel, ethyl acetate/cyclohexane, 2:1, R_fϭ 0.15), and

crystallization (THF), colorless crystals (650 mg, ca. 60%) were iso-

in THF (150 mL) was slowly added (2 h) at room temperature to

a stirred suspension of the MeLi/CeCl₃reagent prepared at Ϫ78

°C in THF (CeCl₃, 2.60 g, 10.6 mmol, THF, 150 mL, MeLi,

6.4 mL, 1.6  diethyl ether, 10.3 mmol). Stirring was continued for

10 h. After hydrolysis (aqueous NH₄Cl), standard workup (diethyl

4260

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Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

ether) and filtration through silica gel [R_f(ethyl acetate) ϭ 0.27],

colorless crystals (620 mg, 71%) were isolated; m.p. 109Ϫ110 °C

ride (363 mg, 2.1 mmol) and workup, the oily mixture (379 mg) of

at least three components was chromatographically separated (sil-

(CHCl₃). UV(CH₃CN): λ_max(ε) ϭ 212 nm (1010), 335 (500). IR ica gel, cyclohexane/ethyl acetate, 4:1). From the fraction with R_fϭ

1

(KBr): ν˜ ϭ 1556 cm^Ϫ1(NϭN). H NMR: δ ϭ 2.73 (d, 5-,13-H_s),

1.50 (t, 10-,12-H), 1.37 (s, 4 CH₃), 1.29 (d, 5-,13-H_a), 1.26 (t, 11- °C. IR (KBr): ν˜ ϭ 1685 cm^Ϫ1(CϭO). H NMR: δ ϭ 7.4Ϫ7.2 (m,

H) ppm; J_5,5Ј15.3, J_10,11

3.3 Hz. ¹³C 20 H), 5.15 (d, 2 CH₂), 5.05 (d, 2 CH₂), 4.06 (d, 2 CH₂), 3.89 (2

0.15, colorless, crystalline 35a (58 mg, 35%) was isolated; m.p. 97

1

ϭ

(11,12)

(13,13Ј)

NMR(400 MHz): δ ϭ 91.6 (C-1,-4,-6,-9), 38.5 (C-10,-12), 33.9 (C- CH₂), 2.16 (d, 5-,13-H_s)*, 2.04(t, 10-,12-H), 1.94 (d, 5-,13-H_a)*,

5,-13), 28.8 (CH₃), 18.0 (C-11) ppm. MS (CI, NH₃): m/z (%) ϭ 250 1.86 (t, 11-H), 1.57 (s, 2 CH₃), 0.93 (2 CH₃) ppm; J_C,H2ϭ 12.5,

(15) [M ϩ NH₄] ^ϩ, 233 (30) [M ϩ H]^ϩ, 176 (12) [M Ϫ 2N₂]·^ϩ, 161

J_C,H2Јϭ 14.7, J_{5,5Ј(13,13Ј)}ϭ 16.5, J_10,11(11,12)ϭ 3.1 Hz. ¹³C NMR:

(22) [M Ϫ 2N₂Ϫ CH₃]^ϩ. C₁₃H₂₀N₄(220.3): calcd. C 67.21, H 8.68, δ ϭ 153.7, 140.0, 136.9, 128.3, 128.0 127.7, 126.6 (20 C), 66.7

N 24.12; found C 67.52, H 8.72, N 23.98. From 35a: See 8a. 35a (CH₂), 63.7 (C-5,-13), 62.9 (CH₂), 58.2 (C-1,-6), 48.3(C-4,-9),

(84 mg, 0.12 mmol)/ethanol/ethyl acetate (25 mL, 1:1)/Pd/C (10%, 46.3(C-10,-12), 30.1 (CH₃), 22.7 (CH₃), 16.9 (C-11) ppm. MS: m/z

80 mg)/H₂(1 bar). 26 mg (92%).

(%) ϭ 684 (19) [M·^ϩ], 549 (48) [M Ϫ OCOCH₂C₆H₅]^ϩ, 458 (7) [(M

Ϫ OCOCH₂C₆H₅Ϫ CH₂C₆H₅]·^ϩ, 323 (25) [M Ϫ 2OCOCH₂C₆H₅

Ϫ CH₂C₆H₅]^ϩ, 91 (100) [CH₂C₆H₅]. C₄₃H₄₈N₄O₂(684.9): calcd. C

79.10, H 7.16, N 8.61; found C 78.93, H 7.41, N 8.58.

1,6-Dimethoxy-4,9-dimethyl-2,3,7,8-tetraazatetracyclo-

[7.3.1.0^4,12.0^6,10]trideca-2,7-diene (34d): See 4e. After a solution of

33b (100 mg, 0.50 mmol) in anhydrous methanol (5 mL) had been

warmed at 40 °C until total conversion (6 h), three products were

detected (TLC). Concentration in vacuo afforded a solid residue,

which was chromatographed (silica gel, ethyl acetate) to afford col-

orless, crystalline 34d (50 mg, 40%); [R_f(ethyl acetate) ϭ 0.46], m.p.

194 °C, besides two oily components (mono-CH₃OH-addition/sub-

6β-Hydroxy-6-methyl-bicyclo[3.3.1]nona-3,7-dien-2-one (36): See 32.

Compound 31a (300 mg, 2.0 mmol)/THF (8 mL))/MeLi (1.25 mL,

1.6  in diethyl ether, 2.0 mmol). Colorless crystals (230 mg, 70%),

m.p. 61 °C (cyclohexane), were isolated by flash chromatography

(silica gel, cyclohexane/ethyl acetate, 1:1) (36, R_fϭ 0.25), besides

residual 31a and 32 (10Ϫ15%). IR (KBr): ν˜ ϭ 3344 cm^Ϫ1(OH),

1658 (CϭO). ¹H NMR: δ ϭ 7.02 (ddd, 4-H), 5.91 (d, 3-H), 5.77

(ddd, 8-H), 5.58 (d, 7-H), 2.90 (m. 1-H)*, 2.79 (m, 5-H)*, 2.32 (m,

9-H), 2.15 (m, 9-HЈ), 1.71 (s, OH), 1.52 (s, CH₃) ppm; J_1,8ϭ 6.2,

stitution). IR (KBr): ν˜ ϭ 1657 cm^Ϫ1, 1619 (NϭN). H NMR: δ ϭ

3.30 (s, 2 OCH₃), 3.00 (d, 5-,13-H_s), 1.70 (t, 10-,12-H), 1.65 (d,

1

5-,13-H_a), 1.51 (t, 11-H) ppm; J_{5,5Ј(13,13Ј)}ϭ 15.3, J_10,11(11,12)

ϭ

3.2 Hz. ¹³C NMR: δ ϭ 119.5 (C-1,-6), 99.9 (C-4,-9), 50.7 (OCH₃),

35.2 (C-10,-12), 32.7 (C-5,-13), 27.3 (CH₃), 17.7 (C-11) ppm.

HRMS: calcd. for C₁₃H₂₀N₄O₂264.1586; found 264.1572.

J_3,4ϭ 10.5, J_4,5ϭ 6.6, ,Ј ϭ 2.3, J_7,8ϭ 9.8, J_8,9ϭ 1.5, J_9,9Ј

ϭ

13.5 Hz. ¹³C NMR (CDCl₃): δ ϭ 199.8 (C-2), 150.9 (C-4), 135.3

(C-8), 126.8 (C-3)*, 126.1 (C-7)*, 71.1 (C-6), 44.7 (C-1)**, 41.6 (C-

5)**, 31.6 (C-9), 29.4 (CH₃) ppm. MS: m/z (%) ϭ 164 (20) [M·^ϩ],

149 (50), 131 (95) [(M Ϫ CH₃Ϫ H₂O]^ϩ, 43 (100). C₁₀H₁₂O₂

(164.2).

4,9-Dibromo-1,6-dimethyl-2,3,7,8-tetraazatetracyclo-

[7.3.1.0^4,12.0^6,10]trideca-2,7-diene (34e): See 4f. A solution of dry

bromine (1.00 g, 5.0 mmol) in CH₂Cl₂(10 mL) was slowly added

(2 h) at Ϫ78 °C to a solution of 34b (50 mg, 0.25 mmol) in CH₂Cl₂.

After the mixture had been stirred at room temperature (5 h), TLC

monitoring confirmed the exclusive formation of 34e [R_f( cyclohex-

ane/ethyl acetate, 1:1) ϭ 0.50]. Standard workup, filtration of the

crude solid (silica gel), and crystallization (CH₂Cl₂/cyclohexane,

1:1) provided colorless prisms (73 mg, 82%); m.p. 165 °C (dec., N₂

elimination). UV (CH₃CN): λ_max(ε) ϭ 338 nm (300). IR (KBr):

3,7-Bis(diethoxyphosphoryloxy)-9,10-benzobicyclo[3.3.2]deca-2,6,9-

triene (40): nBuLi (6.8 mL of 2.7  solution in n-heptane,

18.4 mmol) was added at Ϫ78 °C to a solution of diisopropylamine

(2.05 g, 20.2 mmol) in anhydrous THF (15 mL). After the mixture

had been stirred for 15 minutes a solution of 39 (2.00 g, 9.35 mmol)

in anhydrous THF (70 mL) was added dropwise. After 30 minutes,

TMEDA (8 mL) and diethyl chlorophosphate (3.58 g, 20.8 mmol)

were added to the orange reaction solution. Upon warming to

room temperature and stirring for 10 h, it was hydrolyzed (satd.

aqueous NH₄Cl, 10 mL). Standard workup (diethyl ether) and fil-

tration of the crude, oily product (4.7 g) through silica gel (CHCl₃/

MeOH, 10:1) delivered a yellowish oil (3.03 g, 66%). IR (KBr): ν˜ ϭ

1

ν˜ ϭ 1538 cm^Ϫ1(NϭN). H NMR: δ ϭ 3.36 (d, 5-,13-H_s), 2.25 (t,

10-,12-H), 2.11 (d, 5-,13-H_a), 1.93(t, 11-H), 1.51 (s, 2 CH₃) ppm;

J_5,5(13,13Ј)ϭ 14.7, J_10,11(11,12)ϭ 3.0 Hz. ¹³C NMR: δ ϭ 98.2(C-1,-

6), 93.2 (C-4,-9), 42.1(C-10,-12), 38.0 (C-5,-13), 27.7 (CH₃), 17.3

(C-11) ppm. C₁₁H₁₄Br₂N₄(362.1): calcd. C 36.48, H 3.91, N 15.48;

found C 36.87, H 4.00, N 15.12.

1

1272 cm^Ϫ1(PϭO). H NMR: δ ϭ 6.95Ϫ7.20 (4 H), 5.92 (ddd, 2-,

1,4,6,9-Tetrabromo-2,3,7,8-tetraazatetracyclo[7.3.1.0^4,12.0^6,10]-

trideca-2,7-diene (34f): See 34e. Compound 34a (176 mg,

1.0 mmol)/CH₂Cl₂(70 mL)/bromine (6.50 g, (41.0 mmol)/CH₂Cl₂

(70 mL). The crude product was purified by filtration [silica gel,

R_f(CH₂Cl₂) ϭ 0.60] and crystallization (cyclohexane/ethyl acetate,

1:1) to afford colorless prisms (414 mg, 84%); m.p. 181 °C (dec.,

N₂elimination). UV(CH₃CN): λ_max(ε) ϭ 339 nm (300). IR (KBr):

6-H), 4.10 (q, 4 OCH₂), 3.53 (ddd, 1-,5-H), 2.66 (m, 4-,8-H), 1.27

(t, 4 CH₃) ppm; J_1,2(5,6)ϭ 9.2 Hz. ¹³C NMR: δ ϭ 148.9, 148.8 (C-

3,-7), 142.1, 127.7, 127.2, 114.2, 114.1 (6 C), 64.4, 64.3 (4 OCH₂),

38.8, 38.7 (C-4,-8), 22.6 (C-1,-5), 16.3, 16.2, 16.1 (4 CH₃) ppm. MS:

m/z (%) ϭ 486 (2) [M^ϩ], 332 (15), 178 (100). C₂₂H₃₂O₈P₂(486.4).

9,10-Benzobicyclo[3.3.2]deca-2,6,9-triene (41): NH₃(ca. 50 mL) was

condensed into diethyl ether (10 mL) at Ϫ78 °C. After addition of

thinly cut Li (1.05 g, 152 mmol), stirring for 30 minutes, and ad-

dition of tBuOH (5.7 mL, 59.7 mmol), a solution of 40 (3.02 g,

6.35 mmol) in THF (20 mL) was added dropwise. Stirring was con-

tinued for 3 h, and NH₄Cl was then added until total decoloriz-

ation. After concentration and standard workup, the crude, color-

less oil (1.7 g) was filtered through silica gel (cyclohexane). Color-

less, crystalline 41 (up to 1.11 g, 96%) was isolated, occasionally

1

ν˜ ϭ 1530 cm^Ϫ1(NϭN). H NMR (CDCl₃/[D₆]DMSO): δ ϭ 3.50

(d, 5-,13-H_s), 2.97 (d, 5-,13-H_a), 2.95 (t, 10-,12-H), 2.34 (t, 11-H)

ppm; J_{5,5Ј(13,13Ј)}ϭ 15.8, J_10,11(11,12)ϭ 3.4 Hz. ¹³C NMR (CDCl₃/

[D₆]DMSO): δ ϭ 93.6 (C-1,-4, Ϫ6,-9), 44.8 (C-10,-12), 39.6 (C-5,-

13), 15.3 (C-11) ppm. C₉H₈Br₄N₄(491.8): calcd. C 21.98, H 1.68,

N 11.39; found C 22.50, H 2.01, N 11.78.

3,8-Dibenzyl-2,7-di(benzyloxycarbonyl)-1,4,6,9-tetramethyl-2,3,7,8-

tetraazatetracyclo[7.3.1.0^4,12.0^6,10]tridecane (35a): See 8a. CeCl₃containing some higher hydrogenated material, which did not,

(257 mg, 1.04 mmol)/THF (5 mL), Ϫ78 °C, MeLi (0.65 mL, however, interfere with the subsequent oxidation. IR (KBr): ν˜ ϭ

1

1.04 mmol)/diethyl ether, 33c (100 mg (0.26 mmol)/THF (3 mL)/

3 h. After warming to Ϫ5 °C, addition of benzyloxycarbonyl chlo-

1657 cm^Ϫ1, 1569 (CϭC). H NMR: δ ϭ 7.15 (m, 4 H), 5.89 (dd,

2-,6-H), 5.65 (dddd, 3-,7-H), 3.44 (m, 1-,5-H), 2.46 (m, 4-,8-H)

Eur. J. Org. Chem. 2003, 4248Ϫ4264

www.eurjoc.org

 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

4261

E. Beckmann et al.

FULL PAPER

ppm; J_1,2(5,6)ϭ 1.8, J_2,3(6,7)ϭ 11.6, J_1,3(5,7)ϭ 0.6, J_2,4(6,8)ϭ 2.4 Hz.

(CD₃OD): δ ϭ 160.7 (C-1,-6), 135.6 (C-11,-12), 131.6 (C-13,-16)*,

¹³C NMR: δ ϭ 144.4, 129.2 (4 C), 128.3 (C-2,-6), 127.5 (C-3,-7), 129.7 (C-14,-15)*, 75.1 (C-4,-9), 56.5 (C-10,-13), 32.8 (C-5,-14)

126.5 (2 C), 44.4 (C-1,-5), 34.0 (C-4,-8) ppm. MS: m/z (%) ϭ 182 ppm. MS: m/z (%) ϭ 238 (51) [M·^ϩ], 223 (36), 183 (56), 169 (100).

(40) [M·^ϩ], 167 (50), 141 (75), 128 (100). HRMS: calcd. for C₁₄H₁₄HRMS: calcd. for C₁₄H₁₄N₄238.1218; found 238.1206.

182.1095; found 182.1080.

3,8-Diacetyl-11,12-benzo-2,3,7,8-tetraazatetracyclo[7.4.1.0^4,13.0^6,10]-

tetradeca-1,6,11-triene (45b): A solution of 45a (24 mg, 0.10 mmol)

and acetic anhydride (108 mg, 15.1 mmol) in anhydrous pyridine

(2 mL) was stirred for 10 h. After concentration in vacuo and fil-

tration through silica gel (cyclohexane/ethyl acetate, 1:1), crystals

(23 mg, 71%) were isolated; m.p. Ͼ 250 °C; R_f(CHCl₃/MeOH,

9,10-Benzobicyclo[3.3.2]deca-2,6,9-triene 2,3(α);6,7(α)-Dioxide (42):

A freshly prepared solution of DMDO in acetone (170 mL ca. 0.06

, 10.2 mmol) was added dropwise at room temperature to a solu-

tion of 41 (475 mg, 2.61 mmol) in CH₂Cl₂(20 mL). After the mix-

ture had been stirred for 10 h and concentrated in vacuo, the solid

residue (560 mg, 100%) consisted of a mixture of 47 (80%, m.p.

183 °C) and its exo/endo isomer. Since chromatographic separation

(silica gel) was not possible without significant decomposition, this

mixture was used as such. ¹H NMR: δ ϭ 6.95Ϫ7.20 (m, 4 H), 3.50

1

10:1) ϭ 0.51. IR (KBr): ν˜ ϭ 1658 cm^Ϫ1(CϭO), 1594 (CϭC). H

NMR: δ ϭ 7.4Ϫ7.25 (m, 4 H), 5.12 (ddd, 4-,9-H), 4.14 (m, 10-,13-

H), 2.93 (ddd, 5-,14-HЈ), 2.35 (ddd, 5-,14-H), 2.43 (s, CH₃), 2.35

(s, CH₃) ppm; J_4,5(9,14)ϭ 3.4, J_{4,5Ј(9,14Ј)}ϭ 1.8, J_4,13(9,10)ϭ 7.9,,

J

_{5Ј,13(10,14Ј)}ϭ 0.9, J_5,13(10,14)ϭ 0.6, J_{5,5Ј(14,14Ј)}ϭ 13.1 Hz. ¹³C NMR:

(ddd, 1-,5-H), 3.40Ϫ3.10 (m, 2-,3-,6-,7-H), 2.52 (dd,

2 H),

2.35 (ddd, H) ppm; J_4,4Ј(8,8Ј)

2

ϭ

16.2 Hz. ¹³C NMR:

δ ϭ 170.8 (C-1,-6), 159.7(CO), 132.9 (C-11,-12), 130.7 (C-15,-18),

129.3 (C-16,-17), 68.0 (C-4,-9), 54.8 (C-10,-13), 29.1 (C-5,-14), 21.9

(CH₃) ppm. MS: m/z (%) ϭ 322 (84) [M^ϩ], 280 (77) [(M Ϫ C₂H₂O]

^ϩ, 238 (100) [M Ϫ 2C₂H₂O]^·ϩ. C₁₈H₁₈N₄O₂(322.4): calcd. C 67.07,

H 5.63, N 17.38; found C 67.19, H 5.12, N 17.11.

δ ϭ 136.7 (C-9,-10), 129.8 (C-11,-14), 127.5 (C-12,-13), 56.7, 54.3

(C-2,-3,-6,-7), 42.9 (C-1,-5), 27.4 (C-4,-8) ppm. MS: m/z (%) ϭ i.a.

214 (42) [M·^ϩ], 171 (7), 141 (26), 131 (52), 128 (100). C₁₄H₁₄O₂

(214.3).

11,12-Benzo-2,3,7,8-tetraazatetracyclo[7.4.1.0^4,13.0^6,10]tetradeca-

2,7,11-triene (46): NaCNBH₃(120 mg, 2.0 mmol) was added (trace

of methyl red) under exclusion of air to a solution of 45a (120 mg,

0.50 mmol) in anhydrous MeOH (20 mL). HCl (2 ) was added

until the color of the indicator changed from yellow to red (pH 4).

After the mixture had been stirred for 48 h at room temperature.,

conc. HCl (1 mL) was added. The solution was stirred (10 min)

and hydrolyzed (aqueous NaHCO₃). After filtration and concen-

tration in vacuo, the residue [highly oxygen-sensitive bis(pyrazolid-

ine) 47] was dissolved in ethanol (10 mL). An ethanolic CuCl₂solu-

tion, and after 10 min a conc. NH₃solution, were added until a

deep blue color persisted. After standard workup (CHCl₃), the

crude solid (118 mg, 98%) was filtered through deactivated silica

gel (triethylamine, CHCl₃/MeOH, 30:1). Colorless crystals (75 mg,

63%) were isolated; m.p. 153 °C (dec., elimination of N₂). UV

(MeOH): λ_max(ε) ϭ 336 nm (810), 200 (12880). IR (KBr): ν˜ ϭ

1552 cm^Ϫ1(NϭN), 1492(CϭC). ¹H NMR: δ ϭ 7.23 (m, 15-,18-

H)*, 7.15 (m, 16-,17-H)*, 5.03 (ddd, 1-,4-,6-,9-H), 3.16 (t, 10-,13-

H), 3.12 (dt, 5-,14-H_s), 1.51 (dt, 5-,14-H_a) ppm; J_{1,13(4,13)(6,10)(9,10)}ϭ

9,10-Benzobicyclo[3.3.2]deca-3,7,9-triene-2α,6α-diol (43): nBuLi

(10.4 mL of 2.5  solution in n-hexane, 26.0 mmol) was added at

Ϫ78 °C to a solution of diisopropylamine (3.32 g, 32.8 mmol) in

anhydrous THF (130 mL). After the mixture had been stirred for

15 minutes, a solution of 42 (560 mg, 2.61 mmol) in anhydrous

THF (30 mL) was added dropwise. After stirring for 10 h at room

temperature, it was hydrolyzed (phosphate buffer, pH ca.7). Stand-

ard workup (CH₂Cl₂) provided a crude solid material (540 mg),

which was chromatographed (silica gel, cyclohexane/ethyl acetate,

1:1) to afford colorless crystals (402 mg, 72%); m.p. 188 °C. IR

(KBr): ν˜ ϭ 1458 cm^Ϫ1, 1415 (CϭC). ¹H NMR: δ ϭ 6.95Ϫ7.20 (m,

4 H), 6.10 (ddd, 4-,8-H), 5.68 (ddd, 3-,7-H), 4.25 (m, 2-,6-H), 3.35

(ddd, 1-,5-H) ppm; J_1,2(5,6)ϭ 4.0, J_1,8(4,5)ϭ 8.8, J_2,3(6,7)ϭ 5.4,

J_3,4(7,8)ϭ 11.8 Hz. ¹³C NMR: δ ϭ 140.4 (C-9,-10), 131.2 (C-4,-8)*,

130.7 (C-3,-7)*, 129.4 (C-11,-14), 127.2 (C-12,13), 67.9 (C-2,-6),

51.7 (C-1,-5) ppm. MS: m/z (%) ϭ 214 (4) [M^ϩ], 196 (100) [M Ϫ

H₂O]·^ϩ. HRMS: calcd. for C₁₄H₁₄O₂214.0993; found 214.0984.

9,10-Benzobicyclo[3.3.2]deca-3,7,9-triene-2,6-dione (44a): Pyridin-

ium dichromate (423 mg, 1.12 mmol) was added in small portions

to a solution of 43 (151 mg, 0.70 mmol) in anhydrous CH₂Cl₂.

After total conversion (ca. 2 h), the mixture was filtered (celite) and

chromatographed (silica gel, CHCl₃). Colorless crystals

(96Ϫ120 mg, 45Ϫ60%) were isolated, m.p. 148 °C. UV (MeOH):

λ_maxϭ 363, 236 nm. IR (KBr): ν˜ ϭ 1654 cm^Ϫ1(CϭO), 1561 Cϭ

C). ¹H NMR: δ ϭ 7.25Ϫ7.30 (m, 4 H), 7.02 (dd, 4-,8-H), 5.93 (dd,

3-,7-H), 4.61 (dd, 1-,5-H) ppm; J_1,8(4,5)ϭ 9.8, J_1,7(3,5)ϭ 1.5,

J_3,4(7,8)ϭ 11.6 Hz. ¹³C NMR: δ ϭ 189.6 (C-2,-6), 143.2 (C-4,-8),

135.2 (C-9,-10), 129.8 (C-11,-14), 128.7 (C-4,-8)*, 128.5 (C-3,-7)*,

64.4 (C-1,-5) ppm. MS: m/z (%) ϭ 10 (71) [M·^ϩ], 181 (100) [M Ϫ

CHO]^ϩ, 153 (98) [M Ϫ CH₂ϭCHCHϭOH]^ϩ. C₁₄H₁₀O₂(210.2):

calcd. C 79.88, H 4.79; found C 79.91, H 4.72.

11.0, J_{1,14a(4,5a)(5a,6)(9,14a)}

ϭ

5.4, J_{1,14s(4,5s)(5s,6)(9,14s)}

ϭ

3.0,

J_{5a,5s(14a,14s)}ϭ 16.1 Hz. ¹³C MR: δ ϭ 135.3 (C-11,-12), 131.8 (C-

15,-18), 127.8 (C-16,-17), 85.2 (C-1,-4,-6,-9), 41.3 (C-10,-13), 21.1

(C-5,-14) ppm. MS: m/z (%) ϭ 238 (3) [M·^ϩ], 182 (4) [M Ϫ 2N₂]·^ϩ,

167 (96), 128 (100). C₁₄H₁₄N₄(238.3): calcd. C 70.57, H 5.92; found

C 70.84, H 6.05.

Acknowledgments

Support by the Deutsche Forschungsgemeinschaft and the Fonds

der Chemischen Industrie is gratefully acknowledged. Thanks go

to Dr. D. Hunkler and Dr. J. Wörth for NMR and MS analyses,

to Prof. Dr. G. Gescheidt for ESR, to Prof. Dr. J. Heinze for CV

measurements, and to Dr. P. R. Spurr for help with the manuscript.

11,12-Benzo-2,3,7,8-tetraazatetracyclo[7.4.1.0^4,13.0^6,10]tetradeca-

1,6,11-triene (45a): A solution of 44a (105 mg, 0.50 mmol) in meth-

anol (30 mL) was slowly added at room temperature to a stirred

solution of hydrazine hydrate (500 mg, 10.0 mmol) in methanol

(5 mL). After 2 h only one product was present (TLC). After con-

centration in vacuo the oily, uniform, air-sensitive residue (119 mg,

100%) slowly solidified [R_f(MeOH,CuCl₂) ϭ 0.30] and was used

[1] [1a]

H. Prinzbach, G. Fisher, G. Rihs, G. Sedelmeier, E. Heil-

bronner, Z.-Z. Yang,, Tetrahedron Lett. 1982, 23, 1251Ϫ1254.

[1b]

W. Marterer, H. Prinzbach, G. Rihs, J. Wirz, J. Lecoultre,

[1c]

E. Heilbronner, Helv. Chim. Acta 1988, 71, 1937Ϫ1965.

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1989, 111, 4627Ϫ4635.

Ann. 1996, 1213Ϫ1216.

E. Tauer, R. Marchinek, Liebigs

1

as such. H NMR (CD₃OD): δ ϭ 7.3Ϫ7.4 (m, 4 H), 4.18 (m, 4-,9-

[2]

[2a]

H), 4.11 (d, 10-,13-H), 2.41 (d, 5-,14-HЈ), 2.32 (dd, 5-,14-H) ppm;

Dissertations (University of Freiburg):

G. Fischer, 1987

J_4,5(9,14)ϭ 3.7, J_4,13(9,10)ϭ 7.2, J_{5,5Ј(14,14Ј)}ϭ 13.7 Hz. ¹³C NMR

(Diplomarbeit, 1982). ^[2b]E. Beckmann, 1991. ^[2c]N. Bahr, 1994.

4262

 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjoc.org Eur. J. Org. Chem. 2003, 4248Ϫ4264

Proximate, “Parallel-In-Plane” Preoriented Bis(diazenes)

FULL PAPER

6e monoanions through addition of organometallic reagents to

[2d]

[2e]

M. Lugan, 1994.

O. Cullmann, 1997 (Diplomarbeit

[2f]

[2g]

[2h]

[18b]

1994).

2001.

1993؊1999).

M. Exner, 1994.

Research reports of Dr. F. Yang (Humboldt Fellow

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M. Kegel,

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J. Geier, K. Exner, M. Vögtle,

[2i]

M. Kegel, F. Yang, D. Hunkler, O. Cullmann, H. Prinzbach,

Tetrahedron 2002, 58, 1137Ϫ1145. Like A-type dienes and A-

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mate’’ bis(azine) shown resisted reduction (Li/THF) to give

[3]

[3a]

For their use as ligands in metal complexes, see::

N. Bahr,

E. Beckmann, K. Mathauer, D. Hunkler, M. Keller, H.

4C4N/9(10)e

cyclically

delocalized/σ-bis(homoaromatic)

Prinzbach, H. Vahrenkamp, Chem. Ber. 1993, 126, 429Ϫ440.

[3b]

anions; neat twofold deprotonation occurred instead (C₂-sym-

metrical bisanion);^[2g]α-peralkylated analogues could not be

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Zuman, J. Ludvik, Tetrahedron Lett. 2000, 41, 7851Ϫ7853. M.

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G. Fischer, G. Sedelmeier, H. Prinzbach, K. Knoll, P. Wil-

harm, G. Huttner, J. Organomet. Chem. 1975, 297, 307Ϫ312.

[4]

[5]

See ref.^[2,3]in ref.^[13]

MMX version 87.200: MM2 1977(Allinger-QCPE 395). ϩ

MMP1 (Allinger Ϫ QCPE 318)ϩ more atoms and constants

by K. E. Gilbert and J. J. Gajewski, Indiana University, 1987.

^[6a]M. J. S. Dewar, E. G. Zoebisch, E. F. Healy, J. J. P. Stewart,

[6]

[7]

[6b]

J. Am. Chem. Soc. 1985, 107, 3902Ϫ3909.

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K. Exner, Dip-

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Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Chee-

seman, T. Keith, G. A. Petersson, J. A. Montgomery, K.

Raghavachari, M. A. Al-Laham, V. G. Zakrzewski, J. V. Ortiz,

J. B. Foresman, J. Cioslowski, B. B. Stefanov, A. Nanayakkara,

M. Challacombe, C. Y. Peng, P. Y. Ayala, W. Chen, M. W.

Wong, J. L. Andres, E. S. Replogle, R. Gomperts, R. L. Martin,

D. J. Fox, J. S. Binkley, D. J. Defrees, J. Baker, J. P. Stewart, M.

Head-Gordon, C. Gonzalez, and J. A. Pople, Gaussian, Inc.,

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B 1988, 37, 785Ϫ789.

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Received May 21, 2003

4264

 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjoc.org

Eur. J. Org. Chem. 2003, 4248Ϫ4264

Article Doi

Proximate, "Parallel-In-Plane" Preoriented Bis(diazenes) - In-Plane Delocalized Bis(homoconjugated) 4N/5(6)e Anions

DOI: 10.1002/ejoc.200300298

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Authors:

Article abstract of DOI:10.1002/ejoc.200300298

Full text of DOI:10.1002/ejoc.200300298

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