Jul-Aug 2001
About 1-Triphenylmethyl-3-tert-butylaziridinone and Some of Its Reactions
1001
butyl), 4.27 (s, 1H, CH-Br), 7.23 (m, 16H, N-H and 15 aromatic
101°C; lit. [5] 84%, mp 101 °C; TLC: (90% n-hexane/ 10%
protons); 13C-NMR (CDCl ): δ 27.88 (methyl carbons in tert-
ethyl acetate) R = 0.62; IR (CCl ): 3410 (N-H), 3100-3000
3
f
4
-
1
butyl group), 35.51 (quaternary carbon in tert-butyl group), 65.51
(aromatic C-H), 2980-2850 (aliphatic C-H), 1692 cm (amide
C=O); H-NMR (CDCl ): δ 1.01 (s, 9H, tert-butyl), 3.18 (s, 1H
CH), 3.42 (s, 3H, OCH ), 7.28 (s, 15H, aromatic protons), 7.70
1
(
C-Br), 71.00 (quaternary carbon in trityl group), 127.31 (p-car-
bons of phenyl groups), 128.20 (m-carbons of phenyl groups),
28.70 (o-carbons of phenyl groups), 144.41 (C -carbons of
3
3
1
3
1
(s, 1H, N-H exchangeable in CDCl /CF COOD). C-NMR
1
3 3
phenyl groups), 166.59 (carbonyl carbon).
Anal. Calcd. for C H BrNO: C 68.81; H 6.01; Br 18.31; N
(CDCl ): δ 26.63 (methyl carbons in tert-butyl group), 35.35
3
(quaternary carbon in tert-butyl group), 59.87 (-OCH ), 70.13
2
5
26
3
3
.21; Found C 68.90; H 6.03; Br 18.30; N 3.16.
(quaternary carbon in trityl group), 91.37 (CH-OCH ), 127.18
3
(
p-carbons in phenyl groups), 128.12 (m-carbons in phenyl
1-Triphenylmethyl-3-tert-butylaziridinone (4).
groups), 128.80 (o-carbons in phenyl groups), 144.96 (C -car-
1
A variation of the procedure of Sheehan and Lengyel [3] was
bons in phenyl groups), 170.54 (carbonyl carbon);GC-MS: sin-
gle peak, with molecular ion at m/z 387; significant fragment
used. N-Triphenylmethyl-2-bromo-3,3-dimethylbutanamide (3)
1.00 g, 0.0023 mol) was dissolved in 100 mL of dry diethyl ether
and cooled to 0 °C in an ice bath. Sodium tert-butoxide (0.66 g,
.0069 mol) was added to the solution in one portion, and the
+
+
+
(
ions: m/z 330 [M-C H ·] ; 243 ((C H ) C ); 165 (C H9 );
4 9 6 5 3 13
+
+
101, base peak, [(C H CH-OCH ) or (C H -CH=O-CH ) ], 69
4
9
3
4
9
3
+
+
0
(C H ) , and 41 (C H ) .
5 9 3 5
resulting suspension was stirred for 2.5 hours. Then the reaction
mixture was washed with distilled water (100 mL). The organic
layer was dried over anhydrous sodium sulfate and the ether
removed on a rotary evaporator under reduced pressure. The
residual crude α-lactam 4 was dissolved in 5 mL of hexane and
cooled to –23 °C for 3 days. Pure 1-triphenylmethyl-3-tert-butyl-
aziridinone (4) precipitated as a white crystalline solid and was
collected, 0.75 g (93%), mp 103-104 °C; lit. [5] 76%, colorless
Anal. Calcd. for C H NO : C 80.59; H 7.54; N 3.61; Found
26 29 2
C 80.81; H 7.64; N 3.71.
Reaction of α-Lactam 4 with Benzylamine.
α-Lactam 4 (0.355 g, 1 mmol) was dissolved in 3 mL of dry
THF, and freshly distilled benzylamine (0.428 g, 4 mmol, 4 equiv-
alents) was added. After stirring at room temperature for 40 hours
the THF and excess benzylamine were removed under reduced
pressure, the latter at 0.1 mm. The white crystalline residue, 0.461
g (100%) showed one spot on TLC (80% n-hexane/ 20% ethyl
acetate). It was chromatographed on silica gel, with 70%
n-hexane/25% chloroform/5% 2-propanol as eluent, to yield 0.43
g (92%) of pure N-triphenylmethyl-2-benzylamino-3,3-
dimethylbutanamide (8a), mp 131-132 °C; lit. [5] 95%, colorless
oil; TLC: (90% n-hexane/ 10% ethyl acetate) R = 0.71; IR
f
(
1
CCl ): 3100-3000 (aromatic C-H), 2980-2850 (aliphatic C-H),
4
-1
1
840 cm (α-lactam C=O); H-NMR (CDCl ): δ 0.90 (s, 9H,
3
tert-butyl), 2.14 (s, 1H, CH); 7.28-7.46 (m, 15H, phenyl protons
in the trityl group); C-NMR (CDCl ): δ 27.66 (methyl carbons
1
3
3
in tert-butyl group), 32.20 (quaternary carbon in tert-butyl
group), 56.18 (methine carbon in α-lactam ring), 78.12 (quater-
nary carbon in trityl group), 127.72 (p-carbons in phenyl groups),
gum; TLC: (80% n-hexane/ 20% ethyl acetate) R = 0.50; IR
f
(CCl ): 3440 (amide N-H), 3334 (amine N-H), 3063, 3029 (aro-
4
1
28.26 (m-carbons in phenyl groups), 128.95 (o-carbons in
matic C-H), 2959, 2868 (aliphatic C-H), 1690 (amide C=O), 1520
-1
1
phenyl groups), 142.73 (C -carbons in phenyl groups), 162.09
cm (amide II); H-NMR (CDCl ): δ 1.02 (s, 9H, tert-butyl), 1.76
1
3
(carbonyl carbon).
(s, 1H, amine N-H exchangeable in D O), 2.13 and 2.79 (d, 1H,
2
Anal. Calcd. for C H NO: C 84.47; H 7.09; N 3.94; Found C
CH-C=O), 3.57 (d, 1H benzylic methylene proton) 3.71 (d, 1H
2
5 25
8
4.59; H 7.09; N 3.98.
benzylic methylene protons), 7.07-7.30 (m, 20H, trityl and ben-
1
3
zylic phenyl protons); 8.74 (s, 1H, amide N-H); C-NMR
CDCl ): interpreted with the aid of the Attached Proton Test
Thermal Decomposition of α-Lactam 4.
(
3
α-Lactam 4 (0.1 g, 0.028 mol) was dissolved in n-octane (4
mL, bp 126 °C) and refluxed for 2.75 hours. Then the mixture
was cooled to room temperature and subjected to analysis by FT-
IR and GC-MS. The reaction yielded pivalaldehyde (5) and
triphenylmethyl isonitrile (6) as the only products, in agreement
(APT) 27.46 δ (CH - carbons in tert-butyl group), 34.22 (quater-
3
nary carbon in tert-butyl group), 53.73 (benzylic CH - carbon),
2
70.06 (quaternary carbon in trityl group), 72.68 (N-CH-C=O),
126.91 (p-carbon in benzylic phenyl), 127.27 (p-carbons in trityl
group), 127.87 (m-carbons in benzylic phenyl), 128.21 (m-car-
bons in trityl group), 128.50 (o-carbons in benzylic phenyl),
-1
with prior observations [2,12]; IR (octane): 2124 cm (N=C);
-1
1
732 cm (aldehyde C=O); GC-MS: two components; first peak
128.76 (o-carbons in trityl group), 139.42 (C in benzylic phenyl),
1
molecular ion at m/z 86 (pivalaldehyde), second peak molecular
ion at m/z 269 (triphenylmethyl isonitrile).
The IR and GC-MS of the two thermal decomposition prod-
ucts were identical with those of authentic pivalaldehyde
145.02 (three C -carbons in trityl group), 171.45 (carbonyl car-
bon); MS (EI): m/z of the major fragment ions, their relative
abundance (%), elemental composition and structure: m/z 357,
1
+
+
+
17.12% (C H NO , M-NCH C H ); 243, 100% (C H ,
2
5
27
2
6
5
19 15
+
+
(Lancaster) and trityl isonitrile. The latter was synthesized [13]
the trityl group); 182, 93.26% (C H N , [(C H ) C=NH ] );
176, 83.45% (C H N , [(CH ) CCH=NHCH C H ] ); 174,
12 18 3 3 2 6 5
38.77% (C H N , [(CH ) CCHN=CHC H ] ); 165, 40.35%
13 12 6 5 2 2
+
+
in our laboratory for comparison, from tritylamine by a modified
Hofmann "carbylamine" synthesis [14].
+
+
1
2
16
3 3
6 5
+
+
(
C H , the fluorenyl ion); 106, 4.71% (C H N , the benzyl-
13 9 7 8
Reaction of α-Lactam 4 with Methanol.
+
+
amino ion); 105, 6.57% (C H N , [C H CH=NH] ); 104,
7
7
6 5
+
+
+
α-Lactam 4 (0.2 g, 0.56 mmol) was dissolved in methanol (3
mL) and refluxed (65 °C) for 3.7 hours. The methanol was
removed on a rotary evaporator to yield 0.19 g of an oily residue,
which was taken up in boiling n-hexane. Upon cooling, N-triph-
enylmethyl-2-methoxy-3,3-dimethylbutanamide (7) precipitated
and was collected on a Büchner funnel, 0.19 g (86%), mp 100-
24.67% (C H N , C H C=NH ); 91, 49.60% (C H , the tropy-
7 6 6 5 7 7
+
lium ion); and 77, 13.33% (C H , the phenyl ion); MS/MS (ESI
6
5
+
+
& CID): (MNa) at m/z 485.3; (MH) at 463.3; fragment ions at
+
+
m/z 243.1 (C19H15 , the trityl group); 221.2 (C13H21N O ,
2
+
+
[(CH ) CCH(NHCH C H )CONH ] ); 165.0 (C13H9 , the
3
3
2
6
5
3
fluorenyl ion).