Layered compounds. XX. Some heterophanes layered with condensed aromatic nuclei

Tetr8hdroll

Letters

lie. 10, pp 799 - 802, 1974.

LAYERED COMPOUNDS.

SOME HETEROPHANES

XX."

CONDENSED Shigeyoshi Mizogami, Yoshiteru

Perguvn Rsse.

AROMATIC

Printed in Qeat Rritsin.

LAYERED WITH

NUCLEI

Norihisa Osaka, Tetsuo Otsubo,

Sakata. and Soichi Misumi

The Institute of Scientific

and Industrial

Research, Osaka University

Suita, Osaka, Japan (Reoeivedin Japan 17 December1973; received in UK for publiostion28 January 1974)

In the previous properties

communication,"

of some multilayered

we have reported the synthesis

cyclophanes

containing

furan and thiophene,

for the investigation

tion between benzene

ring and heteroaromatic

fied with condensed

heterophanes,

I-V.

We reported the constrained on paracyclophane

(2,5)thiophenophane,

ring.

accordingly,

electronic

quaternary

so far.3' 405'

by cross-breeding

strati-

We wish

Hofmann degrada-

ammonium hydroxides. ring which

In the case of [2_2](1,4)naphthaleno-

two isomers, anti-form

799

interac-

and anthraceno-

internal inversion of the thiophene rings.

nuclei,

A few heterophahes

of several naphthaleno-

They were synthesized

tion method of the corresponding

was stratified

of transannular

aromatic nuclei have been reported

report the synthesis and properties

heteroaromatic

and

(I) and syn-form

(II),

800

IJO. 10

can be anticipated conformer

to exist, and the latter isomer may be a less stable

due to n-n repulsion between both nuclei.

quaternary

When a mixture

of two

ammonium hydroxides,

VII and IX, in a 2:l molar ratio was pyrolyzed . in boiling xylene with catalytic amount of phenothiasine, a small amount of

unstable

conformer,

actually obtained

syn-[2.21(1,4)naphthaleno(2,5)thiophenophane

together with anti-form

(2,5)thiophenophane,

(I), [2.2](1,4)naphthalenophane,

[2.2.21(2,5)thiophenophane

the first of layered thiophenophanes

(VI), and polymers.

to be separated

isomers, were purified by careful chromatography I, 4.1% yield, colorless

(II), was [2.21-

I and II,

into conformational

on silicagel or neutral

alumina:

prisms from n-hexane-iBenzene (l:l), m.p. 182-183“C; The

II, 0.3% yield, colorless plates from the same solvent, m.p. 142-143'C. mass spectra of I and II show an identical pattern,

indicating

isomeric with each other, but thermal isomerization

of II to I could not be

detected

that both are

because of ready decomposition.

$e30H tMe3.. qpH @$*

@

VII

VI

2 IX

VIII

On the other hand, pyrolysis gave only anti-form

a mixture

thiophenophane dec.*-154°C; methane,

CH2NMe30H

3 X

XI

(III) of [2.2](1,4)anthraceno(2,5)thiophenophane, (l:l), dec.-195°C.

of VIII and x in 2:l ratio afforded

IV, whereas

2

of a mixture of VII and X in a 2:l molar ratio

pale yellow prisms from n-hexane-benzene mixture

3

2.8% yield,

Similarly,

a

[2.2](1,4)anthraceno(2,5)furanophane

of VII and XI in 2:l ratio gave

[2.2] (9,10)anthraceno(2,5)-

V; IV, 0.8% yield, pale yellow prisms from n-hexane-benzene

(l:l),

V, 5.5% yield, greenish yellow needles from n-pentane-dichloroAll new heterophanes

dec.-100°C.

spectra and elemental

were characterized

analysis.

The NMR spectral data of various heterophanes cates an interesting protons of syn-form

by NMR and mass

difference

between

II exhibit upfield

I and II.

are shown in Pig. 1. Thus, the thiophene

shift due to diamagnetic

It indiring

shielding effect

Fig. 1. NMR data

(T value) of naphthaleno-

and anthraceno-heterophanes

in deuteriochloroform.

of opposed naphthalene ring downfield

ring and the protons at 2 and 3 positions

shift due to deshielding

atom.

The chemical

quently

III can be assigned

In contrast

effect of lone pair electrons

to the anti-conformation

ring rapidly undergoes

patterns were essentially

unchanged

protons are not appreciably nuclei.

without difficulty.

ring, it is well-known

affected

that the furan ring strati-

internal inversion

rature, but it is fixed at low temperature.

sed aromatic

of sulfur

shifts of III are rather similar to those of I, and conse-

to thiophene

fied on paracyclophane

of naphthalene

In IV and XII",

even at low temperature by the diamagnetic

So these compounds

at room tempe-

however,

and the furan ring

shielding

exist exclusively

the NMR

due to conden-

in anti-conformation

rather than in syn-conformation. Figs. 2, 3, and 4 show the electronic ceno-heterophanes.

It is apparent

spectra of naphthaleno-

that all the spectra of thiophenophanes

are very similar to those of the corresponding the transannular aromatic systems.

electronic

interactions

rings are comparable

to reflect the difference thalene r-system

paracyclophanes,

between thiophene

in the short wavelength

between

and of thiophene

the overlappings n-system

that

paracyclophane

bands of I and II appears

of sulfur lone pair on naph-

on naphthalene

phanes XII, XIII,4' and IV, the transannular

suggesting

ring and condensed

to those of the corresponding

The marked difference

and anthra-

electronic

n-system.

interactions

In furanobetween

No.

802

I Fig. 2. IJVspectra phanes.

of

250

300

350

400

10

450 nm

Fig. 3. UV spectra of (9,10)anthracenophanes.

naphthaleno-

..... III furan ring and condensed aromatic ---IV

nuclei seem to be considerably weak since the spectra exhibit relatively

in TW

smaller bathochromic shifts compared to those of the corresponding other cyclophanes. Further studies on the properties of these compounds are under way. 250

350

300 Fig.

References

400 .

450 nm

4. uv spectra of (1,4)anthracenophanes.

1) Part XIX: II.Horita, N. Kannen, T. Otsubo, and S. Misumi, Tetrahedron Lett., 1974, in press. 2) s. Mizogami, T. Otsubo, Y. Sakata, and S. Miami, 3) H. H. Wasserman and P. M.

Keehn,

ibid., 2791 (1971).

ibid., 3227 (1969).

4) H. Wynberg and R. Helder, ibid., 4317 (1971). 51 J. F. Haley, Jr. and P. M. Keehn, ibid., 4017 (1973).