tt . __ 1 1 2 l,b R= NHCHO - Science Direct

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C16H2SN (MS and l3 C NMR) and showed IR absorption at 2140 cm -l (i&C). Its planar structure was .... Rappoport ed., John Wiley & Sons Ltd,. 1983, p. 836. 5. M.L. Maheswari, T.G. Jain, R.B. Bates and S.C. Bhattacharrya,. Tetrahedron, 19 ...
Tetrahedron Letters,Vol.28,No.l3,pp Printed in Great Britain

STYLOTELLINE, Stylotella

A NEW SESQUITERPENE APPLICATION

sp.

Mary

*

PaPs,

de Chimie

oo40-4039/87 $3.00 + .OO Pergamon Journals Ltd.

ISOCYANIDE

OF ZD-NMR

FROM THE SPONGE

IN STRUCTURE

DETERMINATION

Catherine

Fontaine, Dominique Laurent+ La Barre tt and Eric Guittet

Stsphane

Institut

1409-1412,1987

des Substances

Naturelles,

CNRS,

91190 Gif-sur-Yvette,

France.

’ Centre ORSTOM, BP A5, Noumsa, New Caledonia. tt Laboratoire des Plantes Msdicinales, CNRS,

RP 463, Noumga,

New

Caledonia.

Abstract: The __ sesquiterpene isocyanide stylotelline isolated from the marine . __ sponge Stylotella sp. was assigned the structure la (absolute stereochemistry) on the basis of spectral - essentially 2D-NME-- and chemical data.

Terpenoid still

isocyanides

represent

toxic,

a relatively

antibiotic

or

and

structure

la,

from the sponge

Silica

(yield 0.16%

of

Stylotella

was

gel

Stylotelline C16H2SN

(MS and

planar

structure

la,

a new 2

[aID-47' and

of

2

assigned

isocyanide,

but

cyto-

the

isolation

stylotelline

crude

extracted

with

methylene

extract

gave

-la as an oil

8

/‘I1

‘2

k.

13

la

R=

iEc

l,b

R=

NHCHO tram ___-

on

at

the

2140 basis

cm -l of

formula (i&C). NMR

/PY /

c5, =

the

IR absorption

0

,

showing here

(CHC13, c = 1.7) had the molecular showed

readily

10

15 :I

report

sesquiterpene

14

=

products

We

sponges,

dry weight).

l3 C NMR)

1

1

and continuously

chromatography

was

of natural

properties.

in marine

sp.

freeze-dried

of the sponge

found previously

rare class

antifeedant

determination

The sponge chloride.

have been

2

1409

Its data.

1410

13

In the lation

C spectrum,

sequence3

1.0~ field

(4C,

part

the

1).

In

in

bound

to nitrogen field

lowed

part

of

H-6 range

4CH3). was

broad as

further

with

Attribution

decoupled

triplets

spectrum,

was established

coupled

deduced

from

the

the

(C-5,

14N

by a J moducarbons

C-6, C-7, 13 C-5 and

spectrum

to

heteronuclear of l3 C and

2) appeared

of

straightforward

band

of the pairs

in Fig.

coupling

5CH2,

the

the

were

(not shown

of the carbons

spectrum

appeared

identification

connectivities

3CH,

of

shown

high

Fig.

multiplicity

(J z 4 H2).4

6-6 correlation

in

the

NC

as

13C-16 In the

(lH-13C)

al-

directly bonded nuclei. Proton 11 H- H COSY spectrum (Fig. 2).

as a multiplet

at

6 5.44

showing

a long

H-8.

24.1

Fig.1 - 13C

The planar at C-10

and

l3 C NMR)

The

same diene

the

crude

The The value tion

Evidence

the

was The

rence nates

with

those

was

also

or

identified of

12

of

authentic

have the

in the presence

Proton the

junction

spectrum'

observation (CHC13,

a NOE

c = 0.5}

identified formamide

of

in -lb

also'coupled - C-10

between

H NMR

of

deduced

were

of

-la during the 8s? group

came,

on

H-3ax

prepared

and

and,

NMR

data.

orienta-

(3JN H_4 = 3 Hz).~ one' hand,

the

a coupling

NH

from

an axial

to nitrogen

orientation

spectrum

fractions

from

elimination

(Fig. 2) showing diaxial

(Cal,, IR, 1H 5,6 eudesmols.

of acid.

assignments

readily 1

since

from

secondarly

3J3 4 = 12 Hz required

C-5

of -la trans

their

prepared

c1

diene

chromatographic

formed

sponge

constant

4 appeared

trans

been

the known

its properties

sample

of traces

stereochemical

of the coupling

by comparing

in the least polar

could

extraction

remaining

COSY

an

found

but

establishing

[a] +122' H-3ax

2 was

slowly

for

long-range CH3-14 from

2.

for H-4.

of

rt) giving

(MeOH, HCl l%, 30 min,

extract,

conservation proceeded

data

of -la was confirmed and the absolute configuration facile elimination of the tertiary isocyanide group

by

bond

(+)-6-selinene

NMR

structure

established

to the double

I 21.5

158.8

16:4

between on

the

from

H-3ax

other

a

and

hand,

in compound

-lb {F 124'-', ether, 16h, rt).

from -la (AcOH, by decoupling from H-4

.

-lb was not found in the sponge extract, although cooccuof isocyanides with the corresponding formamides and also isothiocya1 has often been observed in other sponges.

MULTIPLE

Fig.

2.

Contour

plot

COSY

of the 400 MHZ homonuclear

(20 mg, CD3COCD3) and a multiple

QUANTA

between

quanta

spin correlations

0 and 2.5 ppm corresponding filtered COSY experiments. 8

maps of la to a long range

1412

Acknowledgements:

We wish to thank Prof. C. Levi for his kind identification

of the sponge.

References and Notes 1. Review Articles:

D.J. Faulkner, Tetrahedron, 33, 1434 (1977);

Nat.Prod.Rep., I, 560 (1984);

ibid., 1,

w,

14 (1986).

2. The sponge was collected in the south-east of New-Caledonia at a depth of 250 m in the frame of the CNRS-ORSTOM Programme "Substances Marines d'Int&&t_ Biologique".

The Stylotella

genus is close to Hymeniacidon previously. 1

from which isocyanides have been isolated

3. C. Le Cocq and J.-Y. Lallemand, J.Chem.Soc.,Chem.Commun.,

150 (1981).

4. H.M. Walborsky and M.P. Periasamy, "The Chemistry of Functional Group", Supplement C, S. Patai and 2. Rappoport ed., John Wiley & Sons Ltd, 1983, p. 836. 5. M.L. Maheswari, T.G. Jain, R.B. Bates and S.C. Bhattacharrya, Tetrahedron, 19, 1079 (1963). 6. We thank Prof. D.H.R. Barton for a sample of eudesmols from natural 9 source. The 'H NMR spectrum of 2 has been previously reported. 13C NMR (benzene-d6): 142.69 (C), 133.81 (Cl, 125.53 (C), 118.13 (CH), 38.66 (CH2, 38.22 (CH2), 35.91 (CH), 33.56 (CH2), 32.57

(C),

23.69

KHZ) I 23.40 (CH3), 22.05 (CH3), 21.62 (CH3), 19.20 (CH2, 18.68 (CH3). 7. A. Bax and R. Freeman, J.Magn.Reson., 44, 542 (1981);

J.C. Steffens, J.L.

Roark, D.G. Lynn and J.L. Riopel, J.Am.Chem.Soc., 105, 1669 (1983). 8. The 2-D correlation maps consisted of 512 x lk data points spectra, each composed of 32 transients. A 1s delay was allowed between each scan. The additional delays used in the long range COSY experiment were set at 0.5 s. 9. G. Mehta and B.P. Singh, Tetrahedron Lett. 3961 (1975); A.F. Thomas, M. Ozainne, R. Decorzant, F. Nlf and G. Lukacs, Tetrahedron, 32, 2261 (1976); M. Suzuki, M. Segouva, H. Kikuchi, T. Suzuki and E. Kurosawa, Phytochemistry, 2,

2011 (1985).

(Received in France 6 January 1987)