Efficient Conversion of Carboxylic Acids into N-Acylbenzotriazoles

Article abstract of DOI:10.1055/s-2003-42462

An improved one-pot procedure for the preparation of N-acylbenzotriazoles involves mild reaction conditions and allows the preparation of several derivatives not accessible by the previously reported methods.

Full text of DOI:10.1055/s-2003-42462

PAPER
2795
Efficient Conversion of Carboxylic Acids into N-Acylbenzotriazoles
Efficient
Conversi
l
on of
C
a
arboxylic
A
n
cids into
N
-Acylb
R
enzotriazoles . Katritzky,* Yuming Zhang, Sandeep K. Singh
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
Fax +1(352)3929199; E-mail: Katritzky@chem.ufl.edu
Received 18 August 2003
in providing RCOBt in one step from acid and generally
gives excellent yields; however, we have encountered
problems with some base-sensitive, olefinic, acetylenic
and dicarboxylic acids. Herein, we describe a mild and
general procedure for access to N-acylbenzotriazoles.
Abstract: An improved one-pot procedure for the preparation of N-
acylbenzotriazoles involves mild reaction conditions and allows the
preparation of several derivatives not accessible by the previously
reported methods.
Key words: N-acylbenzotriazole, carboxylic acid, benzotriazole,
thionyl chloride, acylation reagent
Our new procedure involves reaction of 1 equivalent of a
carboxylic acid with 4 equivalents of benzotriazole and 1
equivalent of thionyl chloride in CH2Cl2 at room temper-
ature for 2 hours. Success with a wide range of carboxylic
acids demonstrates the general applicability of this proce-
dure (Table 1). Aliphatic short chain propionic acid, long
chain palmitic acid, and alicyclic 1-phenyl-cyclopropane-
carboxylic acid gave the corresponding N-acylbenzotriaz-
ole derivatives 2a–c in 89–92% yields. Benzoic acid was
converted into N-benzoylbenzotriazole 2d in 93% yield.
4-Hydroxybenzoic acid also gave p-hydroxybenzoylacyl-
benzotriazole 2e. As heterocyclic examples, 2-thiophene-
carboxylic acid and indole-2-carboxylic acid reacted with
thionyl chloride and benzotriazole to give the desired
product 2f and 2g (97% yield in each case).
N-Acylbenzotriazoles show great potential in organic
synthesis as activated derivatives of carboxylic acids. N-
Acylbenzotriazoles have been used (i) as neutral N-acyla-
tion agents for the preparation of primary, secondary and
tertiary amides1a–c and peptides;1d including N-form-
ylation2a and N-trifluoroacylation;2b (ii) for O-acylation in
additions to aldehydes to give esters;3 (iii) for C-acylation
reagents for the synthesis of 1,3-4a and 1,2-diketones,4b for
the conversion of imines into enaminones,4c and for the re-
giospecific acylation of pyrroles and indoles;4d and (iv) in
the preparation of benzoxazoles by flash vacuum pyroly-
sis (Scheme 1).5
Using the new procedure, methacrylic acid and crotonic
acid were each successfully converted into the corre-
sponding N-acylbenzotriazoles 2h and 2i in 83% and 86%
yields, respectively. Similarly, 1-(1H-1,2,3-benzotriazol-
1-yl)-2-propyn-1-one (2k) was obtained in 83% yield.
Phenylpropiolic acid gave a 92% yield of 2l.
O
R
NHR1
R1NH2
(i)
O
O
(ii)
(iv)
-Halocarboxylic acids have now also been directly con-
verted into N-acylbenzotriazole derivatives 2m–o in ex-
cellent yields. Carboxylic acids substituted at -position
by methoxy, phenylthio or oxo groups also gave high
yields of the corresponding N-acylbenzotriazole deriva-
tives 2p (96%), 2q (90%) and 2r (72%). Bis(N-acylben-
zotriazole) derivatives 2s–u with potential uses in the
synthesis of polymers or macromolecules, were also pre-
pared from the corresponding dicarboxylic acids in good
yields. The unsymmetrical dicarboxylic acid monoester,
mono benzotriazole derivative 2v was also prepared by
this method; 2v can undergo regioselective functional
group transformations.
O
R2CHO
F.V.P.
R2
R
R
Bt
O
N
O
Bt
R
C-Acylation
(iii)
R4
N
SmI2
F-C Reaction
R3 CH2
-
R5
R4
O
O
O
O
HN
R
N
R
R
R3
R
R5
R
H
O
O
Scheme 1
Interestingly, furanones 3w and 3w were obtained in 53%
and 19% yields, respectively from levulinic acid, presum-
ably due to intramolecular O-acylation from intermediate
N-acylbenzotriazole 2w (Scheme 2).
N-Acylbenzotriazoles have usually been prepared by two
routes: (a) heating benzotriazole with an acid chloride;6
(b) reaction of 1-(methylsulfonyl)benzotriazole (1) with a
carboxylic acid salt.1a The second method is advantageous
In conclusion, a mild one-pot general procedure has been
devised for the efficient conversion of carboxylic acids
into the corresponding N-acylbenzotriazoles.
SYNTHESIS 2003, No. 18, pp 2795–2798
x
x.
x
x
.
2
0
0
3
Advanced online publication: 04.11.2003
DOI: 10.1055/s-2003-42462; Art ID: M03703SS
© Georg Thieme Verlag Stuttgart · New York

2796
A. R. Katritzky et al.
PAPER
Table 1 Preparation of N-Acylbenzotriazole Derivatives 2a–v
O
O
O
O
25 °C
SOCl2
+ BtH
+
25 °C
Bt
OH
CH2Cl2
RCO2H
SOCl2
+
+ BtH
RCOBt
CH2Cl2
2
2w
Bt = benzotriazol-1-yl
Me
Bt2
Me
Bt1
+
O
O
O
O
Entry RCO2H
Yield (%) Lit.
Ref.
Yield (%)
3w
3w'
53%
19%
1
2
C2H5CO2H
2a (92)
2b (92)
90a
6
–
Scheme 2
–
Ph
HO2C
N-Acylbenzotriazoles 2a–w; General Procedure
3
4
5
6
C15H31CO2H
2c (89)
2d (93)
2e (84)
2f (97)
–
–
6
–
8
To a solution of benzotriazole (4.8 g, 40 mmol) in CH2Cl2 (50 mL)
was added SOCl2 (1.2 g, 10 mmol) at 25 °C with stirring. After 0.5
h, carboxylic acid (10 mmol) was added in one portion and stirring
was continued for 2 h. The white precipitate was filtered off and
washed with CH2Cl2 (2 × 50 mL). The combined organic solution
was washed with aq 2 N NaOH (3 × 60 mL), dried over Na2SO4 and
the solvent was removed under reduced pressure. The residue was
purified by flash chromatography (silica gel; hexanes–EtOAc, 4:1).
In the case of 2w, the organic layer was washed with 6 N HCl (3 ×
60 mL), dried over Na2SO4 and the solvent was removed under re-
duced pressure to give crude unstable product 2w.
PhCO2H
90a
–
4-HOC6H4CO2H
89a
CO2H
S
7
8
2g (97)
2h (83)
36b
–
4d
–
CO2H
NH
1-(1H-1,2,3-Benzotriazol-1-yl)-1-propanone (2a)
CO2H
CO2H
CO2H
CO2H
CO2H
Yield: 92%; mp 73–74 °C (Lit.6 mp 80–82 °C).
9
10
11
12
13
2i (86)
2j (96)
2k (83)
2l (92)
2m (86)
–
–
7
–
–
–
1H NMR: = 8.30 (d, J = 8.2 Hz, 1 H), 8.12 (d, J = 8.2 Hz, 1 H),
7.68–7.63 (m, 1 H), 7.51 (td, J = 8.1, 1.0 Hz, 1 H), 3.47 (q, J = 7.4
Hz, 2 H), 1.43 (t, J = 7.4 Hz, 3 H).
13C NMR: = 173.3, 146.1, 131.1, 130.3, 126.0, 120.1, 114.3, 29.1,
8.3.
90a
Ph
Ph
0b,c
50b,c
–
Cl
1H-1,2,3-Benzotriazol-1-yl(1-phenylcyclopropyl)methanone
(2b)
CO2H
Yield: 92%; mp 73–74 °C.
14
15
16
17
18
19
BrCH2CO2H
Cl2HCCO2H
CH3OCH2CO2H
PhSCH2CO2H
PhCOCO2H
2n (87)
2o (80)
2p (96)
2q (90)
2r (72)
2s (82)
–
–
–
–
–
–
–
–
–
–
–
–
1H NMR: = 8.21 (d, J = 8.2 Hz, 1 H), 8.00 (d, J = 8.2 Hz, 1 H),
7.59–7.50 (m, 3 H), 7.43–7.37 (m, 1 H), 7.30–7.17 (m, 3 H), 1.88–
1.84 (m, 2 H), 1.55–1.51 (m, 2 H).
13C NMR: = 171.2, 145.4, 139.0, 131.5, 130.0, 129.1, 128.4,
127.3, 125.8, 119.8, 114.3, 32.7, 14.8.
Anal. Calcd for C16H13N3O: C, 72.99; H, 4.98. Found: C, 73.11; H,
4.89.
1-(1H-1,2,3-Benzotriazol-1-yl)-1-hexadecanone (2c)
Yield: 89%; mp 54–55 °C.
HO2C
CO2H
20
21
22
HO2C(CH2)4CO2H
HO2C(CH2)18CO2H
2t (75)
2u (63)
2v (87)
–
–
–
–
1H NMR: = 8.29 (d, J = 8.2 Hz, 1 H), 8.12 (d, J = 8.2 Hz, 1 H),
7.67–7.62 (m, 1 H), 7.52–7.47 (m, 1 H), 3.42 (t, J = 7.6 Hz, 2 H),
1.98–1.84 (m, 2 H), 1.51–1.26 (m, 24 H), 0.88 (t, J = 6.3 Hz, 3 H).
13C NMR: = 172.6, 146.1, 131.1, 130.2, 126.0, 120.1, 114.4, 35.5,
31.9, 29.6, 29.6, 29.4, 29.3, 29.3, 29.1, 24.4, 22.6, 14.1.
0b,c
MeO2CCH2CH2CO2H
–
a Method (a), reaction of benzotriazole with acylchloride.
b Method (b), reaction of carboxylic acid salt with MsBt.
c Unpublished results.
HRMS: m/z calcd for C22H35N3O: 357.2780; found: 357.2791.
1H-1,2,3-Benzotriazol-1-yl(phenyl)methanone (2d)
Yield: 93%; mp 116–117 ° C (Lit.6 mp 124–126 °C).
1H NMR: = 8.39 (d, J = 8.4 Hz, 1 H), 8.23–8.20 (m, 2 H), 8.17 (d,
J = 8.2 Hz, 1 H), 7.73–7.67 (m, 2 H), 7.61–7.53 (m, 3 H).
13C NMR: = 166.7, 145.8, 133.6, 132.3, 131.7, 131.5, 130.3,
128.4, 126.3, 120.2, 114.8.
Materials were obtained from commercial suppliers and used with-
1
out further purification. CH2Cl2 was distilled from CaH2. H (300
MHz) and 13C NMR (75 MHz) spectra were recorded in CDCl3 with
TMS or CDCl3 as internal reference. Elemental analyses were per-
formed on a Carlo Erba-1106 instrument. HRMS were measured on
a Kratos/AE1-MS 30 mass spectrometer.
1H-1,2,3-Benzotriazol-1-yl(4-hydroxylphenyl)methanone (2e)
Yield: 84%; mp 199–200 °C.
Synthesis 2003, No. 18, 2795–2798 © Thieme Stuttgart · New York

PAPER
Efficient Conversion of Carboxylic Acids into N-Acylbenzotriazoles
2797
1H NMR: = 8.27–8.25 (m, 2 H), 8.14–8.11 (m, 2 H), 7.82–7.76 (m,
1 H), 7.66–7.60 (m, 1 H), 7.06–7.03 (m, 2 H).
1-(1H-1,2,3-Benzotriazol-1-yl)-3-phenyl-2-propyn-1-one (2l)
Yield: 92%; mp 124–125 °C.
13C NMR: = 165.2, 162.9, 145.0, 134.4, 131.9, 130.2, 126.2,
121.1, 119.8, 115.3, 114.3.
1H NMR: = 8.32 (d, J = 8.2 Hz, 1 H), 8.17 (d, J = 8.2 Hz, 1 H),
7.80 (d, J = 7.0 Hz, 2 H), 7.07 (t, J = 7.3 Hz, 1 H), 7.55 (t, J = 7.9
Hz, 2 H), 7.46 (t, J = 7.0 Hz, 2 H).
13C NMR: = 150.5, 146.4, 133.8, 131.8, 131.1, 130.7, 128.9,
126.8, 120.5, 119.2, 114.4, 96.2, 81.4.
Anal. Calcd for C13H9N3O2: C, 65.27; H, 3.79; N, 17.56. Found: C,
65.28; H, 3.73; N, 17.59.
1H-1,2,3-Benzotriazol-1yl(2-thienyl)methanone (2f)
Anal. Calcd for C15H9N3O: C, 72.86; H, 3.67; N, 16.99. Found: C,
72.72; H, 3.67; N, 16.95.
Yield: 97%; mp 173–175 °C (Lit.8 mp 175–176 °C).
1H NMR: = 8.50 (dd, J = 4.1, 1.3 Hz, 1 H), 8.34–8.28 (m, 3 H),
7.85–7.80 (m, 1 H), 7.68–7.63 (m, 1 H), 7.42 (dd, J = 5.0, 1.3 Hz, 1
1-(1H-1,2,3-Benzotriazol-1-yl)-2-chloro-1-propanone (2m)
H).
Yield: 86%; mp 87–88 °C.
13C NMR: = 158.7, 145.1, 138.7, 132.5, 131.6, 130.9, 128.5,
128.4, 126.7, 120.1, 114.4.
1H NMR: = 8.28 (d, J = 8.2 Hz, 1 H), 8.15 (d, J = 8.2 Hz, 1 H),
7.71 (td, J = 7.1, 1.0 Hz, 1 H), 7.55 (td, J = 8.2, 1.1 Hz, 1 H), 5.96
(q, J = 6.9 Hz, 1 H), 1.96 (d, J = 6.9 Hz, 3 H).
1H-1,2,3-Benzotriazol-1-yl(1H-indol-2-yl)methanone (2g)
Yield: 97%; mp 213–215 °C.
1H NMR: = 12.37 (br s, 1 H), 8.40 (d, J = 8.2 Hz, 1 H), 8.33 (d,
J = 8.2 Hz, 1 H), 8.03 (d, J = 1.3 Hz, 1 H), 7.86–7.81 (m, 2 H), 7.68–
7.59 (m, 2 H), 7.93 (t, J = 7.6 Hz, 1 H), 7.16 (t, J = 7.5 Hz, 1 H).
13C NMR: = 168.1, 146.2, 131.1, 130.9, 126.7, 120.4, 114.3, 51.1,
20.8.
Anal. Calcd for C9H8ClN3O: C, 51.56; H, 3.85; N, 20.04. Found: C,
51.76; H, 3.72; N, 20.18.
13C NMR: = 158.7, 145.2, 138.7, 132.1, 131.2, 127.3, 127.1,
127.0, 126.9, 123.5, 121.2, 120.4, 114.9, 114.7, 113.2.
1-(1H-1,2,3-Benzotriazol-1-yl)-2-bromo-1-ethanone (2n)
Yield: 87%; mp 91–92 °C.
Anal. Calcd for C15H10N4O: C, 68.68; H, 3.85; N, 21.36. Found: C,
68.44; H, 3.67; N, 21.29.
1H NMR: = 8.26 (d, J = 8.2 Hz, 1 H), 8.15 (d, J = 8.2 Hz, 1 H),
7.73–7.68 (m, 1 H), 7.58–7.52 (m, 1 H), 4.92 (s, 2 H).
13C NMR: = 165.0, 146.3, 130.9, 126.7, 120.4, 114.2, 26.5.
1-(1H-1,2,3-Benzotriazol-1-yl)-2-methyl-2-propen-1-one (2h)
Yield: 83%; colorless oil.
Anal. Calcd for C8H6BrN3O: C, 40.03; H, 2.52; N, 17.50. Found: C,
40.52; H, 2.30; N, 17.43.
1H NMR: = 8.27 (d, J = 8.2 Hz, 1 H), 8.13 (d, J = 8.2 Hz, 1 H),
7.69–7.64 (m, 1 H), 7.52 (td, J = 8.1, 1.0 Hz, 1 H), 6.28 (s, 1 H),
6.08–6.07 (m, 1 H), 2.29 (d, J = 0.9 Hz, 3 H).
13C NMR: = 167.5, 145.7, 137.2, 132.0, 130.2, 129.6, 126.1,
120.0, 114.5, 19.8.
1-(1H-1,2,3-Benzotriazol-1-yl)-2,2-dichloro-1-ethanone (2o)
Yield: 86%; mp 87–88 °C.
1H NMR: = 8.29 (d, J = 8.2 Hz, 1 H), 8.18 (d, J = 8.2 Hz, 1 H),
7.76 (t, J = 7.1 Hz, 1 H), 7.61 (t, J = 8.1 Hz, 1 H), 7.54 (s, 1 H).
Anal. Calcd for C10H9N3O: C, 64.16; H, 4.85; N, 22.45. Found: C,
63.82; H, 4.71; N, 22.35.
13C NMR: = 161.5, 146.4, 131.4, 130.9, 127.2, 120.8, 114.2, 63.5.
Anal. Calcd for C8H5Cl2N3O: C, 41.77; H, 2.19; N, 18.27. Found:
C, 42.01; H, 2.17; N, 18.16.
(E)-1-(1H-1,2,3-Benzotriazol-1-yl)-2-buten-1-one (2i)
Yield: 86%; mp 87–88 °C.
1H NMR: = 8.31 (d, J = 8.2 Hz, 1 H), 8.10 (d, J = 8.2 Hz, 1 H),
7.65–7.60 (m, 1 H), 7.50–7.43 (m, 3 H), 2.12 (d, J = 5.2 Hz, 3 H).
13C NMR: = 163.3, 149.7, 146.1, 131.2, 130.0, 125.9, 121.3,
119.9, 114.5, 18.7.
1-(1H-1,2,3-Benzotriazol-1-yl)-2-methoxy-1-ethanone (2p)
Yield: 96%; mp 103–104 °C.
1H NMR: = 8.28 (d, J = 8.2 Hz, 1 H), 8.12 (d, J = 8.2 Hz, 1 H),
7.71–7.65 (m, 1 H), 7.56–7.50 (m, 1 H), 5.15 (s, 2 H), 3.66 (s, 3 H).
13C NMR: = 168.6, 145.7, 130.8, 130.6, 126.3, 120.1, 114.0, 71.1,
59.8.
Anal. Calcd for C10H9N3O: C, 64.16; H, 4.85; N, 22.45. Found: C,
64.29; H, 4.97; N, 22.52.
Anal. Calcd for C9H9N3O2: C, 56.54; H, 4.74; N, 21.98. Found: C,
56.55; H, 4.76; N, 21.92.
(E)-1-(1H-1,2,3-Benzotriazol-1-yl)-3-phenyl-2-propen-1-one
(2j)
Yield: 96%; mp 151–152 °C (Lit.7 mp 158–159 °C).
1-(1H-1,2,3-Benzotriazol-1-yl)-2-(phenylsulfanyl)-1-ethanone
(2q)
Yield: 90%; mp 63–64 °C.
1H NMR: = 8.24–8.21 (m, 1 H), 8.12–8.09 (m, 1 H), 7.66–7.6 (m,
1 H), 7.53–7.47 (m, 3 H), 7.32–7.24 (m, 3 H), 4.66 (s, 2 H).
13C NMR: = 167.6, 146.1, 133.8, 131.0, 131.0, 130.5, 129.1,
127.6, 126.3, 120.2, 114.2, 37.9.
1H NMR: = 8.40 (d, J = 8.2 Hz, 1 H), 8.16–8.12 (m, 3 H), 7.76–
7.64 (m, 3 H), 7.55–7.45 (m, 4 H).
13C NMR: = 163.9, 148.7, 146.3, 134.1, 131.4, 130.2, 129.1,
129.0, 126.2, 120.1, 116.0, 114.8.
1-(1H-1,2,3-Benzotriazol-1-yl)-2-propyn-1-one (2k)
Yield: 83%; mp 99–100 °C.
1H NMR: = 8.24 (d, J = 8.2 Hz, 1 H), 8.16 (d, J = 8.4 Hz, 1 H),
7.74–7.68 (m, 1 H), 7.56 (td, J = 8.2, 1.0 Hz, 1 H), 3.72 (s, 1 H).
13C NMR: = 149.2, 146.2, 130.9,130.6, 126.9, 120.5, 114.1, 83.9,
74.5.
Anal. Calcd for C14H11N3OS: C, 62.43; H, 4.12; N, 15.60. Found:
C, 62.73; H, 4.05; N, 15.67.
1-(1H-1,2,3-Benzotriazol-1-yl)-2-phenyl-1,2-ethanedione (2r)
Yield: 72%; mp 72–73 °C.
1H NMR: = 8.36 (d, J = 8.1 Hz, 1 H), 8.18 (d, J = 8.2 Hz, 1 H),
8.03–8.00 (m, 2 H), 7.80–7.69 (m, 2 H), 6.63–7.53 (m, 3 H).
Anal. Calcd for C9H5N3O: C, 63.16; H, 2.94; N, 24.55. Found: C,
63.16; H, 2.87; N, 24.80.
Synthesis 2003, No. 18, 2795–2798 © Thieme Stuttgart · New York

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A. R. Katritzky et al.
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13C NMR: = 186.6, 164.6, 146.0, 135.6, 132.2, 131.1, 130.5,
129.9, 129.2, 127.2, 120.7, 114.0.
1H NMR: = 8.06 (d, J = 8.4 Hz, 1 H), 7.87 (d, J = 8.4 Hz, 1 H),
7.52 (t, J = 8.0 Hz, 1 H), 7.41 (t, J = 8.1 Hz, 1 H), 4.00–3.91 (m, 1
H), 2.81–2.61 (m, 3 H), 2.11 (s, 3 H).
13C NMR: = 174.5, 146.7, 131.5, 128.0, 124.4, 119.9, 111.9, 97.0,
33.2, 28.1, 26.5.
Anal. Calcd for C14H9N3O2: C, 66.93; H, 3.61. Found: C, 67.06; H,
3.57.
1,3-Di(1H-1,2,3-benzotriazol-1-yl)-2,2-dimethyl-1,3-propanedi-
one (2s)
Yield: 82%; mp 174–175 °C.
Anal. Calcd for C11H11N3O2: C, 60.82; H, 5.10. Found: C, 60.80; H,
4.98.
1H NMR: = 8.39 (d, J = 8.2 Hz, 2 H), 7.94 (d, J = 8.3 Hz, 2 H),
5-(2H-1,2,3-Benzotriazol-2-yl)-5-methyldihydro-2(3H)-fura-
7.71–7.65 (m, 2 H), 7.49–7.44 (m, 2 H), 2.03 (s, 6 H).
none (3w )
Yield: 19%; mp 95–96 °C.
1H NMR: = 7.88–7.84 (m, 2 H), 7.43–7.39 (m, 2 H), 3.36–3.14 (m,
2 H), 2.83–2.74 (m, 1 H), 2.67–2.56 (m, 1 H), 2.35 (s, 3 H).
13C NMR: = 170.0, 145.6, 131.1, 130.8, 126.5, 120.0, 114.6, 53.4,
24.4.
Anal. Calcd for C17H14N6O2: C, 61.07; H, 4.22; N, 25.14. Found: C,
61.27; H, 4.00; N, 25.15.
13C NMR: = 175.2, 144.2, 127.2, 118.5, 98.7, 34.8, 28.8, 25.6.
Anal. Calcd for C11H11N3O2: C, 60.82; H, 5.10; N, 19.34. Found: C,
60.73; H, 5.12; N, 19.39.
1,6-Di(1H-1,2,3-benzotriazol-1-yl)-1,6-hexanedione (2t)
Yield: 75%; mp 170–171 °C.
1H NMR: = 8.29 (d, J = 8.2 Hz, 2 H), 8.13 (d, J = 8.2 Hz, 2 H),
7.69–7.63 (m, 2 H), 7.54–7.49 (m, 2 H), 3.58–3.54 (m, 4 H), 2.16–
2.12 (m, 4 H).
13C NMR: = 171.9, 146.2, 131.1, 130.4, 126.1, 120.2, 114.4, 35.1,
23.7.
Acknowledgment
Financial support for this work from the Office of Naval Research
under Grant No. 166626712 is gratefully acknowledged. We thank
Dr. Clifford D. Bedford (Office of Naval Research, VA) and Dr.
David A. Ciaramitaro (Naval Air Weapons Station, CA) for very
helpful discussions.
Anal. Calcd for C18H16N6O2: C, 62.06; H, 4.63; N, 24.12. Found: C,
62.41; H, 4.64; N, 24.44.
18-Di(1H-1,2,3-benzotriazol-1-yl)-1,18-octadecanedione (2u)
Yield: 63%; mp 121–122 °C.
References
1H NMR: = 8.30 (d, J = 8.2 Hz, 2 H), 8.13 (d, J = 8.2 Hz, 2 H),
7.66 (t, J = 8.2 Hz, 2 H), 7.51 (t, J = 8.2 Hz, 2 H), 3.42 (t, J = 7.6
Hz, 4 H), 2.00–1.80 (m, 4 H), 1.56–1.20 (m, 28 H).
13C NMR: = 172.7, 146.1, 131.1, 130.3, 126.0, 120.1, 114.5, 35.5,
29.6, 29.6, 29.4, 29.3, 29.1, 24.4.
(1) (a) Katritzky, A. R.; He, H.-Y.; Suzuki, K. J. Org. Chem.
2000, 65, 8213. (b) Katritzky, A. R.; Wang, M.; Yang, H.;
Zhang, S.; Akhmedov, N. G. Arkivoc 2002, viii, 134.
(c) Katritzky, A. R.; Yang, H.; Zhang, S.; Wang, M. Arkivoc
2002, xi, 39. (d) Katritzky, A. R.; Suzuki, K.; Singh, S. K.,
unpublished results.
(2) (a) Katritzky, A. R.; Chang, H.-X.; Yang, B. Synthesis 1995,
503. (b) Katritzky, A. R.; Yang, B.; Semenzin, D. J. Org.
Chem. 1997, 62, 726.
Anal. Calcd for C32H44N6O2: C, 70.56; H, 8.14; N, 15.43. Found: C,
70.27; H, 8.30; N, 15.54.
(3) Karitzky, A. R.; Pastor, A.; Voronkov, M. V. J. Heterocycl.
Chem. 1999, 36, 777.
Methyl 4-(1H-1,2,3-benzotriazol-1-yl)-4-oxobutanoate (2v)
Yield: 87%; mp 51–52 °C.
(4) (a) Katritzky, A. R.; Pastor, A. J. Org. Chem. 2000, 65,
3679. (b) Wang, X.; Zhang, Y. Tetrahedron Lett. 2002, 43,
5431. (c) Katritzky, A. R.; Fang, Y.; Donkor, A.; Xu, J.
Synthesis 2000, 2029. (d) Katritzky, A. R.; Suzuki, K.;
Singh, S. K.; He, H.-Y. J. Org. Chem. 2003, 68, 5720.
(5) Baradarani, M. M.; Khalafy, J.; Prager, R. H. Aust. J. Chem.
1999, 52, 775.
1H NMR: = 8.25 (d, J = 8.2 Hz, 1 H), 8.11 (d, J = 8.2 Hz, 1 H),
7.67–7.62 (m, 1 H), 7.53–7.47 (m, 1 H), 3.78 (t, J = 6.3 Hz, 2 H),
3.76 (s, 3 H), 2.94 (t, J = 6.3 Hz, 2 H).
13C NMR: = 172.3, 171.0, 146.0, 130.9, 130.3, 126.1, 120.1,
114.2, 52.0, 30.5, 27.9.
Anal. Calcd for C11H11N3O3: C, 56.65; H, 4.75; N, 18.02. Found: C,
56.77; H, 4.83; N, 17.89.
(6) Katritzky, A. R.; Juliusz, N.; Pernak, J.; Afridi, A. S.; Fan,
W.-Q. Tetrahedron 1992, 48, 7817.
(7) Kreutzberger, A.; Dietz, E. Tetrahedron Lett. 1970, 11,
1457.
(8) Katritzky, A. R.; Huang, T.-B.; Voronkov, M. V. J. Org.
Chem. 2000, 65, 8069.
5-(1H-1,2,3-Benzotriazol-1-yl)-5-methyldihydro-2(3H)-fura-
none (3w)
Yield: 53%; mp 52–53 °C.
Synthesis 2003, No. 18, 2795–2798 © Thieme Stuttgart · New York