The preparation of some 1,7b-disubstituted cyclopropa[c]isoquinolines via nitrile ylide cyclisations and their rearrangement to 2-benzazepines and 4-alkenyl-1,4-dihydroisoquinolines

Article abstract of DOI:10.1039/a705531e

Diene-conjugated nitrile ylides of the type 1a, having substituents other than hydrogen in the R¹ position, cyclise normally to give the C-7b substituted cyclopropa[c]isoquinolines 2a. In cases where R² or R³ = H the latte

Full text of DOI:10.1039/a705531e

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The preparation of some 1,7b-disubstituted cyclopropa[c]isoquinolines
via nitrile ylide cyclisations and their rearrangement to
2-benzazepines and 4-alkenyl-1,4-dihydroisoquinolines
Jon-Paul Strachan, John T. Sharp* and Simon Parsons
Department of Chemistry, University of Edinburgh, West Mains Road, Edinburgh,
UK EH9 3JJ
Diene-conjugated nitrile ylides of the type 1a, having substituents other than hydrogen in the R1 position,
cyclise normally to give the C-7b substituted cyclopropa[c]isoquinolines 2a. In cases where R2 or R3 ؍ H
the latter undergo the usual thermal rearrangement to give 5-substituted 2-benzazepines 5a. However,
when R2 and R3 ≠ H and either is a CH3 group, then the presence of the C-7b substituent in 2a diverts
the thermal rearrangement into a new reaction path leading to the formation of 1,4-dihydro-4-
alkenylisoquinolines 14 in high yield.
between 2a and 4a is accompanied by a slower [1,5] sigmatropic
Introduction
hydrogen shift which leads irreversibly to the 2-benzazepine 5a
in high yield. The reaction thus provides a useful synthetic route
to the latter. Work in other groups2,3 has shown that the analo-
gous nitrile imines 1b (Scheme 1, X = N) undergo an almost
exactly parallel series of reactions giving the cyclopropa[c]cin-
nolines 2b as the primary products and, similarly, providing a
good route to the 1,2-benzodiazepines 5b. However, an add-
itional product 6b was also isolated2 in two cases where R1 was
a methyl group, possibly formed by a prototropic rearrange-
ment in the intermediate 3b or in the final product 5b. In the
earlier work1 on the nitrile ylides 1a, no reactants with a methyl
group in the R1 position had been studied and thus formation
of products such as 6a was not possible.
It has been shown in earlier work1 that nitrile ylides of the type
1a (Scheme 1, X = CH), when generated at room temperature
R1
R2
R3
R2
R3
R1
••
CR
X
N
+
-
X
N
CR
1
1–6a, X = CH (nitrile ylide reactions)
1–6b, X = N (nitrile imine reactions)
0 °C
R2
N
R1
R
R3
This paper reports the generation and reactions of the range
of nitrile ylides 10a,b,d–h, (Scheme 2) all of which have R1 =Me
R1
R2
R3
B(OH)2
X
i
2
CH2NHCOPh
CH2NHCOPh
60 °C
R1
7
R2
8
R3
ii
R
N
X
R3 = H
R1
R2
R3
R1
R2
R3
N
3
R1 = Me
X = N
iii
+
60 °C
R1
-
CH
N
CPh
CH2
CPh
Cl
R1
R2
R2
5
10a,b,d–h
R3
R3
R2
9
R
R
+
R
N
N
N
X
X
H
X
H
R2
R1
Ph
R3
6
4
5
Scheme 1
or below, react to give cyclopropa[c]isoquinolines 2a. The reac-
tion is formally a 1,1-cycloaddition and is stereospecific in that
R2 and R3 are in the exo and endo positions, respectively, in the
primary products. The latter, on heating, undergo an equilibra-
tion with their isomers 4a via ring expansion to 3a. In cases
where either R2 or R3 is a hydrogen atom this equilibration
N
11a,b,d–h
Scheme 2 Reagents: i, R2R3C᎐C(R1)Br, Pd(0); ii, PCl5 or SOCl2–
᎐
HCONMe2; iii, KOBut or LiN(SiMe3)2 at 0 ЊC
J. Chem. Soc., Perkin Trans. 1, 1998
807

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Table 1 Identification of substituents
H
R3
Me
H
Me
Ph
R3
Compounds
Substituents
heat
Ph
N
8–16
N
a
b
c
d
e
f
R1 = Me; R2 = H; R3 = H
R1 = Me; R2 = H; R3 = Ph
R1 = Me; R2 = Ph; R3 = H
R1 = Me; R2 = Me; R3 = Me
R1 = Me; R2 = Me; R3 = Ph
R1 = Me; R2 = Ph; R3 = Me
R1 = Et; R2 = Me; R3 = Me
R1 = Me; R2 = Ph; R3 = Ph
11a,b
(R3 as shown in Table 1)
12a,b
[1,5] H shift
g
h
Me
R3
5
or Et (the substituents are identified in Table 1). The work had
two initial objectives. Firstly, it was of interest to find out
whether the presence of groups larger than hydrogen in the R1
position would impede the cyclisation reaction, i.e. whether it
would be possible to use this route to prepare 2-benzazepines
such as 5a with a substituent on C-5. This was in question
because it had been shown earlier4 that 1.7 electrocyclisation
reactions in analogous biaryl systems are inhibited by steric
factors which prevent the reactant adopting the helical transi-
tion state required for cyclisation. It was thought possible that
the interaction between the R1 group in 10 and the adjacent
aromatic hydrogen atom could have a similar effect. Secondly, if
the cyclisation should take place, the main interest was to find
out whether it would lead to compounds of the type 6a, ana-
logues of the nitrile imine products 6b. Such products could
arise via a base-induced hydrogen shift in intermediates of the
type 3a (R1 = Me, Et) and, if formed, would be of use in the
further chemical elaboration of the 2-benzazepine system.
Ph
N
H
H
13a,b
Scheme 3
The compound 11a (R3 = H) isomerised easily and quantita-
tively in refluxing benzene (12 h) and even converted slowly at
room temperature, whereas 11b (R3 = Ph) required 24 h at the
higher temperature of refluxing toluene. It is difficult to see how
the presence of the phenyl group in the latter could disfavour
the first step (11b→12b) and it therefore seems likely that the
observed effect is due to the combined effect of the three sub-
stituents on the shape of 12b which, probably by flattening the
ring, makes the ring inversion or the transition state for the
sigmatropic hydrogen migration less accessible.
Cyclopropa[c]isoquinolines with R2 and R3 ≠ H. All the other
examples in the series 11d–h were of this type and hence were
unable to follow the general reaction path (Scheme 1) leading to
5a. The alternative path for nitrile imines (Scheme 1) which gave
compounds of the type 6b was reported to occur for the cyclis-
ation of 1b (R1 = R2 = R3 = Me). In the reaction of the analo-
gous nitrile ylide 10d it was found that the cyclopropa[c]iso-
quinoline 11d was the only product even though the reaction
was carried out in the presence of excess base. The thermal isom-
erisation of 11d required 24 h at reflux in p-xylene and gave,
not 6a (R = Ph, R2 = R3 = Me), but 1,4-dihydro-4-isopropenyl-
4-methyl-3-phenylisoquinoline 14d (R1 = R2 = Me) (Scheme 4)
Results and discussion
Preparation of precursors 8a–h and generation of the nitrile
ylides 10a,b,d–h
The nitrile ylides were generated from the amides 8 (Scheme 2)
by the method used in earlier work,1,4 i.e. conversion into the
imidoyl chlorides 9 followed by 1,3-dehydrochlorination of the
latter in THF at 0 ЊC using a strong non-nucleophilic base.
Preparation of precursors 8a–h. The amides 8 were easily pre-
pared in high yields by the Suzuki coupling of the boronic acid
75 with a set of bromoalkenes whose substituents are shown in
Table 1. Interestingly, in most of these compounds, the
polysubstituted alkenyl groups were sufficiently bulky to be
inhibited from free rotation on the NMR timescale at room
R2
R1
R1
Me
R2
Ph
Ph
heat
1
temperature and hence to give H NMR spectra in which the
N
N
C
H
benzylic methylene protons were diastereotopic (J ca. 14.5 Hz).
The cyclisation reactions. In the event it proved that the pres-
ence of non-hydrogen substituents (methyl or ethyl) in the R1
position of 10 did not in any way impede the cyclisation reac-
tionandinallcasesthereactionsgavethecyclopropa[c]isoquino-
lines 11 (Scheme 2) in yields (66–80%) not inferior to those
obtained in the earlier work. The products were identified by
comparison of their 1H and 13C NMR spectra with those
obtained previously.1
11d–g
(R1, R2 as shown in Table 1)
14d,f,g
Scheme 4
in quantitative yield. It seems likely that the product is formed
via a homo [1,5] sigmatropic hydrogen shift which, although it
is a well known reaction for appropriately substituted cyclo-
propanes,6 is a new mode of rearrangement for this system.
The structure of the product was confirmed by X-ray crystal-
lography (Fig. 1).
Thermal isomerisation of the cyclopropa[c]isoquinolines
11a,b,d–h
Cyclopropa[c]isoquinolines with R2 or R3 ؍ H. The first two
examples studied 11a,b (Scheme 3) (R3 = H, Ph, respectively)
both isomerised, as expected, via the general route determined
earlier (Scheme 1) to give the 2-benzazepines 13a,b in yields of
100 and 75%, respectively. The products were identified by
comparison of their 1H and 13C NMR spectra with similar
compounds prepared in the earlier work.1 These conversions
show that the general route can be used for the synthesis of
these 5-substituted derivatives even in the case 13b (R3 = Ph)
where there are three adjacent substituents. There was however
a marked difference in the rate of the isomerisation reactions.
The generality of the reaction was explored by studying three
other examples 11e–g (substituents identified in Table 1). The
isomeric pair of compounds 11e and 11f reacted more slowly
but both gave 14f in high yield. The isomer 11e has its methyl
group in the exo position and obviously cannot directly under-
go a homo [1,5] sigmatropic hydrogen shift and must therefore
react via isomerisation to give 11f before the hydrogen migra-
tion. These clean conversions of compounds 11e and 11f into
14f contrast strongly with the previously studied1 thermolysis
of compound 11 (R1 = H, R2 = Ph, R3 = Me) (Scheme 5) (and
its isomer with the groups on C-1 transposed) which gave the
808
J. Chem. Soc., Perkin Trans. 1, 1998

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ition in 2a completely diverts the thermal rearrangement into a
new path (Scheme 4) leading to the formation of 1,4-dihydro-4-
alkenylisoquinolines 14 in high yield; and (iii) 5-alkylidene-2-
benzazepines 6a analogous to the products obtained from simi-
lar nitrile imines are not formed in these reactions.
Experimental
NMR spectra were run as solutions in deuteriochloroform
unless otherwise stated. Chemical shifts are recorded as δ
values. J Values are given in Hz. In the 13C NMR spectra car-
bon multiplicity was established by single frequency off reson-
ance decoupling or by DEPT. Mass spectra were obtained using
electron ionisation at 70 eV unless otherwise stated. Preparative
chromatography was carried out by the ‘dry-column flash’
technique7 using silica gel (15 µm, Fluka Kieselgel GF254) or the
‘medium pressure’ (MPLC) technique8 using 100 × 2.5 cm col-
umns packed with Merck Kieselgel 60 (230–240 mesh), and
eluting solvents based on hexane admixed with ether or ethyl
acetate. Ether refers to diethyl ether. ‘Evaporation’ of solvents
indicates evaporation under reduced pressure using a rotary
evaporator. All drying of solutions was done with anhydrous
magnesium sulfate.
Fig. 1 Crystal structure of compound 14d
R3
R2
R3
R2
Ph
R1
Ph
R1
7b
heat
N
C
N
C
Solvents, reactants and starting materials
H
H
Tetrahydrofuran (THF) was distilled from sodium and benzo-
phenone as required. Cyclohexane, hexane and N,N-
dimethylformamide (DMF) were distilled from calcium hydride
as required. 1,2-Dimethoxyethane (DME) was passed through
a column of activated alumina and stored over 4 Å molecular
sieves. The following materials were obtained from the suppliers
indicated or were prepared by literature routes: 2-bromo-
propene (Avocado Research Chemicals Ltd.), (Z)- and (E)-2-
bromo-1-phenylpropene9,10 as a mixture, 2-bromo-3-methyl-
but-2-ene (Avocado Research Chemicals Ltd.), (Z)- and (E)-
2-bromo-3-phenylbut-2-ene11 (separated by dry-column flash
chromatography), 3-bromo-2-methylpent-2-ene,12 2-bromo-1, 1-
diphenylpropene13 and 2-(benzoylaminomethylphenyl)boronic
acid5 7.
11
15
R2
R3
R1
Ph
N
16
Scheme 5
5H-2-benzazepine 16 (R1 = H, R2 = Ph, R3 = Me) (structure
confirmed by X-ray crystallography). Compound 11f differs
from this reactant only in the presence of the methyl group (R1)
at C-7b but this clearly serves to divert completely the reaction
into the new path. The cause of this effect is not understood at
present. The next reactant in the series, 11g (R1 = Et, Scheme 4),
also followed the same path to give 14g in 90% yield, so the
ethyl group can be seen to have a similar effect.
Synthesis of the N-(2-alkenylbenzyl)benzamides 8a–h
These compounds were synthesised by the general method
described in detail for the first example, in all cases the reaction
time was 20 h.
N-(2-Isopropenylbenzyl)benzamide 8a. 2-Bromopropene (1.52
g, 12.0 mmol) and tetrakis(triphenylphosphine)palladium(0)
(0.66 g, 0.58 mmol, 4.8 mol% catalyst) were stirred in 1,2-
dimethoxyethane (50 cm3) under dry nitrogen for 20 min. 2-
(Benzoylaminomethylphenyl)boronic acid 7 (3.38 g, 13.2 mmol)
and sodium carbonate (3.42 g, 12.0 mmol) in water (16.5 cm3)
were added and the mixture heated at reflux for 20 h. The reac-
tion mixture was allowed to cool to room temperature and
passed through a pad of alumina. The DME was removed in
vacuo and dichloromethane (100 cm3) was added. The organic
layer was separated, dried and the solvent removed in vacuo to
give a brown oil. Dry-column flash chromatography (silica,
hexane–ethyl acetate, 9:1) gave N-(2-isopropenylbenzyl)-
benzamide 8a as a white solid (1.96 g, 65%), mp 92–93 ЊC from
ethanol [Found: C, 81.1; H, 6.8; N, 5.5%; (M ϩ 1)ϩ, 252.1391.
C17H17NO requires C, 81.2; H, 6.8; N, 5.6%; (M ϩ 1)ϩ,
252.1388]; δH(200 MHz, CDCl3) 2.07 (3 H, m, CH3), 4.64 (2 H,
d, J 5.5, CH2), 4.90 (1 H, m, CH), 5.24 (1 H, m, CH), 6.57 (1 H,
br, NH), 7.14–7.51 (7 H, m, Ar-H), 7.72–7.79 (2 H, m, Ar-H);
δC(50 MHz, CDCl3) 24.8 (CH3), 41.8 (CH2), 115.5 (CH2), 126.7
(CH), 127.2 (CH), 127.3 (CH), 128.2 (CH), 128.4 (CH), 128.7
(CH), 131.2 (CH), 134.3 (quat.), 143.5 (quat.), 144.8 (quat.),
The final reactant 11h by the nature of its substituents (R1 =
Me; R2 = R3 = Ph) was unable to follow either of the reaction
paths in Schemes 3 or 4 and was studied to find out whether the
presence of the C-7b methyl group would completely inhibit the
path in Scheme 5. In the event the reactant isomerised very
slowly (40% after 6 days at reflux in p-xylene) to give a product
whose mass and 1H NMR spectra were consistent with structure
16h (R1 = Me; R2 = R3 = Ph) but which proved to be too unstable
to characterise fully. The C-7b methyl group in the reactant
therefore does not fully suppress this reaction path but does
slow it down.
In none of these cases was any product of the type 6a formed
either in the initial nitrile ylide cyclisations, or in the subsequent
thermal rearrangements of the cycloprop[c]isoquinolines, or
when the latter were heated in the presence of lithium
bis(trimethylsilylamide).
This work has therefore shown that for diene-conjugated
nitrile ylides of the type 1a, the presence of substituents Me or
Et in the R1 position does not impede the cyclisation to give 2a,
and that (i) if R2 or R3 = H then the latter undergo the normal
thermal rearrangement to give 5-substituted 2-benzazepines 5a;
(ii) where R2 and R3 ≠ H and either is a CH3 group then the
presence of the non-hydrogen R1 substituent in the C-7b pos-
167.0 (quat.); νmax(Nujol)/cmϪ1 1636 (C᎐O), 3331 (NH).
᎐
(Z)- and (E)-N-[2-(1-Methyl-2-phenylethenyl)benzyl]benz-
amide 8b and 8c. The usual work-up gave a brown oil which on
dry-flash column chromatography (silica, hexane–ethyl acetate,
J. Chem. Soc., Perkin Trans. 1, 1998
809

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9:1) followed by MPLC (silica, hexane–ethyl acetate, 9:1) gave
(a) (Z)-N-[2-(1-methyl-2-phenylethenyl)benzyl]benzamide 8b
as a white solid (21%), mp 147–148 ЊC from hexane–ethanol
[Found: C, 84.4; H, 6.5; N, 4.3%; (M ϩ 1)ϩ, 328.1701.
C23H21NO requires C, 84.4; H, 6.5; N, 4.3%; (M ϩ 1)ϩ,
328.1701]; δH(250 MHz, CDCl3) 2.22 (3 H, m, CH3), 4.12 (1 H,
dd, J 14.2 and 3.5, CH2), 4.77 (1 H, dd, J 14.2 and 7.6, CH2),
5.74 (1 H, br, NH), 6.57 (1 H, m, CH; 12% NOE enhancement
on irradiation at δ 2.22), 6.83–7.46 (14 H, m, Ar-H); δC(63
MHz, CDCl3) 28.1 (CH3), 41.5 (CH2), 126.6 (CH), 126.7 (CH),
127.6 (CH), 127.7 (CH), 128.1 (CH), 128.2 (CH), 128.3 (CH),
130.3 (CH), 131.0 (CH), 133.9 (quat.), 134.0 (quat.), 136.9
(quat.), 137.7 (quat.), 141.8 (quat.), 166.6 (quat.); νmax(Nujol)/
2.49 (1 H, m, CH3CH2), 4.54 (2 H, m, CH2NH), 6.25 (1 H, br,
NH), 7.00–7.80 (9 H, m, Ar-H); δC(63 MHz, CDCl3) 12.6
(CH3), 19.3 (CH3), 22.1 (CH3), 27.1 (CH2), 41.7 (CH2), 126.7
(2 × CH), 127.2 (CH), 128.1 (CH), 128.5 (2 × CH), 129.8 (CH),
131.3 (CH), 134.4 (quat.), 134.6 (quat.), 135.2 (quat.), 143.0
(quat.), 167.0 (quat.); νmax(Nujol)/cmϪ1 1636 (C᎐O), 3340 (NH).
᎐
N-[2-(1-Methyl-2,2-diphenylethenyl)benzyl]benzamide
8h.
White solid (0.56 g, 54%), mp 144–146 ЊC from hexane–ethanol
[Found: C, 86.4; H, 6.4; N, 3.3%; (M ϩ 1)ϩ, 404.2001.
C29H25NO requires C, 86.3; H, 6.3; N, 3.5%; (M ϩ 1)ϩ,
404.2014]; δH(250 MHz, CDCl3) 2.11 (3 H, s, CH3), 4.18 (1 H,
dd, J 14.4 and 3.6, CH2), 4.88 (1 H, dd, J 14.4 and 7.7, CH2),
5.54 (1 H, br, NH), 6.89–7.59 (19 H, m, Ar-H); δC(63 MHz,
CDCl3) 24.6 (CH3), 40.8 (CH2), 126.1 (CH), 126.7 (CH), 126.9
(2 × CH), 127.2 (CH), 127.3 (CH), 127.4 (2 × CH), 128.1
(2 × CH), 128.2 (2 × CH), 129.1 (CH), 129.7 (CH), 129.8
(2 × CH), 130.2 (2 × CH), 131.2 (CH), 133.9 (quat.), 134.2
(quat.), 134.5 (quat.), 139.6 (quat.), 141.9 (quat.), 142.4 (quat.),
cmϪ1 1632 (C᎐O), 3317 (NH); (b) (E)-N-[2-(1-methyl-2-
᎐
phenylethenyl)benzyl]benzamide 8c as a white solid (10%), mp
112–113 ЊC from hexane–ethanol [Found: C, 84.4; H, 6.5; N,
4.3%; (M ϩ 1)ϩ, 328.1701. C23H21NO requires C, 84.4; H, 6.5;
N, 4.3%; (M ϩ 1)ϩ, 328.1701]; δH(250 MHz, CDCl3) 2.24 (3 H,
d, J 1.5, CH3), 4.73 (2 H, d, J 5.5, CH2), 6.45 (1 H, m, CH; no
NOE enhancement on irradiation at δ 2.24), 6.57 (1 H, br, NH),
7.24–7.77 (14 H, m, Ar-H); δC(63 MHz, CDCl3) 20.2 (CH3),
41.9 (CH2), 126.6 (CH), 126.7 (CH), 127.3 (CH), 127.5 (CH),
128.1 (CH), 128.4 (CH), 128.5 (CH), 128.6 (CH), 128.8 (CH),
129.9 (CH), 134.2 (quat.), 134.5 (quat.), 137.2 (quat.), 137.8
(quat.), 145.3 (quat.), 167.1 (quat.); νmax(Nujol)/cmϪ1 1632
142.9 (quat.), 167.1 (quat.); νmax(Nujol)/cmϪ1 1640 (C᎐O), 3291
᎐
(NH).
Generation of the nitrile ylides 10a,b,d–h derived from the amides
8a,b,d–h and their cyclisation to give the 1a,7b-dihydro-1a-
phenyl-1H-cyclopropa[c]isoquinolines 11a,b,d–h
The amides were converted into the imidoyl chlorides 9a,b,d–h
by reaction with phosphorus pentachloride or (chloro-
methylidene)(dimethyl)iminium chloride (prepared in situ by
reaction of thionyl chloride with the reaction solvent DMF).
This is described in detail for the preparation of 11a and 11g
respectively. The imidoyl chlorides (not isolated or purified)
were converted into the nitrile ylides (10) by reaction, as solu-
tions in THF at 0 ЊC, with lithium bis(trimethylsilyl)amide (1.0
 in THF) or solid potassium tert-butoxide as described in
detail for the preparation of 11a and 11f, respectively. The reac-
tions were all worked-up as described for 11a.
(C᎐O), 3317 (NH); and (c) N-(2-phenylbenzyl)benzamide as a
᎐
white solid (40%), mp 95–96 ЊC from hexane–ethanol (lit.,4
94.5–95.5 ЊC).
N-[2-(1,2-Dimethylprop-1-enyl)benzyl]benzamide 8d. White
solid (70%), mp 105 ЊC from hexane–ethanol [Found: C, 81.4;
H, 8.0; N, 4.7%; (M ϩ 1)ϩ, 280.169 98. C19H21NO requires C,
81.7; H, 7.6; N, 5.0%; (M ϩ 1)ϩ, 280.170 14]; δH(250 MHz,
CDCl3) 1.42 (3 H, m, CH3), 1.80 (3 H, m, CH3), 1.90 (3 H, m,
CH3), 4.47 (1 H, dd, J 14.7 and 5.5, CH2), 4.56 (1 H, dd, J 14.7
and 5.6, CH2), 6.45 (1 H, br, NH), 7.01–7.77 (9 H, m, Ar-H);
δC(63 MHz, CDCl3) 19.7 (CH3), 20.6 (CH3), 21.8 (CH3), 41.6
(CH2), 126.5 (CH), 126.7 (2 × CH), 127.5 (CH), 128.2 (CH),
128.2 (CH), 128.4 (2 × CH), 128.9 (CH), 131.2 (CH), 134.3
(quat.), 134.7 (2 × quat.), 144.5 (quat.), 167.0 (quat.);
1a,7b-Dihydro-7b-methyl-1a-phenyl-1H-cyclopropa[c]iso-
quinoline 11a. N-(2-Isopropenylbenzyl)benzamide 8a (0.5 g,
1.99 mmol), dry ether (40 cm3) and phosphorus pentachloride
(0.54 g, 2.2 mmol) were heated at reflux under dry nitrogen for
24 h. The solvent was removed in vacuo and the residue dried
under high vacuum at 30–40 ЊC for 2–3 h. Dry THF (30 cm3)
was added and the solution cooled to 0 ЊC. Lithium bis(tri-
methylsilyl)amide (2.99 cm3, 2.99 mmol) was added dropwise
with rapid stirring under dry nitrogen. The mixture was stirred
at 0 ЊC for 1 h, then allowed to warm to room temperature.
Ammonium chloride (25% w/v, 30 cm3) was added and the mix-
ture stirred for 10 min. The organic layer was separated and the
aqueous layer extracted with dichloromethane (DCM) (2 × 30
cm3). The combined organic layers were dried and the solvent
removed in vacuo. Dry-column flash chromatography (silica,
hexane–ethyl acetate, 9:1) gave 11a as a yellow oil (0.35 g, 75%)
[Found: (M ϩ 1)ϩ, 234.1279. C17H15N requires (M ϩ 1)ϩ,
234.1283]; δH(250 MHz, CDCl3) 0.18 (1 H, d, J 5.1, CH2), 1.29
(3 H, s, CH3), 2.51 (1 H, d, J 5.1, CH2), 7.25–7.63 (9 H, m, Ar-
H), 8.29 (1 H, s, CH); δC(63 MHz, CDCl3) 19.0 (CH3), 24.6
(CH2), 31.0 (quat.), 57.4 (quat.), 123.5 (quat.), 124.7 (CH),
125.5 (CH), 127.0 (CH), 128.1 (2 × CH), 129.1 (2 × CH), 129.5
(CH), 131.2 (CH), 140.2 (quat.), 140.6 (quat.), 153.8 (CH);
νmax(Nujol)/cmϪ1 1637 (C᎐O), 3327 (NH).
᎐
(Z)-N-[2-(1-Methyl-2-phenylprop-1-enyl)benzyl]benzamide
8e. White solid (63%), mp 141–143 ЊC from hexane–ethyl acet-
ate [Found: C, 84.8; H, 7.1; N, 4.0%; (M ϩ 1)ϩ, 342.1844.
C24H23NO requires C, 84.4; H, 6.8; N, 4.1%; (M ϩ 1)ϩ, 342.1858];
δH(200 MHz, CDCl3) 2.06 (3 H, s, CH3), 2.13 (3 H, s, CH3), 3.96
(1 H, dd, J 14.3 and 3.7, CH2), 4.61 (1 H, dd, J 14.3 and 7.5,
CH2), 5.36 (1 H, br, NH), 7.06–7.54 (14 H, m, Ar-H); δC(63
MHz, CDCl3) 20.5 (CH3), 22.5 (CH3), 41.1 (CH2), 125.9 (CH),
126.8 (CH), 126.9 (2 × CH), 127.1 (CH), 127.5 (2 × CH), 128.2
(2 × CH), 128.6 (2 × CH), 128.7 (CH), 129.8 (CH), 131.2 (CH),
131.4 (quat.), 133.0 (quat.), 134.3 (quat.), 134.4 (quat.), 143.6
(quat.), 143.8 (quat.), 167.1 (quat.); νmax(Nujol)/cmϪ1 1635
(C᎐O), 3301 (NH).
᎐
(E)-N-[2-(1-Methyl-2-phenylprop-1-enyl)benzyl]benzamide
8f. White solid (78%), mp 125–127 ЊC from hexane–ethyl acet-
ate [Found: C, 84.6; H, 7.0; N, 4.1%; (M ϩ 1)ϩ, 342.1855.
C24H23NO requires C, 84.4; H, 6.8; N, 4.1%; (M ϩ 1)ϩ, 342.1858];
δH(200 MHz, CDCl3) 1.67 (3 H, CH3), 1.78 (3 H, s, CH3), 4.61
(2 H, br m, CH2), 6.32 (1 H, br, NH), 6.91–7.72 (14 H, m, Ar-
H); δC(63 MHz, CDCl3) 22.2 (CH3), 22.4 (CH3), 41.6 (CH2),
126.3 (CH), 126.7 (2 × CH), 127.0 (CH), 127.8 (CH), 128.0
(2 × CH), 128.1 (2 × CH), 128.4 (CH), 128.5 (2 × CH), 128.7
(CH), 131.3 (CH), 134.3 (quat.), 134.4 (quat.), 134.6 (quat.),
143.2 (quat.), 143.6 (quat.), 167.1 (quat.); νmax(Nujol)/cmϪ1
νmax(Nujol)/cmϪ1 1615 (C᎐N).
᎐
1a,7b-Dihydro-7b-methyl-1-endo,1a-diphenyl-1H-cyclopropa-
[c]isoquinoline 11b. Similarly the reaction of (Z)-N-[2-(1-
methyl-2-phenylethenyl)benzyl]benzamide 8b (0.24 g, 0.31
mmol) with phosphorus pentachloride (0.20 g, 0.34 mmol) for
24 h followed by lithium bis(trimethylsilyl)amide (1.10 cm3, 1.10
mmol) gave 11b as a white crystalline solid (0.15 g, 66%), mp
156–158 ЊC from pentane–DCM [Found: C, 89.4; H, 6.2; N,
4.2%; (M ϩ 1)ϩ, 310.1591. C23H19N requires C, 89.3; H, 6.2; N,
4.5%; (M ϩ 1)ϩ, 310.1596]; δH(250 MHz, CDCl3) 1.54 (3 H, s,
CH3), 3.30 (1 H, s, CH), 6.76–7.76 (14 H, m, Ar-H), 8.07 (1 H,
1636 (C᎐O), 3344 (NH).
᎐
N-[2-(1-Ethyl-2-methylprop-1-enyl)benzyl]benzamide
8g.
White solid (41%), mp 105 ЊC from hexane–ethyl acetate
(Found: C, 81.8; H, 8.2; N, 4.5. C20H23NO requires C, 81.9; H,
7.9; N, 4.8%); δH(200 MHz, CDCl3) 0.92 (3 H, t, J 7.5, CH3),
1.42 (3 H, s, CH3), 1.82 (3 H, s, CH3), 2.14 (1 H, m, CH3CH2),
d, J 0.7, HC᎐N); δ (63 MHz, CDCl ) 21.1 (CH ), 30.3 (C1),
᎐
C
3
3
810
J. Chem. Soc., Perkin Trans. 1, 1998

View Article Online
34.6 (quat., C-7b), 61.2 (quat., C-1a), 125.6 (CH), 125.7 (CH),
125.9 (CH), 127.2 (CH), 128.2 (CH), 129.2 (CH), 131.2 (CH),
132.0 (CH), 132.8 (quat.), 136.9 (quat.), 141.8 (quat.), 155.2
(HC᎐N); νmax(Nujol)/cmϪ1 1600 (C᎐N).
(CH), 137.2 (quat.), 140.8 (quat.), 154.8 (HC᎐N); νmax(Nujol)/
᎐
cmϪ1 1626 (C᎐N).
᎐
1a,7b-Dihydro-7b-methyl-1,1,1a-triphenyl-1H-cyclopropa-
[c]isoquinoline 11h. N-[2-(1-methyl-2,2-diphenylethenyl)-
᎐
᎐
1a,7b-Dihydro-1,1,7b-trimethyl-1a-phenyl-1H-cyclopropa-
[c]isoquinoline 11d. Similarly the reaction of N-[2-(1,2-
dimethylprop-1-enyl)benzyl]benzamide 8d (0.75 g, 2.68 mmol)
and phosphorus pentachloride (0.75 g, 3.59 mmol) for 60 h
followed by lithium bis(trimethylsilyl)amide (4.04 cm3, 4.04
mmol) gave 11d as a white crystalline solid (0.53 g, 75%), mp
143–144 ЊC from hexane–ethanol (Found: C, 87.5; H, 7.5; N,
5.1%; Mϩ, 261.1515. C19H19N requires C, 87.3; H, 7.3; N, 5.4%;
Mϩ, 261.1518); δH(250 MHz, CDCl3) 0.69 (3 H, s, CH3), 1.35
(3 H, s, CH3), 1.49 (3 H, s, CH3), 7.25–7.55 (9 H, m, Ar-H), 8.30
benzyl]benzamide 8h (0.15 g, 0.39 mmol) in dry DMF (0.46 g,
5.89 mmol) was reacted with thionyl chloride (0.034 cm3, 0.46
mmol) as described for 11g. Further reaction with potassium
tert-butoxide (0.26 g, 2.34 mmol) gave 11h as a yellow solid
(0.10 g, 67%) [Found: C, 90.2; H, 6.2; N, 3.35%; (M ϩ 1)ϩ,
386.1935. C29H23N requires C, 90.4; H, 6.0; N, 3.6%; (M ϩ 1)ϩ,
386.1909]; δH(200 MHz, CDCl3) 1.76 (3 H, s, CH3), 6.77–7.80
(19 H, m, Ar-H), 7.83 (1 H, s, HC᎐N); δ (63 MHz, CDCl ) 22.3
᎐
C
3
(CH3), 35.4 (quat.), 42.9 (quat.), 62.6 (quat.), 125.1 (CH), 125.7
(CH), 125.8 (CH), 125.9 (CH), 126.1 (CH), 126.6 (CH), 127.7
(2 × CH), 127.9 (2 × CH), 128.2 (CH), 128.3 (CH), 130.8
(2 × CH), 131.1 (2 × CH), 131.7 (CH), 138.4 (quat.), 140.0
(1 H, s, HC᎐N); δ (63 MHz, CDCl ) 15.7 (CH ), 18.8 (CH ),
᎐
C
3
3
3
18.9 (quat.), 20.1 (CH3), 31.9 (quat.), 62.4 (quat.), 125.5 (CH),
125.6 (CH), 126.1 (CH), 126.8 (CH), 128.1 (CH), 128.3 (2 ×
CH), 130.8 (2 × CH), 131.2 (CH), 139.1 (quat.), 140.6 (quat.),
154.5 (quat.); m/z (EI) (Mϩ, 261, 27%), 260 (100), 158 (33), 143
(80), 141 (12), 128 (34), 115 (20), 103 (11); νmax(Nujol)/cmϪ1
(quat.), 140.1 (quat.), 140.4 (quat.), 155.8 (HC᎐N); νmax(film)/
᎐
cmϪ1 1625 (C᎐N).
᎐
Thermal isomerisation products of the 1a,7b-dihydro-1a-phenyl-
1H-cyclopropa[c]isoquinolines 11a,b,d–h
1618 (C᎐N).
᎐
1a,7b-Dihydro-1,7b-dimethyl-1-endo,1a-diphenyl-1H-
Compounds 11a,b,d–h were heated under reflux under nitrogen
in the solvent indicated and the reactions were worked up by the
method given for the first example.
cyclopropa[c]isoquinoline 11e. A similar reaction of (Z)-N-
[2-(1-methyl-2-phenylprop-1-enyl)benzyl]benzamide 8e (0.20 g,
0.59 mmol) with phosphorus pentachloride (0.17 g, 1.37 mmol)
for 60 h followed by lithium bis(trimethylsilyl)amide (2.36 cm3,
2.36 mmol) gave 11e as a white solid (0.13 g, 70%), mp 179–
181 ЊC from pentane–DCM [Found: C, 88.9; H, 6.4; N, 4.0%;
(M ϩ 1)ϩ, 324.1752. C24H21N requires C, 89.1; H, 6.55; N, 4.3%;
(M ϩ 1)ϩ, 324.1752]; δH(200 MHz, CDCl3) 1.49 (3 H, s, CH3),
1.68 (3 H, s, CH3), 7.03–7.64 (14 H, m, Ar-H), 7.75 (1 H, s,
5-Methyl-3-phenyl-1H-2-benzazepine 13a. Compound 11a
(0.1 g, 0.43 mmol) in dry benzene (2 cm3) was heated under
reflux for 12 h. Evaporation of the solvent and dry-column
flash chromatography of the residual brown oil (silica, hexane–
ethyl acetate, 9:1) gave 5-methyl-3-phenyl-1H-2-benzazepine
13a as a brown crystalline solid (0.1 g, 100%), mp 111–112 ЊC
from pentane–dichloromethane [Found: C, 87.4; H, 6.8; N,
5.9%; (M ϩ 1)ϩ, 234.1264. C17H15N requires C, 87.5; H, 6.5; N,
6.0%; (M ϩ 1)ϩ, 234.1283]; δH(200 MHz, CDCl3, 245 K) 2.49 (3
H, d, J 1.2, CH3), 3.93 (1 H, d, J 10.5, CH2), 5.00 (1 H, d, J 10.5,
CH2), 6.90 (1 H, br s, CH), 7.25–7.78 (9 H, m, Ar-H); δC(63
MHz, CDCl3) 23.8 (CH3), 56.3 (CH2), 107.5 (CH), 124.2 (CH),
125.5 (CH), 126.0 (CH), 127.6 (2 × CH), 127.9 (CH), 128.0
(2 × CH), 129.3 (CH), 129.9 (CH), 137.6 (quat.), 137.8 (quat.),
138.7 (quat.), 147.4 (quat.), 165.1 (quat.); νmax(Nujol)/cmϪ1
HC᎐N); δ (63 MHz, CDCl ) 18.9 (CH ), 23.4 (CH ), 33.5
᎐
C
3
3
3
(quat.), 34.3 (quat.), 62.7 (quat.), 125.2 (CH), 125.4 (2 × CH),
127.0 (CH), 127.1 (2 × CH), 128.0 (CH), 128.4 (2 × CH), 131.0
(2 × CH), 131.2 (CH), 131.5 (quat.), 139.3 (quat.), 139.9
(quat.), 140.6 (quat.), 154.6 (HC᎐N); νmax(Nujol)/cmϪ1 1623
᎐
(C᎐N).
᎐
1a,7b-Dihydro-1,7b-dimethyl-1-exo,1a-diphenyl-1H-cyclo-
propa[c]isoquinoline 11f. A similar reaction of (E)-N-[2-(1-
methyl-2-phenylprop-1-enyl)benzyl]benzamide 8f (0.5 g, 1.50
mmol) with phosphorus pentachloride (0.43 g, 2.0 mmol) for 60
h followed by solid potassium tert-butoxide (0.34 g, 3.0 mmol)
gave 11f as a colourless oil (0.35 g, 72%) [Found: (M ϩ 1)ϩ,
324.1763. C24H21N requires (M ϩ 1)ϩ, 324.1752]; δH(200 MHz,
CDCl3) 1.01 (3 H, s, CH3), 1.58 (3 H, s, CH3), 7.13–7.75 (14 H,
1618 (C᎐N).
᎐
5-Methyl-3,4-diphenyl-1H-2-benzazepine 13b. Compound
11b (0.1 g, 0.32 mmol) in toluene (5 cm3) was heated under
reflux for 24
h and gave 5-methyl-3,4-diphenyl-1H-2-
benzazepine 13b as a yellow glassy foam (0.07 g, 75%) [Found:
(M ϩ 1)ϩ, 310.1606. C23H19N requires (M ϩ 1)ϩ, 310.1596];
δH(200 MHz, CDCl3) 2.35 (3 H, s, CH3), 4.08 (1 H, d, J 9.9,
CH2), 4.91 (1 H, d, J 9.9, CH2), 7.05–7.63 (14 H, m, Ar-H);
δC(63 MHz, CDCl3) 21.6 (CH3), 55.8 (CH2), 126.8 (CH), 126.9
(CH), 127.0 (CH), 127.1 (CH), 127.4 (2 × CH), 127.7 (2 × CH),
128.3 (CH), 128.4 (CH), 128.6 (2 × CH), 130.6 (2 × CH), 136.6
(quat.), 138.8 (quat.), 139.4 (quat.), 139.6 (quat.), 139.7 (quat.),
143.0 (quat.), 167.3 (C᎐N); νmax(Nujol)/cmϪ1 1606 (C᎐N).
m, Ar-H), 8.47 (1 H, s, HC᎐N); δ (63 MHz, CDCl ) 20.8 (CH ),
᎐
C
3
3
22.6 (CH3), 28.8 (quat.), 32.8 (quat.), 61.9 (quat.), 125.9 (CH),
126.3 (CH), 126.4 (CH), 126.5 (CH), 127.3 (quat.), 127.6
(2 × CH), 127.9 (2 × CH), 128.6 (CH), 130.5 (2 × CH), 131.0
(2 × CH), 132.0 (CH), 138.3 (quat.), 140.7 (quat.), 141.4
(quat.), 156.0 (HC᎐N); νmax(Nujol)/cmϪ1 1625 (C᎐N).
᎐
᎐
7b-Ethyl-1a,7b-dihydro-1,1-dimethyl-1a-phenyl-1H-cyclo-
propa[c]isoquinoline 11g. Thionyl chloride (0.06 cm3, 0.81
mmol) was added to N-[2-(1-ethyl-2-methylprop-1-enyl)-
benzyl]benzamide 8g (0.2 g, 0.68 mmol) in dry DMF (0.8 g, 10.2
mmol) and stirred under a nitrogen atmosphere for 30 min. The
solvent was removed in vacuo and the residue dried under high
vacuum at 30–40 ЊC for 2–3 h. Dry THF (15 cm3) was added
and the solution cooled to 0 ЊC. Lithium bis(trimethylsilyl)-
amide (2.72 cm3, 2.72 mmol) was added dropwise with rapid
stirring under dry nitrogen. The mixture was stirred at 0 ЊC for
1 h, then allowed to warm to room temperature. The usual
work-up gave 11g as a yellow oil (0.15 g, 80%) [Found:
(M ϩ 1)ϩ, 276.1761. C20H21N requires (M ϩ 1)ϩ, 276.1752];
δH(200 MHz, CDCl3) 0.59 (3 H, s, CH3), 1.00 (3 H, t, CH3), 1.34
(3 H, s, CH3), 1.44 (1 H, q, CH2), 2.09 (1 H, q, CH2), 7.18–7.41
᎐
᎐
1,4-Dihydro-4-isopropenyl-4-methyl-3-phenylisoquinoline 14d.
Compound 11d (0.1 g, 0.38 mmol) in p-xylene (5 cm3) was
heated under reflux for 24
h and gave 1,4-dihydro-4-
isopropenyl-4-methyl-3-phenylisoquinoline 14d as a white solid
(0.1 g, 100 %), mp 68–69 ЊC from pentane [Found: C, 87.6; H,
7.6; N, 5.0%; (M ϩ 1)ϩ, 262.1601. C19H19N requires C, 87.3; H,
7.3; N, 5.4%; (M ϩ 1)ϩ, 262.1596]; δH(200 MHz, CDCl3) 1.49
(3 H, d, J 0.8, CH3), 1.61 (3 H, s, CH3), 5.02 (1 H, d, J 21, CH2),
5.11 (1 H, m, C᎐CH ), 5.12 (1 H, d, J 21, CH ), 5.26 (1 H, br s,
᎐
2
2
C᎐CH ), 7.17–7.88 (9 H, m, Ar-H); δ (63 MHz, CDCl ) 20.9
᎐
2
C
3
(CH3), 25.1 (CH3), 48.5 (quat.), 56.0 (CH2), 112.8 (CH2), 123.8
(CH), 124.8 (CH), 125.4 (CH), 126.4 (CH), 127.1 (CH), 127.5
(CH), 127.6 (CH), 128.4 (CH), 132.6 (quat.), 134.3 (quat.),
138.3 (quat.), 140.7 (quat.), 147.5 (quat.), 171.4 (quat.);
(9 H, m, Ar-H), 8.21 (1 H, s, HC᎐N); δ (63 MHz, CDCl ) 12.4
νmax(Nujol)/cmϪ1 1628 (C᎐N).
᎐
᎐
C
3
(CH3), 16.5 (CH3), 19.1 (quat.), 20.3 (CH), 23.1 (CH2), 37.1
(quat.), 62.6 (quat.), 125.6 (CH), 126.5 (quat.), 127.0 (CH),
127.4 (CH), 128.3 (2 × CH), 128.6 (CH), 130.7 (2 × CH), 130.9
1,4-Dihydro-4-methyl-3-phenyl-4-(1-phenylethenyl)iso-
quinoline 14f. Compound 11e (0.06 g, 0.18 mmol) in p-xylene
(2 cm3) was heated under reflux for 48 h and gave 1,4-dihydro-4-
J. Chem. Soc., Perkin Trans. 1, 1998
811

View Article Online
methyl-3-phenyl-4-(1-phenylethenyl)isoquinoline 14f as a col-
ourless oil (0.05 g, 83%) [Found: (M ϩ 1)ϩ, 324.1743. C24H21N
requires (M ϩ 1)ϩ, 324.1752]; δH(200 MHz, CDCl3) 1.71 (3 H,
CH3), 4.63 (1 H, d, J 21, CH2), 4.88 (1 H, d, J 21, CH2), 5.41 (1
perature device.15 The structure was solved by direct methods
(SIR92)16 and refined against F with anisotropic displacement
parameters on all non-H atoms, and H-atoms placed in calcu-
lated positions (CRYSTALS).17 The refinement converged to
R = 9.73% and Rw = 10.73% using a Chebychev polynomial
weighting scheme for 1159 data with F >4σ(F ) and 182 param-
eters. The final difference synthesis max and min were ϩ0.49
and Ϫ0.32 e ÅϪ3, respectively. Atomic coordinates, bond
lengths and angles, and thermal parameters have been
deposited at the Cambridge Crystallographic Data Centre.†
H, br s, C᎐CH ), 5.54 (1 H, br s, C᎐CH ), 6.55–7.45 (14 H, m,
᎐
᎐
2
2
Ar-H); δC(63 MHz, CDCl3) 26.1 (CH3), 48.6 (quat.), 52.9
(CH2), 115.3 (CH2), 125.0 (CH), 125.5 (CH), 126.6 (CH), 126.7
(CH), 127.2 (CH), 127.3 (2 × CH), 127.4 (2 × CH), 127.5
(2 × CH), 127.8 (2 × CH), 128.2 (CH), 138.7 (quat.), 140.8
(quat.), 141.0 (quat.), 151.5 (quat.), 154.6 (quat.), 171.8 (quat.);
νmax(Nujol)/cmϪ1 1638 (C᎐N).
᎐
Compound 11f (0.15 g, 0.46 mmol) in p-xylene (5 cm3) was
heated under reflux for 48 h and gave 1,4-dihydro-4-methyl-3-
phenyl-4-(1-phenylethenyl)isoquinoline 14f as a colourless oil
(0.1 g, 66%), identical with the sample obtained in the therm-
olysis of 11e, and 1a,7b-dihydro-1,7b-dimethyl-1-endo-phenyl-
1a-phenyl-1H-cyclopropa[c]isoquinoline 11e (0.03 g, 20%).
4-Ethyl-1,4-dihydro-4-isopropenyl-3-phenylisoquinoline 14g.
Compound 11g (0.05 g, 0.18 mmol) in p-xylene (3 cm3) was
heated under reflux for 24 h and gave 4-ethyl-1,4-dihydro-4-
isopropenyl-3-phenylisoquinoline 14g as a yellow oil (45 mg, 90
%) [Found: (M ϩ 1)ϩ, 276.1685. C20H21N requires (M ϩ 1)ϩ,
276.1752]; δH(200 MHz, CDCl3) 0.46 (3 H, t, J 7.3, CH3), 1.52
(3 H, d, 0.7, CH3), 2.03 (2 H, q, J 7.3, CH2), 5.01 (1 H, br s,
C᎐CH ), 5.05 (2 H, s, CH ), 5.19 (1 H, br s, C᎐CH ), 7.03–7.65
Acknowledgements
We thank the EPSRC for a Studentship (J.-P. S.) and for funding
for a diffractometer.
† Full crystallographic details, excluding structure factor tables, have
been deposited at the Cambridge Crystallographic Data Centre
(CCDC). For details of the deposition scheme, see ‘Instructions for
Authors’, J. Chem. Soc., Perkin Trans. 1, available via the RSC Web
pages (http://www.rsc.org/authors). Any request to the CCDC for
this material should quote the full literature citation and the reference
number 207/172.
References
᎐
᎐
2
2
2
(9 H, m, Ar-H); δC(63 MHz, CDCl3) 9.0 (CH3), 21.5 (CH3), 30.2
(CH2), 52.2 (quat.), 53.1 (CH2), 111.8 (CH), 124.3 (CH), 125.5
(CH), 126.4 (CH), 127.1 (CH), 127.6 (2 × CH), 127.8 (2 × CH),
128.5 (CH), 132.0 (quat.), 135.6 (quat.), 140.7 (quat.), 148.9
1 K. R. Motion, I. R. Robertson, J. T. Sharp and M. D. Walkinshaw,
J. Chem. Soc., Perkin Trans. 1, 1992, 1709.
2 L. Garanti and G. Zecchi, J. Chem. Soc., Perkin Trans. 1, 1977, 2092.
3 A. Padwa and S. Nahm, J. Org. Chem., 1981, 46, 1402.
4 K. E. Cullen and J. T. Sharp, J. Chem. Soc., Perkin Trans. 1, 1993,
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5 H. Finch, D. H. Reece and J. T. Sharp, J. Chem. Soc., Perkin Trans.
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6 D. S. Glass, J. Zirner and S. Winstein, Proc. Chem. Soc., 1963, 276;
R. J. Ellis and H. M. Frey, J. Chem. Soc., 1964, 5578.
7 Practical Organic Chemistry, a Student Handbook of Techniques,
J. T. Sharp, I. Gosney and A. G. Rowley, Chapman and Hall,
London, 1989, p. 160.
8 A. I. Meyers, J. Slade, R. K. Smith, E. D. Mihelich, F. M.
Hershenson and C. D. Liang, J. Org. Chem., 1979, 44, 2247; and
ref. 7, p. 163.
9 A. Graven, K. A. Jorgensen, S. Dahl and A. Stanczak, J. Org.
Chem., 1994, 59, 3543.
10 E. Dancanale and F. Montanari, J. Org. Chem., 1986, 51, 567.
11 A. Schoenberg, I. Bartoletti and R. F. Heck, J. Org. Chem., 1974, 39,
3318.
12 M. Lebedev, Zh. Russ. Fiz. Khim. Ova, 1913, 45; Chem. Zentralbl.,
I, 1914, 1409.
(quat.), 169.0 (quat.); νmax(Nujol)/cmϪ1 1628 (C᎐N).
᎐
4-Methyl-3,5,5-triphenyl-5H-2-benzazepine 16h. Compound
11h (0.05 g, 0.13 mmol) in p-xylene (3 cm3) was heated under
reflux for 168 h and gave 4-methyl-3,5,5-triphenyl-5H-2-
benzazepine 16h as a yellow oil (0.02 g, 40%) [Found:
(M ϩ 1)ϩ, 386.1939. C29H23N requires (M ϩ 1)ϩ, 386.1909];
δH(200 MHz, CDCl3) 1.74 (3 H, s, CH3), 6.78–7.55 (19 H, m,
Ar-H), 8.39 (1 H, br, HC᎐N); and starting material (0.01 g).
᎐
The crystal structure of 1,4-dihydro-4-isopropenyl-4-methyl-3-
phenylisoquinoline 14d
Crystal data. Crystal data for C19H19N, M = 261.37, mono-
clinic, P21/c, a = 8.657(6), b = 24.090(18), c = 7.071(8) Å,
β = 94.95(8)Њ, V = 1469.1 Å3, Z = 4, Dc = 1.18
g ,
cmϪ3
F(000) = 561.32 (obtained from the values of the scattering fac-
tors at θ =0), T = 150 K, µ(Cu-Kα) = 0.48 mmϪ1. Colourless
block, 0.47 × 0.35 × 0.19 mm3.
13 C. F. Koelsch and R. V. White, J. Org. Chem., 1941, 6, 602.
14 A. J. M. Duisenberg, J. Appl. Cryst., 1992, 25, 92.
15 J. Cosier and A. M. Glazer, J. Appl. Cryst., 1986, 19, 105.
16 A. Altomare, M. C. Burla, M. Camelli, G. Cascarano,
C. Giacovazzo, A. Guagliardi and G. Polidori, J. Appl. Cryst., 1994,
27, 435.
17 D. J. Watkin, C. K. Prout, J. R. Curruthers and P. W. Betteridge,
CRYSTALS Issue 10, Chemical Crystallography Laboratory,
University of Oxford, 1996.
Data collection and processing. The crystals grew in clumps,
and despite attempts to cut a single crystal out of the clumps
none of the samples selected for study gave a diffraction pattern
that could be indexed with reference to one orientation matrix.
Indexing was performed using the program DIRAX,14 but the
quality of the sample naturally limited the precision of the final
structure determination, which, although it establishes chem-
ical connectivity, is unsuited to more detailed analysis. Data
were collected using ω-θ scans with graphite-monochromated
Cu-Kα radiation in the range 5 р 2θ р 120Њ on a Stoe Stadi4
diffractometer equipped with an Oxford Cryosystems low tem-
Paper 7/05531E
Received 30th July 1997
Accepted 26th September 1997
812
J. Chem. Soc., Perkin Trans. 1, 1998