Acid-base reactions of adamantanethione S-methylide and its spiro-1,3,4-thiadiazoline precursor

Article abstract of DOI:10.1016/S0040-4020(00)00988-1

The spiro-1,3,4-thiadiazoline 1 loses N₂ at 45°C, and, as recently reported, the short-lived adamantanethione S-methylide (2) is an active 1,3-dipole. Interception of 2 by acids HX consists of CH₂-protonation and ion recombination. Even 1 acts as HX vs 2 and - after electrocyclic ring opening of the anion (13 →15) - affords the dithioacetal C₂₂H₃₂N₂S₂ (14). The Δ³-thiadiazoline 1 is converted by base or acid catalysis to the Δ²-tautomer 21. Amidrazones (25, 26) are formed from 1 and sec-amines. The mechanisms are discussed and the structures elucidated.

Full text of DOI:10.1016/S0040-4020(00)00988-1

TETRAHEDRON
Pergamon
Tetrahedron 57 (2001) 145±151
Acid±base reactions of adamantanethione S-methylide and its
spiro-1,3,4-thiadiazoline precursor
²
Grzegorz Mloston and Rolf Huisgen
*
È È È
Department Chemie der Ludwig-Maximilians-Universitat Munchen, Butenandtstr. 5-13 (Haus F), D-81377 Munchen, Germany
Dedicated to Professor Ivar Ugi, MuÈnchen, on the occasion of his 70th birthday
Received 2 October 2000; accepted 20 October 2000
AbstractÐThe spiro-1,3,4-thiadiazoline 1 loses N2 at 458C, and, as recently reported, the short-lived adamantanethione S-methylide (2) is
an active 1,3-dipole. Interception of 2 by acids HX consists of CH2-protonation and ion recombination. Even 1 acts as HX vs 2 andÐafter
electrocyclic ring opening of the anion (13 !15)Ðaffords the dithioacetal C22H32N2S2 (14). The D3-thiadiazoline 1 is converted by base or
acid catalysis to the D2-tautomer 21. Amidrazones (25, 26) are formed from 1 and sec-amines. The mechanisms are discussed and the
structures elucidated. q 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction
intercepting reagents, it undergoes electrocyclization and
affords spirothiirane 3.1 As an isoelectronic heteroatom
analogue of the allyl anion, 2 shows basic and nucleophilic
properties. Although the anionic charge is distributed over
the two termini of thiocarbonyl ylides, formula 2 symbolises
the reactivity. The cycloaddition with methyl acrylate gives
rise to 4,2 and the CH2 group is the basic centre in the
reaction with thiols affording dithioacetals 6 via thionium
ion 5.1 Further HX additions to other thiocarbonyl ylides
have been reported.7,8
20,50-Dihydrospiro[adamantane-2,20-(1,3,4)-thiadiazole] (1)
is easily available by 1,3-cycloaddition of diazomethane
with adamantanethione.1 The N2 elimination from 1 (half-
life 90 min at 408C in THF) is a 1,3-dipolar cycloreversion
which furnishes adamantanethione S-methylide (2). We
chose 2 as one of the model compounds for studying the
reactivity of thiocarbonyl ylides. 1,3-Dipolar cycloadditions
with CC-multiple bonds2 and heterodouble bonds CvO,
CvS, CvN,3,4 NvS,5 and NvN6 have recently been
described (Scheme 1).
The CH2 group of the 1,3,4-thiadiazoline 1 is acidic. It is
well known that 1-pyrazolines are converted to the thermo-
dynamically more stable 2-pyrazolines by base or acid
The S-methylide 2 cannot be isolated. In the absence of
Scheme 1.
Keywords: D3- and D2-1; 3; 4-thiadiazolines; thiocarbonyl ylides; acid±base reaction; adamantane derivatives.
* Corresponding author. Tel.: 149-89-2180-7712; fax: 149-89-2180-7717.
Present address: Section of Heteroorganic Chemistry, University of Lodz, Narutowicza 68, PL-90-136 Lodz, Poland
²
0040±4020/01/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00988-1

146
G. Mloston, R. Huisgen / Tetrahedron 57 (2001) 145±151
Scheme 2.
catalysis.9,10 A similar prototropy is expected to convert D3-
(1,3,4)-thiadiazolines to the D2-isomers. We report here on a
variety of acid±base reactions of 1 and 2.11
C-2 signal (dC 175.9) is comparable to 171.0 ppm of azino-
2,20-bis(adamantane) (17). The 13C parameters of the
adamantylidene group reveal a plane of symmetry in 14
by means of two sets of 3 CH signals (2:1:1) and 3 CH2
signals (2:2:1). The base peak in the MS of 14, m/z 181,
comes from thionium ion 5, as con®rmed by the intensities
of isotope peaks. The second S-function can also appear as
thionium ion, but [141±SCH3] reaches only 0.1% intensity.
Chemical evidence for 14 was provided by cleavage with
2,4-DNPH, which furnished 1.96 equiv. of hydrazone 16
(Scheme 4).
2. Results and discussion
When 1 was reacted with 1.3 equiv. of malononitrile in THF
at 408C for 8 h, 0.94 equiv. of N2 was set free; 2-(dicyano-
methylene)adamantane (8, 60%) and 2,2-bis(methylthio)-
adamantane (9, 24%) were isolated. A plausible conjecture
asserts deprotonation of malononitrile by S-methylide 2 and
recombination of the ions to yield the HX-type adduct 7.
The latter still contains acidic hydrogen and reacts with a
second molecule of 2, thus furnishing 819 (Scheme 2).
Obviously, the intermediate thiocarbonyl ylide 2 has a
suf®cient life-time at 458C to deprotonate the precursor
molecule, the thiadiazoline 1. The anion of the latter, 13,
undergoes an electrocyclic ring-opening of type `cyclo-
pentenyl anion !pentadienyl anion'.13 The nucleophilic
thiolate function of 15 ®ts into the electrophilic centre of
5, and 14 is formed.
Thiones are superdipolarophiles12 and avidly receive 2 to
afford spiro-1,3-dithiolanes.3 In the case of thiocampher
(10), however, steric hindrance to cycloaddition cannot be
overcome, and deprotonation at position 3 by 2 takes place
instead. Combination of ene-thiolate 11 with 5 furnished the
mixed dithioacetal 12. Cleavage of the latter with
2,4-DNPH in ethanolic sulfuric acid afforded the 2,4-di-
nitrophenylhydrazones of adamantanone and campher
(Scheme 3).
At ®rst glance, it might astonish that an abundance of inter-
ception reactions of 2 suppresses the simple straightforward
cyclization 2!3. The formal simplicity of the latter is
deceptive, however. In fact, the electrocyclic ring closure
of the quasi-planar thiocarbonyl ylide involves two 908
rotations about the two C±S bonds. Most of the resonance
energy of the 1,3-dipole 2 has to be sacri®ced, before the
new C±C bond notably contributes to the bond energy. The
enthalpic barrier to cyclization is high enough to allow
trapping reactions. These interceptions are burdened with
the large negative activation entropies of bimolecular reac-
tions. As cyclization competes with interception of 2, the
®rst-order reaction 2 !3 is expected to show the steeper rise
of the rate constant with increasing temperature. Not at
808C, but at 458C, the protonation of 2 by the second
molecule of 1 successfully competes with the cyclization
2 !3.
In a kinetic experiment with 0.20 M 1 in xylene at 808C, the
N2 evolution (96%) followed the ®rst-order law with a half-
reaction time of 55 s, and 94% of thiirane 3 was found as
reaction product.1 In an experiment at 458C, however, only
0.64 equiv. of N2 was evolved, and the deviation from the
®rst-order plot began, after ,60% of 1 was consumed.
Colourless crystals C22H32N2S2 (14) were isolated in 31%
yield according to the stoichiometry:
2 C11H16N2S ꢀ1† ! C22H32N2S2 1 N2
The NMR spectra of 14 are in accordance with an SCH3
group (s, dH 2.01 and q, dC 10.9) and a thioformimidate
function, ±NvCH±S± (s, dH 8.10 and d, dC 150.6). The
The N2 extrusion of 1 remains to be the rate-determining
step. The reaction at 458C should kinetically still be of ®rst
Scheme 3.

G. Mloston, R. Huisgen / Tetrahedron 57 (2001) 145±151
147
Scheme 4.
order, but stoichiometrically of second order. However, the
capturing of 2 by 1 is incomplete, especially when the
concentration of 1 becomes small. Initially, 2 [1] enters
the rate equation of 2d[1]/dt, and successively diminishes
to [1].
con®rmed (458C):
0:20 M1 ! 56% of 14 and 30% of 18
0:013 M1 ! 33% of 14 and 45% of 18
In the decomposition of 0.2 M 1 at 458C, the percentage of
14 depends on the solvent: methanol 56%, xylene 31%,
hexane 30%, benzene 26%, THF ,5% (1H NMR analysis).
In addition to 56% of 14, the experiment in methanol
produced 30% of S,O-dimethylacetal 18 (2 s at dH 1.87
and 3.31 for SCH3 and OCH3). The result of the competition
suggests that 1 is a stronger acid than methanol versus 2.
The expected dependence of the product ratio on [1]0 was
An experiment with 0.20 M 1 in methanol was run at 458C
in the presence of tri¯uoroacetic acid and provided 84% of
the O,O-dimethylacetal 19. This is due to the fact that 2 is
protonated by the strong acid, and the thionium ion 5 attacks
methanol (Scheme 5).
To study reactions of the thiadiazoline anion 13, 1 was
Scheme 5.

148
G. Mloston, R. Huisgen / Tetrahedron 57 (2001) 145±151
Scheme 6.
deprotonated by 1 equiv. of LDA in THF at 08C. Methyl
iodide converted the lithium salt to the open-chain S-methyl
derivative 22 (s at dH 2.37 for SCH3, s at 7.65 for ±NvCH±
S±). On the other hand, treating the lithium salt with water
furnished the 4,5-dihydro-1,3,4-thiadiazole 21. The IR
absorption at 3355 cm21 and the broad s at dH 6.2 indicate
NH; the NMR spectra are in accordance with 21. However,
tiny dC signals suggest a small equilibrium concentration
(about 1%) of the open-chain tautomer 24: We assign the s
at dC 168.7 to the adamantane±C-2 (171.0 in 17), and the d
at dC 189.0 corresponds to 189.6 ppm for the thioformyl
C-atom of 20.14
The central C-atom of the formamidrazone group appears at
dC 158.6 (25) and 156.1 (26), whereas the C-2 of the
adamantylidene group resonates at higher frequency (s at
171.6 and 173.2 ppm). The 13C parameters of the adaman-
tylidene group reveal a s-plane for 25 and 26. Comparing
with the 13C NMR spectrum of azino-2,20-bis(adamantane)
(17) allowed us to sort out the 13C signals of the cyclic
amine and to unequivocally assign all adamantylidene
C-atoms. Both coalescence phenomena and a second set
of NMR parameters were missing, which indicates that
eventual conformational changes of 25 and 26 (syn±anti)
are fast compared with the NMR time scale.
The ring-chain tautomerism of 4,5-dihydro-1,3,4-thia-
diazoles with Nb-thioacylhydrazones of aldehydes and
ketones has been carefully studied by Zelenin et al.15 and
by Evans and Taylor.16 The equilibria are rapidly estab-
lished at room temperature, and their position depends
markedly on the substituents. It is noteworthy that 20,
prepared on a pathway analogous to that of 21/24, exists
completely in the thioformylhydrazone form.14 The phenyl
conjugation is suf®cient to shift the equilibrium to the side
of the open-chain form.
The NH group of azoles (pyrazole, imidazole, 1,2,4-tria-
zole) no longer reacts with 1, but rather intercepts 2, as
was recently described.17 e.g. 1 reacted with pyrazole at
458C to afford the S,N-acetal 27 in 41% yield.
The main preparative value of thiocarbonyl ylides probably
rests on their 1,3-cycloadditions. However, the colourful
assortment of acid±base reactions of thiocarbonyl ylides
and their 1,3,4-thiadiazoline precursors is of mechanistic
interest and provides manifold modi®cations of the original
thione function.
The structure of the anion (deprotonated 1) is unknown, but
the stabilization of the negative charge by nitrogen and
sulfur is good reason to prefer 15 to 13. The cyclic form
21 is favoured for the protonated species. The hydrazone
group of 21 is superior in bond energy to the cyclic azo
group in 1, thus re¯ecting the energetic preference of
2-pyrazolines over 1-pyrazolines. As in pyrazoline
chemistry,9,10 bases and acids catalyse equilibration. When
1 was treated with CF3CO2H in CDCl3 at 48C (no N2
3. Experimental
3.1. General3
3.1.1. 20,50-Dihydrospiro[adamantane-2,20-(1,3,4)-
thiadiazole] (1).1 13C NMR (20 MHz): d 26.9, 27.4,
2£40.6 (4 CH) and 2£35.4, 36.8, 2£37.5 (5 CH2) indicate
a s-plane; 81.4 (C-50), 119.6 (C-2).
1
extrusion at this temperature), the H NMR signals of 1
were replaced by those of 21 within 3 weeks. By-the-way,
21 is a sensitive substance. In hot ethanol, some azine 17 is
generated by an unknown route. The N-acetyl derivative of
21 was obtained analytically pure.
3.1.2. Reaction of 2 with malononitrile. Compound 1
(300 mg, 1.44 mmol) and freshly distilled malononitrile
(120 mg, 1.82 mmol) in absol. THF (3 mL) were stirred at
408C (bath) for 8 h (34 mL of N2, 94%). After evaporation
of the solvent, the residue was subjected to preparative layer
chromatography (PLC, 2 mm silica gel, petroleum ether/
CH2Cl2 3:2). The ®rst fraction, namely ®ne needles
(160 mg, 60%) from ethanol, mp 179±1818C, was identi®ed
with 2-(dicyanomethylene)adamantane (8) by mixed mp
The methanolic solution of 1 and 1 equiv. of sodium
methanolate did not liberate N2 at 458C, i.e. the deproto-
nation of 1 is virtually complete; this con®rms that 1 is more
acidic than methanol. The reaction of anion 15 with
2,4-dinitrochlorobenzene furnished the thioimidate 23 in
63% yield. When 1 was dissolved in an excess of piperidine
or morpholine at 208C, de- and reprotonation led to D2-
thiadiazoline 21 and its open-chain isomer 24. Like thio-
formamides, Nb-thioformylhydrazone 24 rapidly interacts
with the sec-amines and affords the amidrazones 25 and
26. Isolated 21 and piperidine likewise afforded 25 (85%
yield). A direct interaction of 21 with the sec-amine is also
conceivable, but less probable than the path via 24
(Scheme 6).
1
and H NMR spectrum; the authentic sample, mp 183±
1858C,18 was prepared from adamantanone, malononitrile,
and piperidine. The second fraction (40 mg, 24%), mp 48±
498C, was NMR-identical with bis(methylthio)adaman-
tane (9).1
3.1.3. 2-[(Born-2-en-2-yl)thio]-2-(methylthio)adaman-
tane (12). (a) 1 (416 mg, 2.00 mmol) and (^)-thiocampher19
(10, 353 mg, 2.10 mmol) in THF (6 mL) 1 a drop of

G. Mloston, R. Huisgen / Tetrahedron 57 (2001) 145±151
149
triethylamine were heated to 408C for 8 h (47 mL of N2,
94%). PLC (cyclohexane/CH2Cl2 9:1) furnished 12
(178 mg, 24%), colourless crystals (ethanol), mp 86±
878C. IR (KBr): n 781 (cm21) m, 1100 m, 1385 m, 1453
(75 mL) of methanol. After 7 h at 458C, the solvent was
removed, and the residue in CDCl3 NMR-analysed. The
integrals of the s at dH 8.10 (14) and the s at 3.31 (18)
were compared with that of sym-tetrachloroethane (d
5.97) as weight standard (results given above). The sepa-
ration of 14 and 18 was achieved by triturating the
combined residues with ether, leaving 14 undissolved.
Distillation of the mother liquor at 40±458C (bath)/0.01
Torr gave 2-methoxy-2-(methylthio)adamantane (18) as
a colourless oil, which was further puri®ed by PLC (ether/
pentane 3:2). IR (neat): n 844 cm21 m, 885 st; 1075, 1086,
1101 st (C±O); 1454 st; 2860 st sharp, 2905 vst, br (C±H).
1H NMR: 1.37±1.90, 1.95±2.42 (2 m, 14H), 1.87 (s, SCH3),
3.31 (s, OCH3). MS (808C); m/z (%): 212 (0.7) [M1], 180
(3), 165 (100) [M12SCH3], 150 (28) [C10H14O1, adaman-
tanone1], 133 (4) [C10H113], 91 (20) [C7H17 ], 80 (13), 79 (20).
Anal. calcd for C12H20OS (212.35): C 67.87, H 9.49, S
15.10; found: C 68.17, H 9.40, S 15.09.
1
st, 1473 m; 1561 m, br (S±CvC). H NMR: d 0.77, 0.82,
1.00 (3s, 3 CH3), 1.0±2.75 (m, 19H), 2.05 (s, SCH3), 6.15 (d,
Jˆ3.3 Hz, 30-H). MS (608C); m/z (%): 348 (,1) [M1], 301
(,1) [M12SCH3], 181 (100) [5], 166 (2) [C10H14S1], 133
(3) [166±SH], 91 (9) [C7H17 ], 79 (4). Anal. calcd for
C21H32S2 (368.60): C 72.35, H 9.25, S 18.40; found: C
72.38, H 8.98, S 18.81.
(b) Acid cleavage of 12. 2,4-Dinitrophenylhydrazine
(90 mg, 0.45 mmol), dissolved in ethanol (2.2 mL), water
(0.7 mL), and conc. H2SO4 (0.45 mL), was heated with 12
(74 mg, 0.20 mmol) on the steam bath for 10 min; after
10 min at room temperature, adamantanone 2,4-dinitro-
phenylhydrazone (16, 60 mg, 91%) was ®ltered, mp 213±
2158C, mixed mp without depression (213.5±214.5).20
Within 5 days at room temperature, (^)-campher 2,4-di-
nitrophenylhydrazone crystallised as a second fraction
(40 mg, 60%), mp 155±1598C; recryst. from ethanol, mp
163±1658C, mixed mp (166±1678C).21 The rate difference
in crystallization was used for separation. TLC (silica gel,
CH2Cl2) gave Rf 0.44 for the campher derivative and Rf 0.52
for the adamantanone derivative.
(d) 14 and CF3CO2H in Methanol. 14 (50 mg) was treated
with methanol (5 mL) and 2 drops of CF3CO2H at room
temperature for 24 h. Work-up with Na2CO3/CH2Cl2
afforded 2,2-dimethoxyadamantane (19, 35 mg) as a
colourless oil, 1H NMR-identi®ed (s, d 3.15, 2 OCH3)
with an authentic sample.22
3.1.5. 40,50-Dihydrospiro[adamantane-2,50-(1,3,4)-thia-
diazole] (21). (a) From 1 via anion 15. Lithium diisopropy-
lamide (LDA, 3.1 mmol, freshly prepared) in THF (25 mL)
was slowly introduced to the ice-cooled solution of 1
(625 mg, 3.00 mmol) in THF (50 mL) under argon. After
1 h at room temperature, THF was evaporated, and the resi-
due treated with water (50 mL) and CH2Cl2 (25 mL).
Removal of CH2Cl2 in vacuo and trituration with cold eth-
anol furnished 21 as colourless crystals (380 mg, 61%), mp
141±1438C. 21 is sensitive; attempted recrystallization from
hot ethanol afforded azino-2,20-bis(adamantane) (17). Prop-
erties of 21: IR (KBr): n 863 cm21 m, 885 m, 896 m, 1255
st, 1279 st, br; 1455 vst, 1520 vst, 1629 st (CvN), 3120 st,
3.1.4. Adamantanone Nb-[20-(Methylthio)adamantyl-
(20)-thio]-methylenehydrazone (14). (a) The solution of
1 (416 mg, 2.00 mmol, freshly prepared) in xylene
(10 mL) evolved 32 mL of N2 (64%, nitrometer) in a ther-
mostated 458C-bath in 7 h; the half-life of the N2 extrusion
was 32 min. The residue after removal of the solvent was
triturated with diethyl ether and gave 14 as colourless crys-
tals (120 mg, 31%), mp 178±1828C; after recrystallization
(ethanol/CH2Cl2 4:1) mp 194±1958C. UV (CH2Cl2): lmax
271 nm (log e 5.0), 2.54 (4.96). IR (KBr): n 745 cm21 m,
776 m, 1098 m, 1449 st, 1548 st; 1625 vst (CvN); 2852 st,
2906 vst (C±H). 1H NMR (400 MHz); d 1.62±1.73 (m, 5H),
1.81±2.08 (m, 18H), 2.01 (s, SCH3), 2.38±2.58 (m, 3H),
2.73, 3.37 (2s, br., 1-H, 3-H), 8.10 (s, NvCH±S). 13C
NMR (100 MHz, DEPT): d 10.9 (SCH3); 26.9, 27.0,
2£27.9, 32.8, 2£36.2, 39.3 (2 sets of 4 CH, 2:1:1);
2£33.26, 2£33.34, 36.6, 2£38.3, 38.8, 2£39.4 (2 sets of 5
CH2, 2:2:1); 70.2 (C-20), 150.6 (NvCH±S), 175.9 (C-2).
MS (1108C); m/z (%): 388 (0.02) [M1], 341 (0.10)
[C21H29N2S1 , M12SCH3], 296 (1.1), 208 (2.7)
[C11H16N2S1, C9H14CvN±NH±CHvS1; 13C calcd 0.33,
found 0.35], 181 (100) [5; 13C 12.2/13.7, 13C2134S 5.1/
5.0], 175 (2.1) [208±HS, C9H14CvN±N1;CH possible],
166 (4.3) [C10H14S1, adamantanethione1], 148 (2.7) [181±
HS, C11H116], 133 (5.3) [166±HS], 91 (12) [C7H17 ], 79 (8)
[C6H17 ], 77 (4) [C6H51]. Anal. calcd for C22H32N2S2
(388.62): C 67.99, H 8.30, N 7.21, S 16.50; found: C
67.86, H 8.30, N 7.13, S 16.51.
1
br (N±H); (CHCl3): 3355 w (N±H). H NMR (80 MHz): d
1.43±2.07 (m, 12H), 2.07±2.35 (m, 1-H, 3-H), 6.2 (br, s,
NH, disappears with D2O), 7.04 (s, 20-H). 13C NMR
(20.2 MHz): d 26.2, 26.8, 2£39.0 (4 CH), 2£33.9, 2£36.8,
37.3 (5 CH2); 91.4 (s, C-2), 134.8 (d, C-20); minor partici-
pation of 24 is suggested by small signals: 168.7 (s, C-2),
189.0 (d, thioformyl-C). MS (608C); m/z (%): 208 (75)
[M1], 181 (73) [M12HCN], 175 (50), 165 (19), 149 (73),
113 (51), 91 (42), 87 (100) [C2H3N2S1, thiadiazolium ?].
Anal. calcd for C11H16N2S (208.32): C 63.42, H 7.74, N
13.45, S 15.39; found: C 62.64, H 7.92, N 13.30, S 15.73.
(b) From 1 via protonation. 1 (416 mg, 2.00 mmol) in
CDCl3 (3 mL) was treated with 4 drops of CF3CO2H and
stored at 48C. The 1H NMR spectra, taken from time to time,
1
indicated that 1 had disappeared after 3 weeks. H NMR
analysis with as-tetrachloroethane (d 4.28) as standard
showed 73% of 21. H2S (smell) and azino-2,20-bis(adaman-
tane) (17) were side products.
(b) Acid cleavage of 14. Short re¯uxing of 13 (180 mg,
0.46 mmol) with 2,4-DNPH in ethanolic H2SO4 afforded
adamantanone 2,4-dinitrophenylhydrazone (16, 295 mg,
0.89 mmol), mp 212±2148C (mixed mp, IR).
(c) N-Acetyl derivative: 21 (2.00 mmol) and acetyl chloride
(2.1 mmol) were reacted in pyridine/CH2Cl2. The crude
product was puri®ed by PLC (CH2Cl2/acetone 95:5) and
recrystallized from ethanol, mp 71±728C. IR (KBr): n
(c) Competing reactions of 2 in Methanol. In two experi-
ments, 1 (208 mg, 1.00 mmol) each was dissolved in 5 mL

150
G. Mloston, R. Huisgen / Tetrahedron 57 (2001) 145±151
852 cm21 st, 1318 st, 1328 st, 1366 st, 1551 m (CvN), 1690
vst, br (amide I). 1H NMR: d 1.5±2.75 (2 m, 14H), 2.22 (s,
CH3CO), 7.62 (s, 20-H). MS (408C); m/z (%): 250 (12) [M1],
208 (100) [M12H2CvCO], 181 (23), 175 (14), 149 (60)
[C10H15N1], 91 (16), 87 (28). Anal. calcd for C13H18N2OS
(250.36): C 62.36, H 7.25, N 11.19, S 12.81; found: C 62.50,
H 7.30, N 11.15, S 12.79.
(6), 95 (5), 84 (100) [C5H10N1, piperidino1; 13C 5.6/6.1],
83 (10) [C5H9N1], 79 (10) [C6H71], 77 (6) [C6H15 ]. Anal.
calcd for C16H25N3 (259.38): C 74.08, H 9.72, N 16.20;
found: C 74.10, H 9.72, N 15.95.
(b) 21 (208 mg, 1.00 mmol) in piperidine (5 mL) reacted at
room temperature for 10 h. Work-up as above gave 25
(220 mg, 85%) after recrystallization from acetone, mp
83±848C (mixed mp, IR).
3.1.6. Adamantanone Nb-(Methylthiomethylene)hydra-
zone (22). The dry lithium salt of 1 (3.00 mmol), as
prepared above, and methyl iodide (10 mL) were re¯uxed
for 90 min. After evaporation, work-up with aq. NH3/
CH2Cl2 and subsequent PLC (petroleum ether/acetone 7:3)
provided 22 (453 mg, 68%), mp 56±578C (isopropyl alco-
hol). UV (CH2Cl2): 253 (5.05). IR (KBr): n 817 cm21 st,
832 m, 1077 st, 1290 m, br, 1433 m, 1440 st, 1451 st;
3.1.9. Adamantanone Nb-(morpholinomethylene)hydra-
zone (26). The compound was analogously prepared;
320 mg, 61%, mp 72±738C (pentane). IR (KBr): n
865 cm21 m, 922 m, 990 m, 1029 st, 1119 st, 1231 m,
1
1270 m, 1450 st; 1608 vst, 1640 vst (CvN). H NMR:
1.6±4.0 (several m, 22H), 7.92 (s, CHvN). 13C NMR
(100 MHz, DEPT): Adamantylidene, d 28.2, 31.9, 39.7 (4
CH, 2:1:1), 36.9, 38.1, 39.3 (5 CH2, 1:2:2), 173.2 (C-2);
morpholino, 46.5 (2 N±CH2), 66.6 (2 O±CH2); 156.1
(CHvN). MS (308C): m/z (%): 261 (29) [M1; 13C 4.9/
5.1], 175 (100) [M12NC4H8O], 150 (27) [C10H16N1,
C9H14CvNH12 ; 13C 3.0/2.9], 113 (9) [HN1;C±NC4H8O],
86 (10) [OC4H8N1, morpholino1], 85 (7), 79 (5), 77 (3).
Anal. calcd for C15H23N3O (261.36): C 68.93, H 8.87, N
16.08; found: C 68.59, H 8.85, N 15.94.
1
155611565 vst, br, 1636 vst (CvN). H NMR: d 1.75±
2.19 (appar. d, 12H), 2.69, 3.30 (2 appar. s, br, 2H), 2.37
(s, SCH3), 7.65 (s, HCvN). MS (308C); m/z (%): 222 (45)
[M1], 207 (9) [M12CH3], 175 (100) [M12SCH3,
C9H14CvN±N1;CH], 149 (37) [C10H15N1], 121 (12),
119 (12), 106 (18), 95 (18), 93 (19), 91 (19), 79 (48).
Anal. calcd for C12H18N2S (222.34): C 64.82, H 8.16, N
12.60, S 14.42; found: C 64.83, H 8.24, N 12.45, S 14.37.
3.1.7. Adamantanone Nb-[(2,4-Dinitrophenylthio)methyl-
ene]hydrazone (23). 1 (417 mg, 2.00 mmol) and sodium
methanolate (2.00 mmol) in methanol (20 mL) were reacted
at 458C for 30 min (no N2 elimination). 2,4-Dinitrochloro-
benzene (2.00 mmol) in methanol (10 mL) was slowly
added and heated to 458C for another 30 min. Work-up
with water/CH2Cl2 and PLC (silica gel, CH2Cl2) furnished
23 (470 mg, 63%) as golden-yellow lea¯ets, mp 115±1168C
(isopropyl alcohol). IR (KBr): n 731 cm21 m, 832 m; 1344,
1530 vst (NO2); 1452 m, 1598 st, 1634 st (CvN, arom. ring
3.1.10. Azino-2,20-bis(adamantane)23 (17). The compound
was prepared for spectroscopic comparison. Adamantanone
(10.0 mmol) in ethanol (5 mL) was heated with hydrazine
hydrate (50 mmol) and 2 drops of conc. HCl under re¯ux for
4 h. 17 (0.90 g, 61%) was isolated, mp 312±3148C,
(mp.3008C)23. IR (KBr): n 144311452 cm21 m; 1648 st
(CvN); 2854 st, sharp, 2910 vst, br (C±H). 13C NMR
(20.2 MHz): d 2£28.0, 31.7, 39.6 (3 d, 4 CH), 36.7,
2£38.1, 2£39.4 (3 t, 5 CH2), 171.0 (s, C-2); identical
adamantylidene groups, s-plane. Anal. calcd for C20H28N2
(296.44): C 81.03, H 9.52, N 9.45; found: C 80.70, H 9.35, N
9.45.
1
vibr.). H NMR: same appearance of adamantane-H as for
22, d 2.00 (d, br, 12H); 2.78, 3.44 (2s, br, 1-H, 3-H), 7.25,
7.87 (2s, CHvN, probably two conformations), 7.88 (d,
Jˆ9.0 Hz, 60-H), 8.48 (dd, Jˆ9.0, 2.2 Hz, 50-H), 8.90 (d,
Jˆ2.2 Hz, 30-H). MS (1108C); m/z (%): 374 (1.4) [M1], 328
(41) [M12NO2], 301 (18), 150 (47) [C10H16N1], 148 (51)
[C10H14N1], 121 (29), 93 (37) [C7H19 ], 91 (48) [C7H17 ], 81
(42), 80 (52), 79 (100) [C6H17 ]. Anal. calcd for C17H18N4O4S
(374.41): C 54.53, H 4.85, N 14.97, S 8.56; found: C 54.12,
H 4.73, N 14.74, S 8.58.
Acknowledgements
We express our gratitude to the Fonds der Chemischen
Industrie, Frankfurt, for continued support. Moreover, our
thanks go to Helmut Huber for many NMR spectra, to
Reinhard Seidl for the MS, and to Helmut Schulz and
Magdalena Schwarz for the elemental analyses. G. M.
thanks the Alexander von Humboldt Foundation for a
stipend.
3.1.8. Adamantanone Nb-(Piperidinomethylene)hydra-
zone (25). (a) The solution of 1 (2.00 mmol) in piperidine
(10 mL) developed H2S, but no N2, in 3 h at 208C. Work-up
with H2O/CH2Cl2 and PLC (CH2Cl2/ethanol 9:1) afforded
colourless 25 (275 mg, 53%), mp 84±858C (acetone). IR
(KBr): n 1009 cm21 st, 1198 st; 1605 vst, 1635 vst
References
1
(CvN). H NMR (400 MHz): d 1.52±1.66 (m, 6H),
1.80±1.94 (m, 12H), 2.54 (s, 1H), 3.28±3.35 (m, 2 H2C±
N), 3.86 (s, br, 1H), 7.92 (s, NvCH±N). 13C NMR
(20.2 MHz, H-decoupled and off-resonance): d 24.7 (C-
40), 25.6 (C-30/50), 47.2 (C-20/60 of piperidino); 4 CH of
adamantylidene: 28.3 (C-5/7), 31.9, 39.7 (C-1, C-3); 5
CH2 of adamantylidene: 37.0 (C-6), 38.1, 39.3 (C-4/10,
C-8/9); 158.6 (d, CHvN), 171.6 (s, C-2). MS (308C); m/z
(%): 259 (79) [M1; 13C 14.1/15.0], 175 (93) [M12NC5H10],
150 (96) [C10H16N1, C9H14CvNH12 ; 13C 10.7/9.9], 149 (16)
[C10H15N1], 111 (29) [C6H11N12 , C5H10N±C;NH1], 110
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