Two new insecticidal amides and a new alcoholic amide from Piper nigrum LINN

Article abstract of DOI:10.1002/hlca.200390225

Three new amides, pipgulzarine (1), pipzorine (2), and piptahsine (3), have been isolated from the dried seeds of Piper nigrum LINN. along with nine known constituents: (2E,4E,8Z)-N-(isobutyl)eicosatrienamide, pellitorine, pipercide, piperine, stigmastanol, stigmasterol, decurrenal, stigmasterol 3-O-β-D-glucopyranoside, and 5,10(15)-cadinen-4-ol. The structures of the new constituents have been established as (2E,11E)-12(benzo[1,3]dioxol-5-yl)-N-(2-methylpropyl)dodeca-2,11-dienamide (1), (2E,12Z)-N-(4-methylpentyl)octadeca-2,12-dienamide (2), and (2E,4S)-4-hydroxy-N-(2-methylpropyl)hex-2-enamide (3). The structures of 1-3 were derived by spectral studies and chemical reactions, and by comparison of spectral data in the case of known constituents. Compounds 1 and 2, and most of the already known compounds, exhibited toxicity against fourth instar larvae of Aedes aegypti Liston. The isolated (Z) double bond in 2 was assigned on the basis of its EI-MS fragmentation pattern and its reaction with OsO₄. The (S) configuration at C(4) of 3 was determined by Horeau's method. This is the first report of the isolation of a 4-methylpentylamide from P nigrum, while shorter branched amides have been reported from this genus [1].

Full text of DOI:10.1002/hlca.200390225

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Helvetica Chimica Acta ± Vol. 86 (2003)
Two New Insecticidal Amides and a New Alcoholic Amide from Piper nigrum
Linn.
by Bina S. Siddiqui*, Tahsin Gulzar, Sabira Begum, Munawwer Rasheed, Fouzia A. Sattar, and Farhana Afshan
H.E.J. Research Institute of Chemistry, International Centre for Chemical Sciences, University of Karachi,
Karachi-75270, Pakistan
(
phone: ‡92219243199; fax: ‡92219243190; e-mail: bina@khi.comsats.net.pk)
Three new amides, pipgulzarine (1), pipzorine (2), and piptahsine (3), have been isolated from the dried
seeds of Piper nigrum Linn. along with nine known constituents: (2E,4E,8Z)-N-(isobutyl)eicosatrienamide,
pellitorine, pipercide, piperine, stigmastanol, stigmasterol, decurrenal, stigmasterol 3-O-b-d-glucopyranoside,
and 5,10(15)-cadinen-4-ol. The structures of the new constituents have been established as (2E,11E)-12-
(
2
benzo[1,3]dioxol-5-yl)-N-(2-methylpropyl)dodeca-2,11-dienamide (1), (2E,12Z)-N-(4-methylpentyl)octadeca-
,12-dienamide (2), and (2E,4S)-4-hydroxy-N-(2-methylpropyl)hex-2-enamide (3). The structures of 1 ± 3 were
derived by spectral studies and chemical reactions, and by comparison of spectral data in the case of known
constituents. Compounds 1 and 2, and most of the already known compounds, exhibited toxicity against fourth
instar larvae of Aedes aegypti Liston. The isolated (Z) double bond in 2 was assigned on the basis of its EI-MS
fragmentation pattern and its reaction with OsO . The (S) configuration at C(4) of 3 was determined by
4
Horeau×s method. This is the first report of the isolation of a 4-methylpentylamide from P. nigrum, while shorter
branched amides have been reported from this genus [1].
Introduction. ± Piper nigrum Linn., commonly known as black pepper, belonging to
the Piperaceae family, is a climbing perennial shrub. It is known to be acrid, pungent,
and hot. Some Piper species are listed as remedies for stomach pain, asthma, bronchitis,
fever, abdominal pain, haemorrhoidal afflictions, rheumatism, as anti-inflammatory
and stimulant agents, but also as insect repellents. The chemistry of Piper species has
been widely investigated, and phytochemical investigations from all parts of the world
have led to the isolation of a number of physiologically active compounds, including
alkaloids, amides, propenylphenols, lignans, neolignans, terpenes, steroids, pyrones,
piperolides, chalcones, flavones, and flavanones [2 ± 5]. As part of our research program
towards obtaining plant-based potential insecticides [6], we isolated three new and nine
known compounds from the seed extract of P. nigrum. The petroleum-ether and EtOH
extracts of the fruits exhibited interesting effects on the mosquito Aedes aegypti, as
determined by the WHO method [7]. The petroleum-ether extract afforded one new
compound, pipgulzarine (1), and three known compounds: (2E,4E,8Z)-N-(isobutyl)-
eicosatrienamide [6], pellitorine [6], and pipercide [8]. From the EtOH extract, two
new constituents, pipzorine (2), and piptahsine (3), and six known compounds,
piperine [5][6], stigmastanol [9], stigmasterol [9][10], decurrenal [11], a glucoside of
stigmasterol [12][13], and 5,10(15)-cadinen-4-ol [14] have been isolated. The structures
1
13
of compounds 1 ± 3 were inferred from the H- and C-NMR spectral data, including
1
1
DEPT and 2D-NMR experiments ( H- H COSY, HMQC, HMBC, and NOESY). The
toxicities of 1, 2, and pipercide were found to be 6.0, 70.0 and 19.0 ppm, respectively,

Helvetica Chimica Acta ± Vol. 86 (2003)
2761
against fourth instar larvae of A. aegypti. The toxicities of some of the above-mentioned
known compounds have been reported earlier [6].
Results and Discussion. ± Pipgulzarine (1) formed buff-colored needles from
CHCl /MeOH 1:1, m.p. 98 ± 1008. The HR-EI-MS of 1 showed the molecular ion peak
3
at m/z 371 corresponding to the molecular formula C H NO . The IR spectrum
23
33
3
À1
showed absorptions for a secondary amide function (3343 cm ), an amide CˆO
À1
À1
(
1
(
1664 cm ) group, and aromatic and aliphatic CˆC resonances (four bands at 1612 ±
400 cm ). Characteristic UV-absorption bands at l 313.0 (e ˆ 14,200) and 263.4 nm
max
e ˆ 5,450) were indicative of a conjugated benzo[1,3]dioxol moiety [15]. The signals in
1
the H-NMR spectrum of 1 at d (ppm) 3.15( t, J ˆ 6.5Hz, CH (1'')), 1.80
2
(
m, HÀC(2'')), and 0.91 (d, J ˆ 6.7, Me(3'') and Me(4'')) together with the correspond-
13
ing C-NMR signals at 46.9 (C(1'')), 28.6 (C(2'')), and 20.2 (C(3'') and C(4'')),
respectively, revealed a (2-methylpropyl)amido group, supported by fragments in the
1
EI-MS at m/z 72 for C H N, and 100 for C H NO. The H-NMR spectrum further
4
10
5
10
showed a broad s between 1.35± 1.60 ppm, integrating for 10 H-atoms, corresponding,
13
according to C-NMR measurements (d 29.8 ± 30.5), to C(5) ± C(9). A broad m of four
H-atoms at 2.30 ppm was assigned to CH (4) and CH (10). A one-proton dt at 5.77
2
2
(
J ˆ 15.0, 1.3) and a one-proton dt at 7.10 (J ˆ 15.0, 7.0) were attributed to HÀC(2) and
HÀC(3), respectively, with trans geometry. A two-proton s at 5.92 ppm was character-
istic of a methylenedioxy group attached to an aromatic ring. It showed a cross-peak at
1
1
00.9 (CH , DEPT) in the HMQC spectrum. The H-NMR spectrum further displayed
2
a dt at 6.04 (J ˆ 15.7, 7.0) and a d at 6.28 (J ˆ 15.7) attributable to HÀC(11) and
HÀC(12), respectively, with a trans geometry. Two d at 6.86 (J ˆ 2.0) and 6.70 (J ˆ 8.2)
were assigned to HÀC(2') and HÀC(5'), respectively, while a dd at 6.76 was due to
HÀC(6') (J ˆ 8.2, 2.0). These data led to the assignment of pipgulzarine as (2E,11E)-
1
2-(benzo[1,3]dioxol-5-yl)-N-(2-methylpropyl)dodeca-2,12-dienamide (1). The ob-
13
served mass fragments (Fig. 1) and the C-NMR data (Table 1) are consistent with

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Helvetica Chimica Acta ± Vol. 86 (2003)
the assigned structure and match well the values reported for compounds with similar
partial structures [8].
Fig. 1. Observed HR-EI-MS fragments (in m/z) of pipgulzarine (1)
Table 1. 1H- and 13C-NMR Data of 1 (in CDCl
; d in ppm rel. to Me
Si, J in Hz (parentheses))
3
4
1
3
1
d ( C)
d ( H)
J [Hz]
C(1)
165.0
122.2
141.1
32.2 )
29.8 ± 30.5
32.9 )
128.7 )
127.6 )
130.1
105.4
141.8
141.0
108.2
120.4
46.9
28.6
20.2
100.9
±
±
±
HÀC(2)
5.77
7.10
2.30
1.35± 1.60
2.30
6.04
6.28
±
6.86
±
±
6.70
6.76
3.15
1.80
0.91
5.92
5.45
dt (15.0, 1.3)
dt (15.0, 7.0)
br. m
br.
br. m
dt (15.7, 7.0)
d (15.7)
±
d (2.0)
±
±
d (8.2)
dd (8.2, 2.0)
t (6.5)
m
d (6.7)
s
HÀC(3)
a
CH
CH
CH
2
2
2
(4)
(5± 9)
(10)
s
a
b
HÀC(11)
HÀC(12)
C(1')
b
HÀC(2')
C(3')
C(4')
HÀC(5')
HÀC(6')
2
CH (1'')
HÀC(2'')
Me(3'', 4'')
OCH
NH
2
O
br. s
a) b) Assignments may be interchanged.
Pipzorine (2) was obtained as an amorphous powder. It showed a molecular ion at
m/z 363 corresponding to the molecular formula C H NO, with three degrees of
24
45
unsaturation. The IR spectrum suggested the presence of a secondary amide
À1
À1
À1
(
3450 cm ), an amide CˆO (1667 cm ) and a CˆC (1630 cm ) group. The UV
spectrum showed an absorption peak at l 209.5nm ( e ˆ 6,160). The geometry and
max
position of the isolated double bond at C(12)/C(13) were determined with the help of
1
13
EI-MS, H-NMR, and C-NMR measurements (Table 2), and by reaction with OsO
4
13
and product analysis. The upfield C-NMR shifts at d (ppm) 26.7, 26.9 (C(11), C(14))
suggested the (Z)-geometry of the CˆC bond [16]. The HR-EI-MS showed fragments
with a difference of 14 mass units from m/z 154.1229 ± 266.2483, followed by a fragment
1
2
ion at m/z 292.2639 instead of m/z 280 (Fig. 2), indicating a D double bond [17].
Reaction with OsO afforded hexanal, identified by GC and GC/MS analysis, thus,
4
1
providing conclusive evidence in favor of a double bond at C(12). The H-NMR

Helvetica Chimica Acta ± Vol. 86 (2003)
2763
spectrum of 2 showed a two-proton q at 3.14 (J ˆ 6.7, CH (1')), a one-proton m at 1.80
2
(
HÀC(4')), a broad m at 1.41 ± 1.60 (CH (2') and CH (3')), and a d at 0.91 (J ˆ 6.7,
2
2
Me(5'), Me(6')). Acid hydrolysis of 2 with concentrated HCl and workup [18] yielded
4-methylpentyl)amine, as found by GC (co-injection of authentic samples of similarly
branched amines). Additional support was obtained by fragment-ion peaks at m/z 100
(
1
(
C H N), 128 (C H NO), and 154 (C H NO) in the mass spectrum of 2. The H- and
6 14 7 14 9 16
13
C-NMR spectra showed the presence of another disubstituted double bond by the
signals at 5.75 (dt, J ˆ 15.2, 1.3, HÀC(2)) and 6.92 (dt, J ˆ 15.2, 6.9, HÀC(3)),
indicating a conjugated trans CˆC group. These resonances were connected with d
1
22.0 (C(2)) and 139.0 (C(3)) in the HMQC spectrum. The signals at 2.18 (dq, J ˆ 6.9,
1.3 Hz, CH (4)) and 1.99 ± 2.03 (m, CH (11) and CH (14)) were assigned to three allylic
2
2
2
methylene groups. In the light of the above discussion, the structure of 2 was elucidated
as (2E,12Z)-N-(4-methylpentyl)octadeca-2,12-dienamide.
Fig. 2. Observed HR-EI-MS fragments (in m/z) of pipzurine (2)
Table 2. 1H- and 13C-NMR Spectral Data of 2 (CDCl
)
3
1
3
1
d ( C)
d ( H)
J [Hz]
C(1)
165.0
122.0
139.0
±
5.75
6.92
2.18
1.24 ± 1.33
1.99 ± 2.03
1.99 ± 2.03
±
HÀC(2)
dt (15.2, 1.3)
dt (15.2, 6.9)
dq (6.9,1.3)
br. s
m
m
HÀC(3)
CH
CH
CH
CH
2
2
2
2
(4)
31.7
(5± 10, 15, 16)
(11)
(14)
29.0 ± 29.7
a
26.7 )
a
26.9 )
HÀC(12, 13)
CH (17)
Me(18)
.3
129.55
22.3
13.50.87
48.53.14
29.0 ± 29.7
28.7
t (4.9)
br. s
t (6.7)
q (6.7)
br. m
m
d (6.7)
br. s
2
1.24 ± 1.33
CH
CH
2
(1')
(2', 3')
2
1.41 ± 1.60
1.80
HÀC(4')
Me(5', 6')
NH
19.50.91
±
5.43
a) Assignments may be interchanged.

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Helvetica Chimica Acta ± Vol. 86 (2003)
Piptahsine (3) formed white needles from petroleum ether/AcOEt 7:3. It displayed
a molecular-ion peak at m/z 185in the EI mass spectrum, suggesting the molecular
formula C H NO and two degrees of unsaturation. The IR spectrum showed a broad
1
0
19
2
À1
À1
band at 3300 ± 3450 cm (secondary amide and OH group), and a band at 1676 cm
(
2
a,b-unsaturated amide CˆO). The UV spectrum showed an absorption at l
max
13
13.0 nm (e ˆ 6,965). The C-NMR spectral data showed the presence of ten C-atoms
(
three Me, two CH , four CH and one CˆO group(s)). The signals at 3.15( t, J ˆ 6.3,
2
1
CH (1')), 1.88 (m, HÀC(2')), and 0.85( d, J ˆ 7.0, Me(3') and Me(4')) in the H-NMR
2
spectrum, and their correlated C-resonances at 46.9, 28.3, and 19.9, respectively, in the
HMQC spectrum, indicated the presence of a (2-methylpropyl)amido moiety, as
supported by the fragment ions at m/z 72 (C H N) and 100 (C H NO) (cf. Fig. 3). The
4
10
5
10
1
13
H- and C-NMR spectra (Table 3) further showed the presence of a conjugated,
disubstituted CˆC bond with signals at 6.01 (dd, J ˆ 15.5, 1.5, HÀC(2)), and 6.76
(
dd, J ˆ 15.5, 5.0, HÀC(3)). These resonances displayed connectivities with C(2)
(124.6) and C(3) (141.5ppm) in the HMQC spectrum. An interesting feature in the EI-
MS of 3 was the base peak at m/z 157 (C H NO ) corresponding to N-(2-
8
15
2
methylpropyl)-4-oxobutanamide (4), resulting from McLafferty rearrangement [19]
Scheme). The (S)-configuration at C(4) of 3 was determined by Horeau×s method
20].
(
[
Scheme
Fig. 3. Observed HR-EI-MS fragments (in m/z) of pipthasine (3)

Helvetica Chimica Acta ± Vol. 86 (2003)
Table 3. 1H- and 13C-NMR Spectral Data of 3 (in CDCl
/CD OD (trace amount))
3
2765
3
1
3
1
d ( C)
d ( H)
J [Hz]
C(1)
166.8
124.6
141.56.76
74.2
32.7
13.8
46.9
28.3
19.9
±
±
6.01
±
HÀC(2)
HÀC(3)
HÀC(OH)(4)
dd (15.5, 1.5)
dd (15.5, 5.0)
m
m
t (7.0)
t (6.3)
m
d (7.0)
br. s
4.05
1.22 ± 1.24
0.83
3.15
1.88
CH
Me(6)
CH (1')
2
(5)
2
HÀC(2')
Me(3', 4')
NH
0.85
5.50
Experimental Part
General. Vacuum liquid chromatography (VLC): silica gel 60 PF254 (Merck). Flash column chromatog-
raphy (FC): silica gel 9385 (Merck, 0.040 ± 0.063 mm). Prep. TLC: silica gel 60 PF254 (Merck). GC: Shimadzu
¾
GC-9A gas chromatograph, FID at 2608, N
2
at 1.0 ml/min, SPB-5 capillary column (30 m  0.53 mm ID; 0.3 m
df); split ratio 1 :30, injector temp. 2408; the column temp. was maintained at 508 for the first 5min and then
raised to 2408 (38/min), followed by 5min at 240 8. UV Spectra: Hitachi U-3200 spectrophotometer; lmax in nm.
IR Spectra: Jasco A-302 spectrophotometer; nÄ in cm . H-NMR Spectra (COSY, NOESY, and J-resolved):
Bruker, 400 MHz; chemical shifts d in ppm, coupling consants J in Hz, referenced to residual solvent signals.
C-NMR: Bruker, 100 MHz. The assignments of Tables 1 ± 3 are based on H-, COSY-45, J-resolved, and C-
broad-band and DEPT), HMQC, and HMBC spectra. EI-MS: Finnigan-Mat 311A; source at 2508 and 70 eV;
À1
1
1
3
1
13
(
m/z (%). HR-EI-MS: Jeol JMS-HX-110; source at 2508 and 70 eV; m/z (%).
Extraction and Purification: The seeds of P. nigrum were purchased from the local market in Karachi.
Air-dried, ground seeds of P. nigrum (5kg) were extracted with petroleum ether (3 Â 10 l) at r.t. for 72 h.
Evaporation of the combined extracts in vacuo afforded a dark brown viscous residue (102.1 g). A portion
(
91.8 g) of this extract was partitioned between petroleum ether and 90% MeOH. The MeOH phase was
extracted with AcOEt after saturation with saline H O. The AcOEt layer was dried (Na SO ), and the solvent
2
2
4
was evaporated in vacuo to give a brownish syrupy concentrate (24.8 g). A portion (11.8 g) of this concentrate
was subjected to prep. TLC, yielding eight major bands (petroleum ether/AcOEt 7:3), which were separated by
repeated chromatography on precoated thin-layer sheets. Band 1 (228 mg; petroleum ether/AcOEt 8.5:1.5)
furnished three compounds identified as (2E,4E,8Z)-N-(isobutyl)eicosatrienamide (32.1 mg), pellitorine
(40.3 mg), and pipercide (58.1 mg). Band 6 (1.15g) was further split into Bands 6a, 6b, and 6c in petroleum
ether/AcOEt 6 :4; each consisting of several spots. Band 6a was further purified by prep. TLC (petroleum ether/
AcOEt 7 :3), affording 11.3 mg of pipgulzarine (1), among other mixed products not analyzed. In another batch,
dried fruits (10 kg) of P. nigrum Linn. were crushed and extracted with EtOH (5 Â 10 l) at r.t. After removal of
the solvent in vacuo, the syrupy residue crystallized overnight as a white solid. On recrystallization from MeOH,
it formed fine needles (50.5 g), m.p. 128 ± 1298, and was identified as piperine. The mother liquor of piperine was
partitioned between petroleum ether and 70% EtOH. The EtOH phase was extracted with AcOEt after
saturation with saline H
AcOEt layer was washed, dried (Na
brown syrupy concentrate (159 g), a major portion of which (150 g) was subjected to VLC, eluting with
petroleum ether > petroleum ether/AcOEt > AcOEt > CHCl > CHCl /MeOH > MeOH (in increasing order
of polarity). In total, 18 fractions (F) were obtained. F1 (petroleum ether/AcOEt, 9.9 :0.1 ! 9.0 :1.0 eluate;
75mg) yielded after prep. TLC petroleum ether/AcOEt 9.99 :0.01 several bands, two of which were major and,
2
O, and the AcOEt layer was treated with Na
2 3
CO to remove acidic components. The
2
SO ), and the solvent was evaporated in vacuo to give a dark greenish
4
3
3
2
on further purification (petroleum ether/AcOEt 8.5:1.5) resulted in the isolation of pure stigmastanol (3.0 mg)
and stigmasterol (3.3 mg). F 2 (petroleum ether/AcOEt, 9.0 :1.0 ! 8.0 :2.0; 383 mg) furnished pure stigmasterol
(2.9 mg), decurrenal (1.7 mg), and the 3-O-b-d-glucoside of stigmasterol (1.6 mg) on repeated prep. TLC in
petroleum/AcOEt 8.0 :2.0. F 4 (37.0 g) was subjected to CC (petroleum ether/AcOEt > AcOEt > CHCl
3
>
CHCl /MeOH > MeOH) to afford 14 fractions (F1' to F14'). F1' to F 3' tested positive in CeSO and negative
3
4

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Helvetica Chimica Acta ± Vol. 86 (2003)
in Dragendorff tests. F 2' (petroleum ether/AcOEt 9.5:0.5; 90.0 mg) was purified by prep. TLC (petroleum
ether/AcOEt 8.5:1.5) to give 5,10(15)-cadienen-4-ol (1.9 mg). F 3' (petroleum ether/AcOEt 9.2 :0.8; 45.0 mg)
mainly gave piperine in petroleum ether/AcOEt (7.5:2.5). F 4' (petroleum ether/AcOEt 9.0 :1.0; 457 mg) gave
pipzorine (2; 10.7 mg) after prep. TLC on repeated elution with petroleum ether/AcOEt 7.5:2.5). F 6'
(
petroleum ether/AcOEt 8.9 :1.1; 137 mg) was purified on a small column (petroleum ether > petroleum ether/
AcOEt > AcOEt) to obtain 50 fractions (F1'' to F 50''). F 39'' (petroleum ether/AcOEt 6.0 :4.0) was pure
piptahsine (3; 5.3 mg) obtained as flowers of needles.
Oxidative Cleavage of 2. A soln. of 2 (1 mg) in dioxane (0.25ml) and H
2 4
O (0.15ml) was treated with OsO
(
0.3 mg), followed by addition of NaIO (2.5mg) at 25 8. After stirring for 2 h at r.t., the mixture was
4
2
concentrated using a Sep-Pak diol cartridge (Waters). The sample was then eluted with Et O and subjected to
GC and GC/MS analysis.
Hydrolysis of 2. Compound 2 (5mg) was heated at 100 8 for 2 d with EtOH (0.5ml) and conc. HCl (0.5ml)
in a sealed tube. On cooling, the hydrochloride of (4-methylpentyl)amine separated out as fine needles, which,
on liberation with NH OH and usual workup, gave the free amine as a colorless liquid identified by GC and GC/
4
MS analysis. (3-Methylbutyl)- and (2-methylpropyl)amine for co-injection were purchased from Merck; (4-
methylpentyl)amine was prepared from isocapronitrile (see below).
Reduction of Isocapronitrile. To a cooled (ice-bath) soln. of LiAlH
isocapronitrile (12.5g) in anh. Et O (20 ml) was slowly added, and stirring was continued for 75min. The
mixture was diluted with H O (4 ml), and 20% aq. NaOH soln. (3 ml) was added. The etheral soln. was
decanted from the white, granular inorganic residue. This residue was washed twice with Et O, and the
combined org. phases were washed, dried (Na SO ), and evaporated at r.t. to afford (4-methylpentyl)amine
21].
Absolute Configuration of 3 According to Horeau×s Procedure. Pipthasine (2 mg) was added to a soln. of
racemic 2-phenylbutanoic anhydride (0.1 ml) in pyridine (0.5ml). The resulting mixture was stirred for several h
at r.t. and left overnight. It was then poured over distilled H O (0.3 ml), and the mixture was allowed to stand at
r.t. for 30 min. An aq. soln. of NaOH (0.1m) was added dropwise, until the pH was 9.0. The soln. was extracted
with CHCl , the aq. layer was acidified to pH 3 with HCl (1m) and extracted with benzene (10 ml). The benzene
extract was dried (Na SO ) and evaporated to a volume of 1 ml. The optical rotation of the resulting 2-
4 2
(3.8 g) in anh. Et O (200 ml), a soln. of
2
2
2
2
4
[
2
3
2
4
phenylbutanoic acid soln. was measured, which showed a positive value (R)-configuration, thereby establishing
the (S)-configuration at C(4) of 3.
Pipgulzarine (ˆ(2E,11E)-12-(Benzo[1,3]dioxol-5-yl)-N-(2-methylpropyl)dodeca-2,11-dienamide; 1). Yel-
low crystals. M.p. 98 ± 1008. IR (KBr): 3343, 2850 ± 2900, 1664, 1612, 1482, 1440, 1400, 1140, 890 ± 860, 840 ± 780.
1
13
‡
UV (MeOH): 313.0 (14,200), 263.4 (5,450). H-NMR and C-NMR data: Table 1. EI-MS: 371 (23.5, M ), 328
(
(
2
(
1
16), 231 (2), 203 (5), 175(10), 161 (99), 135(87), 131 (100), 103 (87), 72 (15), 57 (15.2). HR-EI-MS: 371.2469
‡
‡
‡
‡
‡
M , C23
17.1235([C 14
H
33NO ; calc. 371.2460), 299.1653 ([C19
H
23
O
3
] ), 271.1701 ([C18
H
23
O
2
] ), 245.1547 ([C16
H
21
O
2
] ),
3
‡
‡
‡
‡
H
17
O
2
] ), 210.1861 ([C13
H
24NO
2
] ), 203.1079 ([C13
H
15
O
2
] ), 175.0763 ([C11
H
11
O
2
] ), 161.0610
‡
‡
‡
‡
‡
[C10H
9
O
2
] ), 135.0451 ([C
8
H
7
O
2
] ), 131.0497 ([C
9
H
7
O] ), 126.0923 ([C
7
H
12NO] ), 103.0551 ([C
8
H
7
] ),
‡
‡
00.0767 ([C
5
H
10NO] ), 72.0819 ([C
4
H
10N] ).
Pipzorine (ˆ(2E,12Z)-N-(4-Methylpentyl)octadeca-2,12-dienamide; 2). Amorphous powder. IR (KBr):
1
13
‡
3
2
1
450, 1667, 1630. UV (MeOH): 209.5 (6,160). H- and C-NMR data: Table 2. EI-MS 363 (23.5; M ), 334 (71),
92 (23.7), 263 ( 35), 238 (18.2), 181 (21), 167 ( 19), 166 (53), 154 (62), 153 (22), 139 (21), 138 (94), 128 (25),
‡
25 (29), 111 (67), 100 (39), 97 (50), 71 (75), 69 (94), 67(73), 55 (100). HR-EI-MS: 363.3497 (M , C24
H
45NO;
‡
‡
‡
calc. 363.3501), 334.3109 ([C22
H
H
40NO] ), 320.2951 ([C21
32NO] ), 266.2483 ([C17
H
H
38NO] ), 306.2795([C 20
H
H
36NO] ), 292.2639
‡
‡
‡
‡
(
(
9
[C19
[C17
H
34NO] ), 278.2481 ([C18
32NO] ), 263.2371 ([C18
31O] ), 235.2423
‡
‡
‡
‡
‡
H
31] ), 209.2267 ([C15
H
29] ), 154.1229 ([C
9
H
16NO] ), 128.1075([C
7
H
] ).
14NO] ), 100.1126 ([C
6
H
14N] ),
‡
‡
‡
‡
7.1015([C
7
H
13] ), 85.1017 ([C
6
H
13] ), 71.0860 ([C
5
H
11] ), 57.0701 ([C
4
H
9
Piptahsine (ˆ(2E,4S)-4-Hydroxy-N-(2-methylpropyl)hex-2-enamide; 3). White needles. M.p. 115± 116 8.
1
13
IR (KBr): 3300 ± 3450, 1676, 1640, 1460 ± 1440, 1100, 980. UV (MeOH): 213.0 (6,965). H- and C-NMR data:
‡
Table 3. EI-MS: 185(33.5; M ), 167 (93), 157 (100), 110 (25), 100 (50), 95 (65), 85 (71), 72 (55), 41 (45). HR-
‡
‡
‡
EI-MS: 185.1410 (M , C10
H
19NO
2
; calc. 185.1415), 167.1304 ([C10
H
17NO] ), 157.1101 ([C
8
H
15NO
2
‡
] ), 139.0991
‡
‡
‡
(
(
(
5
[C
[C
8
H
H
12NO] ), 128.1081 ([C
7
H
14NO] ), 128.0710 ([C
6
H
10NO
2
‡
] ), 126.0911 ([C
NO] ), 100.0757 ([C
O] ), 85.0292 ([C
7
H
H
12NO] ), 114.0551
10NO] ), 100.0401
] ), 72.0809 ([C
‡
‡
‡
5
8
NO
2
] ), 113.0600 ([C
] ), 95.0491 ([C
6
H
9
‡
O
2
] ), 110.0600 ([C
6
H
8
5
‡
‡
‡
‡
[C
4
H
6
NO
2
6
H
7
O] ), 85.0649 ([C
5
H
9
4
H
5
O
2
4
H
10N] ),
‡
‡
7.0701 ([C
4
H
9
] ), 54.0491 ([C
3
H
7
O] ).

Helvetica Chimica Acta ± Vol. 86 (2003)
2767
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Received March17, 2003