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SHKLYAEV, NIFONTOV
Scheme 5.
Me
S
Me
Me
Me
Me
Me
NH
Me
Me
morpholine
THF
morpholine
boiling
Me
N
HgCl2,
N
SMe
N
O
Id
VId
IIId
hydrobenzo[f]isoquinoline-1-thione (IIId) and 1,2,2-tri-
methyl-4-methylsulfanyl-1,2-dihydrobenzo[f]isoquinoline
(Ib) with morpholine. In both cases, the reactions
smoothly afforded the corresponding amidine VId
(Scheme 5).
1,2,3,4-tetrahydroisoquinolin-1-one and 6.66 g of phos-
phorus(V) sulfide in 30 ml of anhydrous pyridine was
heated for 2 h. The mixture was left overnight, the
solution was separated from the solid material and
poured into 150 ml of water under stirring, and the pre-
cipitate was filtered off, dried, and recrystallized from
appropriate solvent. Yield 73%. The physical constants
of the product coincided with those given in [8].
Thus the inertness of 8-substituted 1,2,3,4-tetra-
hydroisoquinoline-1-thiones toward secondary amines
is determined exclusively by steric factor. When HgCl2
was preliminarily stirred with amine for 15 min at 65°C
(before addition of IIIa), the results were the same as
in the reaction with 1.5 equiv of HgCl2 according to
the procedure described in [6]. Presumably, the main
factors responsible for the reaction of thiolactams of
the tetrahydroisoquinoline series with amines are (1)
the possibility for complex formation of HgCl2 with
amine and (2) steric hindrances related to the presence
of a substituent in position 8 of the quinoline ring.
Compounds IIIb–IIIe were synthesized in a similar
way.
Reaction of 3,3-dimethyl-1,2,3,4-tetrahydroiso-
quinoline-1-thione (IIIa) with aniline. Mercury(II)
chloride, 5.44 g, was added in several portions to a
solution of 2.19 g of compound IIIa and 0.93 g of
freshly distilled aniline in 30 ml of anhydrous THF at
50°C. The mixture was heated for 2–2.5 h and filtered,
the solvent was removed from the filtrate under
reduced pressure, the residue was dissolved in 30–40
ml of ethyl acetate, and the solution was washed with
aqueous sodium thiosulfate. The organic phase was
separated, dried over magnesium sulfate, and filtered,
and the filtrate was evaporated on heating on a water
bath. Yield of VIa 62%. The physical constants of the
product coincided with those given in [4].
EXPERIMENTAL
The IR spectra were recorded on a UR-20
spectrophotometer from samples dispersed in mineral
1
oil. The H NMR spectra were measured on a Bruker
AM-300 spectrometer (300 MHz) in DMSO-d6 using
tetramethylsilane as internal reference. The progress of
reactions and the purity of products were monitored by
TLC on Silufol UV-254 plates using chloroform–
acetone (9:1) as eluent; the chromatograms were
developed by treatment with a 0.5% solution of
chloranil in toluene.
Reactions of compounds IIIa–IIIe with other
amines were carried out following an analogous
procedure.
1,2,2-Trimethyl-1,2,3,4-tetrahydrobenzo[f]isoquino-
lin-1-one (IX). A mixture of 5 g of compound Id [9]
and 20 ml of 90% acetic acid containing 3 drops of tri-
ethylamine was treated as described in [4]. Yield 3.7 g
(87%), mp 269–271°C. Compound IX was then con-
verted into IIId as described above for the synthesis of
thione IIIa.
Compounds IVa–VIIIa were reported previously
[4], and their yields differed within experimental error
from those given in [4]. Compounds Ia, VIIa [4], Ib,
IIIb, VIIb [5], Ic [9], and Id [10] were also described
previously.
The yields, melting points, and elemental analyses
of newly synthesized compounds are given in Table 1,
3,3-Dimethyl-1,2,3,4-tetrahydroisoquinoline-1-
thione (IIIa) [5]. A mixture of 4.06 g of 3,3-dimethyl-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 2 2009
Shklyaev
